Discuss on Meso-Neoproterozoic succession and its mineralization environments in Middle Asia and adjacent area
|Location||International Geological Congress,oslo 2008|
|Author||Gao, Linzhi; Geng, Shufang|
|Holding Date||23 September 2008|
Meso-Neoproterozoic unmetamorphosed and less metamorphosed rocks and in thickness is well developed in Middle Asia, which shows serious tectonic stages and clear depositional features. Some stratotype sections developed in three blocks of China and Russia-Siberia Plate. The common character is that a huge BIF developed in the Mesoproterozoic and new Archean and Paleoproterozoic.
1. Meso-Neoproterozoic succession in three blocks in China
There are five systems including Changcheng (1800-1400Ma), Jixian (1400-1000Ma), Qingbaikou (1000-800Ma), Nanhua (800-630Ma) and Sinian (630-530Ma) in Chinese geological stratigraphic chart. The Changcheng System is overlain disconformably with underlies the Qianxi Groups. The Qianxi Group is mainly composed by ferriferous rocks and formed a series of BIF. Some intrusive granite developed zircon U-Pb dating 2591-2513 Ma in the Qianxi Groups, which shows the sources rock formed in Middle Archean. Mesoproterozoic strata consists of two systems (Changcheng and Jixian). The Changcheng is composed of the Changzhougou, Chuanligou, Tuanshanzi, Dahongyu, Gaoyuzhuang Fms, 4468 m. The Jixian consists of the Yangzhuan, Wumishan, Hongshuizhuang, Tieling and Xiamaling Fms, 4607m. Neoproterozoic strata consist of three systems. The Qingbaikou consists of the Luotuoling and Jing’eryu Fms, >385m. The Nanhua is the Liantuo, Gucheng, Fulu, Nantuo Fms., 360m. The Sinian consists of the Duoshantuo and Dengying Fms., 990m.
2. Meso-Neoproterozoic succession in South Ural area, Russia
Meso-Neoproterozoic succession is Rephean and Vendian in Russia stratigraphic chart. Lower Rephean Ai conglomerate underlie disconformably with Archean Taratash complex in 4800m. The Burjia Group consists of three formations. Ai is conglomerate, sandstone, shale and basal in 1700-2500 m. Satka is 2400-3000m. At top of Bakal, Malobakal subformation consists of ore bedding developed in carbonate rocks, ore is mainly magnesite and limonite. Molar tooth structures and stratiform or lens of magnesite developed in the lower part of the Shuydin member. Bakal is 1200-1400m. The Yurmata Group composed of four formations. Mashak is 2500-3100m, Ziglga is sandstone and shale, 250-600m, Zigazin-Komarov is 1000-1200m and Avzyan is molar tooth micrite. The Karatau Group consists of six formations, Zilmerdak is 1400-2400m, Katav is 200-400m, Inzer is 400-700m. Minyar is 500-600m, UK is 180-200m and Krivoluk is >200 m. Asha in Ural area is composed of Bakeev, Uryuk, Basa, Kukkarauk and Zigan.
3. Strata correlation in Middle Asia
The correlation is as: 1) Bottom boundary age of Mesoproterozoic; 2) Correlation with Neoproterozoic glaciations with age 680-570 Ma; 3) global metazoan correlation of the Ediacaran fauna (the White Sea Fauna) in Middle Asia.