Petrology, mineralogy and metamorphic p-T path of eclogites from the Qianmai area, Lancang County, western Yunnan Province
-
摘要:
澜沧谦迈地区位于西南三江昌宁-孟连结合带中段。新近在该地区发现榴辉岩，与双江县勐库地区退变榴辉岩一样，谦迈地区榴辉岩也产于湾河蛇绿混杂岩带内，岩石新鲜，后期退变质作用改造弱，岩石学信息保留完整。主要矿物成分为石榴子石、绿辉石、多硅白云母、金红石、角闪石、绿帘石、石英等，直接围岩为白云（钠长）片岩和斜长角闪岩，白云（钠长）片岩主要由多硅白云母、石英和长石构成。根据岩石学和矿物学特征将谦迈地区榴辉岩划分为4个变质阶段，其中峰期矿物组合为石榴子石+绿辉石+多硅白云母+硬柱石+蓝闪石+金红石+石英。初步研究表明，峰期榴辉岩相变质温度和压力分别为600℃和2.5GPa。新发现的榴辉岩为研究三江地区特提斯构造演化提供了关键性资料，该榴辉岩变质演化p-T轨迹的研究对探讨古特提斯洋的俯冲-造山过程具有重要意义。
Abstract:Eclogite was newly discovered in the Qianmai area within the Changning-Menglian suture zone in the Sangjiang area, southwest China. Qianmai eclogites, like retrograded eclogites in the Mengku area of Shuangjiang County, occur within the Wanhe ophiolitic mélange. The studied eclogites are fresh with weak retrogression. The main mineral compositions include garnet, omphacite, phengite, rutile, amphibole, epidote and quartz. The surrounding rocks include muscovite (albite) schist and plagioclase amphibolite. The muscovite (albite) schist is mainly composed of phengite, quartz and feldspar. Four-stage metamorphic evolution was identified in according to the petrological and mineralogical analyses. The peak mineral association includes garnet+omphacite+ phengite+ lawsonite+glaucophane+rutile+quartz. The peak eclogite-facies metamorphic temperature and pressure are 600℃ and 2.5GPa, respectively. The newly discovered eclogite provides important information for the study of the Tethyan tectonic evolution in Sanjiang region. The metamorphic p-T path of the eclogites is of great significance for investigating the subduction-orogeny process of the Paleo-Tethys Ocean.
-
Keywords:
- eclogite /
- mineralogy /
- petrology /
- p-T path /
- Changning-Menglian suture zone /
- Qianmai area in Lancang County
-
致谢: 在岩相学研究过程中，得到中国地质科学院地质研究所刘福来研究员和云南省地质调查院李静教授级高工的大力帮助并进行了有益的讨论；云南省地质调查院徐桂香教授级高工对岩石显微镜下观察提供了帮助；审稿专家对文章提出了细致、中肯的建议，在此一并致以衷心的谢忱。
-
![]()
![]()
图 2 澜沧县谦迈地区地质简图
（底图据参考文献①）
Pt1D.—古元古界大勐龙岩群；Pt2L.—中元古界澜沧岩群；Pt2t.—中元古界团梁子岩组；Pz2dx.—上古生界大新山岩组；DCn—泥盆系-石炭系南段组；C1pz—石炭系平掌组； Pl—二叠系拉巴组；J2mh2—侏罗系芒汇组二段；J2h—侏罗系花开组；J3b—侏罗系坝注路组；N2m—新近系芒棒组；Qh—第四系冲积层；γK—白垩纪花岗岩；ηγaT—三叠纪片麻状黑云二长花岗岩；ηγbT—三叠纪似斑状黑云二长花岗岩；ηγcT—三叠纪中-粗粒黑云二长花岗岩；γδP—二叠纪花岗闪长岩；NPt2—中元古代基性岩Figure 2. Simplified geological map of the Qianmai area in Lancang County
![]()
图版Ⅰ
a.澜沧县糯扎渡镇黑河剖面白云母片岩；b.澜沧县糯扎渡镇黑河剖面条带状榴辉岩；c.澜沧县糯扎渡镇黑河剖面榴辉岩呈透镜体产出；d.澜沧县糯扎渡镇黑河剖面致密块状榴辉岩；e.澜沧县谦迈乡谦迈河剖面白云母片岩；f.澜沧县谦迈乡谦迈河剖面中细粒致密块状榴辉岩
图版Ⅰ.
![]()
图版Ⅱ
a.榴辉岩中石榴子石呈自形近等轴多边形，正高突起，内部发育不规则裂纹（单偏光），部分颗粒具蓝绿色角闪石反应边；b.绿辉石呈他形柱状、粒状、无色-淡绿色，具微弱多色性，正高突起，具辉石式解理（单偏光）；c.早期角闪石呈褐色，晚期角闪石呈淡绿色，围绕石榴子石形成环状反应边，为降压退变形成退变边（单偏光）；d.金红石呈褐红色，不规则粒状，正高突起，以包裹体形式产于绿辉石中（单偏光）；e.石榴子石中细小石英包裹体（正交偏光）；f.定向、半定向绿辉石、石榴子石和少量多硅白云母之间以简单近平直边界相互紧密镶嵌，为近平衡共生组合（正交偏光）；g.自形-半自形石榴子石变斑晶内残留绿辉石包体，局部见钠云母、绿帘石集合体组成硬柱石假象（BSE）；h.蓝闪石发生退变转化为钠钙闪石（？）（BSE）
图版Ⅱ.
![]()
图 3 榴辉岩中石榴子石Grs-(Alm+Sps)-Prp成分图解
（据参考文献[35]修改）
Prp—镁铝榴石；Grs—钙铝榴石；Alm—铁铝榴石；Sps—锰铝榴石Figure 3. Grs-(Alm+Sps)-Prp diagram of garnet from eclogites
![]()
![]()
图 5 榴辉岩中单斜辉石成分分类图解
（底图据参考文献[37]）
Aug—普通辉石；Omp—绿辉石；Agt—霓辉石；Jd—硬玉；Aeg—霓石Figure 5. Compositional classification of clinopyroxenene in the eclogite
![]()
图 6 榴辉岩中角闪石成分投影图
（底图据参考文献[38]）
Gln—蓝闪石；Win—蓝透闪石；Act—阳起石；Brs—冻蓝闪石；Ktp—红钠闪石；Mg-Hbl—镁角闪石Figure 6. Compositional plots of amphiboles in the eclogite
![]()
表 1 澜沧谦迈地区榴辉岩部分矿物的成分分析结果
Table 1 Representative mineral analysis in eclogites from Qianmai area, Lancang County
元素 18HH-1-1（围岩） 18HH-1-3 18HH-1-4 18HH-1-7 18QM-1-3 Phe Phe Grt Omp Gln Gln Grt Grt Omp Omp Grt Omp Phe Grt Omp Phe SiO2 51.48 53.88 37.59 54.97 57.93 58.73 36.92 37.81 52.65 51.68 38.86 57.75 53.48 39.35 55.72 52.52 TiO2 0.63 0.55 0.02 0.00 0.05 0.06 0.13 0.00 0.13 0.16 0.01 0.08 0.14 0.10 0.07 0.31 Al2O3 26.45 23.60 19.83 8.96 9.50 10.17 19.67 20.90 7.65 4.90 21.73 11.92 23.83 21.35 8.81 27.49 Cr2O3 0.09 0.17 0.06 0.06 0.07 0.00 0.01 0.03 0.05 0.02 0.04 0.03 0.04 0.09 0.03 0.36 FeO 2.92 4.09 29.35 7.73 7.78 7.47 32.82 27.73 9.70 9.07 25.41 3.73 1.88 21.73 6.20 1.09 MnO 0.03 0.04 0.26 0.00 0.06 0.02 1.16 1.03 0.18 0.38 0.31 0.01 0.00 0.51 0.07 0.01 MgO 2.54 2.58 5.77 7.34 13.25 13.13 2.09 4.52 15.36 18.38 7.16 6.78 3.85 8.65 8.39 3.60 CaO 0.03 0.06 6.45 12.36 3.36 1.47 7.21 7.80 9.06 11.28 5.85 10.88 0.00 7.43 14.39 0.00 Na2O 0.36 0.41 0.01 7.27 5.51 6.24 0.00 0.00 2.94 1.68 0.01 8.22 0.46 0.02 5.61 0.51 K2O 10.71 10.32 0.00 