Onset Of MIS Research Articles

The how, when, and why of an abandoned bedrock meander of the Colorado River, Utah (U.S.)

AbstractRiver meanders entrenched into bedrock are found worldwide, and they are famously well represented in the Colorado Plateau of the southwestern U.S. Meandering of bedrock streams can eventually lead to cutting off canyon loops, and these abandoned “rincons” are locations with high preservation of fluvial deposits and landforms. We document and luminescence date the fluvial terraces in and around the Jackson Hole rincon along the Colorado River downstream of Moab, Utah. Results indicate cutoff and abandonment of the rincon at ~200 ka and also record the rapid and unsteady incision in this region over the past 300 ky. A convergence of conditions contributed to the cutoff of the rincon, including alluvial‐channel conditions at the onset of MIS 6 glacial‐climate, which provided channel‐bed cover and enhanced lateral erosion of weak strata. Also, a contemporaneous rock‐avalanche partially obstructed the paleochannel just downstream of the breach, potentially creating a backwater that further enabled a flood to avulse across the neck. Although other studies show that bedrock‐channel meandering and cutoff can generate unpaired strath terraces and short‐term increases in incision rates, these are not evident in the record at the Jackson Hole rincon. This novel case study leverages the high preservation potential within abandoned bedrock meanders to illuminate the processes and controls of rincon formation during landscape evolution.

Diversity of MIS 3 Levallois technology from Motravulapadu, Andhra Pradesh, India‐implications of MIS 3 cultural diversity in South Asia

The chronology and hominin association of the South Asian Middle Palaeolithic have attracted much attention in the last few decades. The emergence of Middle Palaeolithic culture in the region has been debated between the local origins (behavioural change) model based on an early date around 380 ka and the diffusion (biological change) model based on Homo sapiens dispersals from Africa around 120–80 ka. The latter has more consensus, whereas the former requires a more robust chronological framework to attribute the emergence of the Middle Palaeolithic to behavioural changes. In the absence of hominin remains, the presence of Middle Palaeolithic technological trajectories are frequently used as behavioural markers of Homo sapiens. Homo sapiens fossil remains from the regions between Africa and South Asia dated to ∼ 200 ka presents more convincing support for the latter model. Here we present contextual, chronological and technological analysis of Middle Palaeolithic assemblages dated to 52 ka from Motravulapadu, Andhra Pradesh, India. Morphometrical analysis of the lithic assemblage indicates diverse Levallois core reductions were practised at the site at the onset of MIS 3. Further this evidence highlights the significance of MIS 3 cultural diversity in South Asia, likely related to changing population dynamics, cultural drift, and the highly variable climatic context of MIS 3.

Behaviourally modern humans in coastal southern Africa experienced an increasingly continental climate during the transition from Marine Isotope Stage 5 to 4

Linking human technological and behavioural advances to environmental changes is challenging, as it requires a robust understanding of past climate at local scales. Here, we present results from regional high-resolution numerical simulations along with climate data directly from the archaeological sequence of Blombos Cave (BBC), a well-studied site in coastal southern Africa. The model simulations cover two distinct periods centred at 82 and 70 thousand years (ka) ago (Marine Isotope Stage [MIS] 5 and the onset of MIS 4, respectively), when orbital parameters and global sea level were markedly different from one another. Climatic changes from 82 to 70 ka are determined through four simulations that use past and present-day coastline configurations. The hydrogen isotopic composition of leaf waxes (δ2Hwax) and n-alkane distributions and abundances are used to reconstruct hydroclimate around BBC. The leaf wax n-alkane record, one of the first produced in an archaeological setting in this region to date, can be interpreted as a drying signal from MIS 5c to 4. This agrees with our modelling results, which indicate a drier and more continental climate over coastal southern Africa at 70 ka, compared to 82 ka. The simulated aridification is most evident from the reduced precipitation amounts in both summer (∼20%) and winter (∼30%). The annual number of summer days (Tmax ≥ 25 °C) and cold nights (Tmin < 5 °C) in the vicinity of BBC increases more than 5 and 3-fold, respectively, under the more continental climate at 70 ka. Weaker westerly winds in winter, a cooler Agulhas Current, and a land surface expansion associated with the coastline shift due to lower sea levels at 70 ka all contribute to the simulated climate shift. Our approach highlights the importance of multiple lines of evidence for achieving robust results, while demonstrating how both large-scale forcing and local influences worked together in shaping the local climate that early humans lived in. Adaptation to a drier climate and increased continentality around BBC might have induced greater mobility, which led to increased population interactions, cultural transmission rates, skill exchange, and material complexity during the so-called Still Bay period.

