Article

Do fossil plants give a climatic signal?

April 1990
Journal of the Geological Society 147(2):343-350

DOI:10.1144/gsjgs.147.2.0343

Authors:

The agreement in the pattern of major biomes with that of climatic zonation of the Earth gives a strong indication that climate is the overriding influence controlling the distribution of plant communities. Three aspects of plants which may be preserved in the fossil state, give a signal of the climatic conditions under which they grew: (1) the present climatic association of their "nearest living relative'; (2) leaf physiognomy of arborescent plants; (3) the character of their secondary xylem ("wood' of ordinary usage) reflecting, by the presence or absence of growth rings, the seasonality (or lack of it) in their environment and the potential for tree growth that it offered. The significance and limitations of these "palaeoclimatic signals' as they may be read from the fossil plant record are reviewed and evaluated. The recent demonstration that stomatal frequency of leaves is responsive to changes in ambient carbon dioxide partial pressure offers promise for direct palaeobotanical evidence for past changes in the level of this climatically significant atmospheric constituent. -Authors

Évolution du climat au cours du Cénozoïque : impact de la paléogéographie, des paramètres orbitaux et du CO2 sur la mousson asiatique et la biosphère terrestre

Thesis

Full-text available

Dec 2020

Delphine Tardif

Les moussons régissent le climat d’une large partie de l’Asie depuis le subcontinent indien jusqu’à l’est de la Chine actuellement. Leur mise en place et leur évolution restent cependant débattues et sont régulièrement réévaluées grâce à l’acquisition de nouveaux indicateurs climatiques. Des données récentes suggèrent que le régime de mousson en Asie fonctionnait déjà il y a environ 40 Ma, à l’Éocène supérieur, dans un contexte climatique globalement plus chaud et dans une configuration paléogéographique très différente d’aujourd’hui. Le but de cette thèse est d’étudier les conditions d’une mise en place des moussons asiatiques au cours de la période 42-33 Ma, englobant la fin de l’Éocène et la transition climatique majeure de l’Éocène-Oligocène. Nous balayons les différents champs d’incertitudes persistantes pour cette époque (paléogéographie, pCO2, niveau marin) et les différentes sources de variabilité climatique (le forçage orbital essentiellement). Nous utilisons le modèle de système- Terre IPSL-CM5A2, récemment adapté à l’étude des paléoclimats. En utilisant une première paléogéographie tardi-Éocène et une pCO2 de 1120 ppm, nous montrons dans un premier temps que le modèle simule des précipitations extrêmement saisonnières en Asie, sans pour autant présenter la circulation atmosphérique caractéristique des moussons. La sensibilité du climat et du couvert végétal tardi-Éocène aux paramètres orbitaux est ensuite évaluée à travers différents tests de sensibilité. Nous démontrons que les variations orbitales ont pu être un forçage majeur de variabilité climatique et biologique en Asie. Les configurations favorisant des gradients thermiques inter-hémisphériques importants (via des obliquités fortes et/ou des précessions induisant des étés boréaux chauds), en provoquant une migration accrue des masses d’air équatoriales humides sur le continent, génèrent des climats saisonnièrement très humides en été sur le sud-est asiatique. Plus globalement, le couvert végétal semble également très sensible aux variations orbitales dans les subtropiques et aux hautes latitudes. Ces résultats ouvrent de nouvelles pistes de réflexion sur de possibles relations entre forçage orbital, climat et ouverture de corridors de dispersion des faunes asiatiques vers l’Europe et l’Amérique (phénomènes nommés Grande Coupure). Enfin, nous comparons les circulations atmosphériques générées par des reconstructions paléogéographiques alternatives de la région asiatique. Elles testent par exemple différentes altitudes du plateau tibétain et différentes morphologies de la phase initiale de collision entre l’Inde et l’Asie, ces deux aspects étant encore extrêmement débattus. Pour finir, ces résultats sont mis en perspective en les comparant à des simulations climatiques à ∼34, ∼20 et ∼10 Ma. Le climat simulé en Asie apparaît finalement très peu sensible aux changements locaux de la paléogéographie indo-tibétaine. À l’inverse, nous notons l’apparition progressive des champs de pressions et des vents caractéristiques des moussons à mesure que le retrait de la mer Paratéthys et de la fermeture de l’océan Néotéthys permet l’exondation de la péninsule arabique et de l’Asie centrale, augmentant ainsi fortement la continentalité de la région. Nous suggérons ainsi que les gradients thermiques induits par la continentalité asiatique sur une échelle de temps géologique, ou par des paramètres orbitaux favorables sur une échelle de temps de quelques milliers d’années constituent les forçages dominants du régime des moussons en Asie.

Heat stress reduces stomatal numbers in Ginkgo biloba: Implications for the stomatal method of palaeo-atmospheric [CO2] reconstruction during episodes of global warming

Article

Full-text available

Dec 2024

New Jersey's paleoflora and eastern North American climate through Paleogene–Neogene warm phases

Article

Apr 2020
REV PALAEOBOT PALYNO

Pollen of middle Oligocene to early Miocene age from core sediments from the New Jersey Shallow Shelf (Atlantic Coastal Plain: IODP-Expedition 313, Site M0027A), was analyzed using light- and scanning electron microscopy, and a pollen-based bioclimatic analysis was performed. The microflora is dominated by Quercus pollen. Pollen ornamentations indicate that Quercus pollen most likely originated from species of sections Quercus, Lobatae, Quercus/Lobatae and aff. section Protobalanus. Eotrigonobalanus, an extinct Fagaceae lineage, was present in the coastal plain. Relative abundances of several tree taxa (e.g., Carya) did not change significantly between the Oligocene warm phases, but contrast to late middle Miocene (comprising most of the Langhian and Serravallian) records from the same area. By assigning terrestrial palynomorphs to paleovegetation units, topographic movements of these units were identified. The mesophytic forest was the most widespread and zonal vegetation type in the hinterland through the analyzed interval. Periodic changes in the relative abundances of paleovegetation units suggest altitudinal vegetation movements responding to global climate change. Observed movement signals are generally weak, but increases in bisaccate pollen, representing spread of high- and mid-latitude forest, probably reflect the onset of cold intervals such as cooling phases at ~ 29.1, ~ 28.5, and 23.5 Ma. Spread of edaphically controlled forest formations during regression phases also indicates climate change. The onset of the Mi-1 event at ~ 23.03 Ma is probably reflected by a decrease in pollen-inferred paleotemperatures, although the event itself occurred during a sedimentation hiatus. Pollen-based paleoclimate reconstructions indicate long-term stability in temperature and precipitation within the humid warm temperate zone.

First record of a petrified gymnospermous wood from the Kungurian (late Early Permian) of the southern Sydney Basin, southeastern Australia, and its paleoclimatic implications

Article

Feb 2020
REV PALAEOBOT PALYNO

For the first time, a silicified wood with well-preserved inner structures is reported from the Kungurian (Early Permian) Snapper Point Formation in the southern Sydney Basin, southeastern Australia. It is characterized by uni- to tetraseriate araucarian radial tracheidal pits and large, simple cross-field pitting. This wood is attributed to Protophyllocladoxylon dolianitii Mussa 1958, and it is assumed to be of cordaitalean affinity, which is one of the dominant and arborescent element of the early Permian Gangamopteris Taiga. Evidence of growth patterns of the fossil wood, and the paleogeographical reconstruction shows that the host tree of the fossil wood was growing in a strongly seasonal polar light regime. The wide growth rings (5.315–12.316 mm) and the large number of tracheids per ring (99–288) indicate the tree flourished under favorable conditions during the growing season, with ample water and clement temperatures, enhanced by the extended daylight hours of the Antarctic-type summer. The occurrence of frost rings in the wood, corroborated by additional sedimentological information suggest that unusual climatic events (aperiodic cold and freezing events) occurred in terrestrial ecosystems of the southern Sydney Basin during the Kungurian. The study demonstrates that fossil wood of exceptional preservation, like the one reported here, can offer valuable and potentially unique information crucial for deep-time paleoclimatic reconstruction.

Vegetation and climate development of the New Jersey hinterland during the late Middle Miocene (IODP Expedition 313 Site M0027)

Article

Jul 2017
PALAEOGEOGR PALAEOCL

We investigated the palynology of sediment cores from Site M0027 (IODP Exp. 313), 45 km off the present-day coast of New Jersey to infer palaeoenvironmental conditions during the second half of the Mid–Miocene Climatic Optimum and the transition to global cooler conditions. In sum 79 taxa were identified via light microscopy (13 gymnosperms, 63 angiosperms, 3 pteridophytes), among them Diospyros and Reveesia, which until now have not been identified from the eastern coast of North America. Most of the identified taxa belong to the extended multi-layered broadleaved mesophytic forest that occupied the lowlands of the New Jersey hinterland and reflects the zonal vegetation during time of deposition. In higher altitudes or on edaphically drier slopes, the mesophytic forest was replaced by conifer forest. Landscape changes probably induced the spread and diminution of several vegetation units during the late Middle Miocene. An expansion of a conifer forest from ~ 15.8 to ~ 15.6 Ma is probably connected to the Appalachian uplift, and a subsequent spreading of Cupressaceae between ~ 15.0 and ~ 14.8 Ma probably reflects a period of enhanced inundation of coastal lowlands. The modern representatives of the main climatic elements among the encountered taxa are characterized by a typical temperate distribution. Climatic parameters (MAT, CMMT, WMMT, MAP) were calculated using bioclimatic analysis. In light of the ongoing discussion concerning identifications of Cupressaceae pollen grains, two different variations of the bioclimatic analysis were performed. Both variations indicate humid warm temperate climatic conditions with mean annual temperatures of ~ 13 °C ± ~ 5 °C, coldest month temperatures of ~ 4.3 °C ± ~ 5.3 °C, and warmest month temperatures of ~ 21.9 °C ± ~ 4.5 °C. Annual precipitation values exceed 1000 mm for all samples. Both zonal vegetation and the calculated regional lowland palaeoclimate show no significant changes. One factor creating generally climatically stable conditions between 15.8 and 12.7 Ma was likely the buffering effect of the Gulf Current loop.

