نتایج جستجو برای: glacial period

تعداد نتایج: 500154  

Journal: :Molecular ecology 2005
Christopher Irwin Smith Brian D Farrell

Pollen cores and plant and animal fossils suggest that global climate changes at the end of the last glacial period caused range expansions in organisms indigenous to the North American desert regions, but this suggestion has rarely been investigated from a population genetic perspective. In order to investigate the impact of Pleistocene climate changes and glacial/interglacial cycling on the d...

2017
Olivier Cartapanis Kazuyo Tachikawa O. E. Romero Edouard Bard

The intensity and/or extent of the northeastern Pacific Oxygen Minimum Zone (OMZ) varied in-phase with the Northern Hemisphere high latitude climate on millennial timescales during the last glacial period, indicating the occurrence of atmospheric and oceanic connections under glacial conditions. While millennial variability was reported for both the Greenland and the northern Atlantic Ocean dur...

2009
Francisco W. Cruz Xianfeng Wang Augusto Auler Mathias Vuille Stephen J. Burns Lawrence R. Edwards Ivo Karmann Hai Cheng

Paleorainfall variability on orbital and millennial time scales is discussed for the last glacial period and the Holocene, based on a multi-proxy study of speleothem records from Brazil. Oxygen isotope (δ18O) records from Botuverá and Santana caves, precisely dated by U-series methods, indicate stronger summer monsoon circulation in subtropical Brazil during periods of high summer insolation in...

2004
Gisela Winckler Robert F. Anderson Martin Stute Peter Schlosser

The cause of the 100 kyr glacial–interglacial cycles during the past 800 kyr is one of the fundamental puzzles in paleoclimatology. The widely accepted Milankovitch theory, relating earth’s climate cycles to variations in insolation caused by periodic changes in orbital parameters, has difficulties to explain the predominant 100 kyr rhythm. Although earth’s eccentricity varies with a period of ...

Journal: :Nature communications 2014
Louisa I Bradtmiller Jerry F McManus Laura F Robinson

The strength of Atlantic meridional overturning circulation is believed to affect the climate over glacial-interglacial and millennial timescales. The marine sedimentary (231)Pa/(230)Th ratio is a promising paleocirculation proxy, but local particle effects may bias individual reconstructions. Here we present new Atlantic sedimentary (231)Pa/(230)Th data from the Holocene, the last glacial maxi...

2018
Encarni Montoya Hayley F. Keen Carmen X. Luzuriaga William D. Gosling

Tropical ecosystems play a key role in many aspects of Earth system dynamics currently of global concern, including carbon sequestration and biodiversity. To accurately understand complex tropical systems it is necessary to parameterise key ecological aspects, such as rates of change (RoC), species turnover, dynamism, resilience, or stability. To obtain a long-term (>50 years) perspective on th...

2011
Michelle A. Hanson Olav B. Lian John J. Clague

Glacial Lake Missoula formed when the Purcell Trench lobe of the Cordilleran ice sheet dammed Clark Fork River in Montana during the Fraser Glaciation (marine oxygen isotope stage 2). Over a period of several thousand years, the lake repeatedly filled and drained through its ice dam, and floodwaters coursed across the landscape in eastern Washington. In this paper, we describe the stratigraphy ...

2017
Diego F. Angulo Leonardo D. Amarilla Ana M. Anton Victoria Sosa

Here we conduct research to understand the evolutionary history of a shrubby species known as Agarito (Berberis trifoliolata), an endemic species to the Chihuahuan Desert. We identify genetic signatures based on plastid DNA and AFLP markers and perform niche modelling and spatial connectivity analyses as well as niche modelling based on records in packrats to elucidate whether orogenic events s...

2013
Soon Do Hur Tseren-Ochir Soyol-Erdene Hee Jin Hwang Changhee Han Paolo Gabrielli Carlo Barbante Claude F. Boutron Sungmin Hong

[1] A record of antimony (Sb) and thallium (Tl) from the European Project for Ice Coring in Antarctica (EPICA) Dome CAntarctic ice core provides the characteristics of climate-related natural changes in concentrations and fluxes of these toxic elements over the time period back to Marine Isotope Stage 20.2, ~800 kyr B.P. A strong variability in concentrations and fluxes are observed for both el...

2007
Kathryn A. Hoppe Paul L. Koch

We used analyses of the strontium isotope (Sr/Sr) ratios of tooth enamel to reconstruct the migration patterns of fossil mammals collected along the Aucilla River in northern Florida. Specimens date to the late-glacial period and before the last glacial maximum (pre-LGM). Deer and tapir displayed low Sr/Sr ratios that were similar to the ratios of Florida environments, which suggest that these ...

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