Lower Permian formations of different geodynamic environments in A'nyemaqen ophiolitic zone (Bu

来源 :Journal of Geoscientific Research in Northeast Asia | 被引量 : 0次 | 上传用户:zyu03
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Lower Permian formations within the Buqingshan Mountains (A’nyemaqen ophiolitic zone, eastern sector of the eastern Kunlun) were formed in the following paleogeodynamic environments (from north to south): (1) shelf and slope of a passive continental margin in a marginal sea; (2) partially Permian metamorphic rocks of subduclion-accretion complexes and volcanogenic rocks of an ensimatic island arc, of the age limited from above by the Asselian - Sakmarian; and (3 ) an island arc slope and oceanic trench. Subduction-accretion complexes and the island arc volcanites are overlain with a sharp angular unconformity by a carbonate-conglomerate sequence, which presents as local molasse of the Early Permian age. Based on fusulinids from the basal limestone, the age of the local molasse is first defined as the Yakhtashian-Bolorian, i.e. Artinskian-Kungurian (?). The thorough investigations revealed that the initial closure of the eastern Paleotethys within the eastern Kunlun corresponded to the Sakmarian-Yakhtashian (Artinskian) boundary, whereas in the western Paleotethys sector (Northern Pamirs) the closure occurred considerably earlier, prior to the Late Bashkirian. Thus, the idea that the Paleotethys in the eastern Kunlun reached its maximum width in the Permian, is highly questionable. During the Early Permian the A’nyemaqen branch of the Paleotethys intensely decreased. Beginning from the Bolorian (Kungurian) and up to the end of the Permian this branch represented its relict in the form of a marginal sea depression. It may be suggested that the Paleotethys closure in the A’nyemaqen took place gradually from the west to the east and covered a long period from the Late Carboniferous to the terminal Early Permian. Lower Permian formations within the Buqingshan Mountains (A’nyemaqen ophiolitic zone, eastern sector of the eastern Kunlun) were formed in the following paleogeodynamic environments (from north to south): (1) shelf and slope of a passive continental margin in a marginal sea ; (2) partially Permian metamorphic rocks of subduclion-accretion complexes and volcanogenic rocks of an ensimatic island arc, of the age limited from above by the Asselian - Sakmarian; and (3) an island arc slope and oceanic trench. Subduction-accretion complexes and the island arc volcanites are overlain with a sharp angular unconformity by a carbonate-conglomerate sequence, which presents as local molasse of the Early Permian age. Based on fusulinids from the basal limestone, the age of the local molasse is first defined as the Yakhtashian -Bolorian, ie Artinskian-Kungurian (?). The thorough investigations revealed that the initial closure of the eastern Paleotethys within the eastern Kunlun corresponded to the Sakmarian-Yakhtashian (Artinskian) boundary, while in the western Paleotethys sector (Northern Pamirs) the closure occurred earlier, prior to the Late Bashkirian. Thus, the idea that the Paleotethys in the eastern Kunlun reached its maximum width in the Permian, is During the Early Permian the A’nyemaqen branch of the Paleotethys intensely decreased. Beginning from the Bolorian (Kungurian) and up to the end of the Permian this branch showing said relict in the form of a marginal sea depression. It may be suggested that the Paleotethys closure in the A’nyemaqen took place gradually from the west to the east and covered a long period from the Late Carboniferous to the terminal Early Permian.
其他文献
近日,为进一步推进浙江省林业信息化工作,浙江省林业厅在龙泉市召开浙江省林业信息化推进工作现场会,浙江省各市、全国林业信息化示范县、部分县(市、区)林业局信息化工作负
总结了台湾南投-花莲MS7 6地震(1999 9 21)和岫岩-海城MS5 4地震(1999 11 29)前后本溪井水位的异常变化情况。认为此次台湾强震群活动导致辽宁地区地壳应变及应力场发生明显
美国“发现”号航天飞机刚刚上天,日本科学界又准备“入地”。根据日本媒体报道,日本学者正积极联手美国、欧盟、中国筹备一项计划,向地球内部深深挖掘,去探索生命起源的奥秘
宗福邦、陈世铙、萧海波等先生编纂的《故训汇纂》一书对于训诂学的研究有极大的推动作用,也一直是从事古典文献研究工作者的案头必备之书,造福学林,为功至巨。然而智者千虑,
【摘要】职业心理是中职生择业、乐业的内动力,了解涉农中职生的职业心理是培养农业后继人才的核心,通过自制问卷,采用随机抽查方式进行调查,分析调查数据发现:50%以上的涉农中职生缺乏牢固的专业思想;缺乏学习动力;自我评价不高;不能吃苦耐劳、无责任心、专业技能学不好、缺乏创新精神;又担心无工作经验、担心人际关系、缺乏归宿感等。针对涉农中职学生存在的主要职业心理问题以及造成这些问题的主要原因提出了解决问题
云南农用机动车辆交易市场是第一个以云南省会城市昆明为中心,辐射大西南、影响东南亚,以农用机动车、农机产品及相关配件为经营主体的批发零售市场。市场由云南广大汽车贸
【摘要】在当今社会,职业教育在进行着不断的改革,高职数学课程教学作为职业教育的学科,改革是必要的。将高职数学课程与社会专业需求融合,针对社会的专业需求建立数学课程教学体系,多在教学中做一些创新。科学的培养人才,才能保障学生的将来。完善课程教学,探索数学价值,提高教师素质是我们所需要思考与实践的。  【关键词】专业需求 高职数学 改革  【中图分类号】G71【文献标识码】A 【文章编号】2095-3
近日来,台湾一些速食店推出各式卡通玩偶,以吸引消费者。除麦当劳、肯特鸡外,台湾的一些本地速食店及百货商店也纷纷推出。这一促销新招的确吸引了不少顾客,有些商 In rece
对加拿大哈得逊海湾存在的地球物理学指示或“记忆”的若干系统进行了检测,用以探讨该地区不同时间长度的预测.文章对三个案例进行了研究.首先对哈得逊海湾海平面的水文学惯
请下载后查看,本文暂不支持在线获取查看简介。 Please download to view, this article does not support online access to view profile.
期刊