Protocupressinoxylon baii sp. nov., a gymnospermous fossil trunk from the Upper Shihhotse Formation (Permian) of Yangquan City, Shanxi Province, North China

Article

Apr 2024
REV PALAEOBOT PALYNO

A new permineralized gymnospermous fossil trunk with only secondary xylem being preserved, Protocupressinoxylon baii sp. nov., is described from the Upper Shihhotse Formation (Permian) in Yangquan City, Shanxi Province, North China. The pith, primary xylem, and bark are not preserved. The wood is pycnoxylic, composed of tracheids, rays, and axial parenchyma. True growth rings are absent. However, growth interruptions are well-developed. In cross section, tracheids in the growth interruption vary gradually in diameter from thin-walled, larger cells to thick-walled, smaller cells, and change at an opposite direction, forming a symmetrical boundary. Radial tracheidal pitting is uni- to biseriate. When uniseriate, pits are contiguous or separately arrayed. When biseriate, pits are mostly alternately arranged. Rims of Sanio and tangential pits are absent. The percentage of abietinean pitting of current fossil wood is 23.6%, and the araucarian pitting is 76.4%. Axial parenchymatous cells are irregularly distributed among the xylem tracheids with opaque contents. Rays are homogeneous, commonly uniseriate, and are 1–24 cells high. The cross-field pitting is mainly of the cupressoid type, and there are commonly 1–2, rarely 3–4 pits in each cross-field unit. The fossil trunk represents the first record of Protocupressinoxylon Eckhold from the Permian of the Cathaysia. Fungal hyphae present in tracheids and rays, demonstrating the association between the current trunk and fungi. The absence of true growth rings, and the presence of growth interruptions suggest suitable climatic conditions with episodic drought for the flourishing of plants during the time when the Upper Shihhotse Formation was deposited in the Permian.

Gymnosperms Through Time. Their History in Mexico

Chapter

Apr 2024

It is difficult to synthesize the evolution of this group from their appearance (310 million years ago) to the present day. During this period, several tectonic processes and climatic changes occurred, which acted as forcing factors on their distribution. Their history begins with the appearance of the Cordaitales during the Carboniferous, reaching their climax in the Triassic with the orders Bennettitales and Cycadales, and their subsequent decline in abundance and dominance at the end of the middle Cretaceous. In this chapter, we attempt to provide a general overview of this group through its global fossil record, with emphasis on the Mexican territory. We also briefly mention the evolutionary trends of this group, which is characterized by the presence of naked seeds, wood produced by the bifacial cambium, and the presence of megaphyllous leaves with linear, dichotomous, and reticulate vein patterns. This group represents an evolutionarily successful and long-lived division, since it is present from the Upper Paleozoic to the present day.

Importance of the Angiosperm Fossil Record for the Paleoenvironmental Reconstruction

Chapter

Apr 2024

In countries such as Mexico, fossil plants has been little used to reconstruct paleoenvironments and paleoclimates, although in other countries different methods have been developed to infer these environmental and climatic conditions in the past. The work on this subject has been carried out by associating fossil organisms (proxies) with their closest living relatives in a general way. Although in recent years a new generation in the paleontology of Mexico is focusing on palaeoecological studies, using ecometric elements (the foliar structure, the anatomical characters in woods). Therefore, this paper summarizes some of the work that has been done and highlights the potential of using methodologies (proxies vs. ecometrics) in Mexican fossil material.

New record of Elatocladus from the Middle Jurassic of Iran, with global diversity and palaeogeography overview

Article

Apr 2023
REV PALAEOBOT PALYNO

Newly discovered impression/compression conifer fossil specimens of Elatocladus are reported from the Middle Jurassic of the Tabas Block in Iran. The occurrence of buds at the base and apex and other characters of the specimens confirm that the present material can be attributed to Elatocladus laxus (Phillips) Harris 1979. This is the first record of E. laxus from Iran and one of the very few Laurasian occurrences of this taxon. Statistical data based on the palaeobotanical distribution of the genus Elatocladus from 337 localities (392 occurrences) suggest that this conifer had its main distribution in mid-to high-latitudinal (>30°N and >45°S) belts. The maximum relative frequency of this genus was restricted to palaeo-latitudes of 45°N to 60°N from the Middle Triassic up to the Late Cretaceous in Laurasia (62.6%) and palaeo-latitudes of 45°S to 60°S in Gondwana (69.31%). Across the Triassic/Jurassic Boundary (TJB), diversity of this genus decreases in the Northern Hemisphere and emigrates to high latitude belts. Therefore, it can be concluded that an event at low latitudes and in Northern Hemisphere was the cause of this disappearance at the TJB, such as environmental and climatic disturbances related to the CAMP (Central Atlantic Magmatic Province). A statistical meta-analysis of the global distribution of Elatocladus records demonstrates that the genus was largely restricted to warm regions during the Mesozoic.

A new conifer stem, Ductoagathoxylon tsaaganensis, from the Upper Permian of the South Gobi Basin, Mongolia and its palaeoclimatic and palaeoecological implications

Article

Jun 2022
REV PALAEOBOT PALYNO

Permineralised stems of Ductoagathoxylon tsaaganensis Cai, Zhang et Feng sp. nov. are described from the Upper Permian strata of the Tsaagan Tolgoy section, South Gobi Basin, Mongolia. The stems were preserved with pith and primary and secondary xylems. The pith is solid, heterocellular, and characterised by regularly arranged clusters of secretory cells at the periphery. The primary xylem is the endarch and mesarch. The tracheid walls exhibited annular, helical, and scalariform thickening from the protoxylem to metaxylem. The secondary xylem is of the Agathoxylon-type and is composed of tracheids and parenchymatous rays. The growth rings of the stems were distinct, with broad earlywood and narrow latewood. Radial tracheid pits in the secondary xylem are contiguous and alternately arranged, uni-or biseriate in the latewood, and bi-to tetraseriate in the earlywood. Rays are uniseriate and 1-7 (mostly 2-4) cells high. Each cross-field possessed 1-19 (mostly 3-9) cupressoid pits. Quantitative analysis of the growth rings indicated that the plant was likely a deciduous conifer that lived in a seasonal, temperate, and wet climate. However, a growth interruption with inflated cells was present in the secondary xylem, indicating that the tree had survived climatic damage, probably an early spring cooling event. Fungal remains, including hyphae and spores, and evident white-rot patterns in the stems revealed a common occurrence of fungal infections in the ecosystem. Our study sheds new light on the plant diversity and climatic and ecological features of the Angara flora during the Late Permian in the South Gobi Basin.

Asian monsoon and vegetation shift: evidence from the Siwalik succession of India

Article

Full-text available

Apr 2022

Quantitative Miocene climate and vegetation data from the Siwalik succession of western Nepal indicate that the development of the Indian summer monsoon has had an impact, though in part, on vegetation changes. The climate and vegetation of the Lower (middle Miocene) and Middle (late Miocene–Pliocene) Siwalik successions of Darjeeling, eastern Himalaya, have been quantified. Reconstructed climate data, using the Coexistence Approach, suggest a decrease in winter temperatures and precipitation during the wettest months (MPwet) from the Lower to Middle Siwalik. The floristic assemblage suggests that Lower Siwalik forests were dominated by wet evergreen taxa, whereas deciduous ones became more dominant during the Middle Siwalik. The vegetation shift in the eastern Himalayan Siwalik was most likely due to a decrease in MPwet. The quantified climate–vegetation data from the eastern and western Himalayan Siwalik indicate that changes in the Indian summer monsoon had a profound impact on vegetation development during the period of deposition. We suggest that the decrease in winter temperature and summer monsoon rainfall during the Middle Siwalik might be linked with the Northern Hemisphere glaciation/cooling or a number of other things that were also going on at the time, including the continued rise of the Himalaya, and drying across the Tibetan region, which may have affected atmospheric circulation regionally.

Warm and humid Trans-Himalaya during the late Miocene: plant fossil evidence

Article

Nov 2021
Palaeoworld

Neogene fossil records from the Indus Basin sedimentary rocks (IBSR), deposited in the Indus Tsangpo Suture Zone (ITSZ), are very rare, but are important to understand the history of plant diversity and paleoclimate in the Himalaya. We report fossil wood ascribed to Ebenoxylon siwalicus Prakash from late Miocene sediments of the Karit Formation belonging to ITSZ. The anatomical details of the fossil wood, such as small to medium-sized vessels occluded with tyloses, scanty paratracheal to diffuse-in-aggregate axial parenchyma, 1–3 seriate homo to heterocellular xylem rays, bordered intervessel pits with lenticular apertures and simple perforations, suggest its close affinity with Diospyros Linnaeus of the family Ebenaceae. Further anatomical details suggest a close resemblance with extant D. ehretioides Don and D. macrophylla Blume. The present fossil, along with previously known fossil records of Lagerstroemia (Lythraceae) and palms, indicate that the Trans-Himalaya was warm and humid during the late Miocene, quite different from the modern cool and dry climate in the study area.

