Low palaeoelevation of the northern Lhasa terrane during late Eocene: Fossil foraminifera and stable isotope evidence from the Gerze Basin.
The Lhasa terrane is a key region for understanding the paleoelevation of the southern Tibetan Plateau after India-Asia collision. The Gerze Basin, located in the northern part of the Lhasa terrane, is a shortening-related basin. We discovered Lagena laevis (Bandy) fossils in upper Eocene strata of the Gerze Basin. This type of foraminifera is associated with lagoon and estuarine environments, indicating that the northern part of the Lhasa terrane was near sea level during the late Eocene. We speculate that these foraminifera were transported inland by storm surges to low elevation freshwater lakes during times of marine transgressions. This inference is consistent with the relatively positive δ(18)O values in carbonate from the same deposits that indicate low palaeoelevations close to sea level. Considering the palaeoelevation results from the nearby Oligocene basins at a similar latitude and the volcanic history of the Lhasa terrane, we infer that large-magnitude surface uplift of the northern Lhasa terrane occurred between late Eocene and late Oligocene time.
Faculty of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, Hubei, China.|State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, Hubei, China.
Yi
Y
Wei
Faculty of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, Hubei, China.|State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, Hubei, China.
Kexin
K
Zhang
Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY, USA.
Carmala N
CN
Garzione
Faculty of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, Hubei, China.|State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, Hubei, China.
Yadong
Y
Xu
Institute of Geological Survey, China University of Geosciences, Wuhan 430074, Hubei, China.
Bowen
B
Song
Faculty of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, Hubei, China.|State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, Hubei, China.
Junliang
J
Ji
D000531:Altitude; D002681:China; D056908:Foraminifera; D005580:Fossils; D005843:Geography; D007554:Isotopes / Q000032:analysis*; D014867:Water
D007554:Isotopes; D014867:Water