January 2019
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17 Reads
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January 2019
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17 Reads
November 2018
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162 Reads
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16 Citations
This paper documents technological and behavioral changes in the southern part of the Upper Santa Cruz River Basin during the Late Holocene and examines possible relationships with environmental changes. The findings suggest an important relationship between human use of space and long-term trends in precipitation. This relationship is emphasized by the inverse correlation between precipitation near the Andes and that in the steppe further east. Evidence of human occupation is more abundant after ca. 4800 cal BP, during a wet period, when lithic technology and raw materials show that different landscapes near the Andes and in the steppe were used by the same population, who also buried their dead at the same site. Although sites in the steppe were abandoned later, western landscapes continued to be occupied, and technology suggests utilization by culturally related groups. Climate changes during the Late Holocene may have changed how the Lake Argentino area was used or even led to the abandonment of the area and its later occupation by new human groups.
October 2018
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189 Reads
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45 Citations
Journal of Archaeological Science Reports
The first direct AMS radiocarbon dating of two rock art motifs in separate rock shelters (VQ1 and VQ2) at Viuda Quenzana (VQ) in Patagonia, has provided median probability ages of 3190 cal BP for two reddish dots, and 520 cal BP (AD 1490) for a pink negative hand. The age of the older paint corresponds closely with collagen ages for two guanaco bones from the VQ8 rockshelter (5470 and 5400 cal BP, Franco et al. 2013), and at a broader scale with ages for human occupation of La Martita Cueva 4 (Rubinos Perez 2003). The younger age of the pink hand motif corresponds with evidence of occupation at the VQ7 rockshelter dating to 1085 cal BP (AD 865), and occupation of La Gruta 1 and 3, about 25 km from VQ (Brook el al. 2015). The pink, stenciled hand is relatively recent, which is consistent with the notion that such artwork continued through the Late Holocene despite changes in other artistic motifs. Additional characterization by Raman spectroscopy, powder x-ray diffraction, and high resolution SEM/EDS studies shows that: 1) hematite is the main pigment in both the dot and hand motifs, 2) the reddish dot paint includes a specific type of hematite, microplaty hematite, and 3) animal fat appears to have been added as a binder to the reddish dot paint. Thus, rock art paint production at VQ involved two different processes. One, used to paint dots, entailed mixing a mineral coloring substance (hematite) with an organic binder (most probably animal fat), which was then applied to the rock substrate with a painting tool and/or with the fingers. The second, used to produce the hand motif, entailed using a mineral coloring substance (hematite) with no binder (or with a binder that left no chemical trace), which was then applied to the rock substrate by spraying it, probably with the mouth.
July 2018
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170 Reads
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10 Citations
Palaeogeography Palaeoclimatology Palaeoecology
Paleodischarge estimates based on the slope-area method and channel boundaries determined from stratigraphic cross-sections indicate that large, terminal Pleistocene meandering paleochannels (“mega-meanders”) in river valleys of the southeastern Atlantic Coastal Plain of the United States represent bankfull flows that were at least double the magnitude of those on modern rivers. Correlation of radiocarbon- and luminescence-dated paleomeanders with previously reported pollen and eolian sedimentary records suggests that greater discharge was driven by seasonally wetter conditions resulting from dynamic changes to regional precipitation and runoff that occurred in association with global warming at the end of the Pleistocene. While reflecting larger channel-forming flows, the exceptionally large widths and radii of curvature of mega-meanders were nonetheless maintained by a relatively modest discharge magnitude that was between two and four times larger than modern bankfull flow and within the size range of the present two- to five-year flood. Despite their large planform, the paleochannels conveyed relatively modest bankfull discharges because a wide, shallow shape limited their cross-sectional area and hydraulic radius. Within the late Quaternary evolution of fluvial systems in the region, scrolled mega-meanders constitute a transitional meandering planform that remained influenced by large volumes of sandy bedload following the sand-bed braided channels of the late Wisconsin interval, circa 30–17 ka. In addition to greater discharge, the large planimetric dimensions of paleochannels reflect a lack of cohesive vertical accretion facies on paleomeander floodplains, a sediment regime that transported large quantities of bedload sand, and the influence of these factors on channel boundary composition, bank stability, and channel shape. Findings underscore the importance of reconstructing channel cross-sectional dimensions and slope when estimating discharge for infilled paleomeanders. This approach reduces uncertainties surrounding channel cross-sectional area, gradient, and boundary composition inherent to studies lacking subsurface data that rely upon meander geometry to retrodict discharge.