Forest biomes of Southern Africa

Article

Aug 2021

The forests of South Africa and the neighbouring countries, including Lesotho, eSwatini, Namibia, Botswana, Zimbabwe, and Mozambique (south of the Zambezi River), were mapped and classified according to the global system of biomes. The new four-tier hierarchical biome system suggested in this paper includes zonobiome, global biome, continental biome (all recognised earlier), and regional biome – a novel biome category. The existing spatial coverages of the forests were revised and considerably improved, both in terms of forest-patch coverage and mapping precision. Southern Africa is home to three zonal forest types, namely Subtropical Forests (Zonobiome I), Tropical Dry Forest (TDF; Zonobiome II) and Afrotemperate Forests (Zonobiome X). These three biomes are characterised by unique bioclimatic envelopes. Five, two, and eight regional biomes, respectively, have been recognised within these zonal biomes. Recognition of the Zonobiome I and the global biome Tropical Dry Forests in southern Africa is novel and expands our knowledge of the biome structure of African biotic communities. The system of the azonal regional biomes is also new and comprehensively covers the variability of the azonal helobiomes (riparian woodlands and swamp forests), mangroves, and azonal coastal forests. In total, 11 azonal regional biomes have been recognised in the study area. The forest biomes in southern Africa were captured in our electronic map in the form of more than 60 000 polygons, covering 42 416 km² (1.27% of the study area). No less than 83% of these forests occur in the territory of southern Mozambique. Abbreviations: for the abbreviation of the biome units, see Table 1; CE: centre of endemism; IOCB: Indian Ocean Coastal Belt; MBSA: the area of the Map of Biomes of Southern Africa; VegMap2006 and VegMap2018: Vegetation Map of South Africa, Lesotho and Swaziland (as released in respective years); for the meaning of the codes of the biome units see Table 1, and for the meaning of the abbreviations of climatic characteristics see Appendix S1

Climate change during the deposition of the Aptian Santana Formation (Araripe Basin, Brazil): Preliminary data based on wood signatures

Article

Jul 2021
J S AM EARTH SCI

This paper presents preliminary results of paleoclimatic signatures of conifer woods during the deposition of the basal Crato and topmost Romualdo members of the Santana Formation within the Tropical Equatorial Hot Arid Belt (late Aptian, Araripe Basin, Brazil). Analysis was carried out using standard thin sections, and the anatomical details were studied in transmitted light. The wood growth pattern from the lowermost laminated lacustrine carbonate level of the Crato Member was characterized by the absence of true growth rings and the common presence of wood growth interruptions, and could be linked to a tropical, equable but erratically humid environment. In an interlayered fine-to-coarse sandstone level attributed to a fluvio-deltaic interval, the wood growth pattern was homogeneous, lacking true growth rings, with weakly delineated growth interruptions over long radial distances. In this level the growth pattern could be related with a transition to a more equable tropical climate during a relatively humid period. In contrast, the wood pattern from the carbonate succession of the uppermost Romualdo Member, interpreted as a lagoon area with marine influence, showed true growth rings with abrupt ring boundaries and rings of variable width, also including frequent growth interruptions. This pattern could be linked to a monsoonal-like climate, subjected to distinct cyclical conditions and periodical droughts during the growing season.

Paleoclimate and paleoecology of the Upper Oligocene Tehuacán Formation, Puebla State, Mexico, as determined from wood anatomical characters

Article

Full-text available

Jan 2021
PALAEONTOL ELECTRON

Climatic conditions that prevailed during the deposition time of the Tehuacán Formation, Mexico (upper Oligocene) are proposed based on a previous model using wood anatomical characters. Different paleoclimatic variables were calculated, and the anatomical characteristics of the Tehuacán Formation paleoflora were compared with the characteristics of other extant and fossil plant communities to infer water conductive capacities of the Tehuacán Fm. plants. The paleoclimatic inference suggests that the environmental conditions under which the fossilized plants of the Tehuacán Fm. grew were seasonally warm and humid. Statistical analysis and the presence of growth rings in some woods suggest that the paleoflora of the Tehuacán Fm. were similar to extant tropical communities such as tropical semi-deciduous forests and the tropical deciduous forests, most probably representing a transitional community: containing plants that were efficient in transporting water like those in the tropical wet forests, but with phenological adaptations typical of drier tropical forests.

Systematics and palaeoecology of fossil plants from the Upper Permian Longtan Formation in western Guizhou Province, southwestern China

Article

Feb 2021

A megafossil flora (i.e., Shuicheng flora) has been collected from the Upper Permian Longtan Formation coal-bearing rock series in the Wangjiazhai coal district, Shuicheng county, western Guizhou Province, southwestern China. Shuicheng flora, as an important part of the late Permian Cathaysian flora in South China, thrived in warm and humid conditions after the eruption of the Emeishan basalt but disappeared during the end-Permian mass extinction event. Here the fossil plants including 13 species in 9 genera were systematically described and compared. Results of systematic taxonomic studies demonstrate that these fossil plants are dominated by ferns and pteridosperms, followed by some sphenopsids, ginkgophytes and lycopsids. Taphonomic analysis shows that these fossil plants are mainly dominated by parautochthonous burial and accompanied by a small number of heterochthonous burial. Meanwhile, the palaeoecological reconstruction of Shuicheng flora suggests that these plants including lepidodendrids presented tall trees, calamites presented trees, ferns and pteridosperms presented trees, small trees, shrub, microphanerophytes and herbaceous plants, and ginkgopsida presented trees grown on detrital substrates under warm and humid climatic conditions and constituted a portion of the terrestrial landscape in western Guizhou Province during the Wuchiapingian.

Climate and vegetation change during the Upper Siwalik—a study based on the palaeobotanical record of the eastern Himalaya

Article

Feb 2021

Today, Northeastern India receives some of the highest annual rainfall totals globally. The major portion of annual precipitation in this region falls during the Indian Summer Monsoon season (June–September); however, this region also receives a significant amount of rainfall during the pre-monsoon season (March–May). Here, we quantitatively reconstruct the climate of the Upper Siwalik subgroup, eastern Himalayan region, based on fossil assemblages using the Coexistence Approach (CA). The age of the fossil assemblage is considered to be late Pliocene–early Pleistocene. Data reconstructed for the present-day and past pre-monsoon rainfall in Northeastern India indicate an increasing trend since the late Miocene–early Pliocene. During the late Pliocene–early Pleistocene (Upper Siwalik), the temperature seasonality between warm (27–28.1 °C) and cold months (22–23.6 °C) was less pronounced compared with present-day warm (27–27.7 °C) and cold (14.8–15.4 °C) months conditions at the fossil locality. The reconstructed rainfall data indicate a monsoonal type of climate having a strong seasonality in wet and dry seasons during the deposition of the Upper Siwalik sediments. Moreover, composition of the fossil floras and reconstructed palaeoclimate suggest a vegetation shift from dominantly wet evergreen to semi-evergreen at the fossil locality, coincident with an increase in length of the dry season. The comparison of reconstructed CA data and climate modelling data of a Gelasian time slice with that of previously reconstructed climate data by using Climate Leaf Analysis Multivariate Programme (CLAMP) analysis of the late Pliocene–early Pleistocene (Upper Siwalik) fossils of the same locality provides nearly the identical result. Furthermore, all the reconstructed data indicate a monsoonal type of climate during the deposition of the Upper Siwalik sediments.

A plot-based elevational assessment of species densities, life forms and leaf traits of seed plants in the south-eastern Himalayan biodiversity hotspot, North Myanmar

Article

Full-text available

Dec 2020

Background : Species density along elevation gradients often shows hump-shaped patterns, but in-depth data for Myanmar is still not available. Aim : The first plot-based study to detect the elevational patterns of life forms and tree leaf traits, and their relation to environmental factors in Myanmar. Methods : All seed plant species were recorded on 76 plots between 400 and 4100 m. Regression models were used to identify the variables with highest predictive power for species densities of different life forms and leaf traits. Results : Species density showed a linear elevational decline except for grasses (increase) and epiphytes (hump-shaped pattern) and were related to temperature and precipitation in all considered life forms. Tree leaf size, the proportion of species with simple leaves and leaves with drip tips decreased with elevation, while the proportion of toothed leaves increased. Conclusions : Our data partly confirm some widely held assumptions about elevation patterns in species density and leaf traits. While the climatic dependence behaves as expected, leaf traits and lifeforms show mixed and sometimes surprising patterns. Previous knowledge of these patterns is partly confirming, but highly scattered regionally, so our study performed in one region offers a rare opportunity towards a natural history image of a biodiversity hotspot..

Early Oligocene Podocarpium (Leguminosae) from Qaidam Basin and its paleoecological and biogeographical implications

Article

Sep 2020
REV PALAEOBOT PALYNO

The extinct legume genus Podocarpium first appeared in the middle Eocene of South China and then became widely distributed throughout Eurasia during the Oligocene andMiocene. Fossil records fromCentral Asia are important for understanding the patterns of floristic change of Podocarpium between Eastern Asia and Europe, but they are relatively rare. Here, we describe well-preserved fossil fruits and leaves of Podocarpium podocarpum (A. Braun) Herendeen from the early Oligocene (Rupelian) of the Qaidam Basin, northwest China. Morphological comparison among fossil fruits of all Podocarpium reported so far confirms the difference in fruit shape between Podocarpium eocenicum and P. podocarpum, and shows a decrease in fruit size during the Oligocene, which might be a response from this thermophilous plant to a cooler condition. The presence of P. podocarpum in the early Oligocene of Qaidam suggests that the Qaidam Basin might play an important role in the migration of this genus between Eastern Asia and Europe during the early Oligocene. Moreover, the expansion of Podocarpium in China during the Cenozoic appears to be strongly influenced by the East Asia monsoon development.

Comprendre la dynamique atmosphérique pour mieux reconstituer l'altitude passée des chaînes de montagnes

Article

Full-text available

May 2020

Comprendre la dynamique de soulèvement d'une chaîne de montagne nécessite d'en estimer l'altitude passée. C'est le but de la paléoaltimétrie. La méthode la plus répandue utilise la composition isotopique en oxygène des roches carbonatées formées dans les sols et à partir des sédiments lacustres. Celle-ci reflète la composition de la pluie passée qui, dans le monde actuel et dans la plupart des chaînes de montagnes, s'appauvrit progressivement en isotopes lourds avec l'altitude. En supposant que cet appauvrissement reste valide dans le passé, l'altitude du plateau tibétain à l'Éocène (il y a environ 42 millions d'années) est estimée à 4 000 m environ. Mais d'autres marqueurs de l'altitude passée indiquent au contraire des altitudes inférieures à 2 000 m. La relation entre composition isotopique des pluies et altitude observée aujourd'hui s'applique-t-elle à l'Éocène ? C'est ce que nous avons essayé de vérifier en utilisant un modèle de circulation générale atmosphérique, LMDZ-iso. On trouve qu'à l'Éocène la circulation atmosphérique et les processus hydrologiques étaient tellement différents de l'actuel que les observations isotopiques dans les roches carbonatées se trouvent finalement être cohérentes avec des altitudes relativement faibles. Les différentes méthodes de paléo-altimétrie se retrouvent ainsi réconciliées et en accord avec un soulèvement récent (post-Éocène) du plateau tibétain. Understanding the uplift dynamics of a mountain range requires estimating past altitude. This is the purpose of the paleo-altimetry. The most commonly applied paleo-altimetry method is based on the isotopic oxygen composition of the carbonate archives. It reflects the composition of past rain, which at present-day and in the most mountain ranges becomes progressively more depleted in heavy isotopes with altitude. Assuming that this depletion remains valid in the past, the elevation of the Tibetan Plateau in the Eocene (about 42 millions years ago) is estimated to be about 4 000 m. However, other proxy data indicate on the contrary low altitudes. Is the relationship between the rain isotopic composition and the altitude that is observed today applicable to the Eocene? This is what we tried to verify using an atmospheric general circulation model, LMDZ-iso. We find that in the Eocene, the atmospheric circulation and hydrological processes were so different to the present-day that the isotopic observations in the Eocene carbonates are actually consistent with relatively low altitudes of the Plateau. This allows us to reconcile different methods of paleo-altimetry in agreement with more recent (post-Eocene) uplift of the Tibetan Plateau.

