Fluvial sedimentology of an Upper Jurassic petrified forest assemblage, Shishu Formation, Junggar Basin, Xinjiang, China
Abstract A remarkable petrified forest assemblage is preserved in the Upper Jurassic Shishu Formation of the northeastern Junggar basin, Xinjiang Uygur Autonomous Region, China. Discovered in 1965, the silicified wood occurs as two horizons of fallen logs and a group of rooted stumps in growth position coincident with the upper log horizon. the largest log is 25.3 m in length; the largest stump is 2.5 m in diameter. The enclosing strata are fluvial silts, sands, and gravels. Wood characteristics indicate that climate was mild, with seasonal variation in precipitation, temperature, or light. Paleohydrology and stratigraphy of the Shishu Formation suggest a wide, shallow, low-sinuosity, mixed-load, meandering stream regime that drained southward into the Junggar basin during the late Jurassic.