June 2018
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153 Reads
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14 Citations
Palaeogeography Palaeoclimatology Palaeoecology
A multi-proxy record of past climate from a stalagmite from Bone Cave in northwestern Botswana suggests relatively wet conditions late in the Little Ice Age and progressively drier conditions in the twentieth century. The proxies include surfaces of dissolution, variation in layer-specific width, changing mineralogy, varying abundance of detrital material, varying growth rate, and oxygen and carbon isotope data. They combine to suggest a period of exceptional wetness that can be assigned with greatest certainty to ~1810–1820 CE and may have been wettest in 1817. The same proxy data conversely suggest relatively dry conditions after about 1835, and increasing dryness after about 1930. Bone Cave lies in the summer rainfall zone, at the southern margin of the tropical rain belt associated with the Inter-Tropical Convergence Zone (ITCZ). Previously published data from other records combine with the Bone Cave record to support wetter conditions in the 1700s and until about 1830, and drier conditions thereafter. The period of exceptional wetness in ~1810–1820 recorded in BC97-14 coincides with a decade of exceptional cold in the Northern Hemisphere, and its acme may be coincident with the Tambora eruption and its resultant “year without a summer” in Europe and North America. These results are thus compatible with movement of the austral-summer ITCZ southward (rather than an increase in rain its customary position) when the Northern Hemisphere cooled relative to the Southern Hemisphere. Conversely, they suggest that the ITCZ has not come as far south as frequently during Earth's warming in the past century.
December 2017
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987 Reads
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34 Citations
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[...]
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Petrographic features, mineralogy, and stable isotopes from two stalagmites, ANJB-2 and MAJ-5, respectively from Anjohibe and Anjokipoty caves, allow distinction of three intervals of the Holocene in NW Madagascar. The Malagasy early Holocene (between ca. 9.8 and 7.8 ka) and late Holocene (after ca. 1.6 ka) intervals (MEHI and MLHI, respectively) record evidence of stalagmite deposition. The Malagasy middle Holocene interval (MMHI, between ca. 7.8 and 1.6 ka) is marked by a depositional hiatus of ca. 6500 years. Deposition of these stalagmites indicates that the two caves were sufficiently supplied with water to allow stalagmite formation. This suggests that the MEHI and MLHI intervals may have been comparatively wet in NW Madagascar. In contrast, the long-term depositional hiatus during the MMHI implies it was relatively drier than the MEHI and the MLHI. The alternating wet–dry–wet conditions during the Holocene may have been linked to the long-term migrations of the Intertropical Convergence Zone (ITCZ). When the ITCZ's mean position is farther south, NW Madagascar experiences wetter conditions, such as during the MEHI and MLHI, and when it moves north, NW Madagascar climate becomes drier, such as during the MMHI. A similar wet–dry–wet succession during the Holocene has been reported in neighboring locations, such as southeastern Africa. Beyond these three subdivisions, the records also suggest wet conditions around the cold 8.2 ka event, suggesting a causal relationship. However, additional Southern Hemisphere high-resolution data will be needed to confirm this.
September 2017
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322 Reads
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14 Citations
Latin American Antiquity
The first systematic research on the funerary record at the Río Bote 1 (RB1) rockshelter, located next to the Bote River, a tributary of the Santa Cruz River in southern Patagonia, has revealed at least three human burial events dating to the very early Late Holocene and one dating to the middle Late Holocene. The RB1 site appears to have been used for both subsistence and inhumation activities. All of the burials uncovered postdate the deposition of a prominent volcanic ash layer. Technological information indicates that RB1 was used by groups that were also using spaces to the west and south. Mortuary evidence indicates connections with groups living in areas extending from the Última Esperanza region to the Pali Aike volcanic field, at least at the beginning of the Late Holocene. The selection of the same place for multiple burials may explain why so few human burials are known in southern Patagonia from the beginning of the Late Holocene and earlier periods, as it is possible that sites like RB1 are yet to be discovered.
