Abstract

The Early Late Paleocene Event (ELPE, 59.5 Ma) was a short-lived climatic perturbation accompanied by prominent biotic changes. Although the ELPE has been widely recognized from pelagic and continental archives, shallow-marine records remain scarce and poorly documented. To constrain the pattern and magnitude of the ELPE and associated environmental changes, we here present a detailed sedimentologic, biostratigraphic, and stable-carbon-isotope study of upper Paleocene platform carbonates continuously exposed in the Jiajin section of southern Tibet. Two distinct negative carbon-isotope excursions (CIEs) are documented: the first one occurred during shallow benthic zone (SBZ) 3 with a magnitude of ∼ 1.0‰, the second one began near the SBZ3–SBZ4 boundary with a magnitude of ∼ 1.5‰. Carbonate microfacies dominated by packstones with rotaliids and/or dasycladacean algae testify to an open shallow-marine environment. Neither a significant change in paleo–water depth nor evidence of early diagenetic dissolution are documented across the ELPE. The microfacies change observed during the ELPE, characterized by a decrease in the abundance of larger benthic rotaliid foraminifera relative to calcareous green algae, is related to environmental perturbations and increased nutrient supply. The changed trophic level may have resulted from intensified continental weathering promoted in turn by global warming. Compared with biocalcification crises observed in deep-water sedimentary records, shallow-water carbonate production remained relatively unaffected by changes in ocean-water chemistry.