in Jurassic and Cretaceous Stratigraphy

Earth Science Frontiers, Vol. 17, Special Issue, Aug. 2010 ISSN 1005-2321
Fig.1 The non-marine Upper Triassic and Jurassic strata, strato-bounderies and fossil biota in the Sichuan Basin
A-The Upper Triassic and Jurassic section along the Jialing River in Hechuan of Chongqing; B-Fossil plant leaves from the Upper
Triassic Xujiahe Fm. in the Hechuan Section, Chongqing; C-Fossil bivalves from the Lower Jurassic in the Hechuan Section,
Chongqing; D-Reconstruction of the Mamenchisaurus from the Middle Jurassic in the Sichuan Basin; E-The Upper Jurassic Suining
Fm. in Pengxi County of Suining City, Sichuan Province; F-The Triassic/Jurassic boundary in the Hechuan Section, Chongqing; F-The
Jurassic Cretaceous boundary in Santai County, Sichuan Province.
The Triassic/Jurassic boundary is defined in
between the Upper Jurassic Xujiahe Formation and the
base of Lower Jurassic Zhenzhuchong Formation
(Fig.1 F). The boundary shows distinct lithological
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features and is distinguished by a scouring surface
with feldspathic sandstones of the Upper Triassic and
quartzose sandstones of the Lower Jurassic. Pre-
liminary analysis shows that across the boundary the