Subdivision of Late Pleistocene Moraines in the Cordillera Blanca, Peru, Based on Rock-Weathering Features, Soils, and Radiocarbon Dates

1993 ◽  
Vol 39 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Donald T. Rodbell
Keyword(s):  
Late Pleistocene ◽  
Linear Models ◽  
Rock Weathering ◽  
Radiocarbon Dates ◽  
Cordillera Blanca ◽  
Progressive Development ◽  
Ca 50 ◽  
Northern Peru ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractThe progressive development of unusual rock-weathering features and soils and minimum-limiting radiocarbon dates provide a basis for subdividing four groups of late Pleistocene moraines on the west side of the Cordillera Blanca, northern Peru (9°20′1°000′S, 77°10′-77°30′W). Boulders on the youngest late Pleistocene moraines have 10 to 14-cm-tall weathering posts; soils on these moraines yield mean profile development index (PDI) values of 0.05 ± 0.04 (±1σ). These moraines date between ca. 13,500 and 9700 ± 500 yr B.P., older than previously postulated. The next older moraines have boulders with weathering-post heights between 20 and 25 cm and soils with PDI values of 0.08 ± 0.07, and were deposited prior to 13,280 ± 190 yr B.P., probably during the last glacial maximum (marine isotope stage 2). Moraines from an older glaciation have boulders with weathering posts between 39 and 50 cm high, soils that yield PDI values of 0.21 ± 0.07, and are older than 19,700 ± 340 yr B.P. Boulders on moraines from a still older glaciation have lost ca. 50% of their above-ground volume, and have weathering posts between 62 and 70 cm high. PDI values for soils on these moraines are 0.32 ± 0.06. Linear and logarithmic models of weathering-post and soil development with time are used to estimate minimum and maximum ages for the two oldest moraine groups. Linear models suggest that the second oldest moraines are between ca. 20,500 and 46,500 yr B.P., and that the oldest moraines are between ca. 29,000 and 72,000 yr B.P. In contrast, logarithmic models suggest ages of greater than ca. 75,500 yr B.P. and greater than ca. 500,000 yr B.P., respectively.

scholarly journals New AMS Radiocarbon Dates from Late Pleistocene Mastodons and Mammoths in New York State, USA

Radiocarbon ◽  
2012 ◽  
Vol 54 (02) ◽  
pp. 275-279 ◽  
Author(s):  
Robert S Feranec ◽  
Andrew L Kozlowski
Keyword(s):  
New York ◽  
Late Pleistocene ◽  
New York State ◽  
Laurentide Ice Sheet ◽  
Radiocarbon Dates ◽  
York State ◽  
State Museum ◽  
The Last Glacial Maximum ◽  
York State Museum ◽  
The Last Glacial

During the Last Glacial Maximum (LGM) about 25,000 yr ago, the area of what is now New York State (USA) was almost entirely covered by the Laurentide Ice Sheet (LIS; Dyke et al. 2002). Subsequent habitation of this area after the melting of the LIS necessitates dispersal of fauna, and the timing of the dispersal of particular species may aid in the understanding of how the modern ecosystems of New York were assembled. Mastodons and mammoths represent the most abundant post-LGM Pleistocene megafauna recovered in New York. However, many of the specimens have not been dated. This paper presents a set of dates from bone and tooth dentine collagen of late Pleistocene mastodon (n= 7) and mammoth (n= 3) specimens housed in the Vertebrate Paleontology Collections at the New York State Museum, Albany, New York, USA.

scholarly journals New AMS Radiocarbon Dates from Late Pleistocene Mastodons and Mammoths in New York State, USA

Radiocarbon ◽  
2012 ◽  
Vol 54 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Robert S Feranec ◽  
Andrew L Kozlowski
Keyword(s):  
New York ◽  
Late Pleistocene ◽  
New York State ◽  
Laurentide Ice Sheet ◽  
Radiocarbon Dates ◽  
York State ◽  
State Museum ◽  
The Last Glacial Maximum ◽  
York State Museum ◽  
The Last Glacial

