Liu Xiaohan

The age of the plant fossil assemblage in the Liuqu Conglomerate of southern Tibet and its tectonic significance

Abstract The Liuqu Conglomerate, situate to the south of Yarlung Tsangbo Suture Zone (YTSZ), is a suit of molasses formed in a foreland basin of the Himalayan orogenic belt after the collision between the two plates of the Indian and Eurasion. It is of great significance in constraining the younger limit time of the collision of the two plates and providing stratigraphic evidence to reveal the post.-collisional tectonic evolution and uplifting history of the Tibet plateau. However, the age of this molasses suit and its correlation to other synchronous strata distributed in southern Tibet have been in great disputes for a long time. Especially in recent years, argues on its ages are growing violently with the recognition of the great sedimentary tectonic significances of this molasses. During the field work carried out recently on this molasses suit, a lot of plan fossils were found preserved in fairly good conditions in the upper part of this strata, which is of great help in determining is its age. By id...

Sedimentary environment of the Dajin conglomerate in Tibet, age of foraminiferan assemblages and their tectonic significance

Abstract The Dajin conglomerate, whih is one of the most important sedimentary successions of the Xigaze forearc basin in Tibet, China, consists of deep-shallow marine tuffaceous turbidites and clastic rocks bearing. Nummulites, Assilina, Alveolina and Lock-hartia. These fossils are very similar to the foraminiferan in the Jialazi and Maila conglomerates, and those in Gangba and Dingri areas. They developed in the Eocene. By analyzing the spatial variation of Eocene sedimentary environments of Tibet Plateau and the foraminiferan in the Dajin conglomerate, we found that Eocene sedimentation should take place on both sides of the Yarlung Tsangpo suture, and the late Eocene tectonic uplifting should make the forearc basin expose out of the sea level and begin to receive nonmarine deposits. * Supported by the Innovative Project of the Chinese Academy of Sciences (Grant No. KZCX2-SW-119) and National Natural Science Foundation of China (Grant No. 40334044)

Late Triassic plant microfossils from Miers Bluff Formation of Livingston Island, South Shetland Islands, Antarctica

A moderately diverse assemblage of plant microfossils has been recovered from the Johnsons Dock Member of the Miers Bluff Formation, Livingston Island, including spores, pollen, acritarchs, wood fragments and cuticles. Containing a total of c. 45 of miospore taxa, the palynoflora is dominated by non-striate bisaccate pollen, but spores of pteridophytes and pollen of gymnosperms are proportionate in diversity. The palynoflora is similar in composition to those indicative of subzones C + D of the Alisporites Zone of Antarctica, and the upper Craterisporites rotundus Zone and the lower Polycingulatisporites crenulatus Zone of Australia as well as the upper Polycingulatisporites crenulatus Zone and Foveosporites moretonensis Zone of New Zealand, suggesting a Late Triassic (possibly Norian–Rhaetian) age. This determination is supported by the sporadic occurrence of Aratrisporites and Classopollis in the palynoflora as well as by the absence of striate bisaccate grains.

Quadrupole Splitting Distributions in Grandidierite and Kornerupine from Antarctica

The Mössbauer spectra of grandidierite and kornerupine at 298 and 90 K were measured. The quadrupole splitting distributions from the Mössbauer spectra were obtained by using the Voigt-based method, and the assignments for QSDs in the Mössbauer spectra of both minerals are presented. Site occupancies of iron in the crystal structures of two minerals were determined, and the chemical formulas of grandidierite and kornerupine were rewritten based on the relative absorption areas and Mössbauer fraction f for Fe3+ and Fe2+.