Olle Hints

Tallinn University of Technology | TTU · Department of Geology

The latest Ordovician time and the transition into the Silurian are represented by a succession of shallow-marine carbonates in northern Estonia. These boundary beds, exposed at the Reinu Quarry in the Rapla County, consist of two distinct units: a lower sandy limestone and an upper carbonate mudstone. These facies are characterized by a relativel...

The oxygen isotope ratio ¹⁸ O/ ¹⁶ O (expressed as a δ ¹⁸ O VSMOW value) in marine sedimentary rocks has increased by ~8‰ from the early Paleozoic to modern times. Interpretation of this trend is hindered by ambiguities in the temperature of formation of the carbonate, the δ ¹⁸ O seawater , and the effects of postdepositional diagenesis. Carbonate c...

The transition from the Ordovician to the Silurian Period marks a crucial time in Earth history. Associated with the Late Ordovician Mass Extinction (LOME), rocks of this age have been characterised by low diversity in body fossil assemblages. Until recently, studies associated with the Ordovician-Silurian boundary in Estonia were mostly restricted...

几丁虫是古生代海洋中一类重要的微体生物化石, 迄今已有近百年的研究历史。作为一类有效的生物地层工具, 几丁虫在奥陶纪和志留纪生物地层研究中发挥着重要作用, 为早古生代油气-矿产资源勘探提供可靠的地层对比资料, 还为一些重大地质-环境-生物事件的全球对比提供可靠依据, 特别是那些缺乏笔石和牙形类的地层。然而, 随着现代古生物学的快速发展以及几丁虫资料的不断积累, 几丁虫研究目前正遭遇着瓶颈期, 主要体现在: (1)受制于有限的技术手段及尚未形成规范的研究标准, 不少早期建立的几丁虫分类单元存在着明显的问题, 如描述简单、展示标本过少、光学显微成像无法很好地揭示壳表的形态特征等, 使得后期相关属种的鉴定存在争议; (2)在全球古生物数据不断被数字化和可视化的进程中, 几丁虫相关工作进展迟缓。目前...

The Silurian Period, a dynamic interval within the Phanerozoic Era, experienced notable climate shifts, fluctuations in the global carbon cycle, and multiple extinctions, including the mid-Silurian Mulde/lundgreni event at ~428 Ma. This Mulde/lundgreni event caused significant declines in various marine organisms, notably graptolites (with a reduct...

In 1930, Alfred Eisenack suggested the term ‘chitinozoan’ for a microfossil group that he discovered from erratic boulders on the Baltic Sea coast. They are known from the Early Ordovician until the end of the Devonian and have a broad paleogeographic distribution in marine deposits. Even though they are useful biostratigraphy markers, their bi...

Jawed polychaetes evolved and diversified extensively during the Ordovician. However, Ordovician polychaete jaws (scolecodonts) have remained poorly documented for many regions. This applies for the Prague Basin of peri-Gondwana, from where the previous study on Late Ordovician scolecodonts was published more than 70 years ago, with just two specie...

The latest Ordovician and earliest Silurian carbonate succession of the East Baltic region has served as a global reference for geochemical studies on the Hirnantian mass extinction and global environmental changes but the data from the area have uneven spatial distribution, with the deeper shelf Livonian Basin poorly covered by integrated geochemi...

This paper summarizes recent knowledge on the palaeontology, biostratigraphy, correlation, sea level and climate history and isotopic geochemistry of the Ordovician rocks in the western and central parts of the East European Craton, in the area extending from the southern margin of the Fennoscandian Shield to the western margin of the Ukrainian Shi...

Early and early Middle Ordovician chitinozoans are relatively poorly known in Baltoscandia, thus the understanding of the early diversification of the group, as well as its biostratigraphic utility, is limited. In this paper, we document the distribution of chitinozoans in the Floian and lower Darriwilian strata of the Baldone drill core from centr...

A global carbonate stratigraphic framework is needed to test models of paleoenvironmental change, but provinciality of age-diagnostic fossils and local controls on chemostratigraphic tools such as marine carbon isotope ratios (δ13C) have historically made long-distance correlation a difficult task. Radiogenic strontium isotope ratios (87Sr/86Sr) of...

Conodont apatite is ubiquitous in Paleozoic shallow- to deep-water carbonate sediments and has served as a crucial archive of seawater 87Sr/86Sr. However, some datasets have reported diagenetically altered 87Sr/86Sr values in apparently well-preserved conodont samples, highlighting a lack of understanding of the factors that affect 87Sr/86Sr signal...

