Late Neoproterozoic Sedimentations of the Carbonate -Detrital Flows in Longshou Mountains, Northwest China: Implications for Its Tectonic Environments

LI Wen yuan; YANG Peng fei

In Longshou Mountains of the southwestern margins of North China. s Plate, there is extensively a se -ries of Pre -Cambrian sedimentary of the detrital flows consisting of dominant carbonate, and the sedimentary rockshave also been found in recent years. The rocks are characterized by chaotic gravels on grain sizes, dominantdolomite gravels, bed -rounded gravelsshowing angulate -subangulate, and textures of matrix support. In the regionthe sediments distributed continuously, but its thickness is various from several meters to tens of meters, locallytransforming to volcanic rocks. On the basis of the isotopic ages and micro -paleobotanic fossils of the over and un -derlain strata, the sedimentary rocks were suggested forming in late Neoproterozoic era. Its origin is thought to bethe sediments of the carbonate - fragmental flows, on a sedimentary- tectonic environment of paleo- continentalrift, coming from large quantities of collapse files on slope of continental rift due to crustal movement rapidly tolead to breakdown of sedimentary rocks on steady platform. So these rocks are the typical sediments of the cont- inental rift, and important significance on implication for the tectonic environments. In Longshou Mountains andneighboring area the distribution of large quantities of the late Neoprozoic sediments of palaeo- fargmental flowsindicate that in that time a large scale of continental rift had occurred and consistent with splitting recognition ofthe Rodinia continent globally.

1. Xi'an Institute of Geology and Mineral Resources, Xi'an 710054;

2. Northwest University,Xi'an 710069

Received Date: 2003-06-10

Rev Recd Date: 2003-08-26

Publish Date: 2004-03-10

Key words:

Abstract: In Longshou Mountains of the southwestern margins of North China. s Plate, there is extensively a se -ries of Pre -Cambrian sedimentary of the detrital flows consisting of dominant carbonate, and the sedimentary rockshave also been found in recent years. The rocks are characterized by chaotic gravels on grain sizes, dominantdolomite gravels, bed -rounded gravelsshowing angulate -subangulate, and textures of matrix support. In the regionthe sediments distributed continuously, but its thickness is various from several meters to tens of meters, locallytransforming to volcanic rocks. On the basis of the isotopic ages and micro -paleobotanic fossils of the over and un -derlain strata, the sedimentary rocks were suggested forming in late Neoproterozoic era. Its origin is thought to bethe sediments of the carbonate - fragmental flows, on a sedimentary- tectonic environment of paleo- continentalrift, coming from large quantities of collapse files on slope of continental rift due to crustal movement rapidly tolead to breakdown of sedimentary rocks on steady platform. So these rocks are the typical sediments of the cont- inental rift, and important significance on implication for the tectonic environments. In Longshou Mountains andneighboring area the distribution of large quantities of the late Neoprozoic sediments of palaeo- fargmental flowsindicate that in that time a large scale of continental rift had occurred and consistent with splitting recognition ofthe Rodinia continent globally.

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Reference (13)

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Late Neoproterozoic Sedimentations of the Carbonate -Detrital Flows in Longshou Mountains, Northwest China: Implications for Its Tectonic Environments

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