Response of a dryland fluvial system to climate–tectonic perturbations during the Late Quaternary: Evidence from Rukmawati River basin, Kachchh, western India

Journal of Earth system science

Archana Das1 2²  Falguni Bhattacharya1²  Gaurav Chauhan2¹  B K Rastogi1²  M G Thakkar2¹  Mamata Ngangom2¹ 

[1] Department of Earth and Environmental Science, K.S.K.V. Kachchh University, Bhuj, Kachchh 370 001, India.$$;Institute of Seismological Research, Raisan, Gandhinagar 382 009, Gujarat, India.$$

关键词: Katrol Hill Fault;    OSL chronology;    palaeoclimate;    tectonic activity;    valley fill sediments;    Kachchh;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Dryland rivers, dominated by short-lived, localised and highly variable flow due to discrete precipitation events, have characteristic preservation potential, which serves as suitable archives towards understanding the climate–tectonic coupling. In the present study, we have investigated the fluvial records of a major, southerly-draining river – the Rukmawati River in the dryland terrain of southern Kachchh, in western India. The sediment records along the bedrock rivers of Kachchh register imprints of the Indian summer monsoon (ISM), which is the major source of moisture to the fluvial system in western India. The Rukmawati River originates from the Katrol Hill Range in the north and flows towards the south, into the Gulf of Kachchh. The field stratigraphy, sedimentology, along with the optical chronology suggeststhat a braided-meandering system existed during 37 ka period due to an overall strengthened monsoon. A gradual decline in the monsoon strength with fluctuation facilitated the development of a braided channel system between 20 and 15 ka. A renewed phase of strengthened monsoon with seasonality after around 15 ka which persisted until around 11 ka, is implicated in the development of floodplain sequences. Two zones of relatively high bedrock uplift are identified based on the geomorphometry and morphology of the fluvial landform. These zones are located in the vicinity of the North Katrol Hill Fault (NKHF) and South Katrol Hill Fault (SKHF). Geomorphic expression of high bedrock uplift is manifested by the development of beveled bedrock prior to or around 20 ka during weak monsoon. The study suggests that the terrain in the vicinity of NKHF and SKHF is uplifting at around 0.8 and >0.3 mm/a, respectively. Simultaneously, the incision in the Rukmawati River basin, post 11 ka, is ascribed to have occurred due to lowered sea level during the LGM and early Holocene period.

【 授权许可】

Unknown