Reconstruction of the Late Miocene climate record in the Himalayan foreland Basin: The impact of Himalayan uplift and monsoon dynamics

• Published in: Journal of Asian earth sciences 2025-03, Vol.280, Article 106445
• Main Authors: Chauhan, Mohd Munazir, Ali, Sajid, Singh, Birendra P., Adlakha, Vikas, Arif, Mohammad, Phartiyal, Binita, Venkateshwarlu, Mamilla, Singh Gahlaud, Sanjay Kumar
• Format: Article
• Language: English
• Subjects: Chemical weathering; Environmental magnetism; Himalayan Foreland Basin; Himalayan Upliftment; Indian monsoon system; Neogene; Stable Carbon isotope
• ISSN: 1367-9120
• DOI: 10.1016/j.jseaes.2024.106445

•The magnetic minerals indicate weathering processes in the source region.•High physical erosion from 12 Ma to 8 Ma controlled by Himalayan uplift and wet climatic conditions.•An increase in chemical weathering around 8 Ma linked with global cooling. The reconstruction of the sedimentation history of the Himalayan Foreland Basin (HFB) during the Neogene period holds great importance in unravelling the evolution of South Asian monsoon systems and establishing a link between the tectonic uplift of the Himalayas and global climate change. In this paper, we introduce the first environmental magnetic record in combination with the stable carbon isotopic composition of the previously magnetostratigraphically dated Kathgodan-Ranibagh and Tanakpur-Sukhidang sections of the HFB. The environmental magnetic parameters suggest co-existence of ferrimagnetic and antiferromagnetic minerals with variable magnetic grain size, along with δ13C values, which are used to infer the paleoclimatic evolution of the HFB during the Neogene. A relatively high values of χlf, χARM, S-ratio and other inter-parametric magnetic ratios such as χARM/χlf and χARM/SIRM indicate that the HFB sediments experienced an intense physical erosion and low chemical weathering corresponding to the Himalayan upliftment and high monsoonal rainfall from approximately 12 to 8 Ma. Subsequently, relatively low values of χlf, χARM, S-ratio and χARM/χlf and χARM/SIRM ratios suggest a decrease in physical erosion and increase in chemical weathering in the source region between ca. 8 and 4 Ma possibly associated with low monsoonal rainfall linked with global cooling. Hence, the changes in the weathering regime since ∼ 12 Ma appear to be primarily controlled by the upliftment of the Himalayan Mountain belt and global cooling.