During the Last Glacial Maximum (LGM) about 25,000 yr ago, the area of what is now New York State (USA) was almost entirely covered by the Laurentide Ice Sheet (LIS; Dyke et al. 2002). Subsequent habitation of this area after the melting of the LIS necessitates dispersal of fauna, and the timing of the dispersal of particular species may aid in the understanding of how the modern ecosystems of New York were assembled. Mastodons and mammoths represent the most abundant post-LGM Pleistocene megafauna recovered in New York. However, many of the specimens have not been dated. This paper presents a set of dates from bone and tooth dentine collagen of late Pleistocene mastodon (n = 7) and mammoth (n = 3) specimens housed in the Vertebrate Paleontology Collections at the New York State Museum, Albany, New York, USA.

scholarly journals Radiocarbon Dates from the Pleistocene Fossil Deposits of Samwel Cave, Shasta County, California, USA

Radiocarbon ◽  
2007 ◽  
Vol 49 (1) ◽  
pp. 117-121 ◽  
Author(s):  
Robert S Feranec ◽  
Elizabeth A Hadly ◽  
Jessica L Blois ◽  
Anthony D Barnosky ◽  
Adina Paytan
Keyword(s):  
Last Glacial Maximum ◽  
Late Pleistocene ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
Cave Deposits ◽  
Shasta County ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Dates obtained from the collagen of 5 mammals from the fossil deposits of Samwel Cave, Shasta County, California, USA, show emplacement during the last glacial maximum. These dates support the assignment of the fauna to the late Pleistocene. The Samwel Cave deposits currently do not appear to be stratified.

Absence of Last Glacial Maximum Records in Lowland Tropical Forests

1998 ◽  
Vol 49 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Marie-Pierre Ledru ◽  
Jacques Bertaux ◽  
Abdelfettah Sifeddine ◽  
Kenitiro Suguio
Keyword(s):  
South America ◽  
Tropical Forests ◽  
Last Glacial Maximum ◽  
Sedimentation Rate ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
Pollen Records ◽  
The Last Glacial

Environmental conditions of the lowland tropical forests during the last glacial maximum (LGM) between ca 20,000 and 18,000 14C yr B.P., are reevaluated in terms of dating control and lithology analyzed in seven pollen records from South America. The reevaluation shows that probably in none of the published records are LGM sediments present or abundant. This conclusion is based on the occurrence of abrupt lithologic changes coupled with changes in sedimentation rate interpolated from radiocarbon dates. These findings suggest that the LGM was represented probably by a hiatus of several thousand years, indicative of drier climates than before or after.

Comparing a new paleomap of European loess landscapes to an atmospheric dust circulation model

2021 ◽  
Author(s):  
Janina J. (Bösken) Nett ◽  
Frank Lehmkuhl ◽  
Erik J. Schaffernicht ◽  
Stephan Pötter ◽  
Philipp Schulte ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Late Pleistocene ◽  
Circulation Model ◽  
Glacial Maximum ◽  
Source Areas ◽  
Last Glacial ◽  
Potential Source ◽  
Aeolian Sediments ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>Loess is an important archive of environmental change covering approximately 10% of the Earth’s terrestrial surface. Numerous studies have analyzed loess deposits and in particular loess-paleosol sequences. To analyze these sequences, it is important to know the spatial distribution of aeolian sediments, their location relative to potential source areas, and the geomorphology of the sink area. We investigated these aspects by compiling a new map of aeolian sediments in Europe using highly resolved geodata from 27 countries (Lehmkuhl et al., in press). To determine the most relevant factors for the European loess distribution, we further mapped potential source areas and divided the map into different facies domains. We analyzed the geomorphological and paleoenvironmental effects on the deposition and preservation of Late Pleistocene loess. Finally, the geodata-based results were compared with results obtained from high-resolved regional numerical climate-dust experiments for the Last Glacial Maximum (LGM) in Europe, which were performed with the LGM-adapted Weather Research and Forecasting model coupled with Chemistry (WRF-Chem-LGM; Schaffernicht et al., 2020).  Complementing the mapping-based findings with the WRF-Chem-LGM experiments results in an improved understanding of the Late Pleistocene loess landscape in Europe.</p><p> </p><p>References:</p><p>Lehmkuhl, F., Nett, J.J., Pötter, S., Schulte, P., Sprafke, T., Jary, Z., Antoine, P., Wacha, L., Wolf, D., Zerboni, A., Hošek, J., Marković, S.B., Obreht, I., Sümegi, P., Veres, D., Zeeden, C., Boemke, B., Schaubert, V., Viehweger, J., Hambach, U. (in press). Loess landscapes of Europe – Mapping, geomorphology, and zonal differentiation. Earth-Science Reviews. Doi: https://doi.org/10.1016/j.earscirev.2020.103496</p><p>Schaffernicht, E.J., Ludwig, P., Shao, Y., 2020. Linkage between dust cycle and loess of the last Glacial Maximum in Europe. Atmospheric Chemistry and Physics 20, 4969–4986. Doi:10.5194/acp-20-4969-2020.</p>