New charcoal evidence at the onset of MIS 4: First insights into fuel management and the local landscape at De Nadale cave (northeastern Italy)

Archaeological evidence of Middle Palaeolithic sites in Europe dating to MIS 4 remains very scarce compared to those belonging to previous (MIS 5) and later (MIS 3) periods. Of the few documented, a very low number have provided anthracological data reflecting the local landscape and fuel gathering strategies during MIS 4 Neanderthal occupations. This factor especially limits our knowledge of local landscape dynamics and the climatic conditions where these human occupations occurred. In this paper we contribute to this context through charcoal data from De Nadale cave, a single-layered Mousterian site located in northeastern Italy (Berici Hills area) and dated to 70.2 + 1/−0.9 ka BP. Anthracological data suggests the preferential use of spruce / larch (Picea - Larix) as firewood together with cryophilous pines (Pinus tp. sylvestris) and birch (Betula sp.) indicating prevailing harsh climatic conditions. Additional analysis focused on taphonomic features affecting charcoal point out to advance decay evidence prior to charring caused by fungi and insects. Although further data is needed, our results provide complementary information agreeing with the faunal spectrum, the small mammals assemblage and the nearby terrestrial pollen sequences

A MIS 9/MIS 8 speleothem record of hydrological variability from Macedonia (F.Y.R.O.M.)

The period corresponding to Marine Isotope Stages 9 (MIS 9) offers the opportunity to study orbital and sub-orbital scale climate variability under boundary conditions different from those of better studied intervals such as the Holocene and the Last Interglacial. Yet, it is poorly represented in independently-dated continental archives around the Mediterranean Region. Here, we present a speleothem stable isotope record (δ18O and δ13C) from the Former Yugoslavian Republic of Macedonia (F.Y.R.O.M., southern Balkans), which consists of two periods of growth broadly covering the ca. 332 to 292 ka and the ca. 264 to 248 ka intervals (MIS 9e-b and late MIS 8). We interpret the speleothem δ18O as mostly related to regional hydrology, with variations that can be interpreted as due to changes in rainfall amount, with higher/lower values associated to drier/wetter condition. This interpretation is corroborated by a change in mineralogical composition between aragonite and calcite at ca. 328 ka, which marks increasing precipitation at the onset of MIS 9 and occurs within a trend of decreasing δ18O values. Also the comparison with the multiproxy climate record available from the nearby Lake Ohrid seems to support the proposed interpretation. The MIS 9e interglacial appears to be characterized by wettest conditions between ca. 326 and 321 ka, i.e. lasting ca. 5 kyr. Decreasing precipitation and enhanced millennial scale variability matches the glacial inception (MIS9 d to b), with drier events at ca. 319 ka (ca. 2 kyr long) and 310 ka (ca. 1 kyr long), and a major rainfall reduction between 306 and 298 ka. The latter is followed by a prominent wetter period between 298 and 295 ka, for which carbon data values suggest high infiltration rate. Rainfall decreases again after 295 ka, and remain low until the growth interruption at ca. 292 ka. Resumption of the growth and progressive soil development, expressed by the carbon isotope record, occurred during the late part of MIS 8. Despite the rather high temporal uncertainty (average 6 ka), the speleothem hydrological record complements the environmental information provided by the Lake Ohrid record and also fits well to the framework of regional and extra-regional variability, showing similarities with pollen records from southern and western Europe, both at orbital and at sub-orbital time scale.

