نتایج جستجو برای: glacial sedimentation

تعداد نتایج: 29015  

2009
M. van Weele

It is an open question to what extent wetlands contributed 4 to the interglacial-glacial decrease in atmospheric methane concentration. 5 Here we estimate methane emissions from glacial wetlands, using newly avail-6 able PMIP2 simulations of the Last Glacial Maximum (LGM) climate from 7 coupled atmosphere-ocean and atmosphere-ocean-vegetation models. These 8 simulations apply improved boundary ...

2006
Eli Tziperman Maureen E. Raymo Peter Huybers Carl Wunsch

[1] The consequences of the hypothesis that Milankovitch forcing affects the phase (e.g., termination times) of the 100 kyr glacial cycles via a mechanism known as ‘‘nonlinear phase locking’’ are examined. Phase locking provides a mechanism by which Milankovitch forcing can act as the ‘‘pacemaker’’ of the glacial cycles. Nonlinear phase locking can determine the timing of the major deglaciation...

Journal: :Geosciences 2021

Seafloor heat flow measurements are utilized to determine the geothermal regime of Danube deep-sea fan in western Black Sea and presented larger context regional gas hydrate occurrences. Heat data were collected across paleo-channels water depths 550–1460 m. levees ranges from 25 30 mW m?2 but is up 65 on channel floors. Gravity coring reveals sediment layers typical Sea, consisting three late ...

Journal: :Quaternary Research 2022

Abstract Continuous records of sediment yield spanning from the late glacial through Holocene to present day provide an important opportunity investigate landscape evolution over various timescales in response a variety natural and anthropogenic forcing mechanisms. This study investigates variations 768 km 2 watershed Ossipee Lake, New Hampshire, USA. We pair subbottom sonar observations with a...

1999
Andrew B. G. Bush George H. Philander

Results from a coupled atmosphere-ocean general circulation model simulation of the Last Glacial Maximum reveal annual mean continental cooling between 48 and 78C over tropical landmasses, up to 268 of cooling over the Laurentide ice sheet, and a global mean temperature depression of 4.38C. The simulation incorporates glacial ice sheets, glacial land surface, reduced sea level, 21 ka orbital pa...

2014
Josep L. Pelegrí Patricia De La Fuente Roger Olivella Antonio García-Olivares

[1] Relaxation-type models have good skill at reproducing glacial-interglacial transitions in climatic variables. Here we propose a simple two-box and two-state relaxation-type model for the upper ocean (surface and permanent thermocline layers) where dissolved inorganic carbon/nutrients are supplied by the deep ocean and through remineralization within the upper ocean. The model is tuned using...

2017
XIN WANG KAIGUO CHAI SHIYIN LIU JUNFENG WEI ZONGLI JIANG QIONGHUAN LIU

Changes of glaciers and glacial lakes and their causes were examined in the Hengduan Shan from 1990 to 2014, based on Landsat TM/ETM+/OLI images. A total glacier area of 1298.8 ± 62.1 km and glacial lake area of 255.8 ± 31.6 km were inventoried in 2014. The area of glaciers declined at an average rate of −0.40 ± 0.26% a, while glacial lakes expanded at average rate of +0.12 ± 0.03% a over the p...

2003
Zhaohui Zhang Meixun Zhao Huayu Lu Anthony M. Faiia

The distribution of C3 and C4 plants changed in regionally contrasting ways during the last glacial period. C4 plant expansion in low-latitude Africa and America coincided with C4 plant decreases in Mesoamerica and the US Great Plains. This C4 plant expansion has been attributed to lower pCO2 and increased aridity and the decline in C4 plants is believed to have been caused by increased winter ...

2006
Lorraine E. Lisiecki Maureen E. Raymo

We describe the evolution of climate system dynamics by examining the climate response to changes in obliquity and precession over the last 5.3Myr. In particular, we examine changes in the shape of glacial cycles and the power of obliquity and precession response in benthic dO. When the exponential trend in dO variance is removed, its spectral power exhibits strong, proportional responses to am...

2013
Ping Fu Arjen P. Stroeven Jonathan M. Harbor Clas Hättestrand Jakob Heyman Marc W. Caffee Liping Zhou

Reconstructing the paleoglaciation of the Tibetan Plateau is critical to understanding linkages between regional climate changes and global climate changes, and herewe focus on the glacial history of the Shaluli Shan, an area of the southeastern Tibetan Plateau that receives much of its precipitation from monsoon flow. Based on field investigation, geomorphological mapping, and 10Be exposure da...

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