The Baltoscandian lower Palaeozoic succession is well known for the abundance, diversity and excellent preservation of various groups of microfossils, such as acritarchs, chitinozoans, scolecodonts and conodonts. This paper describes a new enigmatic Middle Ordovician organic-walled microfossil Vikisphaera kundana gen. et sp. nov., characterized by...

Carbonate rocks are important paleo-environmental records, with bulk chemical and isotopic compositions commonly used to deduce temperatures, redox conditions, etc. Diagenetic (re)crystallization of clasts and cements is common, may perturb the chemical and isotopic systems typically interpreted to reflect conditions at the timing of deposition, ma...

Carbon, sulfur and oxygen isotope profiles in Silurian strata of the Baltoscandian Basin (Estonia), coincident with the Ireviken Bioevent, provide insights into basin-scale and platform-specific depositional processes. Paired carbon isotope records preserve a positive isotope excursion during the early Wenlock, coincident with faunal turnover, yet...

Lagenochitina esthonica is a globally distributed chitinozoan in Early to Middle Ordovician rocks. It is regarded as an index species for the early Floian in North America and has a stratigraphically constrained range in other regions. Lagenochitina esthonica is distinguished from other chitinozoans by a distinct flexure, a nearly rounded-square ch...

The Silurian was a dynamic time characterized by significant climatic and sea level changes, biotic crises, and carbon cycle volatility. The largest magnitude perturbation to the Silurian global carbon cycle was the mid-Ludfordian carbon isotope excursion, termed the Lau CIE, which was coincident with the Lau/Kozlowskii extinction (LKE). Much of th...

The Ordovician–Silurian (~485–419 Ma) was a time of considerable evolutionary upheaval, encompassing both great evolutionary diversification and one of the first major mass extinctions. The Ordovician diversification coincided with global climatic cooling and paleocontinental collision, the ecological impacts of which were mediated by region-specif...

Carina, a sharp extension of the basal margin in some chitinozoans recalling a “skirt”, is a primary character used for classifying chitinozoans at the genus level. However, little is known about this structure. In this study, we present new observations on the carina ultrastructure in the chitinozoan genus Cyathochitina that was investigated by us...

Reproduction is a key aspect of evolution, but the process is rarely preserved in the fossil record. Organisms fortuitously preserved undergoing reproduction provide an exceptional window illuminating the biology of extinct taxa, especially those with unknown phylogenetic position. Here we report exceptional specimens of chitinozoans (enigmatic Pal...

Application of integrated, multi-proxy optical analytical techniques for the assessment of thermal maturity of organic matter was tested in Katian to Hirnantian (Upper Ordovician) sediments from a subsurface succession in southern Estonia. The investigated Valga-10 drill core section consists of a biostratigraphically well-constrained succession de...

It is well documented that Upper Ordovician and Silurian successions record multiple marine turnover events – including the second-largest mass extinction in the Phanerozoic – widespread glaciation, and multiple global carbon cycle perturbations. Whereas causal mechanisms for the Late Ordovician major mass extinction event involving climate, paleoc...

Coprolites (fossil faeces) constitute a group of soft sediment trace fossils that provide useful palaeoecological and sedimentological information, but have generally low preservational potential. In this paper we report abundant occurrence and high diversity of small faecal pellets preserved inside different shelly fossils from Middle and Upper Or...

Coprolites (fossil faeces) constitute a group of soft sediment trace fossils that provide useful palaeoecological and sedimentological information, but have generally low preservational potential. In this paper we report abundant occurrence and high diversity of small faecal pellets preserved inside different shelly fossils from Middle and Upper Or...

The late Ludlow Lau Event was a severe biotic crisis in the Silurian, characterized by resurgent microbial facies and faunal turnover rates otherwise only documented during the "big five" mass extinctions. This asynchronous late Silurian marine extinction event preceded an associated positive carbon isotope excursion (CIE), the Lau CIE, although a...

The lower Silurian strata of the Prague Basin, as well as in many other regions, are primarily represented by black shales, with limited to no record of benthic life. In this paper, we describe an exceptional late Aeronian volcanic-carbonate succession from the Hýskov locality near Beroun, which contains a diverse and well-preserved fossil assembla...

Chitinozoans are organic-walled microfossils widely recorded in Ordovician to Devonian (ca 485-359 Mya) marine sediments and extensively used in high-resolution biostratigraphy. Their biological affinity remains unknown, but most commonly, they are interpreted as eggs of marine metazoans. Here, we provide new insights into their palaeobiology from...

Studying deep time biodiversity and environments is largely based on collections of fossils and sedimentary rocks, and the information acquired thereof. The sedimentary bedrocks of Estonia and neighbouring areas constitute a well-preserved archive of Earth history from the late Precambrian to the Devonian period. This interval of geological time ho...