The MIS 3/2 transition in a new loess profile at Krems-Wachtberg East – A multi-methodological approach

Local to regional paleoenvironmental reactions to past climate changes are preserved in loess-paleosol sequences (LPS). In order to extract this information we used a multi-methodological approach in the Upper Paleolithic site of Krems-Wachtberg East in Lower Austria. Detailed field studies and high-resolution geochemical, colorimetric, and granulometric analyses help to understand the interplay between soil formation, loess accumulation, and surface processes. In comparison to the main profile/excavation of Krems-Wachtberg 2005–2015 it can be stated that OSL- and 14C-ages as well as the (archeological) stratigraphy of both profiles are comparable. However, pedogenic features are more evident at Krems-Wachtberg East. The new investigations show that well-established weathering indices do not clearly trace interstadial soil formation in the studied profile. Apart from this fact, single specific elements like Fe and Mg react more sensitive to initial pedogenic processes. Weak pedogenesis can further be evidenced by quantitative spectrophotometric results. The latter is also capable of refining and supporting the stratigraphy/pedology based on field analyses. As a general rule, next to loess also initial soil horizons of the MIS 3 are remarkably rich in primary carbonates indicating that soil formation took place in an alkaline environment. Due to the fact that hydrolysis of feldspars could not clearly be detected by the application of pedochemical indices, soil formation was probably limited to the oxidation of iron bearing minerals and weak carbonate leaching. These phases of favorable climatic conditions in terms of pedogenesis were terminated by increasing dust input towards the onset of MIS 2. The eolian deposits are overprinted during reducing conditions in soils and/or modified by colluvial processes. Altogether, weak pedogenesis can be reliably detected using a multi-methodological approach which leads to enhanced paleoenvironmental interpretations. The OSL-ages put the profile in a range of ∼41 to 30 ka. We present a tentative correlation of the studied loess profile to the record of the North Greenland Ice Core Project (NGRIP) for the part of the profile where OSL and 14C complement each other.

Making different things, but eating the same food? Correlation between cultural and subsistence changes during the Pleistocene-Holocene boundary in the northeastern Iberian Peninsula

The end of the Pleistocene is characterized by a succession of climatic oscillations from the onset of MIS 2. These oscillations were associated with important environmental transformations that culminated in the Pleistocene to the Holocene transition, with latter climate amelioration. However, the changes during this period are not only restricted to the environment, as important cultural transformations took place. The cultural traditions characteristics from the end of the Upper Paleolithic disappear with the emergence of the traits characteristic of the Mesolithic culture. This is clearly attested in the well-known lithic record, but also in other domains of material culture, like bone industry and art. Nevertheless, the extent to which these cultural and environmental transformations were associated with changes in subsistence strategies remains unclear, at least at the Mediterranean basin of the Iberian Peninsula. Apparently, the exploitation of faunal resources during the Mesolithic does not seem to change so much with respect to the end of the Upper Paleolithic, especially concerning the consumption of small prey.The main goal of this paper is (1) to analyze how environmental transformations could or could not intervene on the modes of life of Prehistoric populations during these transitional periods, and (2) to discuss the apparent dichotomy between cultural changes and subsistence strategies at the end of the Upper Paleolithic and the Mesolithic in northeastern Iberia. In that sense, we will include the case of the Molí del Salt site (Catalonia, Spain) as an example to explain these trends. This site has an archaeological sequence from the Upper Magdalenian to the Mesolithic, which makes it a reference place to comprehend the dynamics of human populations during this period.

The Middle Palaeolithic from Belgium: Chronostratigraphy, territorial management and culture on a mosaic of contrasting environments

The Lower and Middle Palaeolithic in Belgium are represented in 442 find-sites dispersed across a small territory with contrasting geographical and geological characteristics. The close proximity of caves and open-air sites, as well as the variable access to good sources of flint between regions are of special interest. The dataset is composed primarily of lithic assemblages, rich palaeontological and archaeozoological documentation as well as Neandertal remains from 8 cave sites. This large amount of data facilitates the development of a chronostratigraphic framework from the very beginning of the Middle Palaeolithic (onset of MIS 8) to the end (within the MIS 3, around 36 ka uncal BP). This archaeological documentation also reveals that lithic production variability is multifactorial and includes site function, cultural perspectives, and mobility patterns related to the exploitation of natural resources in contrasting environments.

