Date of Award

6-2002

Degree Name

Master of Science

Department

Geological and Environmental Sciences

Department

Geosciences

First Advisor

Dr. R. V. Krishnamurthy

Second Advisor

Dr. Eliot Atekwana

Third Advisor

Dr. Michelle Kominz

Access Setting

Masters Thesis-Open Access

Abstract

Stable isotopes ratio of lake sediments can provide valuable environmental information. This possibility has been investigated using radiocarbon dated fossil lake sediments from the Himalayan region of Northern India. The chronology was established using Radiocarbon dating of both organic and inorganic fractions using (AMS). Inorganic ages are older than organic ages. Organic ages are expected to increase stratigraphically, however several anomalous old ages are found in the younger part of the sediments. Final chronology, determined using selected sensible ages identified two periods of sedimentation. The high sedimentation period is characterized by sedimentation rate of 0.8cm/yr and it fairly coincides with the end of the last glacial period. The low sedimentation regime has sedimentation rate of 0.04cm/yr.

Anomalous organic ages have been interpreted in terms of mixing of lake carbon pool with external carbon pool. δ18O difference between high and low sedimentation period is suggestive of 18O depleted water brought in during high sedimentation regime, which also coincides with the onset of the interglacial period.

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