Abstract:
The chemical weathering processes of sediments in marginal seas are closely linked to global changes, yet there remains controversy regarding how their chemical weathering intensity responds to climatic and sea-level changes. Using various chemical weathering proxies (CIA, WIP, CIX, α
AlE), this study utilized the sediments of core LHSD-1 from the mud area off the Shandong Peninsula to reconstruct the chemical weathering intensity since the Last Glacial Maximum. Firstly, we corrected the influence of grain-size effects using the Al/Si ratio and found that the chemical weathering proxies in the LHSD-1 core sediments were minimally affected by provenance lithology. However, between 11.4-9.0 ka, there was a notable impact of sedimentary recycles on chemical weathering caused by the deglacial sea-level change, which was reflected by the inconsistency between CIA and WIP values. During sea-level highstand (from 7.6 ka to the present), CIA values was predominantly influenced by the East Asian monsoon, particularly during the 8.2 ka, 7.2 ka, and 4.2 ka cold events when the East Asian winter monsoons were strengthened. CIA values exhibited rapid declines, indicating the quick response of chemical weathering intensity to climatic changes in the source region. Conversely, during sea-level lowstand, weathering proxies such as CIA indicated an enhancement in chemical weathering intensity, consistent with previous research findings in equatorial continental shelves. We propose that the exposure of continental shelves caused by the lower sea level during the Last Glacial Maximum is the primary factor for enhancing chemical weathering. Consequently, we suggest that sea-level changes on glacial-interglacial timescales can influence the records of weathering proxies in marginal sediments by controlling sediment residence time. These findings hold significant implications for understanding global climatic changes and carbon cycling on glacial-interglacial timescales.