Palaeohydrological characteristics and palaeogeographic reconstructions of incised‐valley‐fill systems: Insights from the Namurian successions of the United Kingdom and Ireland

Article

Full-text available

Jun 2020

Namurian (Carboniferous) eustatic fluctuations drove the incision and backfill of shelf‐crossing valley systems located in humid subequatorial regions, which are now preserved in successions of the United Kingdom and Ireland. The infills of these valleys archive the record of palaeoriver systems whose environmental, hydrological and palaeogeographic characteristics remain unclear. A synthesis of sedimentological data from fluvial strata of 18 Namurian incised‐valley fills in the United Kingdom and Ireland is undertaken to elucidate the nature of their formative river systems and to refine regional palaeogeographic reconstructions. Quantitative analyses are performed of facies proportions, of geometries of incised‐valley fills and related architectural elements, and of the thickness of dune‐scale sets of cross‐strata. Reconstruction of the size of the drainage areas that fed these valleys is attempted based on two integrative approaches: flow‐depth estimations from dune‐scale cross‐set thickness statistics and scaling relationships of incised‐valley fill dimensions derived from late‐Quaternary examples. The facies organization of these incised‐valley fills suggests that their formative palaeorivers were perennial and experienced generally low discharge variability, consistent with their climatic context; however, observations of characteristically low variability in cross‐set thickness might reflect rapid flood recession, perhaps in relation to sub‐catchments experiencing seasonal rainfall. Variations in facies characteristics, including inferences of flow regime and cross‐set thickness distributions, might reflect the control of catchment size on river hydrology, the degree to which is considered in light of data from modern rivers. Palaeohydrological reconstructions indicate that depth estimations from cross‐set thickness contrast with observations of barform and channel‐fill thickness, and projected thalweg depths exceed the depth of some valley fills. Limitations in data and interpretations and high bedform preservation are recognized as possible causes. With consideration of uncertainties in the inference of catchment size, the palaeogeography of the valley systems has been tentatively reconstructed by integrating existing provenance and sedimentological data. The approaches illustrated in this work can be replicated to the study of palaeohydrological characteristics and palaeogeographic reconstructions of incised‐valley fills globally and through geological time.

Coral Diversity and Temperature: a Palaeoclimatic Perspective for the Oligo-Miocene of the Mediterranean Region

Book

Apr 2012

Scolecopteris minuta sp. nov., a marattialean fern from the early Permian Wuda Tuff Flora of Inner Mongolia, China

Article

Full-text available

Apr 2020
REV PALAEOBOT PALYNO

A new and exceptionally hairy marattialean fern of an early Permian age having pecopterid sterile pinnules and strongly enrolled fertile pinnules, Scolecopteris minuta sp. nov., is described from the uppermost Taiyuan Formation of the Wuda coalfield in Inner Mongolia. The fertile fronds are at least tripinnate, with lanceolate to linear penultimate pinnae and oblong ultimate pinnae. Each pinnule bearing 6–9 ovate to fusiform pedicellate synangia, arranged abaxially in a single row to either side of the midvein. The deeply incised pinnule margins are strongly reflexed downwards and inwards, closely enveloping and sheathing the synangia. Each synangium is comprised of a ring of sporangia which were closely pressed together before dehiscence. The sterile fronds are of pecopterid form. Taken as a whole, the combination of characters of Scolecopteris minuta sp. nov. indicates attribution to the Latifolia group of Scolecopterids sensu Millay (1979). In its exceptionally hairy frond rachises and the equally exceptionally dense growth of smaller hairs both on the adaxial and abaxial sides of the fertile pinnules, and even on the tips of the synangia of S. minuta. We propose that this dense hairiness functioned primarily as a deterrent to spore-eating insects and perhaps also to other predators.

Climate reconstructions based on Miocene leaf flora from NW Bulgaria: Comparing leaf physiognomy and nearest living relative approach

Article

Full-text available

Aug 2019

The problem of paleoclimate reconstruction is an extremely interesting issue, which has been repeatedly discussed in many publications. This topic engages the attention of numerous specialists in many and various scientific disciplines. Fossil plants have vast potential as a source of information about past climatic conditions in the terrestrial realm. Various methods have been developed for the extraction of climate information from fossil land plants, but only few of these methods have provided quantitative data, e.g. Leaf Margin Analysis, Leaf Area Index, CLAMP and Coexistence Approach (CA). In this study we analyzed Middle Miocene floras from Bulgaria aiming to compare the results from different methods. The fossil floras are located in the southernmost part of the Forecarpathian Basin (NW Bulgaria). Two types of models were used to obtain quantitative data about the paleoclimate characteristics in the studied area-Simple Linear Regression (SLR) and Multiple Linear Regression (MLR) model. Furthermore, CLAMP and CA were applied. The obtained results evidence overlapping of CLAMP and CA data for diverse floras, while CLAMP data tend to produce cooler estimates than those obtained with the CA. The temperatures calculated by the SLR and MLR models are more or less consistent, but only when the standard deviations are considered. Moreover, the SLR and MLR intervals have strong correlation with those obtained from the CA. This corroborates statements by other authors, that under favorable circumstances (high diversity of the fossil flora and good taxonomic resolution) the climatic resolution of the CA can be twice as high compared to Leaf Physiognomy Approaches. The results obtained from the CA have less variability, consistently with data obtained from the MLR model. A great advantage of the CA method is that the width of coexistence intervals does not depend on species richness.

The nonglacial diamictite of Toutswemogala Hill (lower Karoo Supergroup, central Botswana): Implications on the extent of the late Paleozoic ice age in the Kalahari–Karoo Basin

Article

Full-text available

Oct 2019

Along the easternmost edge of the Karoo–Kalahari Basin (KKB) of Botswana, the Toutswemogala Hill succession exposes a 30–50-m-thick suite of siliciclastic deposits interpreted by some as glaciogenic in origin tied to the Permo-Carboniferous Late Paleozoic Ice Age (LPIA). Six facies associations (FA) were recognized in this succession, resting unconformably on a highly uneven Archean gneissic basement, and consisting from base to top of: 1) clast-supported breccia made up of angular cobbles and boulders ubiquitously derived from the underlying basement, 2) well-bedded siltstones sealing or locally interdigitated with the underlying breccia, and bearing abundant remnants of Glossopteris sp. leaves, 3) a chaotic to faintly laminated matrix-supported diamictite bearing angular and subrounded clasts and tree logs attributed to the genus Megaporoxylon, 4) cross-bedded conglomerate bearing well-rounded quartz and clasts, 5) planar-laminated to ripple-laminated, poorly sorted, muddy sandstones showcasing dispersed mud chips that grade upward into 6) poorly sorted, cross-bedded coarse-grained sandstones displaying convolute beds and abundant imprints of unidentifiable tree logs. No evidence of glaciogenic processes have been found in this succession, in the form of either pavement or clasts striations. The breccia and diamictite are interpreted as scree and mass-flow deposits, respectively. Along with the age of the deposits, inferred from the plant debris (upper Carboniferous to lower Permian), the stratigraphic position of this sedimentary succession resting on the Archean basement suggests that it corresponds to the Dukwi Formation, a stratigraphic equivalent of the Dwyka Group in the Main Karoo Basin. This would explain the resemblance of the facies to those recovered at the base of the central Kalahari–Karoo Basin and in the neighboring Tuli, Ellisras, and Tshipise basins. The absence of diagnostic criteria for glacial processes in the studied succession raises the question of the extent, in both time and space, of the LPIA-related ice masses over southern Africa and particularly in southeastern Botswana. It is suggested here that during this glacial epoch, spatially restricted ice masses were confined in bedrock valleys (valley glaciers) in an uplifted setting otherwise characterized by non-glaciogenic processes, further strengthening the scenario of fragmented ice masses over southern Gondwana.

A biography and obituary of William G. Chaloner FRS (1928–2016)

Article

Feb 2019

William G. (‘Bill’) Chaloner FRS (1928–2016) was one of the world’s leading palaeobotanists and palynologists. He developed a love of natural science at school which led to a penchant for palaeobotany at university. Bill graduated in 1950 from the University of Reading, and remained there for his PhD, supervised by Tom Harris, on the spores of Carboniferous lycopods. After completing his PhD in 1953, Bill undertook a postdoctoral fellowship in the USA. He returned to the UK and, in 1956, began a long and distinguished academic career at four colleges of the University of London. His first position was at University College London, where he continued to work on Paleozoic palaeobotany and palynology. His 1958 paper on the effects of fluctuating sea levels on Carboniferous pollen-spore assemblages proved highly influential. Bill moved to a Chair at Birkbeck College in 1972, began to use the scanning electron microscope and was elected a Fellow of The Royal Society in 1976. He is the only pre-Quaternary palynologist to have been given the latter honour. In 1979, Bill was appointed to the Chair of Botany at Bedford College where he began to apply plant fossil evidence to general scientific problems. He began to work on arthropod–plant interactions, fossil charcoal and growth rings in wood. Bill was awarded the Medal for Scientific Excellence by the American Association of Stratigraphic Palynologists in 1984. Bedford College and Royal Holloway College merged in 1985, and Bill moved to the amalgamated institution. Bill continued to investigate very diverse topics, and added the analysis of leaf stomata, global environmental change and molecular palaeontology to his portfolio. Following retirement in 1994, Bill continued his research and teaching at Royal Holloway, University of London. His final paper was published in 2016, bringing to an end a research career of 66 years.

