نتایج جستجو برای: glacial period

تعداد نتایج: 500154  

2014
Joseph S. Levy Caleb I. Fassett James W. Head Claire Schwartz Jaclyn L. Watters

Glacial landforms on Mars, including concentric crater fill (CCF), lineated valley fill (LVF), and lobate debris aprons (LDA), were mapped between~±30 and 50° latitude, and geometric constraints were placed on the volume of these deposits based on their topography and relationship with host topography (e.g., massifs, valleys, and craters). LDA deposits were found to have the largest volume (2.6...

2007
D. McGee F. Marcantonio J. Lynch-Stieglitz

Atmospheric dust levels may play important roles in feedbacks linking continental source areas, tropical convection, marine productivity, and global climate. These feedbacks appear to be particularly significant in the tropical Pacific, where variations in local convection and productivity have been demonstrated to have impacts on climate at higher latitudes. Modeling of past dust levels and re...

The morphology of glacial valley can be described in terms of power law or quadratic equations fitted to valley cross-profiles. These two models are used to study the cross-profiles of 86 valley cross-profiles in the Zardkuh Mountain in order to understand the evolutional patterns of valleys. Assessment of using the power law function indicates that b values for both valley sides range from 1.0...

2005
Francisco W. Cruz Stephen J. Burns Ivo Karmann Warren D. Sharp Mathias Vuille José A. Ferrari

We present a high-resolution, 116,000-year carbon stable isotope record from a stalagmite from southern Brazil, which has been precisely dated using the U-series method. Evaluation of carbon and oxygen isotope ratios together with the speleothem growth history suggest that the carbon isotopic composition of the speleothem is primarily controlled by biogenic CO2 supply from the soil, which is in...

Journal: :Quarterly Journal of the Geological Society 1874

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