نتایج جستجو برای: glacial

تعداد نتایج: 11388  

2016
Ziyu Ma Brody Sandel Jens‐Christian Svenning

How fast does biodiversity respond to climate change? The relationship of past and current climate with phylogenetic assemblage structure helps us to understand this question. Studies of angiosperm tree diversity in North America have already suggested effects of current water-energy balance and tropical niche conservatism. However, the role of glacial-interglacial climate variability remains t...

2014
Věra Pavelková Řičánková Jan Robovský Jan Riegert

Pleistocene mammalian communities display unique features which differ from present-day faunas. The paleocommunities were characterized by the extraordinarily large body size of herbivores and predators and by their unique structure consisting of species now inhabiting geographically and ecologically distinct natural zones. These features were probably the result of the unique environmental con...

2017
Sherilyn C. Fritz Paul A. Baker Geoffrey O. Seltzer Ashley Ballantyne Pedro Tapia Hai Cheng Lawrence Edwards

A 136-m-long drill core of sediments was recovered from tropical high-altitude Lake Titicaca, Bolivia-Peru, enabling a reconstruction of past climate that spans four cycles of regional glacial advance and retreat and that is estimated to extend continuously over the last 370,000 yr. Within the errors of the age model, the periods of regional glacial advance and retreat are concordant respective...

2006
LEWIS A. OWEN EDWARD DERBYSHIRE SHAUN RICHARDSON

This paper presents the first glacial chronology for the Lahul Himalaya, Northern India. The oldest glaciation, the Chandra Glacial Stage, is represented by glacially eroded benches at altitudes greater than 4300 m above sea-level. This glaciation was probably of a broad valley type. The second glaciation, the Batal Glacial Stage, is represented by highly weathered and dissected lateral moraine...

2010
A. M. de Boer A. J. Watson N. R. Edwards K. I. C. Oliver

The canonical question of which physical, chemical or biological mechanisms were responsible for oceanic uptake of atmospheric CO2 during the last glacial is yet unanswered. Insight from paleo proxies has led to a multitude of hypotheses but none so far have been convincingly supported in three dimensional numerical modelling experiments. The processes that influence the CO2 uptake and export p...

2012
Cornelya F. C. Klütsch Micheline Manseau Paul J. Wilson

Glacial refugia considerably shaped the phylogeographical structure of species and may influence intra-specific morphological, genetic, and adaptive differentiation. However, the impact of the Quaternary ice ages on the phylogeographical structure of North American temperate mammalian species is not well-studied. Here, we surveyed ~1600 individuals of the widely distributed woodland caribou (Ra...

2002
Thomas M. Marchitto Delia W. Oppo William B. Curry

[1] Benthic foraminiferal dC and Cd/Ca studies suggest that deep Atlantic circulation during the Last Glacial Maximum was very different from today, with high-nutrient (low dC, high Cd) deep Southern Ocean Water (SOW) penetrating far into the North Atlantic. However, if some glacial dC values are biased by productivity artifacts and/or air-sea exchange processes, then the existing dC data may b...

2006
W. W SHILTS

Quaternary stratigraphic units have been mapped in the Appalachian region of southeastern Quebec, and formal stratigraphic names for these units are proposed. Evidence exists for four separate glacial phases, the last three of which are represented by tills. The three tills, from oldest to youngest, have been named Johnville, Chaudiere, and Lennoxville, respectively. Stratified sediments interb...

2005
FRANK LEHMKUHL

Abundant glacial geologic evidence present throughout Tibet and the bordering mountains shows that glaciers have oscillated many times throughout the late Quaternary. Yet the timing and extent of glacial advances is still highly debated. Recent studies, however, suggest that glaciation was most extensive prior to the last glacial cycle. Furthermore, these studies show that in many regions of Ti...

Journal: :Geological Magazine 1880

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