The discovery of conodonts fossils and the strontium isotope composition of Labuchari Formation in Tanggula Range and their stratigraphic significance
-
摘要:
首次在唐古拉地区晚二叠世-早三叠世拉卜查日组中获得牙形石化石，其分子为Hindeodus typicalis、H.eurypyge和H.praeparvus。根据其地层意义并结合层序地层学及海平面变化研究，最终将研究区二叠系与三叠系界线的可能位置定在实测剖面的29层顶、30层底。基于此，作者系统测试了拉卜查日组中的碳酸盐岩87Sr/86Sr比值，结果表明，二叠系/三叠系界线附近87Sr/86Sr比值为0.707017～0.707032，显著小于国内外其他地区二叠系/三叠系界线附近87Sr/86Sr比值。造成这种差异的主要原因，可能是由于唐古拉地区二叠系/三叠系界线附近存在广泛的火山活动以及上扬子地区二叠纪广泛的玄武岩喷发等地方性事件。此外，剖面上锶同位素演化曲线与海平面变化曲线对比显示，87Sr/86Sr比值的最小值与初始海泛面基本一致，锶同位素演化曲线与海平面变化曲线有着很好的一致性，说明全球海平面变化是其最主要的控制因素。
Abstract:Conodont fossils were found for the first time in the Late Permian Labuchari Formation in the Tanggula Range. The conodonts include Hindeodus typicalis, H. eurypyge and H. praeparvus. According to their significance and the investigation of sequence stratigraphy and sea-level changes, the Permian/Triassic boundary may be determined between the top of 29 and the bottom of 30 of the measured section. Here, the carbonatite 87Sr/86Sr ratios of Labuchari Formation were determined. At the Permian/Triassic boundary, 87Sr/86 Sr ratios are from 0.707017 to 0.707032, which are significantly lower than those in other areas. The main reasons for the remarkable difference might be the existence of extensive volcanic activities in Tangula Range at the Permian/Triassic boundary and the basalt eruptions in Yangtze region during the late Permian. In addition, the comparison between the strontium isotope curve and sea-level curve shows that the minimum 87Sr/86Sr ratio has a good consistency with the data of the first flooding surface, suggesting that global sea level change was the main factors controlling the strontium isotope.
-
Keywords:
- Tangula Range /
- Labuchari Formation /
- strontium isotope /
- conodont /
- corresponding sea level change
-
1. 研究目的（Objective）
甘肃省高台县大青山地区地处阿拉善地块龙首山基底杂岩带，位于酒东盆地马营凹陷东段山前沉积盆地北缘（图 1a）。区内主要出露有古元古界—新太古界龙首山岩群、中元古界蓟县系墩子沟群、海西期侵入岩、侏罗系龙凤山组和白垩系庙沟组（图 1b）。
![]()
图 1 甘肃省高台县大青山地区大地构造位置图（a）、区域地质图（b）以及ZK1201岩性柱状图（c），含油气岩心照片（d-g）和油气成藏模式图（h）Figure 1. Tectonic location (a), regional geological map(b), lithology column(c) and drill photos of ZK1201 (d-g), hydrocarbon accumulation pattern (h) in the Daqingshan area of Gaotai County, Gansu Province为实现研究区金属资源和油气资源的综合调查，中国地质调查局发展研究中心联合甘肃省地调院、探矿工程所、吉林大学在前期“甘肃省高台县臭泥墩—西小口子地区三幅1∶5万矿产远景调查”项目基础上，通过开展专题地质填图、矿产综合信息预测、智能找矿预测等工作，部署实施钻孔ZK1201，以期实现找矿突破。
2. 研究方法（Methods）
利用研究区地质调查、磁法、激电测深、化探数据和无人机影像等资料，开展综合信息解译。采用卷积和孪生网络神经网络模型对区内典型金属矿床成矿作用特征标志、油气赋矿层位进行深度学习，提出工程验证建议。钻探验证所采用钻机为汽车钻，整机包括车底盘、动力系统、液压系统、操控系统等。
3. 结果（Results）
在综合研究和智能预测的基础上，布设的ZK1201孔在钻穿早二叠世花岗闪长岩（图 1c）后，钻遇地层，续钻至393.8 m后终孔（图 1c）。此次工作共钻遇中侏罗统龙凤山组地层220 m，共发现14层油层（总厚145 m，单层最大厚度28 m，最小厚度1.4 m）。钻孔含油性由上部砾岩（油斑级以下）向下部砂岩（富含油或饱含油）逐渐增多，其中高角度裂缝普遍见可流动原油（图 1d~g）。经国家地质实验测试中心分析，原油中饱和烃、芳烃含量分别占32.4%和34.6%，为高品质轻质原油。原油中正构烷烃分布完整，主峰碳数、奇偶优势及甾烷和藿烷分布都指示其陆相烃源岩来源。
野外地质调查发现，白垩系庙沟组近水平发育，与下伏侏罗系龙凤山组呈角度不整合接触。庙沟组主要由厚层暗色泥岩组成，并发育薄层暗色粉砂质泥岩，可能为区域烃源岩层。初步判断成熟的烃源岩排出的油气沿角度不整合运移至侏罗系砂砾岩和砂岩储层后，被逆冲推覆花岗岩体封闭，形成构造-岩性油气藏（图 1h）。
研究发现区域内沉积盆地最南缘边界处在祁连山北缘断裂之下，最北缘处在龙首山断裂的下盘，南北跨度约80 km。区域内沉积地层较厚，其中侏罗系龙凤山组厚约2100 m，白垩系庙沟组厚约900 m，说明研究区具有较大的成藏潜力。此次油气藏的发现，预示着大青山地区具有完整的油气成藏系统，显示出良好油气勘探前景。建议进一步加强油气基础地质调查研究工作。
4. 结论（Conclusions）
（1）在大青山地区花岗岩逆冲推覆体之下的中生代沉积地层中发现原油，所发现的高品质轻质原油，具陆相烃源岩来源特征。
（2）研究区具有良好的油气勘探前景，建议进一步加强油气地质调查研究工作。
5. 致谢（Acknowledgement）
感谢甘肃省地质调查院董国强，北京探矿工程研究所渠洪杰、谭春亮以及国家实验测试中心沈斌在野外工作和样品测试过程中的协助。
-
![]()
图 1 研究区区域地质和交通图
1—第四系; 2—古近系; 3—上三叠统侵入岩; 4—上三叠统巴贡组; 5—上三叠统波里拉组; 6—上三叠统甲丕拉组; 7—上二叠统-下三叠统拉卜查日组; 8—上二叠统那益雄组; 9—中二叠统九十道班组; 10—下二叠统诺日巴尕日保组; 11—上石炭统-下二叠统扎日根组; 12—山峰及海拔高程; 13—断层; 14—地层不整合接触面; 15—地质体; 16—地名、主要公路、次要公路和季节性公路; 17—实测剖面位置
Figure 1. Geological map of the study area
1-Quaternary sediments; 2-Paleogene sediments; 3-Late Triassic intrusive rocks; 4-Late Triassic Bagong Formation; 5-Late Triassic Bolila Formation; 6-Late Triassic Jiapila Formation; 7-Late Permian-Early Triassic Labuchari Formation; 8-Late Permian Nayixiong Formation; 9-Middle Permian Jiushidaoban Formation; 10-Early Permian Nuoribagaribao Formation; 11-Late Carboniferous-Early Permian Zharigen Formation; 12-Mountain and elevation above sea level; 13-Fault; 14-Stratigraphic unconformity; 15-Geological body; 16-Place names, major highways, secondary highways and seasonal highways; 17-Location of measured geological section
![]()
图 2 青海省唐古拉地区拉卜查日组典型牙形石化石
a—Hindeodus praeparvus，侧视，产出层位：青海唐古拉地区拉卜查日组；b—Hindeodus typicalis，侧视，产出层位：青海唐古拉地区拉卜查日组；c—Hindeodus eurypyge，侧视，产出层位：青海唐古拉地区拉卜查日组（以上化石放大倍数均为140）
Figure 2. Representative photographs of Conodon from Labuchari Formation in Tanggula Range, Qinghai Province
![]()
图 3 青海省唐古拉地区晚二叠世—早三叠世拉卜查日组柱状图
Figure 3. Geological column of Late Permian Labuchari Formation in Tanggula Range, Qinghai Province
![]()
图 4 青海省唐古拉地区晚二叠世—早三叠世拉卜查日组锶同位素演化曲线和相对海平面变化曲线
Figure 4. Strontium stratigraphy and corresponding sea level change curves of Late Permian Labuchari Formation in Tanggula Range, Qinghai Province
表 1 青海唐古拉地区乌丽群拉卜查日组海相碳酸盐87Sr/86Sr测试结果
Table 1 87Sr/86Sr composition of marine carbonate of Late Permian Labuchari Formation in Tanggula Range, Qinghai Province
下载: 导出CSV
-
[1] Palmer M R, Edmond J M.The strontium isotope budget of the modern ocean[J].Earth Planet Sci.Lett., 1989, 92:11-26. doi: 10.1016/0012-821X(89)90017-4
[2] Palmer M R, Elderfield H.Sr isotope composition of sea water over the past 75 Myr[J].Nature, 1985, 314:526-528. doi: 10.1038/314526a0
[3] Denison R E, Koelpnick R B, Burke W H, et al.Compositon of the Mississippian, Pennsylvanian and Permian Seawater 87Sr/86Sr curve[J].Chem.Geol., 1994, 112:145-167. doi: 10.1016/0009-2541(94)90111-2
[4] Montanez I P, Osleger D A, Banner J L, et al.Evolution of the Sr and C isotope composition of Cambrian oceans[J].GSA Today, 2000, 10:1-7. https://www.researchgate.net/publication/236004404_Evolution_of_the_Sr_and_C_isotope_composition_of_Cambrian_oceans
[5] Verzer J, Ala D, Azmy K, et al.87Sr/86Sr, 13C and 18O evolution of Phanerozoic seawater[J].Chem.Geol., 1999, 161:59-88. doi: 10.1016/S0009-2541(99)00081-9
[6] Denison R E, Denison R E, Koepnick R B, et al.Construction of the Cambrian and Ordovician seawater 87Sr/86Sr curve[J].Chem.Geol., 1998, 152:325-340. doi: 10.1016/S0009-2541(98)00119-3
[7] Denison R E, Kirkland D W, Evans R.Using strontium isotopes to determine the age and origin of gypsum and anhydrite beds[J].J.Geol., 1998, 106:1-17. doi: 10.1086/515996
[8] Alleger C J, Gaillardet J, Meynadier L.The evolution of sea water strontium isotope in the last hundred million years:Reinterpretation and consequence for erosion and climate models.Eos.Transactions, American Geophysical Union, 1996, 77(46, Suppl.):325.
[9] Ebneth S, Diener A, Buhl D, et al.Strontium isotope systematic of conodonts:Middle Devonian, Eifel Mountaions, Germany[J].Palaeogergr Palaeoclimatol Palaeoecol, 1997, 132:79-96. doi: 10.1016/S0031-0182(97)00057-6
[10] Dingle R V, McArthur J M, Vroon P.Oligocene and Pliocene interglacial events in the Antarctic Peninsula dated using strontium isotope stratigraphy[J].J.Geol.Soc.Lond, 1997, 154:257-264. doi: 10.1144/gsjgs.154.2.0257
[11] Diener A, Ebneth S, Veizer J, et al.Strontium isotope stratigraphy of the Middle Devonian:Brachiopods and conodonts[J].Geochim.Cosmochim.Acta, 1996, 60:639-652. doi: 10.1016/0016-7037(95)00409-2
[12] Hess J, Bender M L, Schilling J G.Evolution of the ratio of Strontium-87 to Strontium-86 in sea water from Cretaceous to present[J].Science, 1986, 231:979-984. doi: 10.1126/science.231.4741.979
[13] Miller K G, Feigenson M D, Wright J D, et al.Miocene isotope reference section, deep sea drilling project site 608:An evaluation of isotope and biostratigraphic resolution[J].Paleoceanography, 1991, 6:33-52. doi: 10.1029/90PA01941
[14] McArthur J M, Kennedy W J, Chen M, et al.Strontium isotope stratiaraphy for the Late Creataceoustime:Direct numerical calibration of the Sr-isotope curve based on the U.S.Western Interior[J].Palaeogerogr Palaeoclim Palaeoecol, 1994, 108:95-119. doi: 10.1016/0031-0182(94)90024-8
[15] McArthur J M, Howarth R J, Bailey T R.Strontium isotope strtigraphy:LoWESS Version 3:Best fit to the marine Sr-isotope curve for 0-509 Ma and accompanying look-up table for deriving numerical age[J].J.Geol., 2001, 109:155-170. doi: 10.1086/319243
[16] Howarth R J, McArthur J M.Statistics for strontium isotope stratigraphy:A robust LOWESS fit to marine Sr-isotope curve for 0 to 206 Ma, with lookup table for derivation of numeric age[J].J.Geol., 1997, 105:441-456. doi: 10.1086/515938
[17] 王曦, 万晓樵, 李国彪.西藏岗巴晚白垩世-古近纪早期锶同位素地层[J].中国地质, 2008, 35(4):598-607. http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20080404&flag=1 Wang Xi, Wan Xiaoqiao, Li Guobiao.Late Cretaceous to early Paleogene strontium isotopic stratigraphy in the Gamba area, Tibet[J].Geology in China, 2008, 35(4):598-607(in Chinese with English abstract). http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20080404&flag=1
[18] 马丽艳, 白云山, 牛志军, 等.长江源各拉丹冬地区晚三叠世火山岩锶、钕同位素地球化学特征及其意义[J].中国地质, 2004, 31(2):174-178. http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20040209&flag=1 Ma Liyan, Bai Yunshan, Niu Zhijun, et al.Sr and Nd isotope geochemistry of Late Triassic volcanic rocks at Gêladaindong in the source region of the Yangtze River and its significance[J].Geology in China, 2004, 31(2):174-178(in Chinese with English abstract). http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20040209&flag=1
[19] 牛志军, 马丽艳, 曾波夫.长江源各拉丹东地区晚二叠世乌丽群的腕足类生物组合[J].地球学报, 2003, 24(4):343-348. http://www.cnki.com.cn/Article/CJFDTOTAL-DQXB200304011.htm Niu Zhijun, Ma Yanli, Zeng Bofu.Late Permian Brachiopod Faunas from Wuli Group of Geladandong Mountain area in the source region of the Yangtze River[J].Acta Geoscientia Sinica, 2003, 24(4):343-348(in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTOTAL-DQXB200304011.htm
[20] 牛志军, 姚华舟, 曾波夫, 等.长江源各拉丹东地区晚二叠世乌丽群蜓类生物组合[J].地层学杂志, 2004, 28(3):270-276. http://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ200403013.htm Niu Zhijun, Yao Huazhou, Zeng Bofu, et al.Late Permian Fusulinid assemblages from Geladong in the source region of Yangtze River Qinghai[J].Journal of Stratigraphy, 2004, 28(3):270-276(in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ200403013.htm
[21] 廖卓庭, 徐均涛.青海格尔木市乌丽晚二叠世乌丽群下部的腕足化石群及Waagenites的地理分布[J].古生物学报, 2002, 41(1):130-136. http://www.cnki.com.cn/Article/CJFDTOTAL-GSWX200201012.htm Miao Zhouting, Xu Juntao.Late Permian Brachiopods from the Lower part of the Wuli Group, southwestern Qinghai and the geographic distribution of Waagenites[J].Palaeontologica Sinica, 2002, 41(1):130-136(in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTOTAL-GSWX200201012.htm
[22] 刘广才, 田琪.青海唐古拉山中段二叠纪地层新资料[J].中国区域地质, 1993, (2):113-120. http://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD199302002.htm Liu Guangcai, Tian Qi.New data of Permian strata in the central sector of the Tanggula mountains, Qinghai[J].Regional Geology of China, 1993, (2):113-120(in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD199302002.htm
[23] 季长军, 伊海生, 夏国清.图像分析技术在碎屑岩粒度分析中的应用[J].地质科技情报, 2012, 31(3):122-127. http://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201203020.htm Ji Changjun, Yi Haisheng, Xia Guoqing.Animage——Analysis technique to measure grain-size variation in thin sections of clastic sediments[J].Geological Science and Tenchnology Information, 2012, 31(3):122-127(in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201203020.htm
[24] 张发德, 岳天祥, 宋令莉.通天河上游墩日含煤岩系地层时代的新认识[J].青海地质, 1998, 6-10. http://www.cnki.com.cn/Article/CJFDTOTAL-GTJL199802001.htm Zhang Fade, Yue Tianxiang, Song Linli.New recognition on the stratigraphic age of dunri coal-bearing rock series in the upper reaches of Tongtian River[J].Qinghai Geology, 1998, 6-10(in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTOTAL-GTJL199802001.htm
[25] 程裕淇.中国区域地质概论[M].北京:地质出版社, 1994, 280-290. Cheng Yuqi.China's Regional Geological Survey[M].Beijing:Geological Publishing House, 1994:280-290(in Chinese with English abstract).
[26] 潘桂棠, 肖庆辉, 陆松年, 等.中国大地构造单元划分[J].中国地质, 2009, 36(1)1-28. http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20090101&flag=1 Pan Guitang, Xiao Qinghui, Lu Songnian et al.Subdivision of tectonic units in China[J].Geology in China, 2009, 36(1)1-28(in Chinese with English abstract). http://geochina.cgs.gov.cn/ch/reader/view_abstract.aspx?file_no=20090101&flag=1
[27] 潘桂棠, 丁俊, 姚东生, 等.青藏高原及邻区地质图说明书[M].成都地图出版社, 2000:8-10. Pan Guitang, Ding Jun, Yao Dongsheng, et al.Geological map Specification of The Tibetan Plateau and Its Adjacent Area[M].Chengdu:Map Publishing House of Chengdu, 2000:8-10.