0.01 0.05 0.01 0.00 0.00 0.03 0.04 0.00 0.00 11.92 0.00 0.02 10.08 合计 95.24 95.70 99.34 98.70 97.56 97.30 100.01 99.82 97.75 97.59 99.38 99.40 95.62 99.24 99.32 95.97 O 11 11 12 6 23 23 12 12 6 6 12 6 11 12 6 11 Si 3.45 3.60 2.97 1.99 7.92 7.99 2.97 2.98 1.94 1.91 3.02 2.04 3.57 3.02 2.02 3.44 Ti 0.03 0.03 0.00 0.00 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.00 0.02 Al 2.09 1.86 1.85 0.38 1.53 1.63 1.87 1.94 0.33 0.21 1.99 0.50 1.88 1.93 0.38 2.13 Cr 0.01 0.01 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.02 Fe3+ 0.00 0.00 0.21 0.14 0.04 0.01 0.18 0.11 0.00 0.08 0.00 0.00 0.00 0.01 0.00 0.00 Fe2+ 0.16 0.23 1.72 0.09 0.85 0.84 2.03 1.72 0.30 0.20 1.65 0.11 0.11 1.39 0.19 0.06 Mn 0.00 0.00 0.02 0.00 0.01 0.00 0.08 0.07 0.01 0.01 0.02 0.00 0.00 0.03 0.00 0.00 Mg 0.25 0.26 0.68 0.40 2.70 2.66 0.25 0.53 0.84 1.02 0.83 0.36 0.38 0.99 0.45 0.35 Ca 0.00 0.00 0.55 0.48 0.49 0.21 0.62 0.66 0.36 0.45 0.49 0.41 0.00 0.61 0.56 0.00 Na 0.05 0.05 0.00 0.51 1.46 1.65 0.00 0.00 0.21 0.12 0.00 0.56 0.06 0.00 0.39 0.07 K 0.92 0.88 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.02 0.00 0.00 0.84 阳离子 6.96 6.92 8.00 4.00 15.03 15.01 8.01 8.01 3.99 4.00 7.99 3.99 7.02 8.00 3.99 6.92 注：Phe—多硅白云母；Grt—石榴子石；Omp—绿辉石；Gln—蓝闪石。主量元素含量单位为%，其他为离子数mol 
下载: 导出CSV
-
刘本培, 冯庆来, 方念桥, 等.滇西昌宁-孟连和澜沧江带带古特提斯多岛洋构造演化[J].地球科学, 1993, 18(5):529-539. 钟大赉.滇川西部古特提斯造山带[M].北京:科学出版社, 1998:1-231. Fang N Q, Liu B P, Feng Q L, et al. Late Palaeozoic and Triassic deep-water deposits and tectonic evolution of the Palaeotethys in the Changning-Menglian and Lancangjiang belts, southwestern Yunnan[J]. Journal of Southeast Asian Earth Sciences, 1994, 9(4):363-374. doi: 10.1016/0743-9547(94)90048-5
Wu H R, Boulter C A, Ke B J, et al. The Changning-Menglian suture zone; a segment of the major Cathaysian-Gondwana divide in Southest Asia[J]. Tectonophysics, 1995, 242(3/4):267-280.
潘桂棠, 徐强, 侯增谦, 等.西南"三江"多岛弧造山过程、成矿系统与资源评价[M].北京:地质出版社, 2003. 李文昌, 潘桂棠, 侯增谦, 等.西南"三江"多岛弧盆-碰撞造山成矿理论与勘查技术[M].北京:地质出版社, 2010. Metcalfe I. Gondwana dispersion and Asian accretion:Tectonic and palaeogeographic evolution of eastern Tethys[J]. Journal of Asian Earth Sciences, 2013, 66:1-33. doi: 10.1016/j.jseaes.2012.12.020
Masatoshi S, Metcalfe I. Parallel Tettyan Sutures in mainland SE Asia:new issights for Palaeo-Tethys closure[J]. Comptes Rendus Geoscience, 2008, 340(2/3):166-179.
Burchfiel B C, Chen Z L. Tectonics of the Southeastern Tibetan plateau and Its Adjacent Foreland[J]. Boulder, Colorado:Geological Society of America, 2013, 210:1-64. doi: 10.1130/9780813712109
段向东, 张志斌, 冯庆来, 等.滇西南耿马弄巴地区南皮河组层型剖面地层层序、时代的重新认识[J].地层学杂志, 2003, 27(1):59-65. doi: 10.3969/j.issn.0253-4959.2003.01.011 段向东, 李静, 曾文涛, 等.昌宁-孟连中段干龙塘构造混杂岩的发现[J].云南地质, 2006, 25(1):53-62. doi: 10.3969/j.issn.1004-1885.2006.01.008 张凡, 冯庆来, 段向东, 等.滇西南昌宁-孟连构造带西带研究初探——以耿马弄巴剖面为例[J].地质科技情报, 2006, 25(3):13-20. doi: 10.3969/j.issn.1000-7849.2006.03.003 杨文强, 冯庆来, 段向东, 等.滇西南昌宁-孟连构造带晚泥盆世枕状玄武岩和硅质岩的特征[J].地质通报, 2007, 26(6):739-747. doi: 10.3969/j.issn.1671-2552.2007.06.016 李静.云南省双江县牛井山蛇绿混杂岩的岩石学研究[D].昆明理工大学硕士学位论文, 2004. 赖绍聪, 秦江峰, 李学军, 等.昌宁-孟连缝合带干龙塘-弄巴蛇绿岩地球化学及Sr-Nd-Pb同位素组成研究[J].岩石学报, 2010, 26(11):3195-3195. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201011004 王保弟, 王立全, 潘桂棠, 等.昌宁-孟连结合带南汀河早古生代辉长岩锆石年代学及地质意义[J].科学通报, 2013, 58(4):344-354. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=kxtb201304008 王保弟, 王立全, 王冬兵, 等.三江昌宁-孟连带原-古特提斯构造演化[J].地球科学, 2018, 43(8):2527-2550. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=0120181201777546 Nie X M, Feng Q L, Qian X, et al. Magmatic record of Prototethyan evolution in SWYunnan, China:Geochemical, zircon U-Pb geochronological and Lu-Hf isotopic evidence from the Huimin metavolcanicrocks in the southern Lancangjiang zone[J]. Gondwana Research, 2015, 28(2):757-768. doi: 10.1016/j.gr.2014.05.011
Xing X W, Wang Y J, Cawood P A, et al. Early Paleozoic accretionary orogenesis along northern margin of Gondwana constrained by high-Mg metaigneous rocks, SW Yunnan[J]. Internation Journal of Earth Sciences, 2017, 106(5):1469-1486. doi: 10.1007/s00531-015-1282-z
