Orbitally forced sea-level changes in the upper Turonian-lower Coniacian of the Tethyan Himalaya, southern Tibet

Based on the lithology assemblage, microfacies, and physical and chemical proxies, we reconstruct the relative sea-level curve of late Turonian-early Coniacian in Tethyan Himalaya. Spectral analysis indicates that fourth order sea-level changes were linked to the astronomically stable 405-kyr eccentricity cycle. By comparing with classic global sea-level curves, we suggest that late Turonian-early Coniacian sea-level changes in the southeastern Tethyan margin were controlled by eustasy. Two rapid and significant regressions during late Turonian, which are recorded in different continents, may be interpreted as the result of continental ice expansion, giving some support to the notion that ephemeral polar ice sheets existed even in the super-greenhouse world.