The Chang 7 member of the upper Triassic in the southwest Ordos Basin: Carbon isotope studay of dispersed organic matter and its paleoclimate significance

The carbon isotope δ 13 C value of dispersed organic matter in the Upper Triassic sediments in the Ordos basin is (−24.5 to −26.6) × 10 −3 with the carbon being derived from C3-like pleustons. The paleoclimate of the Late Triassic, especially during the deposition of the Chang 7 member, was characterized by a hot and humid climate. It underwent four small climate cycles from humid and warm to humid and hot.