U-P DATING OF ZIRCONS FROM CENOZOIC SANDSTONE: CONSTRAIN ON THE GEODYNAMIC SETTING OF EAST CHINA SEA SHELF BASIN
-
摘要: 东海陆架西部凹陷带古新统砂岩锆石的U-P年龄表明,陆架西部古新世物源以中生代母岩为主,其次为元古代变质岩及少量古生代母岩。东海陆架东部凹陷带渐新统砂岩锆石的U-P年龄表明陆架东部渐新世物源以元古代变质岩为主,其次为中生代母岩及少量太古代变质岩与古生代母岩。陆架西部古新统砂岩锆石的U-P年龄与闽浙隆起带露头及钻孔揭示的基岩一致,而陆架东部渐新统砂岩锆石的U-P年龄比西部老。根据上述砂岩锆石U-P年龄,可以推测古近纪东海陆架盆地发育过程中,东海陆架东部地势较高。单颗粒锆石REE配分模式表明元古代锆石轻稀土(LREE)明显比其他样品高且含量相近,Ce正异常不明显;中生代锆石Ce正异常明显,但同时Eu负异常也很明显,与中生代基岩锆石相似;古生代锆石稀土元素含量偏低,La含量明显超过其他轻稀土元素。根据上述特征可以清晰指示砂岩的母岩类型与年代,推断古新世东海大陆架的基底性质与构造背景。Abstract: The U-P dating data of zircon from Paleocene sandstones in the west of East China Sea shelf indicate that most zircon grains are of Mesozoic origin, and then are Proterozoic, including sporadic Paleozoic ones. The U-P dating data of zircons from Oligocene sandstones in the east of East China Sea shelf indicate that most zircon grains are Proterozoic, and then are Mesozoic, including sporadic Archean and Paleozoic ones. The dating result indicates that the basement is different between the west and the east of East China Sea shelf basin. The western basement is consistent with the outcrop data in Fujian-Zhejiang offshore area. The U-P dating data of zircons imply that topography was low in the west and high in the east of East China Sea shelf during the development of Eogene basin. Chondrite-normalized REE patterns of the individual zircons determined by ICPMS show that the Proterozoic zircons have high content of LREE and invisible Ce anomalies, whereas Mesozoic zircons have large positive Ce and small negative Eu anomalies, and Paleozoic zircons are characterized by low content of LREE in which La is higher in content than other LREE elements. The LAM-ICPMS data give chronological evidence to us to previously identify basement rocks and to probe into tectonic property of the shelf of East China Sea.
-
Key words:
- sandstone /
- U-P dating /
- REE /
- basement /
- zircon /
- East China Sea shelf
-
-
[1] DU Yuan-sheng, YAN Jia-xin, HAN Xin. Orogenic belt sedimentology and geology research and progress[J]. Geological Science and Technology Information, 1995, 14(1):29-34.
[2] YI Hai-sheng, WANG Cheng-shan, LI Ya-lin. Sedimentary response to tectonic events:Reconstructed spatiotemporal scale of the Indo-Asian continental collision and Qinghai-Xizang Plateau uplift[J]. Sedimentary Geology and Tethyan Geology, 2001, 21(2):1-15.
[3] WANG Guo-zhi, WANG Cheng-shan, ZENG Yun-fu, et al. The uplift of the western Yunnan Plateau and the sedimentary response of the Yinggehai Basin[J]. Acta Sedimentologica Sinica, 2000, 18(2):234-240.
[4] FANG Nian-qiao, CHEN Xue-fang, HU Chao-yong, et al. Deep sea sedimentary records in the northeastern Indian Ocean and their response to the uplift of the Qinghai-Xizang plateau[J]. Quaternary Sciences, 2001,21(6):290-299.
[5] WANG Cheng-sha, DING Xue-lin. New progress of the study on Himalaya uplift and its sedimentary response[J]. Geological Science and Technology Information, 1998,17(1):1-7.
[6] WANG Yue-jun, FAN Wei-ming, LIN Ge. Several indicative methods of mountain uplift-erosion from basin sediments[J]. Geological Science and Technology Information, 1999,18(2):86-89.
[7] Heaman L M, Bowins R, Crocket J. Trace chemical composition of igneous zircon suites:implications for geochemical tracer studies[J]. Geochim Cosmochim Acta, 1990, 54(6):1597.
[8] LI Hui-ming, DONG Chuan-ming, XU Xi-sheng, et al. Single grain zircon dating of gabbro in Quanzhou:the origin of basic rock magma rock science[J]. Science Bulletin, 1995, 40:158-160.
[9] XIE Gui-qing, HU Rui-zhong, JIANG Guo-hao, et al. The progress on zircon petrogenesis and isotope dating[J]. Geology Geochemistry, 2001, 29(4):64-70.
[10] CHEN Zhi-yong, WU Pei-kang, WU Zhi-xuan. Petroleum geology and exploration potential of Liushui sag[J]. China Offshore Oil and Gas (Geology), 2000, 14(6):384-391.
[11] LI Bing-fu, JIAO Xiang-heng, LIU Bao-hua. Discuss on seismic reflection features of volcanic rocks, Diaoyudao uplift, East China Sea[J]. Oil Geophysical Prospecting, 1995, 30(2):150-154.
[12] JIN Bing-fu, LIN Xiao-tong, JI Fu-wu. Sediments of upper Pleistocene in cores 43 north of Diaoyudao Island in the East China Sea[J]. Marine Geology and Quaternary Geology, 2005,25(1):25-31.
[13] LI Gui-qun, LI Xue-lun. Geological tectonic characteristics of the outer margin upwarped zone of the East China Sea shelf[J]. Journal of Ocean University of Qingdao, 1995, 5(2):199-205.
[14] Gray A L. Solid sample introduction by laser ablation for inductively coupled plasma source mass[J]. Spectrometry Analyst, 1985, 110:551-556.
[15] Vavra G. On the kinematics of zircon growth and its petrogentic significance:a cathodolumine scence study[J]. Mineral Journal, 1990, 15:119-128.
[16] Hinton R W, Upton B G J. The chemistry of zircon:variations within and between large crystals from syenite and alkali basalt xenoliths[J]. Geochim Cosmochim Acta, 1991,55(11):3287
[17] HU Ping. A study on the genetic implication of zircon in Wulashan gold orefield[J]. Uranium Geology, 1996,12(4):220-223.
[18] YANG Xiang-hua, LI An-chun. Basement nature and nature and sedimentary basins alone the continental margin in East China Sea[J]. China Offshore Oil and Gas(Geology), 2003,17(1):25-28.
[19] LIU Ben-pei. On the tectono-palaeogeographical development of South China in the Hercynian-Indosinian stage[M]//In:WANG Hong-zhen, YANG Wei-ran,LIU Ben-pei, eds. Tectonic history of the ancient continental margins of South China. Wuhan:China University of Geosciences Publish Press, 1986:63-77.
-
计量
- 文章访问数: 1325
- PDF下载数: 2
- 施引文献: 0
下载: