[First Hit]

Datapages, Inc.Print this page

Abstract: Short Term Climatic Fluctuations in Previous HitAfricaNext Hit and Asia During Holocene — Review and Possible Causes.

PRASAD, SUSHMA and S.K. GUPTA, Physical Research Laboratory, Post Box No. 4218, Navrangpura, Ahmedabad, 380009, India.

A growing database for Holocene palaeoclimate from Asia and Previous HitAfricaNext Hit is increasingly indicative of the not so synchronous nature of climatic changes in different regions and the presence of short term climatic fluctuations which cannot be directly attributed to changes in orbital parameters that seem to explain the long term Quaternary palaeoclimatic changes. This study attempts to document the nature, timing and extent of these short lived events during Holocene, superimposed on the broader climatic trends in Asia and Previous HitAfricaNext Hit. Our studies indicate that (i) there may not be a major difference in the timing of onset of early Holocene wet phase in the African-Asian region. The limited data set that is presently available from S. Previous HitAfricaNext Hit only points to a slightly later onset of Holocene optimum, (ii) there does not seem to be enough evidence to indicate a systematic gradual onset of monsoon following the northward progression of the Inter Tropical Convergence Zone (ITCZ), (iii) a dry episode at ~7 ka previously documented from Previous HitAfricaNext Hit has been found to be far more widespread and also reported from India, Tibet, China and off the coast of Arabia. Other episodes of short term wet and dry phases during mid to late Holocene, in the African-Asian region, have also been found, (iv) there seems to be a difference in the record and timing of short term climatic changes from closely spaced locations, probably due to varying sensitivity of these sites which governs their response to climatic changes, (v) the time of onset of late Holocene arid try ranges from 6-3 ka BP.

Some of these events had earlier been explained as being due to gradual migration of ITCZ, variations in glacier cover and/or input of cold water pulses resulting from melting of ice. We have attempted to examine these hypotheses keeping in view the recently available high resolution palaeoclimatic data from Asia and Previous HitAfricaTop. The results of these studies will be presented.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah