High-resolution holocene environmental changes in the thar desert, northwestern india

Area of Science:

• Paleoclimatology
• Quaternary Geology
• Indian Monsoon Studies

Background:

• The Lunkaransar dry lake in northwestern India preserves a record of past environmental conditions.
• Understanding Holocene climate variability is crucial for regional water resource management and understanding past civilizations.

Purpose of the Study:

• To reconstruct regional water table and lake level fluctuations during the Holocene.
• To correlate these changes with the southwestern Indian monsoon and assess their impact on human settlements.

Main Methods:

• Sedimentological analysis of lakebed deposits from Lunkaransar.
• Radiocarbon dating (14C yr B.P.) to establish a chronological framework.
• Interpretation of paleoenvironmental proxies to infer lake level and monsoon activity.

Main Results:

• Early Holocene lake levels were shallow and fluctuated frequently.
• A significant rise in lake levels occurred around 6300 14C yr B.P., indicating a wet phase.
• The lake desiccated around 4800 14C yr B.P., marking the end of a 1500-year wet period, followed by dune destabilization.
• The major Harappan civilization flourished in the region ~1000 years after lake desiccation, during an arid climate.

Conclusions:

• Holocene lake level changes in northwestern India were primarily driven by variations in the southwestern Indian monsoon.
• The rise and fall of the Harappan civilization were not synchronous with the lacustral (lake) phase but occurred during subsequent arid conditions.
• This study highlights the complex interplay between climate, environment, and human history in the region.