Quaternary Glaciations in the Río Mendoza Valley, Argentine Andes

1993 ◽  
Vol 40 (2) ◽  
pp. 150-162 ◽  
Author(s):  
Lydia E. Espizua
Keyword(s):  
Soil Profile ◽  
Fission Track ◽  
Rock Weathering ◽  
Relative Age ◽  
Glacier System ◽  
The Andes ◽  
Rock Varnish ◽  
The Last Glacial Maximum ◽  
Quaternary Glaciations ◽  
The Last Glacial

AbstractIn the Río Mendoza valley, five Pleistocene drifts and one Holocene drift are distinguished by multiple relative-age criteria, including surface-rock weathering, development of rock varnish, moraine morphology, soil-profile development, and stratigraphic relationships. Several absolute ages suggest a preliminary chronology. During the oldest (Uspallata) glaciation, a system of valley glaciers flowed 110 km from the Andean drainage divide and 80 km from Cerro Aconcagua to terminate at 1850 m. Drift of this ice advance is older than a widespread tephra dated by fission-track at 360,000 ± 36,000 yr. During the Punta de Vacas advance, ice terminated at 2350 m, while during the subsequent Penitentes advance, the glacier system ended at 2500 m. A travertine layer overlying Penitentes Drift has U-series age of 24,200 ± 2000 yr B.P. The distribution of Horcones Drift, which is inferred to represent the last glacial maximum, delimits an independent ice stream that flowed 22 km down Horcones valley to 2750 m. A later readvance (Almacenes) reached 3250 m. Confluencia Drift is considered to be Neoglacial in age and extends downvalley to 3300 m. The moraine sequence is compared with those studied by Caviedes (1972) along Río Aconcagua on the Chilean flank of the Andes.

A Hypothesis for the Sawlike Pattern of World Sea-Level Fluctuations

1985 ◽  
Vol 24 (3) ◽  
pp. 285-294 ◽  
Author(s):  
A. B. Kazanskiy
Keyword(s):  
Sea Level ◽  
Late Pleistocene ◽  
Theoretical Curve ◽  
Ocean Water ◽  
Surface Evaporation ◽  
Sea Level Fluctuations ◽  
Two Parameters ◽  
Continental Glaciation ◽  
The Last Glacial Maximum ◽  
The Last Glacial

A theory of the world's sea-level fluctuations during late Pleistocene time, based on the analysis of the general equation of the mass balance between ocean water and inland water, suggests that the exchange of water masses between the ocean and the land, where at continental glaciation periods water is stored as ice, occurs only as a result of global climatic changes. The tectonic effect is considered insignificant for late Pleistocene time. The proposed theory explains the asymmetric character and the sawlike shape of the curve of the main cycles of sea-level fluctuations. The theory also makes it possible to construct a diagram of sea-level fluctuations from the last glacial maximum to the present time. This diagram is governed by two parameters, the amount of the average “effective” evaporation from the world's ocean surface (evaporation minus rainfall) and the rate of the sea-level rise at the present time. The resulting theoretical curve agrees well with known estimates of sea level within the time span being considered. The comparison of the theoretical curve with these estimates eliminates the apparent discrepancy between data obtained by different methods: measurements of old coastline and the isotopic composition of bottom sediments.

Sedimentary conditioning of a rocky strait during the Holocene transgression: Ría de Ferrol (NW Spain)

2020 ◽  
Author(s):  
Soledad García-Gil ◽  
Víctor Cartelle ◽  
Castor Muñoz-Sobrino ◽  
Natalia Martínez-Carreño ◽  
Iria García-Moreiras
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Late Pleistocene ◽  
Nw Spain ◽  
The Holocene ◽  
Incised Valley ◽  
Sedimentary Evolution ◽  
Holocene Transgression ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>Understanding coastal responses to relative sea level rise is key to be able to plan for future changes and develop a suitable managing strategy. The sedimentary record of the Late-Pleistocene and Holocene transgression provides a natural laboratory to study the long-term changes induced in coastal landscapes by the rapid sea level rise. As sea level rises, coastal morphology continually adapts towards equilibrium changing the landscape and reshaping the distribution of sedimentary environments.<br>The Ría de Ferrol is a confined tide-dominated incised valley located in the mesotidal passive Atlantic margin of western Galicia (NW Spain).  A multidisciplinary approach was used to identify the elements of sedimentary architecture within its sedimentary record since the Last Glacial Maximum. The sedimentary evolution was reconstructed combining seismic and sedimentary facies analysis with radiocarbon, geochemical and pollen data.<br>The Ría de Ferrol is characterised by a particular morphology with a rock-incised narrow channel in the middle of the basin (the Ferrol Strait) connecting an inner shallower sector with an outer deeper sector. The inner sector is characterised by low energetic conditions and is where the main fluvial inputs occur. The outer sector is connected to the shelf.<br>The main factor influencing the sedimentary evolution of the Ría de Ferrol incised valley was Late Pleistocene and Holocene sea-level rise. However, this evolution was modulated by the antecedent morphology, particularly once the middle strait became flooded during the Holocene transgression. Three main phases of evolution are distinguished: a fluvial valley drained by a braided river system, a tide-dominated estuary and a shallow marine basin (ria).<br>During the lowstand of the Last Glacial Maximum (ca 20 kyr BP), the ria was a fluvial valley whose sediments are mainly preserved in the inner sector. Sediments cores recovered sediments from ponds and stagnant areas, dated to be older than 10790-11170 cal yr BP.<br>During the Holocene, the basin turned into a tide-dominated estuary whose facies distribution was conditioned by the strait. The strait acted as a rock-bounded tidal inlet enhancing tidal erosion and deposition at both ends, where an ebb-tidal delta and tidal sandbanks appear. At this time, extensive tidal flats occupied most of the inner sector, dissected by estuarine channels of varied dimensions. Radiocarbon data showed ages from 8610-8910 to 5760-5940 cal yr BP.<br>An erosive episode is identified after 6 cal kyr BP with the formation of a ravinement surface. Wave and tidal energy were split by the middle strait. A wave ravinement surface is identified in the outer sector, while a coetaneous tidal ravinement surface occurs in the inner sector.<br>Slow sea-level rise after ca 4 ka BP finally forced rivers to retreat to the present position, causing the dispersion of their energy and leading to the final evolution of the area into a fully marine system.</p>

Problems in the Stone Age of South-East Asia

1993 ◽  
Vol 59 ◽  
pp. 1-15 ◽  
Author(s):  
T. E. G. Reynolds
Keyword(s):  
East Asia ◽  
Late Pleistocene ◽  
Environmental Changes ◽  
Middle Pleistocene ◽  
South East Asia ◽  
Site Location ◽  
Land Area ◽  
Dominant Characteristic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Whilst research has shown many faults with the Movius scheme of a Middle Pleistocene group of Chopper/Chopping tool industries in South-East Asia, it remains a fact that pebble tool industries are still the dominant characteristic of the South-East Asian record. Exploration has now revealed hundreds of Late Pleistocene and Holocene sites in Mainland South-East Asia and these are archaeologically very different from cave sites in Europe. Further problems exist with the current nomenclature of later industries, such as the Hoabinhian and the Neolithic, for there is a large amount of overlap between such assemblages. Should such factors as economy, site location, etc. be used to assist clarification of such problems?This paper outlines some of these issues and reveals that the pebble tool tradition as it is widely known in South-East Asia is a relatively recent phenomenon dating back to the Last Glacial Maximum (LGM). A possible reason for the change from flake to pebble tool industrial types and in the visibility of sites is the environmental changes and rise in sea level which submerged over half the available land area in the region during the Late Pleistocene. An existing broad spectrum system of exploitation was likely to have been intensified as a result of this.

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