August 2017
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251 Reads
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28 Citations
Air temperature is correlated with precipitation oxygen isotope (δ18Oprcp) variability for much of the eastern and central United States, but the nature of this δ18Oprcp-temperature relationship is largely based on data coarsely aggregated at a monthly resolution. We constructed a database of 6177 weeks of isotope and precipitation-day air temperature data from 25 sites to determine how more precise data change our understanding of this classic relationship. Because the δ18Oprcp-temperature relationship is not perfectly linear, trends in the regression residuals suggest the influence of additional environmental factors such as moisture recycling and extratropical cyclone interactions. Additionally, the temporal relationships between δ18Oprcp and temperature observed in the weekly data at individual sites can explain broader spatial patterns observed across the study region. For 20 of 25 sites, the δ18Oprcp-temperature relationship slope is higher for colder precipitation than for warmer precipitation. Accordingly, northern and western sites with relatively more cold precipitation events have steeper overall relationships with higher slope values than southeastern sites that have more warm precipitation events. Although the magnitude of δ18Oprcp variability increases to the north and west, the fraction of δ18Oprcp variability explained by temperature increases due to wider annual temperature ranges, producing stronger relationships in these regions. When our δ18Oprcp-temperature data is grouped by month, we observe significant variations in the relationship from month to month. This argues against a principal causative role for temperature and suggests the existence of an alternative environmental control on δ18Oprcp values that simply co-varies seasonally with temperature.
July 2017
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110 Reads
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11 Citations
Quaternary International
In view of a scarcity of terrestrial Quaternary pollen records relating to climate change in desert areas, we present new terrestrial sequences from hyrax middens in Namibia. While the few previously available pollen records are mainly Holocene, we present climate time series for Marine Isotope Stages 2 and 3 (MIS 2 and MIS 3). The data are from two sites in central Namibia that are surrounded by desert plains and close to the Namibian escarpment, viz., the D^aures Massif (Brandberg) and 200 km further south, the Mirabib Shelter located in a small inselberg. In the studied material, grass-rich pollen assemblages were more common at Mirabib where the vegetation is desert grassland, than at Brandberg with its mountain vegetation. Hyrax radiocarbon ages range from 21 ka to >50 ka, with inconsistencies in ages near the limit of effective radiocarbon dating. However, correlation of overlapping sequences supports the chronology we present. Despite chronological gaps in the available deposits, pollen assemblages from different middens indicate marked climate cycles, starting with moderately cool dry conditions with grassy karroid vegetation at Mirabib c. 50 ka. After a gap in the record, warmer conditions with savanna woodland are indicated at both Mirabib and Brandberg around 40 ka. Eventually, cool conditions supporting shrubby grassland with wild olives developed at Brandberg during MIS 2, c. 21 ka. Comparison with marine pollen data confirms earlier findings that terrestrial pollen assemblages differ markedly from South Atlantic Ocean marine pollen assemblages of the same age presumably due to mixing of pollen from wide source areas at the marine localities versus the more locally restricted terrestrial pollen sources trapped in hyrax dung. The results therefore add information for the interpretation of local vegetation shifts on land during the interval between 50 ka and 21 ka in Namibia.
May 2017
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156 Reads
Since the work of Alley and co-workers in 1997 1 on the 8.2 ka abrupt cooling event, numerous studies (paleoclimate reconstructions, paleoclimate simulations, and data-model comparisons) have been undertaken to refine our understanding of its climatic forcings, to better understand the influence of the abrupt event on climate at regional scale, and to use such information as a foundation to improve future climate prediction. The 8.2 ka event has been better understood in the Northern Hemisphere (NH) and in the Atlantic region and its surroundings. In 2005, Morrill and Jacobsen 2 documented the spatial extent of the 8.2 ka event and suggested the need for data in the tropical regions of the Southern Hemisphere (SH). A multi-proxy approach using stalagmites, one of the most useful and reliable terrestrial archives, from NW Madagascar revealed a strong signal that parallels the 8.2 signals in the Greenland records. Stable isotopes of oxygen, stable isotopes of carbon, and mineral distribution in the stalagmite combine to suggest wet conditions in NW Madagascar during the 8.2 ka event. This wet condition could be ascribed to the southward migration of the ITCZ, which is believed to have been triggered by weakening of the Atlantic Meridional Overturning Circulation (AMOC). That weakening was linked to an abrupt influx of freshwater from the melting Laurentide ice sheet into the North Atlantic 1. This alteration of the AMOC led to cooling in the NH regions and warming in the SH regions 3. Because the ITCZ migrates from a cold to a warmer hemisphere 4 , the temperature difference between the NH and SH suggest a southward migration of the ITCZ, thus regions in the SH such as Madagascar became wetter. Having such new information from Madagascar could improve the spatial resolution of the 8.2 ka event, and this is useful to test climate models, and this could also be useful to refine future climate predictions.