The Hungshihyen Formation represents the Lower to Middle Ordovician near-shore siliciclastic deposits on the western margin of the Yangtze Platform, South China. However, its age is still debated, largely because of insufficient studies. Here we documented the Bursachitina maotaiensis–B. qianbeiensis chitinozoan assemblage from the lower part of th...

The Tremadocian (Early Ordovician) is currently considered a time span of greenhouse conditions with tropical water surface temperature estimates, interpolated from oxygen isotopes, approaching 40 °C. In the mid-latitude Baltoscandian Basin, conodonts displaying low δ18O values, which suggest high temperatures (>40 °C) in the water column, are in c...

en Silurian and Devonian chitinozoans and scolecodonts are recorded from strata of the Hida‐Gaien Terrane, central Honshu. Silurian chitinozoans include Eisenackitina, Bursachitina, and the species Angochitina elongata. The latter provides a precise biostratigraphical tie between the Japanese succession and the Type Ludlow Series of the Welsh Borde...

The Llandovery–Wenlock carbonate-marl succession of the Baltoscandian Basin has been analyzed in the Viki drill core, western Estonia, for carbonate carbon (δ ¹³ C carb ), organic carbon (δ ¹³ C org ), carbonate-associated sulfate (δ ³⁴ S CAS ) and pyrite (δ ³⁴ S pyr ) isotopes, along with trace element concentrations. Following the End-Ordovician...

Chitinozoans are a group of biostratigraphically valuable microfossils which appeared in the Tremadocian and diversified during the rest of the Great Ordovician Biodiversification Event, to become extinct in the Devonian. The early diversification of chitinozoans on the Baltica palaeocontinent has remained poorly known due to preservation and colle...

Chitinozoans are widespread microfossils in the Ordovician to Devonian strata. Although they have been widely adopted in biostratigraphy, their environmental preferences are rarely discussed. In this study, the palaeoecological distribution of four Floian and Dapingian key chitinozoans in six coeval stratigraphical units based on 13 sections from t...

en Conodont‐bearing Ordovician and Silurian rocks have a wide geographical distribution in Japan. They are exposed on Honshu, Shikoku, and Kyushu islands. Two recently studied samples from Gionyama, in Kyushu, yield conodont assemblages of Telychian (Distomodus sp., Apsidognathus sp. (cf. A. tuberculatus arcticus), Oulodus cf. rectangulus, Ozarkodi...

Trace fossils are common in the Ordovician and Silurian shallow marine carbonate succession of Estonia, with 45 ichnofossil genera and five bioclaustration structures identified, representing 31 categories of architectural designs and nine categories of ethological classification. Diverse soft sediment traces, bioerosional traces and bioclaustratio...

A complete chitinozoan succession through the uppermost Tremadocian to lower Darriwilian (Lower and Middle Ordovician) at Honghuayuan, northern Guizhou Province in South China, was systematically studied and 47 species of 14 genera were identified. Two chitinozoan biodiversity acmes were recognized, which occur in the lower part of the Acrograptus...

Chitinozoans are a key group in Ordovician and Silurian biostratigraphy, and the Baltic region hosts some of the largest collections of these microfossils in the world. Here, we present an online database – ‘CHITDB’ – for documenting and analysing the distribution of chitinozoans in the Baltic region. The system is integrated with the Estonian geoc...

Scolecodonts provide fossil evidence of the evolution and diversification of jaw-bearing polychaetes from the latest Cambrian onwards. However, their record before the Darriwilian (Middle Ordovician) is scarce worldwide, which limits our understanding of key evolutionary events. One such event is the emergence of taxa possessing the asymmetrical la...

The Zlíchovian/Dalejan boundary interval (Emsian, Lower Devonian) of the Pekárek Mill section was studied employing biostratigraphy (dacryoconarid tentaculites, conodonts) and palynology (chitinozoans, prasinophytes, scolecodonts) and microfacies analysis in order to shed more light on the timing and characteristics of the Daleje Event. The results...

The record of scolecodonts (polychaete jaws) from the Ordovician of Sweden is very poor. In this paper, we document a Darriwilian (Middle Ordovician) assemblage recovered from palynological samples from the ?orthoceratite limestone? (Lanna and Holen limestones) of Mount Kinnekulle, Västergötland, southern Sweden. The collection of diminutive specim...

A restudy of the palynology of the Whirlpool Formation and Power Glen Formation in New York (USA) yielded a diverse fossil assemblage with cryptospores, glomalean fungi, acritarchs, chitinozoans, scolecodonts, and small carbonaceous fossils. These new data, and particularly the presence of the chitinozoan index fossil Hercochitina crickmayi, combin...

