『Abstract
Sediment samples from a 50-m-long core representing 〜100 ka of
deposition, taken from the Ganga Plain on the campus of the Indian
Institute of Technology, Kanpur, were analyzed for Sr and Nd isotope
compositions. Both 87Sr/86Sr and εNd vary significantly with depth in the core,
0.72701-0.86708 and-14.4 to -16.6, respectively, within the range
for silicate rocks of the Higher and the Lesser Himalaya. The
variations in the isotope compositions reflect variations in the
mixing proportion of sediments from the Higher and Lesser Himalaya,
the two major sediment sources to the Ganga. The opposite trends
in 87Sr/86Sr and εNd
depth profiles further confirm this hypothesis. The isotope profiles
exhibit two major excursions, ca. 20 ka and ca. 70 ka ago, coinciding
with periods of precipitation minima and larger glacial cover.
These excursions are the result of a decrease in the proportion
of sediment from the Higher Himalaya due to a decrease in monsoon
precipitation and an increase in glacial cover that are in turn
caused by lower solar insolation. This study highlights the significant
influence of climate on erosion in the Himalaya.』
Introduction
Study location and sampling
Results
Discussion
Conclusions
Acknowledgments
References cited