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Now showing items 81-89 of 89
Amundsen Sea sea-ice variability, atmospheric circulation, and spatial variations in snow isotopic composition from new West Antarctic firn cores
(Massachusetts Institute of Technology, 2014)
Recent work has documented dramatic changes in the West Antarctic Ice Sheet (WAIS) over the past 30 years (e.g., mass loss, glacier acceleration, surface warming) due largely to the influence of the marine environment. ...
Lithospheric dynamics of Earth's subduction zones and Martian tectonic provinces
(Massachusetts Institute of Technology, 2015)
This thesis investigates lithospheric dynamics of Earth's subduction zones and Martian tectonic provinces on multiple time scales ranging from short-term earthquake deformation to long-term tectonic loading. In Chapter 2, ...
Quantifying overwash flux in barrier systems : an example from Martha's Vineyard, Massachusetts, USA
(Massachusetts Institute of Technology, 2011)
Coastal barriers are particularly susceptible to the predicted effects of accelerated of sea-level rise and the potential for increased impacts of intense storms. Over centennial scales, barriers are maintained via overtopping ...
Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations
(Massachusetts Institute of Technology, 2012)
The Indian monsoon affects the livelihood of over one billion people. Despite the importance of climate to society, knowledge of long-term monsoon variability is limited. This thesis provides Holocene records of monsoon ...
The cobalt cycle in the tropical Pacific Ocean
(Massachusetts Institute of Technology, 2017)
Although over a dozen elements are needed to support phytoplankton growth, only a few are considered to be growth-limiting. As the central atom in vitamin B12, cobalt is crucial for metabolism, but its status as a limiting ...
The geochemistry of methane isotopologues
(Massachusetts Institute of Technology, 2017)
This thesis documents the origin, distribution, and fate of methane and several of its isotopic forms on Earth. Using observational, experimental, and theoretical approaches, I illustrate how the relative abundances of ...
The marine biogeochemistry of chromium isotopes
(Massachusetts Institute of Technology, 2018)
In the ocean, chromium (Cr) is a redox-sensitive trace metal. The reduction of Cr(VI) to Cr(III) occurs in oxygen deficient zones (ODZs), and Cr reduction in general has been identified as a significant Cr isotope fractionation ...
Geophysical and geochemical constraints on the evolution of oceanic lithosphere from formation to subduction
(Massachusetts Institute of Technology, 2017)
This thesis investigates the evolution of the oceanic lithosphere in a broad sense from formation to subduction, in a focused case at the ridge, and in a focused case proximal to subduction. In general, alteration of the ...
Spatial and temporal variability of tide-induced salt flux in a partially mixed estuary
(Massachusetts Institute of Technology, 2009)
Mechanisms for the tidal component of salt flux in the Hudson River estuary are investigated using a 3D numerical model. Variations with river discharge, fortnightly tidal forcing, and along channel variability are explored. ...