The Upper Ordovician to lower Silurian shallow marine succession of Anticosti Island, eastern Canada, provides one of the most complete records across the Hirnantian in the world. This study reports a diverse assemblage of scolecodonts (polychaete jaws) from the upper Katian and Hirnantian Vauréal, Ellis Bay, and basal Becscie formations of western...

A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blankenheimerdorf section in the type Eifel area, western Germany, is described. The top part of the section also reflects the onset of the global Kačák Event. The sediments of the section were deposited in a shallow to deep subtidal environment on the sout...

Chitinozoans are among the most common and stratigraphically useful microfossils in the Silurian. We examine their regional diversity pattern in the Baltoscandian basin using constrained optimisation (CONOP), based on distributional data of 189 species in 15 sections. The CONOP-derived taxonomic richness curve provides close approximation to the st...

This paper reports the discovery of Late Ordovician scolecodonts from the Qusaiba-1 core hole, central Saudi Arabia. The collection of about 100 relatively well preserved diagnostic jaws represents one of the richest jawed polychaete faunas from the Gondwanan realm and the first record of scolecodonts from the Arabian Peninsula. Scolecodonts were m...

The Viki drill core is one of the reference sections for the Estonian bedrock succession, characterizing strata of Mid Ordovician through early Silurian age in the eastern part of the Baltoscandian basin. In this article, we present the hitherto missing Ordovician stable carbon isotope curve and Middle Ordovician conodont biostratigraphy from the V...

The impact of the Llandovery–Wenlock Ireviken Event (IE) on the jawed polychaete faunas is explored in this study, based on new data on scolecodonts from the Viki drill core of western Estonia. A distinct faunal reorganisation is observed, with the most abrupt changes recorded between datum points 4 and 6 of the IE, which coincides with the major t...

Eunicidan polychaetes formed a significant part of Early Palaeozoic marine invertebrate communities, as shown by the abundance and diversity of scolecodonts (polychaete jaws) in the fossil record. In this study we summarize the early radiation and biodiversity trends and discuss the palaeobiogeography of these fossils. The oldest (latest Cambrian–E...

Université Lille 1 -Sciences et Technologies, UMR 8217 du CNRS: Géosystèmes, Avenue Paul Langevin – bât. SN5, 59655 Villeneuve d'Ascq cedex, France [1] The carbon isotope composition (d 13 C) of bulk organic matter and two palynomorph groups (scolecodonts and chitinozoans) from the Llandovery-Wenlock strata of Gotland (E Sweden) are compared to gai...

The carbon isotope composition (d13C) of bulk organic matter and two palynomorph groups (scolecodonts and chitinozoans) from the Llandovery-Wenlock strata of Gotland (E Sweden) are compared to gain knowledge about carbon cycling in the Silurian (sub)tropical shelf environment. The d13C values of the palynomorphs are mostly lower than the d13C value...

Darriwilian conodonts have been studied in numerous sections of Baltoscandia, but few data are available from the classical outcrop area in northern Estonia. In this paper we report the succession of Darriwilian conodonts and chitinozoans from the bed-by-bed sampled Uuga and Osmussaar cliffs, NW Estonia. Standard Baltoscandian conodont and chitinoz...

This paper deals with a diverse fauna of polychaetes possessing jaws (= scolecodonts) from the late Silurian Kopanina Formation of the Prague Basin (Czech Republic). The most common genera are Kettnerites, Oenonites and Pistoprion; the entire collection contains at least 16 genera. This is in stark contrast to the four genera recorded from this reg...

The polychaete annelid Kingnites diamondi, a new paulinitid genus and species, is described from the Silurian of Baltoscandia. Its large maxillae differ morphologically from those of all other known paulinitids, particularly in being very elongate and having conspicuous myocoele openings and posterior portions of the first maxillae (MI). Albeit rar...

In the Early Palaeozoic, the carbon isotope composition of marine carbonates (δ13Ccarb) are variable and at times much higher (exceeding +7) than values through the rest of the geological column. Organic matter associated with the carbonates have a variable carbon isotope composition (δ13Corg). However, the interpretation of δ13C from bulk organic...

The diversity of several groups of Late Ordovician fossils in the Baltic is discussed and corresponding curves are presented. The curves are correlated with the latest δ13C trend and probable sea surface temperatures of the equatorial ocean in order to link biodiversity and environmental changes. Most groups of macrofossils and acritarchs showed a...

Rich palynological assemblages have been recovered from deposits of Hirnantian age in Anticosti Island (Quebec, Canada), and in borehole Valga-10 in southern Estonia. The assemblages are well preserved, and include acritarchs, chitinozoans. and cryptospores. The age of the deposits is well constrained by means of palynomorphs (acritarchs and chitin...