Sequence stratigraphy, paleoclimate patterns, and vertebrate fossil preservation in Jurassic–Cretaceous strata of the Junggar Basin, Xinjiang Autonomous Region, People's Republic of China

Abstract

Multi-kilometre-thick Jurassic–Cretaceous-age sedimentary successions exposed in the southern, northwestern, and northeastern regions of the Junggar Basin display a consistent and correlative stratigraphy comprising four, stacked second-order megasequences: Badaowan, Sangonghe, Shishugou, and Kalaza. Each consists of a basal erosional unconformity or discontinuity surface and lower, middle, and upper units that are interpreted as forestepping, backstepping, and aggradational systems tracts, respectively. Each megasequence is interpreted as recording an upsection shift from active tectonism and uplift to tectonic quiescence with associated changes in crustal response and sediment supply. Basin-wide analysis of megasequences indicates that tectonism was intermittent and regionally variable. A maximum phase of subsidence and sediment accommodation is recorded in the middle unit of each megasequence and correlates with a notable abundance of fossil vertebrates suggesting a primary tectonic and basin-response control on fossil preservation. Seasonally dry climatic conditions were developed first in the northeastern region of the basin during the Pliensbachian, followed by basin-wide seasonal dryness during the Bajocian. Seasonally dry climatic conditions were permanently established across the basin by the Oxfordian and intensified during the Early Cretaceous. A seasonally dry climate from Oxfordian through the Early Cretaceous correlates positively with the widespread presence of fossil vertebrates and suggests an additional climatic control on fossil preservation.

A previously unrecognized group of Middle Jurassic triconodontan mammals from Central Asia

“…2), from the basal section of the Shishugou Formation at Jianshan Wash in the Junggar Basin, Xinjiang-Uygur Autonomous Region of China (Chow and Rich 1984;Kielan-Jaworowska et al 2004;Zhang 1984). The lower part of the Shishugou Formation was originally determined as late Middle Jurassic to Late Jurassic in age, then as Late Jurassic (Dong 1994;Kielan-Jaworowska et al 2004), but according to more recent data is now regarded as Middle Jurassic (Clark et al 2004;Eberth et al 2001). …”

The first haramiyoid mammal from Asia

“…Here we report a well-preserved left lower molar from the late Middle Jurassic (Bathonian-Callovian, according to Eberth et al 2001, but see discussion below) Toutunhe Formation of the southern Junggar Basin that is referable to E. oxfordensis. The specimen was discovered in a bonebed close to the top of the Toutunhe Formation (14.75 m below the overlying Qigu Formation) in the Liuhuanggou gorge, about 40 km southwest of Urumqi in the Xinjiang Uygur Autonomous Region, People's Republic of China.…”

Introduction to the Special Issue commemorating the 30th anniversary of the Royal Tyrrell Museum of Palaeontology, with a summary of the museum’s early history and its research contributions

“…An analysis by Henderson and Tanke (2010) highlighted the fossiliferous richness of DPP in a different manner, by using historical collection data, the volume of rock contained within DPP, and erosion rates to calculate that about 10 500 dinosaur skeletons have been lost to erosion and that about 11 000 dinosaur skeletons remain to be exposed within the Park's boundaries. Taphonomic work by RTMP researchers and colleagues outside of the DPP area has included the Horseshoe Canyon Formation of southern Alberta (e.g., Straight and Eberth 2002;Eberth and Currie 2010;Eberth and Braman 2012;Evans et al 2015) and farther afield into the Lower Cretaceous of Utah Britt et al 2009), the Cretaceous of Argentina (e.g., Eberth et al 2000b), the Cretaceous and Jurassic of China and Mongolia (e.g., Eberth et al 2001aEberth et al , 2010bQi et al 2007), and the Permian of Germany (Eberth et al 2000a). Other notable taphonomic projects involving RTMP researchers include studies arguing that supposed mosasaur tooth marks on Late Cretaceous ammonites are remnants of limpet resting traces (Kase et al 1998) and using computer simulations to examine how weathering might affect the form of dinosaur tracks and the taxonomic implications of those alterations (Henderson 2006a).…”

“…(H In press), and in the Silurian, Devonian, Late Cretaceous, and Eocene of the Canadian Arctic (e.g., Johnston and Goodbody 1988;Campbell et al 1995;Eberle and Eberth 2015). Outside of Canada, the RTMP has been involved in fieldwork throughout the western USA and into northern Mexico, and on most continents, except Africa (e.g., Currie 1993bCurrie , 1996 and papers therein; Currie et al 1996;Eberth et al 2000aEberth et al , 2000bEberth et al , 2001aEberth et al , 2004Eberth et al , 2009aEberth et al , 2009bEberth et al , 2010bCoria et al 2002;Therrien et al 2009; see also Table 1). …”

“…Off-continent, collaborative geological and palynological work has been undertaken for dinosaur-bearing formations in the Jurassic and Cretaceous of China (e.g., Eberth et al 2001a;Li et al 2010) and in the Upper Cretaceous of Mongolia (e.g., Currie and Eberth 1993;Jerzykiewicz et al 1993;Eberth et al , 2009aEberth et al , 2009b, Argentina (D.A. Eberth, unpublished data), and Romania (Therrien 2006;Therrien et al 2009).…”