Early Pleistocene−to−present paleoclimate archive for the American Southwest from Stoneman Lake, Arizona, USA

2021 ◽  
Author(s):  
Spencer E. Staley ◽  
Peter J. Fawcett ◽  
R. Scott Anderson ◽  
Gonzalo Jiménez-Moreno
Keyword(s):  
Late Pleistocene ◽  
Climate Model ◽  
Volcanic Eruptions ◽  
American Southwest ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Future Climate Change ◽  
Radiocarbon Dates ◽  
Middle And Late Pleistocene ◽  
Natural Climate

Long, continuous records of terrestrial paleoclimate offer insights into natural climate variability and provide context for geomorphological studies, climate model reconstructions, and predictions of future climate change. STL14 is an 80 m lacustrine sediment core that archives paleoenvironmental changes at Stoneman Lake, Coconino County, Arizona, from the early Pleistocene (ca. 1.3 Ma) to present. Full-core sedimentology was analyzed using smear slides and core face observations. Lithofacies strongly correlate with wet bulk density and bulk magnetic susceptibility (MS), and these data resemble a sawtooth pattern characteristic of glacial-interglacial climate cycles. A linkage between deep to shallow lake depth transitions and glacial terminations is supported by an age model that incorporates accelerator mass spectrometry radiocarbon dates and tephrochronology of ashes from the Lava Creek B and multiple Long Valley, California, volcanic eruptions. We correlated middle and late Pleistocene glacial maxima to deep lake deposits defined by well-preserved bedding, increased biosilica, boreal pollen taxa (i.e., Picea), and lower density and MS. Interglacial periods are associated with shallow-water deposits characterized by banded-to-massive siliciclastic material, some authigenic calcite, the alga Phacotus, and higher density and MS. Prior to the marine isotope stage (MIS) 24−22 interval, smaller-amplitude changes in the lake environment suggest milder glacial conditions compared to those of the middle and late Pleistocene. Thus, abrupt intensification of glacial conditions may have occurred ca. 900 ka in the American Southwest, mirroring a global characteristic of the mid-Pleistocene transition. The STL14 record suggests that lake environments throughout the history of this small (3.5 km2), internally drained, basaltic catchment are sensitive to the regional hydrologic balance, which, at orbital time scales, is largely influenced by the northern cryosphere and associated changes in atmospheric circulation. The predominance of quartz in sediment throughout the record indicates significant eolian inputs. Few paleoclimate records from this region extend beyond the last glacial cycle, let alone the middle Pleistocene, making STL14 a valuable resource for studying environmental responses to a range of natural climate states and transitions throughout much of the Quaternary.

Bayesian analysis of sea-level sensitivity to CO2 forcing across the mid-Pleistocene transition: possible implications for early-Pleistocene ice-sheet extent

2021 ◽  
Author(s):  
Parker Liautaud ◽  
Peter Huybers
Keyword(s):  
Energy Balance ◽  
Bayesian Analysis ◽  
Sea Level ◽  
Late Pleistocene ◽  
Radiative Forcing ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Model Parameters

