The Late-carboniferous Rugose Coral Fauna And Its Palaeoenvironmental Significance In Urumqi,Southern Edge Of The Junggar Basin

The Upper Carboniferous is widely exposed in the southern edge of Junggar basin,containing Liushugou Formation,Qijiagou Formation and Aoertu Formation,which are all shallow marine strata.There are a large number of marine organisms in Qijiagou Formation and Aoertu Formation and the most common one is rugose coral.There are 12 genera,11 species and 1 subspecies being identified from Qijiagou Formation and Aoertu Formation in Qijiagou and Shirenzigou of Urumqi.There are 11 genera,10 species and 1 subspecies in Qijiagou Formation,which are Cyathocarinia tuberculata Soshkina,Rotiphyllum cuneatum Wu,Metriophyllum minor Wang,Zaphrentites urumqiensis Wang,Lophophyllidium pendulum qijiagouense Wang,Fomichevella hoeli(Holtedahl),Arctophyllum intermedium Toula,Caninia cornucopiae Michelin in Gervais,Gshelia minor Zeng,Caninella magma Zeng,Pseudozaphrentoides mapingensis(Lee et Yü).There are 1 genus and 1 species in Aoertu Formation,which is Cyathoxonia maximus Yü et al..There are 5 genera(Fomichevella,Arctophyllum,Caninia,Gshelia,Caninella)and 8 species(Fomichevella hoeli(Holtedahl),Arctophyllum intermedium Toula,Caninia cornucopiae Michelin in Gervais,Gshelia minor Zeng,Caninella magma Zeng,Cyathoxonia maximus Yü et al.,Rotipyllum cuneatum Wu,Pseudozaphrentoides mapingensis(Lee et Yü))first reported in this area.Cyathoxonia maximus Yü et al.is located in Aoertu Formation,others are Qijiagou Formation.After studying the texture and structure and morphological features of rugose corals,an conclusion being thrown up is that the habitat of rugose corals of D18002 in Qijiagou Formation(Qijiagou)is shallow water with low energy above the wave base surface that between turbulent and stable environment.The niche is equivalent to the lower part of the benthic assemblage BA2 to the upper part of BA3.The Habitat of D18003 is the shallow lagoon the open platform.The habitat of D18030 in Qijiagou Formation(Shirenzigou)is the middle to low energy environment above the normal wave base,which is roughly comparable with D18002,only the hydrodynamy of D18030 is more calm and the water is deeper.Combined with the carbonate microfacies and the taphonomic features of rugose corals,it is considered that the rugose corals of D18002 and D18030 were transported in a short distance and are heterochthonous,both of which were in the low-energy static water environment at the lower part of the slope facies of the platform edge.The corals at D18002 are well preserved and buried in situ.The taphonomic environment and living environment are both in the shallow lagoon the open platform.