全文快速搜索:          
引用本文:乔秀夫1 张安棣2. 华北块体、胶辽朝块体与郯庐断裂[J]. 中国地质, 2002, (4): 337-345.
QIAO Xiu-fu1, ZHANG An-di2. North China block, Jiao-Liao-Korea block and Tanlu fault[J]. Geology in China, 2002, (4): 337-345(in Chinese with English abstract).
【打印本页】   【HTML】   【下载PDF全文】   查看/发表评论  下载PDF阅读器  关闭
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 1249次   下载 1242 本文二维码信息
码上扫一扫!
分享到: 微信 更多
华北块体、胶辽朝块体与郯庐断裂
乔秀夫1 张安棣21,2
1.中国地质科学院地质研究所,北京 100037;2.中国地质科学院矿产资源研究所,北京 100037
摘要:
提要:华北块体(NVB)与胶辽朝块体(JLKB)是中朝板块东部从震旦纪(680 Ma)开始裂解的两个不同的构造单元。两个块体的界线称古郯庐断裂(PTLF)。古郯庐断裂位置与现今郯庐断裂(TLF)相吻合,即由合肥向北延伸,过渤海,经沈阳以东呈NE走向至吉林南部。古郯庐断裂带附近震旦纪碳酸盐岩中的强地震记录及相应的辉绿岩侵位,是中朝板块内部裂解的基本地质证据,古郯庐断裂带(板内地震带)与元古超大陆Rodinia的裂解时期是一致的。两个块体上,太古宙基底岩石不同;元古宙及古生代的发展历史有别,两个块体于晚石炭世的莫斯科期重新闭合。朝鲜半岛中部的临津江带曾被认为是大别—胶南造山带的东延部分,但临津江带只是一般性断裂,胶南超高压带在朝鲜半岛并未发现。朝鲜半岛南部主体与辽东半岛古生界相似,因此,将中朝板块的南界,也是胶辽朝块体的南界置于朝鲜半岛之南,它与胶南造山带以黄海转换断层(YSTF)联结。辽宁省瓦房店(旧称复县)与山东省蒙阴含金刚石的金伯利岩分布在郯庐断裂带的东、西两侧,南北方向距离约550 km。两地金伯利岩年龄值在500~450 Ma之间,即中奥陶世末侵位。鉴于两地金伯利岩在岩相学、矿物学与侵位年龄等某些方面的相似性,又紧邻郯庐断裂两侧,有些地质学家认为二者在侵位时可能相距颇近,属同一岩省,因而将瓦房店与蒙阴两个金伯利岩岩省之间的距离总是用郯庐断裂的巨大平移来解释。郯庐断裂为切过岩石圈的深断裂,对比瓦房店与蒙阴两地岩石圈剖面的异同,应是判断郯庐断裂有无巨大平移的重要依据。通过对金伯利岩中地幔样品的研究,揭示出了两地岩体侵位时所穿越的古岩石圈剖面是很不一致的,表明二者当时并非连接一起或相距甚近。笔者结合区域地质构造研究的新认识,发现它们实际是分别侵位于中朝板块的两个不同的构造单元上,两地距离与平移无关,不支持郯庐断裂左行走滑巨大平移的观点。本文期望这种交叉学科研究所提供的材料能有助于讨论中国东部这一巨型断裂系统的性质。
关键词:  郯庐断裂  古郯庐断裂  华北块体  胶辽朝块体  金伯利岩  地幔捕虏晶  岩石圈剖面
DOI:
分类号:
基金项目:国家科学技术部国家攀登专项(95-专-04)、中国地质调查局和中国地质科学院地质调查项目(DKD2001010资助。
North China block, Jiao-Liao-Korea block and Tanlu fault
QIAO Xiu-fu1, ZHANG An-di21,2
1. Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China;2. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, China
Abstract:
Abstract: In the Sinian (680 Ma), the Sino-Korean plate began to break up into two different tectonic units, the Jiao-Liao-Korea block (JLKB) and North China block (NCB). The boundary of the two blocks is called the Paleo-Tanlu fault (PTLF). The position of this fault is coincident with he present Tanlu fault, which extends from Hefei northward via the Bohai Sea to east of Shenyang and then turns NE and goes to southern Jilin. Strong earthquake records in Sinian carbonate rocks in the vicinity of the PTLF and corresponding diabase emplacement are basic geological evidence for the intraplate break-up of the Sino-Korean plate. The break-up period of the PTLF (intraplate seismic zone) is consistent with that of Proterozoic Rodinia. Archean basement rocks in the two blocks are different and the Proterozoic and Paleozoic histories of the two blocks on the eastern and western sides of the PTLE are different. The two blocks were again amalgamated in the Late Carboniferous Moscovian stage. The Rimjin River zone on the central Korea Peninsula was considered the eastward extension of the Dabie-Jiaonan orogenic belt. However, the Rimjin River zone is only an ordinary fault and China's Jiaonan ultrahigh-pressure belt bas not been found on the Korea Peninsula. Considering the similarity in the Paleozoic between the southern main area of ??the Korea Peninsula and the Liaodong Peninsula, the southern boundary of the Sino-Korean plate, i. e. the southern boundary of the JLKB is placed on Jizhou Island south of the Korea Peninsula in the paper. It joins the Jiaonan orogenic belt with the presumed Yellow Sea transform fault. Diamondiferous kimberlites in Wafangdian (originally called Fuxian County) of Liaoning Province and Mengyin of Shandong Province are distributed on the eastern and western sides of the Tanlu fault over a longitudinal distance of ~ 550km. The age of the kimberlites in the two areas ranges from 500 to 450Ma, i. e. the rock was emplaced at the end of the Middle Ordovician. Since the kimberlites in the two areas have similarities in some aspects such as petrography, mineralogy and emplacement age and are both close to the Tanlu fault, some geologists think that the kimberlites of the two areas were possibly very close to each other during their emplacement and belong to the same province; therefore they always explain the distance letween the Wafangdian and Mengyin kimlerlite provinces with the great displacement of the Tanlu fault. The Tanlu fault is a deep fault cutting through the lithosphere. Comparison of the differences and similarities between the lithosphere profiles of Wafangdian and Mengyin provides significant evidence for judging whether the Tanlu fault has a great displacement. Study of the mantle samples in the kimberlites reveals that the profiles of the paleo-lithosphere that the kimberlites in the two areas cut through during their emplacement are very different. This indicates that the two areas are neither contiguous nor close to each other at that time. On the basis of the above-mentioned sample study, combined with the new understanding got from a study of the regional geological structure, the authors find that the two kimberlites were actually emplaced separately into two different tectonic units of the Sino-Korean plate and the distance between the two areas is independent of displacement. This finding does not support the view of the great displacement caused by the Tanlu fault.
Key words:  Tanlu fault  Paleo-Tanlu fault  North China block  Jiao-Liao-Korea block  kimberlites  mantle xenocryst  lithosphere profile