<p><span>Foregoing studies have found that sea-level transitioned to becoming approximately twice as sensitive to CO</span><span><sub>2</sub></span><span> radiative forcing between the early and late Pleistocene (Chalk et al., 2017; Dyez et al., 2018). In this study we analyze the relationships among sea-level, orbital variations, and CO</span><span><sub>2</sub></span><span> observations in a time-dependent, zonally-averaged energy balance model having a simple ice sheet. Probability distributions for model parameters are inferred using a hierarchical Bayesian method representing model and data uncertainties, including those arising from uncertain geological age models. We find that well-established nonlinearities in the climate system can explain sea-level becoming 2.5x (2.1x - 4.5x) more sensitive to radiative forcing between 2 and 0 Ma. Denial-of-mechanism experiments show that the increase in sensitivity is diminished by 36% (31% - 39%) if omitting geometric effects associated with thickening of a larger ice sheet, by 81% (73% - 92%) if omitting the ice-albedo feedback, and by more than 96% (93% - 98%) if omitting both. We also show that prescribing a fixed sea-level age model leads to different inferences of ice-sheet dimension, planetary albedo, and lags in the response to radiative forcing than if using a more complete approach in which sea-level ages are jointly inferred with model physics. Consistency of the model ice-sheet with geologic constraints on the southern terminus of the Laurentide ice sheet can be obtained by prescribing lower basal shear stress during the early Pleistocene, but such more-expansive ice sheets imply lower CO</span><span><sub>2</sub></span><span> levels than would an ice-sheet having the same aspect ratio as in the late Pleistocene, exacerbating disagreements with </span><span>𝛿</span><span><sup>11</sup></span><span>B-derived CO</span><span><sub>2</sub></span><span> estimates. These results raise a number of possibilities, including that (1) geologic evidence for expansive early-Pleistocene ice sheets represents only intermittent and spatially-limited ice-margin advances, (2) </span><span>𝛿</span><span><sup>11</sup></span><span>B-derived CO</span><span><sub>2</sub></span><span> reconstructions are biased high, or (3) that another component of the global energy balance system, such as the average ice albedo or a process not included in our model, also changed through the middle Pleistocene. Future work will seek to better constrain early-Pleistocene CO</span><span><sub>2</sub></span><span> levels by way of a more complete incorporation of proxy uncertainties and biases into the Bayesian analysis.</span></p>

scholarly journals A Long-Term Record of Quaternary Facies Patterns and Palaeonvironmental Trends from the Po Plain (NE Italy) as Revealed by Bio-Sedimentary Data

Geosciences ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 401
Author(s):  
Veronica Rossi ◽  
Alessandro Amorosi ◽  
Giulia Barbieri ◽  
Stefano Claudio Vaiani ◽  
Matteo Germano ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Middle Pleistocene ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Environmental Response ◽  
Alluvial Deposits ◽  
Po Plain ◽  
Ne Italy ◽  
Coastal Marine

Understanding Quaternary dynamics of delta-coastal plains across multiple glacial-interglacial cycles in the Milankovitch band (~100 kyrs) is crucial to achieve a robust evaluation of possible environmental response to future climate-change scenarios. In this work, we document the long-term bio-sedimentary record of core 204 S16 (~205 m long), which covers a wide portion of the post-MPR (Mid-Pleistocene Revolution) interval, taking advantage of the highly subsiding context of the SE Po Plain (NE Italy). Detailed facies characterization through an integrated sedimentological and meiofauna (benthic foraminifers and ostracods) approach allowed for the identification of a repetitive pattern of alluvial deposits alternating with four fossiliferous, paralic to shallow-marine units (Units 1–4). The transgressive surfaces identified at the base of these units mark major flooding events, forced by Holocene (Unit 4), Late Pleistocene (Unit 3) and Middle Pleistocene (Units 1, 2) interglacials. Distinct stratigraphic patterns typify the Middle Pleistocene interval, which includes coastal-marine (tidal inlet and bay) deposits. In contrast, lagoonal sediments record the maximum marine influence in the Late Pleistocene-Holocene succession. As a whole, the meiofauna tracks a regressive trend, with the deepest conditions recorded by the oldest Unit 1 (MIS 9/11 age?).

scholarly journals Historical biogeography of the leopard (Panthera pardus) and its extinct Eurasian populations

2018 ◽  
Author(s):  
Johanna L.A. Paijmans ◽  
Axel Barlow ◽  
Daniel W. Förster ◽  
Kirstin Henneberger ◽  
Matthias Meyer ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Dna Sequences ◽  
Sister Group ◽  
Historical Biogeography ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Recent Common Ancestor ◽  
Panthera Pardus ◽  
Phylogenetic Placement ◽  
Out Of Africa

AbstractBackgroundResolving the historical biogeography of the leopard(Panthera pardus)is a complex issue, because patterns inferred from fossils and from molecular data lack congruence. Fossil evidence supports an African origin, and suggests that leopards were already present in Eurasia during the Early Pleistocene. Analysis of DNA sequences however, suggests a more recent, Middle Pleistocene shared ancestry of Asian and African leopards. These contrasting patterns led researchers to propose a two-stage hypothesis of leopard dispersal out of Africa: an initial Early Pleistocene colonisation of Asia and a subsequent replacement by a second colonisation wave during the Middle Pleistocene. The status of Late Pleistocene European leopards within this scenario is unclear: were these populations remnants of the first dispersal, or do the last surviving European leopards share more recent ancestry with their African counterparts?ResultsIn this study, we generate and analyse mitogenome sequences from historical samples that span the entire modern leopard distribution, as well as from Late Pleistocene remains. We find a deep bifurcation between African and Eurasian mitochondrial lineages (∼710 Ka), with the European ancient samples as sister to all Asian lineages (∼483 Ka). The modern and historical mainland Asian lineages share a relatively recent common ancestor (∼122 Ka), and we find one Javan sample nested within these.ConclusionsThe phylogenetic placement of the ancient European leopard as sister group to Asian leopards suggests that these populations originate from the same out-of-Africa dispersal which founded the Asian lineages. The coalescence time found for the mitochondrial lineages aligns well with the earliest undisputed fossils in Eurasia, and thus encourages a re-evaluation of the identification of the much older putative leopard fossils from the region. The relatively recent ancestry of all mainland Asian leopard lineages suggests that these populations underwent a severe population bottleneck during the Pleistocene. Finally, although only based on a single sample, the unexpected phylogenetic placement of the Javan leopard could be interpreted as evidence for exchange of mitochondrial lineages between Java and mainland Asia, calling for further investigation into the evolutionary history of this subspecies.

Biostratigraphic Correlation of Pleistocene Marine Deposits and Sea Levels, Atlantic Coastal Plain of the Southeastern United States

1980 ◽  
Vol 13 (2) ◽  
pp. 213-229 ◽  
Author(s):  
Thomas M. Cronin
Keyword(s):  
North Carolina ◽  
South Carolina ◽  
Sea Level ◽  
Late Pleistocene ◽  
Coastal Plain ◽  
Atlantic Coastal Plain ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Sea Levels ◽  
Atlantic Coastal

AbstractMarine ostracodes from 50 localities were studied to determine the age and elevation of Pleistocene sea levels in the Atlantic coastal plain from Maryland to northern Florida. Using ostracode taxon and concurrent ranges, published planktic biostratigraphic, paleomagnetic, and radiometric data, ostracode assemblage zones representing early (1.8-1.0 my), middle (0.7-0.4 my), and late (0.3-0.01 my) Pleistocene deposition were recognized and used as a basis for correlation. Ostracode biofacies signifying lagoonal, oyster bank, estuarine, open sound, and inner sublittoral environments provided estimated ranges of paleodepths for each locality. From these data the following minimum and maximum Pleistocene sea-level estimates were determined for the southeastern coastal plain: late Pleistocene, 2–10 m from Maryland to northern Florida; middle Pleistocene, 6–15 m in northern South Carolina; early Pleistocene, 4–22 m in central North Carolina, 13–35 m in southern North Carolina, and 6–27 m in South Carolina. Climatically induced glacio-eustatic sea-level fluctuations adequately account for the late Pleistocene sea-level data, but other factors, possibly differential crustal uplift, may have complicated the early Pleistocene record.

Into the Woods Early Homo sapiens and Tropical Forest Colonization

2019 ◽  
Author(s):  
Patrick Roberts
Keyword(s):  
Tropical Forests ◽  
Late Pleistocene ◽  
Homo Sapiens ◽  
Homo Erectus ◽  
Rapid Expansion ◽  
Early Pleistocene ◽  
Human Populations ◽  
Tropical Regions ◽  
Early Homo ◽  
Middle And Late Pleistocene

Popular philosophical associations of tropical forests, and forests in general, with an inherent ancestral state, away from the stresses, pollution, and technosphere of modern life, are nicely summarized by Murakami’s quote above (2002). Given the probable origins of the hominin clade in tropical forests, this quote is also apt from an evolutionary standpoint. Yet, somewhat surprisingly, tropical forests have frequently been considered impenetrable barriers to the global migration of Homo sapiens (Gamble, 1993; Finlayson, 2014). As was the case with the focus on ‘savannastan’ in facilitating the Early Pleistocene expansion of Homo erectus discussed in Chapter 3 (Dennell and Roebroeks, 2005), the movement of H. sapiens into tropical regions such as South Asia, Southeast Asia, and Australia has tended to be linked to Late Pleistocene periods when forests contracted and grasslands expanded (Bird et al., 2005; Boivin et al., 2013). Alternative narratives have focused on the importance of coastal adaptations as providing a rich source of protein and driving cultural and technological complexity, as well as mobility, in human populations during the Middle and Late Pleistocene (Mellars, 2006; Marean, 2016). The evidence of early art and symbolism at coastal cave sites such as Blombos in South Africa (Henshilwood et al., 2002, 2011; Vanhaeren et al., 2013) and Taforalt in North Africa (Bouzouggar et al., 2007) is often used to emphasize the role of marine habitats in the earliest cultural emergence of our species. Indeed, for the last decade, the pursuit of rich marine resources (Mellars, 2005, 2006) has been a popular explanation for the supposed rapidity of the ‘southern dispersal route’, whereby humans left Africa 60 ka, based on genetic information (e.g., Macaulay et al., 2005), to reach the Pleistocene landmass that connected Australia and New Guinea (Sahul) by c. 65 ka (Clarkson et al., 2017). In both of these cases, the coast or expanses of grassland have been seen as homogeneous corridors, facilitating rapid expansion without novel adaptation.

scholarly journals Long-term landscape evolution of the Molise sector of the central-southern Apennines, Italy

2017 ◽  
Vol 68 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Vincenzo Amato ◽  
Pietro P.C. Aucelli ◽  
Vito Bracone ◽  
Massimo Cesarano ◽  
Carmen Maria Rosskopf
Keyword(s):  
Late Pleistocene ◽  
Landscape Evolution ◽  
Temporal Distribution ◽  
Structural Data ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Southern Apennines ◽  
Geomorphological Evolution ◽  
Present Setting

AbstractThis paper concerns the reconstruction of the main stages of the long-term landscape evolution of the Molise portion of the central-southern Apennines along a transect divided into three sectors (SW, Central and NE). Analysis mainly focused on geomorphological, stratigraphical and structural data supported by chronological constraints, coming from an overall review of past literature and several studies carried out by the authors of the paper during the last 20 years. The results obtained allowed the elaboration of a conceptual model of the long-term evolution of the Molise sector of the central-southern Apennines. Starting from the Pliocene, the emersion of the Molise area occurred gradually from SW to NE, allowing a polycyclic landscape to evolve under the major controls first of compression then transtensional to extensional tectonics as well as climatic variations. Principal markers of the Quaternary geomorphological evolution of the Molise area are represented by the infill successions of the intermontane tectonic depressions located in its internal, SW sector and by four orders of palaeosurfaces that developed between the Early Pleistocene and the beginning of the Late Pleistocene across the region. These markers testify to the alternation of phases of substantial tectonic stability and uplift whose spatial-temporal distribution could be assessed along the investigated transect. Results highlight that the most important stages of landscape evolution occurred during the Early and Middle Pleistocene. At the beginning of the Late Pleistocene, the Molise sector of the Apennine chain had already reached its present setting and further landscape evolution occurred under the major control of climate and land-use.

scholarly journals Late Pleistocene age and archaeological context for the hominin calvaria from GvJm-22 (Lukenya Hill, Kenya)

2015 ◽  
Vol 112 (9) ◽  
pp. 2682-2687 ◽  
Author(s):  
Christian A. Tryon ◽  
Isabelle Crevecoeur ◽  
J. Tyler Faith ◽  
Ravid Ekshtain ◽  
Joelle Nivens ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Homo Sapiens ◽  
Morphological Variability ◽  
Modern Human ◽  
Middle Stone Age ◽  
Upper Paleolithic ◽  
Stone Age ◽  
Radiocarbon Dates ◽  
Middle And Late Pleistocene ◽  
Age Range

Kenya National Museums Lukenya Hill Hominid 1 (KNM-LH 1) is a Homo sapiens partial calvaria from site GvJm-22 at Lukenya Hill, Kenya, associated with Later Stone Age (LSA) archaeological deposits. KNM-LH 1 is securely dated to the Late Pleistocene, and samples a time and region important for understanding the origins of modern human diversity. A revised chronology based on 26 accelerator mass spectrometry radiocarbon dates on ostrich eggshells indicates an age range of 23,576–22,887 y B.P. for KNM-LH 1, confirming prior attribution to the Last Glacial Maximum. Additional dates extend the maximum age for archaeological deposits at GvJm-22 to >46,000 y B.P. (>46 kya). These dates are consistent with new analyses identifying both Middle Stone Age and LSA lithic technologies at the site, making GvJm-22 a rare eastern African record of major human behavioral shifts during the Late Pleistocene. Comparative morphometric analyses of the KNM-LH 1 cranium document the temporal and spatial complexity of early modern human morphological variability. Features of cranial shape distinguish KNM-LH 1 and other Middle and Late Pleistocene African fossils from crania of recent Africans and samples from Holocene LSA and European Upper Paleolithic sites.

scholarly journals ABOUT THE REASONS OF CLIMATE WARMING BASED ON STUDYING THE HISTORY OF QUATERNARY GLACIOSES OF THE CAUCASUS (ON THE EXAMPLE OF THE INTERDURCHIE TEREK AND THE ANDIAN KOISU)

2020 ◽  
Vol 12 (3) ◽  
pp. 461-471
Author(s):  
Valeriy DOTSENKO ◽  
◽  
Ibragim KERIMOV ◽  
Keyword(s):  
Climate Change ◽  
Late Pleistocene ◽  
Volcanic Activity ◽  
Late Holocene ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
The Caucasus ◽  
Late Pliocene ◽  
Climate Fluctuations ◽  
Greater Caucasus

The Greater Caucasus experienced repeated glaciation during the Quaternary (early, middle, upper Pleistocene, late Glacial, and late Holocene), which occurred under changing climatic conditions and differentiated tectonic movements. These glaciations, of course, are associated with changes in terrain, the formation of new deposits, transgressions and regressions of the Caspian Sea, changes in vegetation and soil types, so the problem of glaciation affects all earth Sciences to varying degrees. The study of Quaternary glaciation, especially Holocene glaciation, is currently relevant for understanding climate change. Against the background of significant climate fluctuations within the epochs of glaciation, there are smaller cooling phases that cause the temporary onset of glaciers. Short-term climate fluctuations are manifested in oscillations – minor fluctuations in the languages of glaciers. All this indicates that the climate undergoes significant changes in a short time, which are reflected in the morphosculpture of the terrain, the latest deposits and modern precipitation. Glaciation of the Greater Caucasus in the Prikazbeksky region reached its maximum in the middle Pleistocene,when glaciers went far into the Ossetian basin. All these traces have been preserved due to the lower capacity of the Chanty-Argun glacier and its fluvioglacial flow, which developed during the late Pleistocene epoch. Volcanic activity, especially active in the late Pliocene and continuing up to the present time, is associated with the late horn stage of development of the Caucasus. The formation of the Rukhs-Dzuar molass formation more than 2 km thick in the late Pleistocene in the Ossetian basin of the Tersky-Caspian flexure is associated with the activity of volcanoes in the Kazbek volcanic region. In the early Pleistocene, volcanic activity on the BC decreased significantly. The most intense outbreak of volcanism in the Kazbek and Elbrus volcanic regions occurred at the beginning of the late Pleistocene, which roughly coincided with the maximum phase of the late Pleistocene (Bezengian) glaciation. Then, in the second half of the late Pleistocene, volcanic activity was manifested on the mount Kazbek. The last outbreak of volcanic activity occurred in the Holocene no more than 2-3 thousand years ago. Fresh lavas are available on Elbrus, Kazbek, in the Terek valley near villages. Sioni and on the Kel volcanic plateau. Fumarolic activity still continues on Elbrus. Thus, in the Kazbek region, eruptions occurred from the late Pliocene to the late Holocene inclusive. Keywords: Pleistocene, Holocene, glaciation stages, nival-glacial processes, causes of glaciations, climate change, anthropogenic factors, natural factors, Earth degassing, magmatogenic degassing branch, seismotectonic degassing branch, greenhouse gases, newest geodynamics, volcanism, mud regimes, volcanism, methane hydrates, land degradation, water reclamation.

scholarly journals Quaternary terraces of the Želivka River

Geografie ◽  
2010 ◽  
Vol 115 (2) ◽  
pp. 113-130
Author(s):  
Břetislav Balatka ◽  
Jan Kalvoda
Keyword(s):  
Late Pleistocene ◽  
Bohemian Massif ◽  
Early Pleistocene ◽  
Fluvial Sediments ◽  
Entire System ◽  
River Terraces ◽  
Genetic Interpretation ◽  
Neogene Sediments ◽  
Middle And Late Pleistocene ◽  
Geomorphological Analysis

This article presents the results of a geomorphological analysis of localities of Quaternary river terraces along the Želivka River and its historical-genetic interpretation in light of the formation of the Sázava terrace system. In addition, the morphogenetic characteristics of the Želivka Valley are presented and the fluvial sediments and terrace system of its river are described, including a chronostratigraphic correlation with other river terraces of the Bohemian Massif. Situational data concerning the Neogene sediments and Quarternary terraces of the Želivka River, including correlation with the Sázava River’s terrace system, are presented in Table 1. In accordance with current Quaternary stratigraphic classification, the entire system of terraces along both the Želivka and Sázava Rivers corresponds mainly with the Middle and Late Pleistocene, since the Cromerian Complex up to the Weichsel periods. The erosion phase previous to the accumulation of the first terrace in the Želivka and Sázava valleys belongs to the end of the Early Pleistocene. Older levels of fluvial sediments in the studied area, which are situated in a higher morphological position and which had previously been classified as Pliocene, have, therefore, been stratigraphically shifted into the Early Pleistocene.

Increased sea-level sensitivity to CO2 forcing across the Middle Pleistocene Transition from ice-albedo and ice-volume nonlinearities

2021 ◽  
pp. 1
Author(s):  
Parker Liautaud ◽  
Peter Huybers
Keyword(s):  
Sea Level ◽  
Late Pleistocene ◽  
Radiative Forcing ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Early Pleistocene ◽  
Balance Model ◽  
Middle Pleistocene ◽  
Model Parameters ◽  
The Past

AbstractProxy reconstructions indicate that sea level responded more sensitively to CO2 radiative forcing in the late Pleistocene than in the early Pleistocene, a transition that was proposed to arise from changes in ice-sheet dynamics. In this study we analyse the links between sea level, orbital variations, and CO2 using an energy-balance model having a simple ice sheet. Model parameters, including for age models, are inferred over the late Pleistocene using a hierarchical Bayesian method, and the inferred relationships are used to evaluate CO2 levels over the past 2 My in relation to sea level. Early-Pleistocene model CO2 averages 246 ppm (244 ppm - 249 ppm 95% c.i.) across 2-1 Ma and indicates that sea level was less sensitive to radiative forcing than in the late Pleistocene, consistent with foregoing δ11B-derived estimates. Weaker early-Pleistocene sea-level sensitivity originates from a weaker ice-albedo feedback and the fact that smaller ice sheets are thinner, absent changes over time in model equations or parameters. An alternative scenario involving thin and expansive early-Pleistocene ice sheets, in accord with some lines of geologic evidence, implies 15 ppm lower average CO2 or ~10-15 m higher average sea level during the early Pleistocene relative to the original scenario. Our results do not rule out dynamical transitions during the middle Pleistocene, but indicate that variations in the sea-level response to CO2 forcing over the past 2 My can be explained on the basis of nonlinearities associated with ice-albedo feedbacks and ice-sheet geometry that are consistently present across this interval.

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