Fire in the paradise: evidence of repeated palaeo-wildfires from the Araripe Fossil Lagerstätte (Araripe Basin, Aptian-Albian), Northeast Brazil

Article

Jan 2019

Reports on Cretaceous charcoals are relatively common on a global scale and have been increasing in recent years. Fossil charcoal from the Early Cretaceous mostly belongs to conifers (and other gymnosperms) and ferns whereas angiosperms become more common only during the Late Cretaceous. However, so far, reports of Cretaceous acroscopic charcoal are rare (three) for South America. Here, charcoal is identified from the Crato, Ipubi and Romualdo formations of the Early Cretaceous Santana Group within the Araripe Basin, Brazil. The presence of charcoal provides for the first time compelling evidence for the repeated occurrence of Early Cretaceous palaeo-wildfires in this region. The charred wood remains were identified as belonging to gymnosperms, which were important components of the palaeoflora during the Cretaceous in Northeast Brazil. The results presented here provide additional evidence for the occurrence of palaeo-wildfires in Northern Gondwana during the Early Cretaceous, increasing our understanding for the relevance of such events and their influence on palaeoenvironmental dynamics.

Reconstructing Paleoclimate and Paleoecology Using Fossil Leaves: Reconstructing Cenozoic Terrestrial Environments and Ecological Communities

Chapter

Full-text available

Oct 2018

Plants are strongly influenced by their surrounding environment, which makes them reliable indicators of climate and ecology. The relationship between climate, ecology, plant traits and the geographic distribution of plants based on their climatic tolerances have been used to develop plant-based proxies for reconstructing paleoclimate and paleoecology. These proxies are some of the most accurate and precise methods for reconstructing the climate and ecology of ancient terrestrial ecosystems and have been applied from the Cretaceous to the Quaternary. Despite their utility, the relationships between plant traits and climate that underlie these methods are confounded by other factors such as leaf life-span and phylogenetic history. Work focused on better understanding these confounding factors, incorporating the influence of phylogeny and leaf economic spectrum traits into proxies, expanding modern leaf trait-climate and ecology calibration datasets to additional biogeographic areas and climate regimes, and developing automated computer algorithms for measuring leaf traits are important growing research areas that will help considerably improve plant-based paleoclimate and paleoecological proxies.

Miocene pollen assemblages from the Zeku Basin, northeastern Tibetan Plateau, and their palaeoecological and palaeoaltimetric implications

Article

Sep 2018
PALAEOGEOGR PALAEOCL

Reconstructing paleoclimate and paleoecology using fossil leaves

Preprint

Full-text available

Aug 2017

Lagerstroemia L. wood from the Kimin Formation (Upper Siwalik) of Arunachal Pradesh and its Climatic and Phytogeographic Significance

Article

Full-text available

Jun 2018

A fossil wood of Lagerstroemia L. from the Upper Siwalik sediments of Arunachal Pradesh is described. The genus is recorded for the first time from this state. The modern analog of the fossil species i.e. L. tomentosa C. Presl is not found in the fossil locality at present.. The most plausible reason for the disappearance of the species from the fossil locality is an increase in temperature seasonality caused by the upheaval of the Himalaya during the Pleistocene.

Lagerstroemia L. fossil wood from the Indus molasse sediments (possibly late Miocene) of Trans-Himalayan region and its phytogeographic and climatic significance

Article

May 2018
REV PALAEOBOT PALYNO

The collision of the Indian and Eurasian plates led to the formation of Himalaya. The uplift of Himalaya had a direct impact on the intensification of South Asian monsoon which has influenced the evolution of many Asian biotas. The plant fossil records from the Indus-Tsangpo-Yarlung Suture Zone are exceptionally significant for the reconstruction of palaeoclimate during the collision and uplift of the Himalaya. However, these records from the Himalayan region are poorly known. Here we report a fossil wood from the Trans-Himalayan region unearthed from the possibly late Miocene Indus molasse sedimentary succession (Karit Formation) of the Kargil district, Jammu and Kashmir. The anatomical features of the fossil wood such as semi ring porosity, simple perforation plates, vestured intervessel pits, vasicentric to confluent axial parenchyma, exclusively uniseriate, homocellular rays, septate fibres and crystalliferous parenchyma strands suggest its close affinity with Lagerstroemia L. and particularly with Lagerstroemia parviflora Roxb. of the family Lythraceae. The climatic tolerance and anatomical details of the nearest living relative of the fossil indicate that during the late Miocene the climate of the Trans-Himalayan region was warmer and the area was lower in comparison to the modern day elevation of ~ 3559 m

Quantification of rainfall during the late Miocene–early Pliocene in North East India

Article

Full-text available

Dec 2017
CURR SCI INDIA

Miocene vegetation shift and climate change: Evidence from the Siwalik of Nepal

Article

Mar 2018
GLOBAL PLANET CHANGE

We reconstruct climate and vegetation applying the Coexistence Approach (CA) methodology on two palaeofloras recovered from the Lower (middle Miocene; ~ 13–11 Ma) and Middle Siwalik (late Miocene; 9.5–6.8 Ma) sediments of Surai Khola section, Nepal. The reconstructed mean annual temperature (MAT) and cold month mean temperature (CMT) show an increasing trend, while warm month mean temperature (WMT) remains nearly the same during the period. The reconstructed precipitation data indicates that the summer monsoon precipitation was nearly the same during the middle and late Miocene, while the winter season precipitation significantly decreased in the late Miocene. The overall precipitation infers increased rainfall seasonality during the late Miocene. The vegetation during the middle Miocene was dominated by wet evergreen taxa, whereas deciduous ones increased significantly during the late Miocene. The reconstructed climate data indicates that high temperature and significantly low precipitation during the winter season (dry season) in the late Miocene might have enhanced forest fire which favoured the expansion of C4 plants over C3 plants during the period. This idea gets further support not only from a recent forest fire in northern India that was caused by the weakening of winter precipitation, but also from the burnt wood recovered from the late Miocene Siwalik sediments of northern India.

Plantas fósiles e inferencia paleoclimática: aproximaciones metodológicas y algunos ejemplos para México

Article

Full-text available

Jan 2014

Himalayan uplift and the evolution of a Mediterranean-type climate in the Kashmir Basin of India: Palaeobotanical evidence from the late Pliocene Dubjan Member (Karewa Group)

Article

May 2025
PALAEOGEOGR PALAEOCL

The Kashmir Valley is an intermontane basin in the northwestern Himalayan region, characterized by a Mediterranean-type climate, where the primary source of moisture is winter precipitation brought by Western Disturbance low-pressure system. This basin was formed around ~4 Ma due to the uplift of the Pir Panjal Range (Lesser Himalaya), which obstructed the ancient Himalayan drainage system, leading to the formation of a vast lake. The sediments deposited in this lake are assigned to the Karewa Group. In this paper, we reconstruct palaeoclimate using the Climate Leaf Analysis Multivariate Program (CLAMP) and the Coexistence Approach (CA), based on late Pliocene leaf assemblages recovered from the Dubjan Member of the Hirpur Formation (Karewa Group). CLAMP-based climate reconstruction indicates a mean annual temperature (MAT) of 18.1 ± 2.3 °C and a cold month mean temperature (CMMT) of 11.1 ± 3.5 °C, suggesting a warm subtropical climate with a 9–10 month growing season. Estimated growing season precipitation (GSP) was 159.2 ± 64.3 cm, with a strong seasonal rainfall pattern (WET:DRY ratio of 6.9:1). Higher Vapour Pressure Deficit (VPD) and specific humidity (11.7 g kg−1) during summer and autumn indicate ample atmospheric moisture. CA-based estimates yield a MAT of 17.4 ± 0.6 °C, CMMT of 6.9 ± 3.1 °C, and warm month mean temperature (WMMT) of 25.5 ± 0.5 °C. Precipitation data suggest a mean annual precipitation (MAP) of 123.4 ± 8.8 cm, with monthly extremes ranging from 22.1 ± 0.5 cm (wettest) to 1.1 ± 0.2 cm (driest). The aforesaid quantitative climate reconstruction and fossil leaf physiognomy reveal a warm, summer monsoon-dominated regime preceding the modern Mediterranean-type climate. This climatic transition is linked to the uplift of the Pir Panjal Range (Lesser Himalaya), offering valuable insights into orographic influences on regional hydrology, climate evolution, and associated biodiversity patterns.

Coniferous wood fossils as records of paleoecology, paleoclimatology, and paleoenvironment: A review

Article

Dec 2024
REV PALAEOBOT PALYNO

Discovery and geological significance of black carbon in Triassic Yanchang Formation in Ordos Basin and its influences on source rock evaluation, NW China

Article

Dec 2024

The Relationship Between Normal-range Ejection Fraction and Diastolic Function

Article

Aug 2024

Paleoclimatic implications of a vascular plant from the lowermost Itararé Group

Article

Jul 2024
J S AM EARTH SCI

Plant fossils serve as critical proxies for interpreting past climates and environments, offering insights into the history of biosphere and climatic conditions. Here we describe a large tracheophyte cast, as well as the sedimentological settings in which it is preserved, expanding the paleobotanical database of the Itararé Group and contributing to the understanding of the LPIA in the Paraná Basin. This fossil occurs in Ponta Grossa, Paraná state, Brazil, within sedimentary levels interpreted as glacially dominated and deposited during the Late Paleozoic Ice Age (LPIA). The plant macrofossil is preserved as a cast, and the log is vertically oriented with a slight inclination in relation to the bedding plane. Taphonomic data indicate an allochthonous preservation, suggesting that the log was transported from inland areas to a plain before final burial. The identification of the tracheophyte cast within these glacial beds suggests that even in a dominantly glacial context, there were periods of episodic climatic amelioration. This finding implies that the climatic conditions during the Mississippian were not uniformly harsh, allowing the growth of vegetation as represented by the reported tracheophyta

High rainfall afforded resilience to tropical rainforests during Early Eocene Climatic Optimum

Article

Aug 2023
PALAEOGEOGR PALAEOCL

The rainforests near the early Eocene palaeo-equator were more resilient to greenhouse warming than mid-latitude vegetation. The mechanism underlying that resilience remains poorly known due to the lack of reliable terrestrial climate data from the palaeo-equator. In this paper, we quantify terrestrial temperature data using a plant proxy approach and infer that early Eocene climate near the palaeo-equator (~2.6° N) was warmer than in mid- to high palaeolatitudes. The data also suggest that high levels of rainfall near the palaeo-equator might have afforded greater resilience to tropical rainforests by increasing the water use efficiency of trees during the warm greenhouse world of the Early Eocene Climatic Optimum.