[28] 林甲兴.论加罗威蜓(Gallowayinella)的时代及其地层意义[J].中国地质科学院院报宜昌地质矿产研究所分刊, 1980, 1(2):37-45. Lin Jiaxing.Discussing age and stratigraphical significance of Gallowayinella[J].Journal of Chinese Academy Of Geological Sciences, Part of Yichang Institute of Geology and Mineral Resources, 1980, 1(2):37-45.
[29] 盛金章, 苪琳.Gallowayinella的时代——兼论长兴阶与吴家坪阶的分界[J].地层学杂志, 1980, 4(3):233-235 http://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ198003008.htm Sheng Jinzhang, Bin Lin.Age of Gallowayinella and Wuchiapingian Changhsingian boundary[J].Journal of Stratigraphy, 1980, 4(3):233-235(in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ198003008.htm
[30] Kozur H.The taxonomy of the gondolellid conodonts in the Permian and Triassic[J].Courier Forschungsinstitut Senckenberg, 1989, 116:409-469.
[31] Ding Meihua, Lai Xulong, Zhang Kexin.Conodont sequences and their lineages in the Permian-Triassic boundary strata at the Meishan section, south China[C]//Wang N, Remane J (eds.).Proceedings of 30th International Geological Congress.Vol.11.Netherland:VSP.1997:153-162.
[32] Ding Meihua, ZhangKexin, Lai Xulong.Evolution of Clarkinalineage and Hindeo dus-Isarcicellalinea geat Meishan Section, South China.In:Yin Hong-fu (ed.), The Palae ozoic Mesozoic Boundary Candidates of Global Stratotype Section and Point of the Permian-Triassic Boundary[M].Wuhan:China U niversity of Geosciences Press, 1996:65-71.
[33] Wang Chengyuan, Kozur H, Ishiga H et al.Permian-Triassic boundary at Meishan of Changxing County, Zhejiang Province, China——a proposal on the Global Stratotype Section and Point (GSSP) for the base of Triassic[J].Acta Micropalaeontologuca Sinica, 1996, 13(2):109-124. http://en.cnki.com.cn/Article_en/CJFDTOTAL-WSGT602.000.htm
[34] Tian Shugang.Evolution of conodont genera Neogondolella, Hindeodus and Isarcicella in northwestern Hunan, China[J].Stratigraphy and Palaeontology of China, 1993, 2:173-191
[35] Mei Shilong, Zhang Kexin, Wardlaw B R.A refined succession of Changhingian and Griesbachian neogondolellid conodonts from the Meishan section, candidate of the global stratotype section and point of the Permian-Triassic boundary[J].Palaeogeography, Paleoclimatology, Palaeoecology, 1998, 143:213-226. doi: 10.1016/S0031-0182(98)00112-6
[36] Jiang Haishui, Lai Xulong, Luo Genming, et al.Restudy of conodont Zonation and evolution across P/T Boundary at Meishan Section, Changxing, Zhejing, China[J].Global and Planetary Changes.2007, 55:39-55. doi: 10.1016/j.gloplacha.2006.06.007
[37] 陈军, Charles M Henderson, 沈树忠.浙江黄芝山剖面二叠-三叠系界线附近的牙形类序列及其地层对比[J].古生物学报, 2008, 47(1):91-114. Chen Jun, Charles M Henderson, Shen Shuzhong.Conodont succession around the Permian-Trisssic Boundary at The Huangzhishan Section, Zhejiang and its stratigraphic correlation[J].Acta Palaeontologica Sinica, 2008, 47(1):91-114(in Chinese with English abstract).
[38] 王训练, 苏文博.选择全球界线层型剖面点的一个重要参考标准[J].科学通报, 1999, 44(18):2008-2016. http://www.cnki.com.cn/Article/CJFDTOTAL-KXTB199918019.htm Wang Xunlian, Su Wenbo.An important reference standard of selecting the global boundary stratotype section (GSSP).Chinese Science Bulletin[J].1999, 44(18):2008-2016(in Chinese). http://www.cnki.com.cn/Article/CJFDTOTAL-KXTB199918019.htm
[39] Korte C, Jasper T, Kozur H W, et al.87Sr/86Sr record of Permian seawater[J].Paleogeogr Paleoclimatol Paleoecol, 2006, 240:89-107. doi: 10.1016/j.palaeo.2006.03.047
[40] Jasper T Strontium, Sauerstoff, Kohlenstoff Isotopische Entwicklung des Meerwassers:Perm[D].Ph.D.Thesis.Ruhr-Universitat Bochum.1999.
计量
- 文章访问数:
- HTML全文浏览量: 0
- PDF下载量:
