新疆阿克陶县奥依塔格红帘石石英岩的发现及其意义

Discovery and geological significance of a piemontite-quartzite of the Aoyitag of Aketao County, Kezillesu kerkezi autonomous state of Xinjiang, China

红帘石石英岩位于新疆克孜勒苏柯尔克孜自治州阿克陶县奥依塔格乡皮拉里。构造单元隶属于西昆仑的北蛇绿岩带或奥依塔格—库地缝合带。红帘石石英岩产出层位为上石炭统一下二叠统,岩性主要为薄层大理岩、钙质粉砂岩和粉砂质泥岩等韵律层。矿物成分主要为石英、红帘石和少量方解石、绿泥石等。红帘石的主要化学成分:Al_2O_3(19.58～21.33)、Fe_2O_3/FeO(7.66～9.12)和Mn_2O_3/MnO(11.02～11.32)。红帘石—石英岩形成于低温(405.5℃)高压环境,其原岩—母岩可能是高铁锰的不纯硅质岩。它是始新世—渐新世期间,印度板块与欧亚板块碰撞、青藏高原强烈挤压隆升,逆冲推覆构造不断向前陆塔里木盆地扩张,塔里木板块相应地作陆内(A型)俯冲过程中的产物,属低绿片岩相变质岩。

Piemontite-quartzite is from the ductile shear zone of the southern Kudi-western Gaizi in the Aoyitag of Aketao County, Kezilesu kerkezi autonomous state of Xinjiang, China. It is a part of the ophiolite suite of nothern part of the Western Kunlun Mountains,or a part of the Aoyitag- Kudi suture zone of the Western Kunlun Mountains, in the alternation of strata made up of piemontite-quartze, marbles, calcareous sihites, silty mudrock. Its mineral composition is simple, and mainly made up of quartz, piemontite, a litter of calcite and so on. Oxides of primary importance of piemontite-quartze are SiO2 （ 35.45 - 36.64 ） , AI203 （ 19.58 - 21.33 ） , Fe203/ FEO（7.66 - 9. 12）, Mn203/MnO （11.02 - 11.32） and CaO （22.83 - 24.14）. It is a conditions of formation which lower temperature （405.5） and high pressure. Formed the protolith of the piemontite-quartzite is derived from highly oxidized ferromanganese oxide-and impure silieeous pelagic sediments for the piemontite schist. Piemontite-quartzite are eonsidered low greenschist and high pressure metamorphic faeies series, in the process of A-pattern subduction of Tarim plate,since Eoeene-Oligocene.