Floral Diversity and Climate Change in the Siwalik Succession

Chapter

Jan 2023

Siwalik sediments were deposited during the Himalayan orogeny in the Himalayan Foreland Basin. They were deposited in a coarsening upward succession to form the Siwalik Group which is further classified into Lower, Middle and Upper Siwalik. These sediments archive abundant plant fossils in the form of wood, leaves, flowers, fruits, seeds and pollen throughout the succession. These fossils have been used to understand the depositional environment of the Siwalik basin. In the Siwalik succession, the vegetation reconstruction indicates an increasing trend of deciduous forest taxa over the evergreen ones due to increased seasonality in rainfall and temperature. The quantitative estimation of climate based on plant megafossils indicates a monsoonal climate, particularly South Asia Monsoon, since the Lower Siwalik.KeywordsPlant fossilsClimateMioceneNeogene

Histogenesis and growth dynamics of the tiny Vegagete rhabdodontomorph hindlimb (Ornithischia, Ornithopoda): Paleoecological and evolutionary implications

Article

Aug 2022
CRETACEOUS RES

The Vegagete rhabdodontomorph is an as-yet unnamed ornithopod known from tiny and fragmentary remains, and was collected in the upper Barremian – lower Aptian of the Salas de los Infantes municipality (Burgos Province, Spain). As the earliest known rhabdodontomorph and a stem member of the lineage leading to Rhabdodontidae, this animal is key to better understanding growth within basal Iguanodontia. To do so, we prepared histological thin-sections of a sample of differently sized femora and tibiae. Here we combined anatomical, micro-anatomical and histological observations to analyse the growth and life-history traits of this little animal, and reinterpreted growth and postural shifts within the broader evolutionary framework of Rhabdodontomorpha. We find that the largest Vegagete ornithopod individual was a late subadult, making it the smallest ornithopod ever recovered. This taxon would have shifted from a quadrupedal stance to a bipedal one at a juvenile stage. In sharp contrast, Late Cretaceous rhabdodontids would retain the juvenile quadrupedal stance of their ancestors, and maintain quadrupedality until their adulthood most probably through progenetic development. No sampled Vegagete ornithopod individual shows Lines of Arrested Growth (LAGs). However, a minimal age greater than one year is most likely. Given the many signs of histologic maturity, the absence of LAGs is here interpreted as uninterrupted, fast growth of the hindlimbs.

Evaluating Northern High-Latitude Paleoclimate Model Results Using Paleobotanical Evidence from the Middle Cretaceous

Chapter

Apr 2019

Megaporoxylon sinensis sp. nov., a new coniferous trunk from the Upper Triassic of northern Bogda Mountains, northwestern China

Article

Full-text available

Sep 2021
REV PALAEOBOT PALYNO

A coniferous trunk, Megaporoxylon sinensis sp. nov., is described from the Carnian–Norian (Triassic) Huangshanjie Formation in the Dalongkou section, Jimsar County, Xinjiang, northwestern China. The trunk is composed of pith, primary and secondary xylem. The pith is solid, circular, heterocellular, with pitted parenchyma and secretory cells and canals. The primary xylem is endarch, with spiral and scalariform thickenings on tracheidal walls. The secondary xylem is pycnoxylic, consisting of tracheids and rays. Radial tracheidal pitting is araucarian. Tangential pitting and axial parenchyma are absent. Uniseriate pits with oval apertures are commonly present on radial tracheid walls. Biseriate pitting occurs only on radial walls of the first to fifth tracheids outward the primary xylem. Rays are parenchymatous, uniseriate, and 1–7 cells high. Cross-field pitting is window-like or phyllocladoid. Previous records of species of Megaporoxylon Kräusel were limited to the Southern Hemisphere during the Carboniferous to Triassic. Its occurrence from the Upper Triassic of northern Xinjiang is the first report in the Northern Hemisphere and suggests a floristic exchange between Gondwana and Laurasia. The new trunk and two previously described fossil stems, including Medulloprotaxodioxylon triassicum Wan et al. and Xenoxylon junggarensis Wan et al., demonstrate that conifers were important elements of Carnian–Norian terrestrial ecosystems and had a higher diversity in northern China than previous thought. The growth ring pattern of the trunk and palaeogeographic reconstruction of the research area at high latitudes suggest that the growth of the trees was limited by the seasonality of the light regime.

Anatomically preserved cordaitalean trees from the Pennsylvanian of Yangquan City, Shanxi Province, and their implication for a perhumid climate in North China Block

Article

Jul 2021
Palaeoworld

Fifty-six cordaitalean trunks with anatomical features are discovered and described from the Moscovian (Pennsylvanian) Benxi Formation in Yangquan City, Shanxi Province, North China. They are allochthonously preserved in fluvial channel deposits and classified into two types based on the anatomy. The first type is characterized by a solid and heterocellular pith, endarch primary xylem and pycnoxylic secondary xylem with araucarian radial tracheidal pits and araucarioid cross-field pitting. The second type contains a septate pith and a pycnoxylic secondary xylem which is comparable to that of the first type. Primary xylem is absent in the second type. The diameter of these trunks ranges from 0.11 m to 0.55 m. The largest tree is estimated to be 29.96 m high using an allometric approach. The trunks represent the oldest and largest trees from the North China Block during the Pennsylvanian due to the absence of Silurian, Devonian, and Mississippian there. The fossil evidence shows that cordaitaleans were large arborescent trees growing on clastic substrates in the Cathaysia during the Pennsylvanian. Their occurrence from the upper Pennsylvanian in North China Block suggests that the previously reported diversity of cordaitaleans, which were estimated based on impressions, is a gross underestimate. The absence of growth rings in the trunks and co-occurrence of arborescent lycopsids in the same interval, together with coal seams and bauxite around the fossil-bearing horizons, indicate that the trees grew under perhumid tropical conditions.

Dipterocarpus Gaertn. (Dipterocarpaceae) leaf from the Middle Siwalik of eastern Nepal and its phytogeographic and climatic significance

Article

Full-text available

Sep 2017

A leaf of Dipterocarpus (Dipterocarpaceae) is described from the Lower member of Middle Siwalik of eastern Nepal. Its presence indicates that during the deposition of the sediments there was a warm and humid climate with dry season of not more than 3-4 months. The modern distribution of the genus and family reveals that nowadays they have disappeared from the modern flora of Nepal. The most plausible reason for their disappearance might be an increase in length of the dry season caused by the upliftment of the Himalaya.

Mesozoic woods from India: Nomenclature review and palaeoclimatic implications

Article

Jan 2018
Palaeoworld

Nomenclature reappraisal, diversity pattern and palaeoclimatic implications of Jurassic, Triassic and Early Cretaceous pycnoxylic woods in India are undertaken in the present study. Among the fourteen generic names published previously, only eight are validly published and the rest are nomenclaturally illegitimate. About 51 species were reported under these genera to date. There is a gradual increase of species diversity of fossil wood from the Triassic to Early Cretaceous. The nature of the growth rings was applied to understand the palaeoclimate. The lack of distinct growth rings in the Triassic woods suggests absence of seasonality. The Jurassic woods with an inconsistency in growth rings and presence of growth interruptions suggest climate was seasonal and turbulent. During the Early Cretaceous, conifer dominated vegetation and with wider growth rings and gradual transition suggests warm environments with pronounced seasonality. The general increase in mean ring width from the Triassic to Early Cretaceous indicates ameliorating climatic conditions, particularly benign summer conditions. © 2018 Elsevier Ireland Ltd Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS.

Bildung der Kontinente und Evolution — eine Reise durch Raum und Zeit

Chapter

Jan 2005

Richard Pott

Mapping Past Climates

Chapter

Jun 2015

C. P. Summerhayes

The truest analysis of past climates comes from combining many different lines of evidence. Wegener's concept of drifting continents provided a testable means of predicting where past climate zones were. Wegener expanded his understanding of past climates by collaborating with Wladimir Köppen, one of the founders of modern meteorology and climatology. In April 1972, experts at a NATO Advanced Study Institute at the University of Newcastle upon Tyne reviewed evidence for the relationship between continental positions and past climates. By the very early 1980s, climatologists were using a brand new tool called the numerical general circulation model (GCM), to simulate the behaviour of the present climate system. Much of the work reviewed in this chapter dates from before the mid 1980s, when there was little or no discussion in the geological community of the possible role of CO2 as a modifier of Earth's climate through time.

Palynology, climate, and the development of Late Cretaceous floral provinces in the Northern Hemisphere; a review

Chapter

Full-text available

Jan 1984

David J. Batten

Variation in Leaf Size with Respect to Climate in the Tropics of the Western Hemisphere

Article

Full-text available

Apr 1980

Leaf size variation with respect to climate was studied at 35 sample sites reported in the literature from the Western Hemisphere. The variation in leaf size was analyzed by plotting the sample sites on Holdridge's (1967) life zone chart and comparing the percentage of species having large leaves (greater than 20.25 sq cm in area) in the different life zones. Four foliar belts were identified in the tropical basal and altitudinal belts. Three of these foliar belts were identified earlier in a field study carried out in Costa Rica (Dolph and Dilcher in press). The fourth foliar belt is not found in Costa Rica because it is confined to very dry basal belt life zones. It was concluded that leaf size cannot be used to identify specific life zones or climates in either extant or fossil floras.

