作　　者： (张芳荣）; (王会敏）; (滑鑫）; (余泉）; (曾凡淼）;

机构地区： 江西省地质调查研究院,南昌330030

出　　处： 《华东地质》 2017年第3期161-167,共7页

摘　　要： 新疆纸房东地区出露一套火山岩,其形成时代缺乏年代学依据,地层单元划分也存在争议。文章采用LA-ICP-MS锆石U-Pb定年,获得新疆纸房东地区火山岩成岩年龄为304±4.0 Ma,属晚石炭世。该套火山岩地层不整合于早石炭世条山群(C1T)或姜巴斯套组(C1j)之上,被早侏罗世八道湾组(J1b)不整合覆盖,地层中产晚石炭世芦木类化石Calamites undulatus sternberg。该地层以陆源碎屑岩为主,偶夹少量英安岩及英安质角砾凝灰岩,而早石炭世巴塔玛依内山组(C1b)发育基性火山岩,夹极少量陆源碎屑岩,火山岩形成于早石炭世。该套火山岩与巴塔玛依内山组火山岩在岩性组合、喷发特征及形成时代方面均具有明显差异,因此,本文将该套火山岩地层重新厘定为晚石炭世奥尔吐组(C2o)。 One set of the volcanic rocks exposes in the Zhifangdong area, Xinjiang, but its formation age is poorly constrained and its stratigraphic unit division is also controversial. In this paper, LA-ICP-MS zircon U-Pb dating yielded an age of 303.7±3.9 Ma for the volcanic rocks, suggesting that the rocks formed in Late Carboniferous. The volcanic-sedimentary rock unit unconformably overlies on the Early Carboniferous Tiaoshan Group （C1 T） and/or Jiangbasitao Formation （Clj）, both of which are uncon- formably overlain by the Early Jurassic Badaowan Formation （Jib）. Late Carboniferous fossils, Calarnites undulates sterkerg., was found to occur in this volcanic-sedimentary sequence. The sequences are mainly composed of terrigenous clastic rocks, with minor andesite porphyries and andesite brecciated tufts. In con-trast, the Batamayineishan Formation is characterized by widespread Early Carboniferous mafic volcanic rocks, with minor amount of terrigenous clastic rocks. The volcanic rocks are evidently different from that of the Batamayineishan Formation in lithology, eruption features and formation time. Therefore, the volcanic rocks should be re-classified into Late Carboniferous Aoertu Formation （C2O）.

关 键 词： 形成时代 火山岩 奥尔吐组 纸房东 新疆