... Techniques in which landscape features were used in hunting also occurred in the Upper Pleistocene. At the 77 ka open-air site #Gi in the Kalahari, MSA points are associated with significant quantities of zebra and extinct hartebeest teeth and this likely indicates an area where prey was ambushed at the margins of the lake (Robbins et al., 2023). A dense concentration of extinct wildebeest-like remains with butchery marks and lithics at Bovid Hill, Kenya, dating to around 70 ka, also suggests tactical hunting (Thompson et al., 2023a). ...
August 2023
... Strong similarities are evident in the stable nitrogen isotope records (interpreted as a reflection of water availability) from middens recovered from Aba Huab/Austerlitz , Spitzkoppe (Chase et al., 2009(Chase et al., , 2019, Zizou (Chase et al., 2019), and Pella (Chase et al., 2019), indicating a generally common climate response signal across a 900-km transect of the Namib Desert (Fig. 1). Evidence of associated changes in vegetation, however, is often restricted to the Holocene (Scott et al., 1991(Scott et al., , 2022Scott, 1996;Gil-Romera et al., 2006, with the only indications of glacial-age vegetation coming from the continuous 50-kyr record from Pella (Lim et al., 2016), and shorter MIS 2-3 time slices from the Brandberg (Scott et al., 2004) and Mirabib (Scott et al., 2018). While each record expresses changes specific to its environmental context, evidence from all of these sites contrasts markedly with pollen records recovered from marine cores off the coast of Namibia (Shi et al., 2000(Shi et al., , 2001Urrego et al., 2015). ...
August 2022
Review of Palaeobotany and Palynology
... The flickering wet-dry events prior to major climate transitions, which seem to recur throughout the~620 kyr Chew Bahir record, combined with the HadCM3 modeling results presented here, confirm the existence of precursor events prior to a tipping point, previously predicted only in theory. data sets showing excursions at the termination and flickering during the AHP include a lake record from Lake Dendi 33 , a lake record from Lake Abiyata 34 , and a record from Congo stalagmites 35 . The discovery of flickering prior to and during the transition from wet to dry conditions in Africa has significant implications for interpreting the relationship between climate change, cultural developments, and human migrations in those regions. ...
June 2022
Quaternary Science Reviews
... Presentan un frente casi vertical, muy cuarteado, con numerosos fragmentos de roca al pie y un faldeo que se prolonga suavemente hacia el centro del cañadón, desembocando en un pequeño arroyo. Se encuentra aproximadamente 40 km al oeste del extremo sur del Macizo del Deseado, donde se localizaron ocupaciones humanas discontinuas comprendidas entre la transición Pleistoceno-Holoceno y el Holoceno tardío (Brook et al. 2018;Franco et al. 2010Franco et al. , 2020, y a unos 45 km de los espacios al aire libre de 17 de Marzo (Fig. 1), en los que la ocupación humana ha sido datada en el Holoceno tardío . ...
April 2020
Revista del Museo de La Plata
... There is therefore a compelling need to understand drought, and rainfall variability in general, at the Mid-to Late-Holocene transition, along with any potential association with the 4.2 ka event and societal change. This is particularly true in the tropics and southern hemisphere where there have been only a few detailed studies (Marchant and Hooghiemstra, 2004;Railsback et al., 2018Railsback et al., , 2022. In the tropics, there may be conflation of the 4.2 ka event and what is now a widely recognised shift in tropical climate at 4.0 kyr BP (Denniston et al., 2013;Gagan et al., 2004;Giosan et al., 2018;Li et al., 2018;MacDonald, 2011;Marchant and Hooghiemstra, 2004;Toth and Aronson, 2019). ...