A new age within MIS 7 for the Homo neanderthalensis of Saccopastore in the glacio-eustatically forced sedimentary successions of the Aniene River Valley, Rome

Field observations as well as borehole, sedimentological and geochronologic data allow us to reconstruct the geologic setting of the Aniene River Valley in northern Rome, framing it within the recently recognized picture of temporally constrained, glacio-eustatically forced aggradational successions of this region. The sedimentary successions cropping out in this area include those described in the literature of the early 20th century in Saccopastore, where two skulls of Homo neanderthalensis were recovered. Based on the geometry, elevation and sedimentologic features of the investigated sedimentary deposits, the stratigraphic record of Saccopastore is correlated with the aggradational succession deposited in response to sea-level rise during glacial termination III at the onset of MIS 7 (i.e. ∼250 ka), corresponding to the local Vitinia Formation, as opposed to previous correlation with the MIS 5 interglacial and a locally defined “Tyrrhenian” stage (∼130 ka). This previous attribution was based on the interpretation of the sedimentary succession of Saccopastore, occurring between 15 and 21 m a.s.l., as a fluvial terrace formed around 130 ka during the Riss-Würm interglacial, ca. 6 m above the present-day alluvial plain of the Aniene River. In contrast to this interpretation, a 40Ar/39Ar age of 129 ± 2 ka determined for this study on a pyroclastic-flow deposit intercalated in a fluvial-lacustrine sequence forming a terrace ∼37 m a.s.l. near the coast of Rome constrains the aggradational succession in this area to MIS 5, precluding the occurrence of an equivalent fluvial terrace at lower elevation in the inland sector of Saccopastore. We therefore interpret the stratigraphic record of Saccopastore as the basal portion of the aggradational succession deposited in response to sea-level rise during MIS 7, whose equivalent fluvial terrace occurs around 55 m a.s.l. in this region. We also review the published paleontological and paleoethnological records recovered in Saccopastore and demonstrate their compatibility with the faunal assemblages and lithic industries occurring in the sedimentary deposits of the Vitinia Formation, while we show the lack of any unequivocal Late Pleistocene (MIS 5) affinity. We therefore propose that the chronostratigraphic position of the Saccopastore deposits containing the two skulls should be around 250,000 years, as opposed to a previously preferred age of 130,000 years. The revised age makes these skulls the oldest Italian occurrences of H. neanderthalensis and provides evidence for a substantially coeval appearance and evolutionary path with respect to central-northern Europe.

Environmental interpretation of fossil insect assemblages from MIS 5 at Ziegler Reservoir, Snowmass Village, Colorado

Organic-rich lake sediments from a trench exposed at the Ziegler Reservoir fossil site near Snowmass Village, Colorado yielded a sequence of 27 insect fossil assemblages, spanning the time interval from about 125 to 77ka. The assemblages appear to represent MIS 5e, 5c, 5b, and 5a. A total of 99 taxa were identified, mostly beetles. The fossils represent the oldest known Pleistocene insect faunas from high elevation in the Rocky Mountains, and document a series of climatic oscillations from full interglacial to stadial and interstadial environments, accompanied by changes in regional biological communities. The MIS 5e fauna indicates summer temperatures similar to modern values, with winter temperatures 5–7°C cooler than today. Regional climates cooled somewhat by MIS 5c, and during MIS 5b summer temperatures were 5–6°C colder than modern values. Summer temperatures recovered to near-modern levels during early MIS 5a, and cooled by 1–2°C at its end, although winter temperatures were apparently above modern levels. The indication of milder but wetter winters, strengthened by the inclusion of species found today only in the Pacific Northwest region, suggests conditions that may have led to increased snowpack at high elevations in this part of the Rocky Mountains, linked with the onset of MIS 4 glaciation.

The latest Ursus spelaeus in Italy, a new contribution to the extinction chronology of the cave bear

The skeleton of a young prime adult cave bear, Ursus spelaeus, was found in Chiostraccio Cave (Siena, Tuscany, central Italy), only slightly buried under rock falls. The specimen was dated yielding a conventional age of 24,030±10014CyrBP (29,200–28,550calyrBP), which makes it the latest known representative of the species in Italy. The skeleton was accompanied by the remains of wolf (Canis lupus), wild boar (Sus scrofa), aurochs (Bos primigenius), red deer (Cervus elaphus), roe deer (Capreolus capreolus), bat (Vespertinus murinus), and crow (Corvus monedula). The site seems confirming that the latest Italian U. spelaeus populations shared the risk of intrusion. The association of the cave bear with other animals suggests that the assemblage is an attritional palimpsest of remains of different species not originally associated in life. Cave bears were probably more vegetarian than brown bears and possibly became extinct when plant productivity dropped at the onset of MIS 2. Central and southern Italy may have offered isolated and sheltered refugia for cave bears.

