Congruent Weathering of Continental Silicates During Warm Periods: Evidence From Lithium Isotopes in Marine Sediments
Year: 2025
Type: article
Abstract: Dissolution of secondary clay minerals during continental weathering (hereafter clay dissolution) has been proposed as a mechanism to explain some of the low seawater lithium isotopic ratios (δ 7 Li) observed in the geologic past. However, direct evidence for clay dissolution on Earth surface remains limited, and the controlling factors are poorly understood. Here, we suggest that δ 7 Li of fine sediments can serve as a proxy for clay dissolution. We analyzed δ 7 Li of the sediments from the Ocean Drilling Program site 1148, and developed a stoichiometric model to disentangle the respective contributions of source rock fragments and marine authigenic aluminosilicate clays to the sediment Li budget. Our results reveal low δ 7 Li in continentally formed clays during the warm interval of 23–15 Ma, followed by a progressive increase during 15–5 Ma, coinciding with global cooling. We suggest that warm and tectonically stable conditions might have promoted clay dissolution on continents.
Source: Geophysical Research Letters
DOI: 10.1029/2025gl119016
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,190
OpenAlex ID: W4416460246