November 2021
Palaeogeography Palaeoclimatology Palaeoecology
... Outcropping salt karst has been reported from the Mt. Sedom diapir in Israel (Frumkin, 1994a(Frumkin, , 1994b(Frumkin, , 1998Frumkin and Ford, 1995), the Cordillera de la Sal Mts., Atacama, Chile (De Waele et al., 2020), the Cardona diapir in Spain (Lucha et al., 2008), and the Vrancea Hills in Romania (Giurgiu, 2005). The most extensive outcropping salt karst occurs in the Zagros Mts. and along the Persian Gulf in southern and southwestern Iran (Bruthans et al., 2010;Abirifard et al., 2017). ...
August 2020
Geomorphology
... ka BP (Burney, 1987a(Burney, , 1987cStraka, 1996). Similar trends have been recorded almost across the entire island, for instance in the Southwest (Razanatsoa et al., 2022), and in the Northwest suggesting climate and human activities (Railsback et al., 2020;Voarintsoa et al., 2017a) as drivers. ...
April 2020
Quaternary Science Reviews
... No obstante, se pueden reconocer sectores con mayor abundancia de elementos cerámicos que otros. Entre éstos, cabe señalar los espacios localizados al NE costero y NW pericordillerano de la provincia de Santa Cruz, incluyendo la porción chilena, al este de la cordillera de los Andes (Cassiodoro & Tchilinguirian, 2007;Chaile et al. 2020;Cirigliano et al. 2019 y citas allí incluidas; Mena & Jackson, 1991;Roumec et al. 2020;Zilio et al. 2018; entre otros). La frecuencia de este registro es menor en los espacios localizados al sur del río Santa Cruz (Martinic & Prieto, 1998), donde sólo se identificaron elementos cerámicos en muy pocos sectores. ...
December 2019
Magallania (Punta Arenas)
... Early reconstructions of palaeoclimatic conditions during the Holocene in the Namib Desert and surroundings were based on microfaunal studies, geomorphological research and radiocarbon dating of inclusions in riverine deposits and dunes (e.g., Brain and Brain, 1977;Heine, 1982;Vogel and Rust, 1987;Lancaster and Teller, 1988;Vogel, 1989), followed by studies on Atlantic Ocean pollen from marine boreholes (Fig. 1), dust geochemistry, isotopes and micropalaeontology (Scott et al., 1991;Shi et al., 1998Shi et al., , 2000Shi et al., , 2001Stuut et al., 2002;Farmer et al., 2005;Dupont et al., 2008) and terrestrial records like stalagmites, geomorphology, and archaeology (e.g., Stokes et al., 1997;Stute and Talma, 1998;Brook et al., 1999Brook et al., , 2011Brook et al., , 2015Thomas and Shaw, 2002;Eitel et al., 2005;Heine, 2005;Srivastava et al., 2005;Chase et al., 2009Chase et al., , 2011Thomas and Burrough, 2012;Sletten et al., 2013;Marais et al., 2015;Railsback et al., 2016Railsback et al., , 2018Railsback et al., , 2019Voarintsoa et al., 2017;Kinahan, 2018;Schüller et al., 2018). These studies have added critical information on past hydrological regimes of southern Africa, especially rainfall ( Fig. 1), which is one of the major shifting climate features in the subcontinent. ...
August 2019
Palaeogeography Palaeoclimatology Palaeoecology
... Testimonian la colonización temprana por Homo sapiens en regiones de diferentes continentes, como el sudeste asiático (Aubert et al., 2017;Standish et al., 2020), el norte de Australia (David et al., 2013;Ross et al., 2016), la región Franco-Cantábrica (Quiles et al., 2016) y el cono sur de Sudamérica, (Gradin et al., 1979;Carden y Miotti 2020) 1 . En su gran mayoría, estos motivos son el producto de prácticas desarrolladas por sociedades cazadoras-recolectoras, lo cual explica su larga perduración en Australia y la región patagónica, donde este modo de vida perduró hasta momentos de contacto con los europeos (Bradley et al., 2021;Brook et al., 2018;McDonald, 2005;Morwood, 2002;Mulvaney, 1996Mulvaney, , 2013. ...
October 2018
Journal of Archaeological Science Reports