The Khormusan: Evidence for an MSA East African industry in Nubia

There is clear evidence of lithic technological variability in Middle Paleolithic (MP) assemblages along the Nile valley and in adjacent desert areas. One of the identified variants is the Khormusan, the type-site of which, Site 1017, is located north of the Nile's Second Cataract. The industry has two distinctive characteristics that set it apart from other MP industries within its vicinity. One is the use of a wide variety of raw materials; the second is an apparent correlation between raw material and technology used, suggesting a cultural aspect to raw material management. Stratigraphically, site 1017 is situated within the Dibeira-Jer formation which represents an aggradation stage of the Nile and contains sediments originating from the Ethiopian Highlands. While it has previously been suggested that the site dates to sometime before 42.5 ka, the Dibeira-Jer formation can plausibly be correlated with Nile alluvial sediments in northern Sudan recently dated to 83 ± 24 ka (MIS 5a). This stage coincides with the 81 ka age of sapropel S3, indicating higher Nile flow and stronger monsoon rainfall at these times.Other sites which reflect similar raw material variability and technological traditions are the BNS and KHS sites in the Omo Kibish Formation (Ethiopia) dated to ∼100 ka and ∼190 ka respectively. Based on a lithic comparative study conducted, it is suggested that site 1017 can be seen as representing behavioral patterns which are indicative of East African Middle Stone Age (MSA) technology, adding support to the hypothesis that the Nile Valley was an important dispersal route used by modern humans prior to the long cooling and dry trend beginning with the onset of MIS 4. Techo-typological comparison of the assemblages from the Khormusan sites with other Middle Paleolithic sites from Nubia and East Africa is used to assess the possibility of tracing the dispersal of technological traits across the landscape and through time.

Establishing a luminescence chronology for a palaeosol-loess profile at Tokaj (Hungary): A comparison of quartz OSL and polymineral IRSL signals

We present a comparative study of quartz OSL, polymineral IRSL at low temperature (50 °C, IR50) and post-IR elevated temperature (290 °C) IRSL (pIRIR290) feldspar dating on nine samples from the Tokaj loess section in NE Hungary (SE Europe). Preheat plateau tests show a drop in quartz OSL De between 160 and 240 °C but above 240 °C a clear De plateau is present. Quartz OSL SAR is shown to be generally appropriate to these samples (recycling, recuperation) but a satisfactory dose recovery result was only obtained when a dose was added to a sample without any prior optical or thermal pre-treatment; this gave a dose recovery ratio of 1.04 ± 0.05 after subtracting the natural dose from the measured dose. The pIRIR290 SAR protocol also results in acceptable dose recovery results for the pIRIR290 signal (1.08 ± 0.01) when a large dose is added to the natural dose. Bleaching experiments suggest a detectable non-bleachable residual pIRIR290 dose of 10 ± 4 Gy. Agreement with quartz OSL ages is best achieved by correcting the IR50 ages for fading; however this is not necessary when using the pIRIR290 signal. With respect to Hungarian Late Quaternary geology our results indicate that the major part of the Tokaj loess has been deposited during MIS 3 (60–24 ka), with periods of soil formation occurring during the onset of MIS 3 (≥58 ka) and between about 35 and 25 ka. Our results also indicate episodic deposition of loess and varying, non-linear sedimentation rates during MIS 3. Proxy analyses in the literature are based on the traditional concept of continuous deposition; in the light of our new data the use of such simple assumptions must be reconsidered.

Paleolithic socionatural relationships during MIS 3 and 2 in central Portugal

Throughout the Pleistocene climatic shifts repeatedly impacted the Mediterranean region. In response to these perturbations, the Mediterranean bioclimatic zones evolved as some of the most diverse, dynamic and resilient in the world. The appearance of modern humans in western Iberia ∼30–35 ka co-occurred with important environmental changes, especially regarding animal communities. These transformations are associated with the onset of MIS 2 and introduction of new land-use practices. Combined data from zooarchaeological, paleontological and paleovegetation records are used to identify patterns in human–environment interaction at different spatial and temporal scales. Evidence suggests that humans modified their environment creating long-term dynamic and resilient socionatural systems during the Upper Paleolithic.

Oscillations of the siliceous imprint in the central Benguela Upwelling System from MIS 3 through to the early Holocene: the influence of the Southern Ocean

AbstractBased on a high‐resolution analysis of the diatom signal and biogenic bulk components at site GeoB3606‐1 (25°S, off Namibia), we describe rapid palaeoceanographic changes in the Benguela Upwelling System (BUS) from early MIS 3 through to the early Holocene (55 000 to 7 000 14C yr BP). Coastal upwelling strongly varied at 25°S from MIS 3 through to MIS 2. The abrupt decrease in the accumulation rate of biogenic silica and diatoms from MIS 3 into MIS 2 records rapid oceanographic changes in the BUS off Namibia. During MIS 3, leakage of excess H4SiO4 acid from the Southern Ocean into low‐latitude surface waters, as indicated by the occurrence of Antarctic diatoms, enhanced the production of spores of Chaetoceros at the expense of calcareous phytoplankton. Furthermore, shallower Antarctic Intermediate Water (AAIW) would have enriched the thermocline off Namibia with silicate transported from the Southern Ocean. The strong decrease of the siliceous signal throughout MIS 2 represents a decrease in the nutrient input to the BUS, even though the diatom assemblage is still dominated by spores of the upwelling‐associated diatom genus Chaetoceros. Depletion of silicate in the thermocline from the onset of MIS 2 through to the early Holocene reflects the shutdown of AAIW injection from the Southern Ocean into the BUS, causing upwelled waters to become reduced in silicate, hence less favourable for diatom production. The deglaciation and early Holocene are characterised by the replacement of the upwelling‐associated flora by a non‐upwelling‐related diatom community, reflecting weakened upwelling, retraction of the seaward extension of the chlorophyll filament off Lüderitz, and dominance of warmer waters. Copyright © 2003 John Wiley & Sons, Ltd.

Variations in Calcite Dissolution Fluxes in the Equatorial Atlantic and Pacific and Evaluation of Carbonate Dissolution Due to Oxidation of Corg

To explain the glacial drop of atmospheric CO 2 it is necessary to understand the conditions for CaCO3 dissolution in the oceans. We measured high resolution profiles of 23~ normalized carbonate in pairs of cores from the Ceara Rise in the Western equatorial Atlantic and from the Ontong Java Plateau in the Western equatorial Pacific. In each case one core (GeoB 1523-1 in the Atlantic and RNDB 74P in the Pacific) is located at a depth above the lysocline and the other core (EW9209 1JPC in the Atlantic and ERDC 127P in the Pacific) at a depth below the lysocline. We then reconstructed (i) the dissolution of CaCO3 due to variations of the depth of the lysocline and (ii) the depth of the sedimentary lysocline during the last 250 kyrs. In the Atlantic we deduced an increase of the lysocline-induced carbonate dissolution during the glacials and even during some of the cooler interglacial substages. The correlation to the Southern Ocean deep water carbonate preservation index (SOPI) (Howard and Prell, 1994) suggests that during the glacials and during the glacial substages of isotope marine isotope stage five (MIS 5) a reduction in the production of NADW and/or an enhanced northern penetration of AABW occurred. On the Ontong Java Plateau we found a dissolution peak at the onset of MIS 6, as well as enhanced lysoclineinduced dissolution in MIS 5 and at the end of the MIS 4. 'Excess' carbonate dissolution takes place at all times on the seafloor even at depths lying above the calcite saturation horizon (Emerson and Bender, 1981). Dissolution has at least two causes. The first one arises from the geochemical environment (e.g. the CO 2concentration in the water column) bathing the sediments. The other one is due to the oxidation of organic matter in the sediments, as proposed by Archer and Maier-Reimer (1994). We evaluated total excess carbonate dissolution in the same way as done by Broecker and Sanyal (1997). In the Atlantic total excess CaCO3 dissolu-