Physiological Characteristics of Land Plants in Relation to Environment through time

Article

Full-text available

Jan 1989

Robert A. Spicer

The spatially fixed sporophyte body of vascular land plants has to be adapted to both atmospheric and substrate environments. Potentially almost all stages in the life cycle of a land plant are fossilisablc and the physiological adaptations to these environmcnts are reflected in the morphology, anatomy, and chemistry of the plant. Although solutions to the plant's physiological problems have been refined through evolution, the basic responses to fundamental environmental parameters such as temperature, water availability, nutrient supply, gas exchange and light, evolved early in land plant history. These taxon-independent solutions can be used qualitatively and sometimes quantitatively, to track changcs in atmospheric and edaphic conditions throughout much of the Phanerozoic. Increase in body size and height in Middle and Late Devonian times was coupled with intense demand for light, nutrients and water supply and with elaborations of vascular systems, photosynthetic surfaces, organ abscission and 'root' organisation. During the Carboniferous extreme adaptations to substrate waterlogging evolved. Mycorrhizal associations and "phi" layers in Triassic roots represent early aspects of modem root physiology. From the mid-Cretaceous, angiosperms exhibit leaf architectural characteristics which in modern plants relate qualitatively to moisture and light. and quantitatively to temperature, while vessel size and distribution in trunk wood is related to water stress and susceptibility to freezing. The relative proportion of plants utilising C3, CAM, and C4 photosynthetic pathways varies with environment. Isotopic analysis of plant fossils may demonstrate changing relative frequencies of photosynthetic pathways through time in relation to atmospheric composition and temperature.

What use are fossil plants ?

Article

Full-text available

Jan 1977
Hermathena

North American nonmarine climates and vegetation during the Late Cretaceous

Article

Full-text available

Oct 1987
PALAEOGEOGR PALAEOCL

Analyses of physiognomy of Late Cretaceous leaf assemblages and of structural adaptations of Late Cretaceous dicotyledonous woods indicate that megathermal vegetation was an open-canopy, broad-leaved evergreen woodland that existed under low to moderate amounts of rainfall evenly distributed through the year, with a moderate increase at about 40–45°N. Many dicotyledons were probably large, massive trees, but the tallest trees were evergreen conifers. Megathermal climate extended up to paleolatitude 45–50°N. Mesothermal vegetation was at least partially an open, broad-leaved evergreen woodland (perhaps a mosaic of woodland and forest), but the evapotranspirational stress was less than in megathermal climate. Some dicotyledons were large trees, but most were shrubs or small trees; evergreen conifers were the major tree element. Some mild seasonality is evidenced in mesothermal woods; precipitational levels probably varied markedly from year to year. Northward of approximately paleolatitude 65°N, evergreen vegetation was replaced by predominantly deciduous vegetation. This replacement is presumably related primarily to seasonality of light. The southern part of the deciduous vegetation probably existed under mesothermal climate. Comparisons to leaf and wood assemblages from other continents are generally consistent with the vegetational-climatic patterns suggested from North American data. Limited data from equatorial regions suggest low rainfall.

Climatic indications from growth rings in fossil wood

Article

Jan 1984

Wood of a Cordaitean, Taxopitys arctica sp. nov. from the Upper Carboniferous of Eastern Siberia

Article

Jan 1960
Paleontol J

I.A. Shilkina

The contribution of growth rings to the reconstruction of past climates

Article

Jan 1987

Phanerozoic palaeocontinental maps

Article

Growth rings in Cretaceous and Tertiary wood from Antarctica and their palaeoclimatic implications

Article

Jan 1986

J.E. Francis

Fossil forests from the Lower Cretaceous of Alexander Island, Antarctica

Article

Jan 1982

T.H. Jefferson

Tertiary centers and migration routes

Article

Jan 1947

R.W. Chaney

Phototrophy, diazotrophy and palaeoatmospheres: biological catalysis and the H, C, N and O cycles

Article

Feb 1989

Photolithotrophy (use of light as energy source, CO2 as carbon source) and then diazotrophy (use of N2 as N source), became important as prebiotically-synthesized organic compounds were consumed. 13C/12C data suggest that ribulose bisphospate carboxylase-oxygenase has dominated photolithotrophic CO2 fixation over the last 3.5 Ga. The long-term decline in atmospheric CO2 can be related to carbon isotope evidence for a CO2 accumulating mechanism in aquatic plants over the last 100 Ma and of C4 metabolism in terrestrial plants over 10 Ma. Increasing biogenic O2 levels permitted, via an O3 UV screen, photolithotrophs to grow in high-light environments and, via O2 availability for respiration and biosyntheses, to produce large and (on land) homiohydric plants. This greatly increased the productivity and diversity of photolithotrophy. Diazotrophy is less strongly coupled to homoiohydry and to photochemistry than is CO2 fixation. Symbiotic N2 fixation in land plants partially effects these two couplings, and permits novel methods of dealing with O2 inactivation of nitrogenase. -Authors

Principles of Environmental Physics

Article

Mar 1974

PREFACE TO THE SECOND EDITION LIST OF SYMBOLS 1. SCOPE OF ENVIRONMENTAL PHYSICS 2. GAS LAWS Pressure, volume and temperature Specific heats Lapse rate Water and water vapour Other gases 3. TRANSPORT LAWS General transfer equation Molecular transfer processes Diffusion coefficients Radiation laws 4. RADIATION ENVIRONMENT Solar radiation Terrestrial radiation Net radiation 5. MICROCLIMATOLOGY OF RADIATION (i) Interception Direct solar radiation Diffuse radiation Radiation in crop canopies 6. MICROCLIMATOLOGY OF RADIATION (ii) Absorption and reflection Radiative properties of natural materials Net radiation 7. MOMENTUM TRANSFER Boundary layers Wind profiles and drag on uniform surfaces Lodging and windthrow 8. HEAT TRANSFER Convection Non-dimensional groups Measurements of convection Conduction Insulation of animals 9. MASS TRANSFER (i) Gases and water vapour Non-dimensional groups Measurement of mass transfer Ventilation Mass transfer through pores Coats and clothing 10.MASS TRANSFER (ii) Particles Steady motion 11.STEADY STATE HEAT BALANCE (i) Water surfaces and vegetation Heat balance equation Heat balance of thermometers Heat balance of surfaces Developments from the Penman Equation 12.STEADY STATE HEAT BALANCE (ii) Animals Heat balance components The thermo-neutral diagram Specification of the environment Case studies 13.TRANSIENT HEAT BALANCE Time constant General cases Heat flow in soil 14.CROP MICROMETEOROLOGY (i) Profiles and fluxes Profiles Profile equations and stability Measurement of flux above the canopy 15.CROP MICROMETEOROLOGY (ii) Interpretation of measurements Resistance analogues Case studies: Water vapour and transpiration Carbon dioxide and growth Sulphur dioxide and pollutant fluxes to crops Transport within canopies APPENDIX BIBLIOGRAPHY REFERENCES INDEX

Tree growth in the Mesozoic and Early Tertiary and the reconstruction of palaeoclimates

Article

Nov 1985
PALAEOGEOGR PALAEOCL

Evidence from the distribution and characteristics of fossil wood in the Mesozoic and Early Tertiary indicates that a much warmer global climate prevailed in those times. There appears to have been a broad zone of largely non-seasonal climate stretching from about 32° N to 32° S (palaeolatitudes). In addition to this low-latitude zone, forest growth extended into very high palaeolatitudes where trees cannot grow at the present day. A number of theories have been proposed to account for the palaeoclimate responsible for this distribution of forests. Most notable have been those involving changes in the amount of carbon dioxide in the atmosphere, in the positions of the continents or in the obliquity of the earth's axis of rotation. Evidence from fossil forests indicates that a combination of the effects of an increased quantity of carbon dioxide in the atmosphere and the palaeopositions of the continents in the Mesozoic and Early Tertiary appears at the moment to be the simplest explanation for the climate of those geological times, without the need to invoke axial movement.

Tree Rings: Basics and Applications of Dendrochronology

Book

Jan 1988

Fritz H. Schweingruber

Temperature parameters of Humid to Mesic Forests of Eastern Asia and relation to forests of other regions of the Northern Hemisphere and Australasia

Article

Jan 1979
U S Geol Surv Prof Pap

Jared Wolfe

Contribution of Different-aged Needles to Growth and Wood Formation of Young Red Pines

Article

Jun 1964

Philip R. Larson

Light-proof coverings were used to isolate Pinus resinosa Ait. needles of different-aged internodes for an entire growing season. The contribution of each complement of needles to growth of the current-year shoot was determined by weekly measurements of internodal extension and needle elongation, and to wood formation by anatomical evaluation of trees harvested periodically. Internodal extension in all treatments was primarily at the expense of reserve foods although additional complements of exposed needles improved growth considerably. The curves of needle elongation of trees with either the 2nd- or 3rd-year needles exposed alone were similar to the uncovered controls, but growth ceased earlier and total growth was reduced. Needles of the current-year shoot, when exposed alone to light, grew continuously with no indication of ceasing at the final harvest date. Diameter of the tracheids comprising the wood of the current-year internode paralleled, in general, the patterns of needle elongation; large-diameter tracheids were produced during periods of active or prolonged needle growth, and the transition to narrow-diameter tracheids was associated with the reduction or cessation of needle growth. The thick tracheid walls, typical of latewood, were first evident when the new shoot attained a certain stage of maturity. Tracheid wall thickness is therefore believed to be a function of net assimilation. Distribution of radial growth, primarily the latewood zone of the growth ring, was strongly influenced by the age of the needles exposed to light. Several probable explanations for the observed growth distributions are presented.

Tertiary climatic fluctuations and methods of analysis of Tertiary floras

Article

Jan 1971
PALAEOGEOGR PALAEOCL

Jack A. Wolfe

On theoretical grounds, an analysis of the physiognomy of a Tertiary leaf assemblage is more direct and reliable than a circuitous floristic analysis in assigning thermal regimes to fossil assemblages. Using primarily foliar physiognomy and secondarily floristic composition, it can be shown that: (1) some middle latitude Tertiary assemblages probably lived under meteoroligically tropical climates; (2) a major and rapid climatic deterioration occurred in the Oligocene; and (3) a major climatic fluctuation probably occurred in the Late Eocene.These analyses thus substantiate the conclusions of several other paleobotanists regarding climatic fluctuations. Recent criticisms of these analyses are shown to be invalid and to be based largely on misinterpretations.

Influence of environmental factors on the wood structure of living and fossil trees

Article

Oct 1984

The mechanism of wood development records in varying degree the effects of both external and internal factors that are operating at the time of development. As a result, fossil woods spanning the last 370 million years represent a unique palaeo-environmental data-store. Data concerning external factors that can be reclaimed consist of: presence or absence of growth rings; ring widths; relative proportions of earlywood and latewood and the nature of the transition between them; “false” and “frost” rings and evidence of damage by animals or fire; occurrence of reaction wood. These effects have to be seen against a background of the influences of the internal factors. The development of wood involves the action of plant growth regulators. The production of an entire season’s growth of wood depends on a supply of photosynthate, partly stored from the previous year, and the remainder directly from photosynthesis during the current one. In any population of trees of the same species there will be genetic variation which will lead to differences in the wood formed by the individual trees even if they have all grown in a largely similar environment. However the external factors exert a much greater influence than the internal ones. Our earliest fossil woods (Upper Devonian) show either seasonless growth patterns or, if weak rings are perceptible, then the increments are extensive. This is consistent with the palaeo-equatorial position of all recorded Devonian woods. In the Carboniferous a few sites (marginal in the tropical belt?) show subdued (weak) growth rings. By the time of the Gondwana glaciation strong rings are shown in high southern latitudes, but most surprisingly there are sizeable increments well inside the palaeoantarctic circle. This phenomenon persists into the Mesozoic where lack of growth rings shows consistency with positions within the palaeo-equatorial latitudes. However occurrence of Cretaceous high latitude wood growth demonstrates that given an adequate ambient temperature, forest growth was possible close to both poles. It is shown that this is consistent with the total energy flux known to occur now in high latitudes. Le mécanisme de développement du bois enregistre à des degrés variables les effets des facteurs, à la fois externes et internes, opérant au moment du développement. C’est pourquoi les bois fossiles des dernières 370 millions d’années représentent un fonds d’information unique en ce qui concerne le paléo-environnement. Les informations qui ont pu être recueillies au sujet des facteurs externes sont les suivantes: la présence ou l’absence des zones d’accroissement; le diamètre des cernes; les proportions relatives du bois initial et du bois final et la nature de la transition entre eux; les “faux cernes” et les “cernes de gelée” et les traces de dommage causé par les animaux ou le feu; l’existence de bois de réaction. On doit analyser ces effets à la lumière des influences des facteurs internes. Le développement du bois nécessite l’action de régulateurs de croissance des plantes. La production totale de bois pendant une saison depend de l’alimentation en produits de photosynthèse dont une partie provient des stocks de l’année précédente, le reste ayant été synthétisé pendant l’année en cours. Dans toutes les populations d’arbres d’une même espèce il existe des variations génétiques qui conduisent à des différences dans le bois formé par chaque arbre individuel même s’ils ont tous poussé dans un environnement semblable. Néanmoins les facteurs externes exercent une influence beaucoup plus importante que les facteurs internes. Nos bois fossiles les plus anciens (Dévonien Supérieur) montrent soit des modèles de croissance qui ne tiennent pas compte des saisons, soit, si les cernes faibles sont visibles, ils sont larges. Ceci est compatible avec la position paléo-équatoriale de tous les bois Dévoniens observés. Pendant le Carbonifère, quelques sites (marginaux dans la ceinture tropicale?) montrent de faibles zones d’accroissement. A l’époque de la glaciation Gondwana, des cernes remarquables apparaissent dans les hautes latitudes méridionales, mais on observe avec surprise des accroissements de taille dans le cercle paléo-antarctique. Ce phénomène persiste pendant le Mesozoïque où l’absence des zones d’accroissement est compatible avec les positions dans les latitudes paléo-équatoriales. Cependant l’existence de forêts dans les hautes latitudes pendant le Crétacé démontre que si la température ambiante était adéquate, la pousse de forêts était possible près des deux pôles. On démontre que ceci est compatible avec le flux total d’énergie que l’on sait exister aujourd’hui dans les hautes latitudes.

Nature and Structure of the Climax

Article

Jan 1936

F.E. Clements

Principles of environmental physics / John L. Monteith

Article

John L Monteith

Stomatal Numbers Are Sensitive to Increases in CO2 from Pre-Industrial Levels

Article

Jun 1987

Ian Woodward

Recent measurements of atmospheric CO2 levels in ice cores1 have shown that global CO2 has increased by about 60 µmol mol-1 over the past 200 years. Evidence for the response of plants in the field to this change in CO2 levels is here presented in the form of a significant change in stomatal density-an anatomical response of considerable ecophysiological importance. A 40% decrease in density of stomata was observed in herbarium specimens of leaves of eight temperate arboreal species collected over the last 200 years. This decline was confirmed for some of the species observed as herbarium specimens by experiments under controlled environmental conditions. In these an increase in the mole fraction of CO2 from 280 mumol mol-1 to the current ambient level of 340 µmol mol-1 was found to cause a decrease in stomatal density of 67%. Experiments have shown that the combination of this previously unreported response of stomatal density to the level of CO2, with the known responses of stomatal aperture2, cause water use efficiency to be much lower than expected at low levels of CO2 and over a wide range of humidities.

A botanical index of Cretaceous and Tertiary climate

Article

Jul 1915

Our Future World. The Natural Environment Research Council The principles of forest yield study A botanical index of Cretaceous and Tertiary climates

Jan 1915
831-834

Anon Wiltshire
Uk Assmann
E W Sinnott

References ANON. 1989. Our Future World. The Natural Environment Research Council, Swindon, Wiltshire, UK. ASSMANN, E. 1970. The principles of forest yield study. Pergamon Press, London. BAILEY, I. W. & SINNOTT, E. W. 1915. A botanical index of Cretaceous and Tertiary climates. Science, 41, 831-834.

Principles of Environmental Physics Some features of the regional history of the forests of southern Sweden in post-arctic time

Jan 1924
161-170

X X Li
Academia
Sinica
Nanjing
K G Magdefrau
Jena Fischer
J L Monteith
Amold
London
Post
L Von
J A Raven
J I Sprent

LI, X. X. 1981. A Bibliography of Chinese Palaeobotany. Institute of Geology and Palaeontology, Academia Sinica, Nanjing. MAGDEFRAU, K. 1968. Palaeobiologie der Pflanzen. (4th Ed.) G. Fischer, Jena. MONTEITH, J. L. 1973. Principles of Environmental Physics. Edward Amold, London. POST, VON, L. 1924. Some features of the regional history of the forests of southern Sweden in post-arctic time. Geologisk Forenningen Stockholm Forhandlinger, 38, 384. RAVEN, J. A. & SPRENT, J. I. 1989. Phototrophy, Diazotrophy and Palaeoatmospheres: biological catalysis and the H, C, N and 0 cycles. Journal of the Geological Society, London, 146, 161-170.

The Flora of the London Clay Tree Rings: Basics and applications of dendrochronology (eds) Implications of Continental Drip to the Earth Sciences A preliminary study of the London Clay pyritised twigs from the Isle of Sheppey

Jan 1933
73-82

E M Chandler
M E J London
F H Schweingruber
Reidel
Holland
J M Schopf

REID, E. M. & CHANDLER, M. E. J. 1933. The Flora of the London Clay. British Museum (Nat. Hist.) London. SCHWEINGRUBER, F. H. 1987. Tree Rings: Basics and applications of dendrochronology. Reidel, Holland. SCHOPF, J. M. 1973. Coal, Climate and Global Tectonics. In: TARLING, D. H. & RUNCORN, S. K. (eds) Implications of Continental Drip to the Earth Sciences, 1. Academic Press, London. SCOTT, A. C. & DE KLERK, R. 1974. A preliminary study of the London Clay pyritised twigs from the Isle of Sheppey. Tertiary Times, 2, 73-82.

Fossil Spores of the London Clay SEWARD, A. C. 1892. Fossil plants as tests of Climate Cordaitalean wood-Taxopitys arctica sp. nov. from the Upper Carboniferous of eastern Siberia

Jan 1960
123-126

Ma Sein
Khin

SEIN, MA KHIN. 1%1. Fossil Spores of the London Clay. PhD Thesis, University of London. SEWARD, A. C. 1892. Fossil plants as tests of Climate. London. SHILKINA, I. A. 1960. Cordaitalean wood-Taxopitys arctica sp. nov. from the Upper Carboniferous of eastern Siberia. Palaeontologicheskii Zhurnal, 3, 123-126.

Forest Management Tables (Metric). Forestry Commission HMSO

G J Hamilton
J M Christie

The Flora of the London Clay

E M Reid
M E J Chandler

Climate and plant distribution: Cambridge Studies in Ecology

Jan 1987

F I Woodward
Woodward F. I.

The principles of forest yield study

Jan 1970

E Assmann
Assmann E.

Fossil Plants of the London Clay

Jan 1983
1

M E Collinson
Collinson M. E.

Productivity in fossil forests

G T Creber
J E Francis

1840) A history of the fossil fruits and seeds of the London Clay

J S Bowerbank

Growth rings in fossil woods as evidence of past climatesImplications of Continental Drift to the Earth Sciences

Jan 1973
425

W G Chaloner
G T Creber
D H Tarling
S K Runcorn
Chaloner W. G.

The Lower Tertiary Floras of Southern England IV. A Summary and Survey of Findings in the Light of Recent Botanical Observations

M E J Chandler

1892. Fossil plants as tests of Climate

A C Seward

Effects of atmospheric and climate change on terrestrial ecosystems. The International Geosphere-Biosphere Programme: a Study of Global Change

B H Walker
R D Graetz

Our Future World. The Natural Environment Research Council

Anon

A Bibliography of Chinese Palaeobotany. Institute of Geology and Palaeontology Academia Sinica Nanjing

X X Li

Some features of the regional history of the forests of southern Sweden in post-arctic time

Jan 1924
384

Post von. L

Fossil Spores of the London Clay

Sein Ma Khin

The History of the British Flora1975second edCambridge

Jan 1975

H Godwin
Godwin H.

A history of the fossil fruits and seeds of the London Clay

Jan 1840

J S Bowerbank
Bowerbank J. S.

Climate and Global TectonicsImplications of Continental Drift to the Earth Sciences

Jan 1973

J M Schopf
D H Tarling
S K Runcorn
Schopf J. M.

climate and the development of Late Cretaceous floral provinces in the Northern Hemisphere; a reviewFossils and Climate

Jan 1984

D J Batten
P Brenchley
Palynology
Batten D. J.

Do fossil plants give a climatic signal?

Abstract

No full-text available

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