王冬兵, 罗亮, 唐渊, 等.昌宁-孟连结合带牛井山早古生代埃达克岩锆石U-Pb年龄、岩石成因及其地质意义[J].岩石学报, 2016, 32(8):2317-2329. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201608006 王冬兵, 罗亮, 唐渊, 等.昌宁-孟连结合带斜长角闪岩锆石UPb年龄、地球化学特征及其地质意义[J].沉积与特提斯地质, 2017, 37(4):17-28. doi: 10.3969/j.issn.1009-3850.2017.04.004 刘桂春, 孙载波, 曾文涛, 等.滇西双江县勐库地区湾河蛇绿混杂岩的厘定、地球化学特征及其地质意义[J].岩石矿物学杂志, 2017, 36(2):163-174. doi: 10.3969/j.issn.1000-6524.2017.02.003 孙载波, 曾文涛, 周坤, 等.昌宁-孟连结合带奥陶纪洋岛玄武岩的识别及其构造意义——来自地球化学和锆石U-Pb年龄的证据[J], 地质通报, 2017, 36(10):1760-1772. doi: 10.3969/j.issn.1671-2552.2017.10.008 毛晓长.保山-镇康地块及邻区早古生代地质特征及特提斯构造演化[D].中国地质大学(北京)博士学位论文, 2016. http://cdmd.cnki.com.cn/Article/CDMD-11415-1016067860.htm 彭智敏, 张辑, 关俊雷, 等.滇西"三江"地区临沧花岗岩基早-中奥陶世花岗质片麻岩的发现及意义[J].地球科学, 2018, 43(8):2571-2582. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=0120181201779100 李静, 孙载波, 徐桂香, 等.滇西双江县勐库地区榴闪岩的发现与厘定[J].矿物学报, 2015, 35(4):421-424. http://d.old.wanfangdata.com.cn/Periodical/kwxb201504001 李静, 孙载波, 黄亮, 等.滇西勐库退变质榴辉岩的p-T-t轨迹及地质意义[J].岩石学报, 2017, 33(7):2285-2291. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201707022 徐桂香, 曾文涛, 孙载波, 等.滇西双江县勐库地区(退变质)榴辉岩的岩石学、矿物学特征[J].地质通报, 2016, 35(7):1036-1045. http://dzhtb.cgs.cn/gbc/ch/reader/view_abstract.aspx?file_no=20160701&flag=1 陈光艳, 徐桂香, 孙载波, 等.滇西双江县勐库地区退变质榴辉岩中闪石类矿物的成因研究[J].岩石矿物学杂志, 2017, 36(1):36-47. doi: 10.3969/j.issn.1000-6524.2017.01.003 孙载波, 李静, 周坤, 等.滇西双江县勐库地区退变质榴辉岩的岩石地球化学特征及其地质意义[J].岩石矿物学杂志, 2017, 31(4):746-756. http://d.old.wanfangdata.com.cn/Periodical/xddz201704009 孙载波, 李静, 周坤, 等.滇西双江县勐库地区退变质榴辉岩的锆石U-Pb年代学及其地质意义[J].地质通报, 2018, 37(11):2032-2043. http://dzhtb.cgs.cn/gbc/ch/reader/view_abstract.aspx?file_no=20181109&flag=1 Wang H N, Liu F L, Li J, et al. Petrology, geochemistry and p-T-t path of lawsonite bearing ecloites in the ChangningMengkian orogenic belt, southeast Tibetan Plateau[J]. Journal of Metamorphic Geology, 2018, 290:32-48.
沈其韩.推荐一个系统的矿物缩写表[J].岩石矿物学杂志, 2009, 28(5):495-500. doi: 10.3969/j.issn.1000-6524.2009.05.011 Whitney D L, Evans B W. Abbreviations for nanmes of rockforming minerals[J]. American Mineralogist, 2010, 95(1):185-187. doi: 10.2138/am.2010.3371
Coleman R G, Lee D E, Beatty L B, et al. Eclogites:their difference and similarities[J]. Geological Society America Bulletin, 1965, 76:483-508. doi: 10.1130/0016-7606(1965)76[483:EAETDA]2.0.CO;2
Morimoto N. Nomenclature of pyroxense[J]. Mineralogical Magazine, 1988, 52:535-550. doi: 10.1180/minmag.1988.052.367.15
Clarke G L, Aitchison J C, Cluzel D. Eclogites and blueschists of Pam Penisula, NE New Caledonia:a reappraisal[J]. Journal of Petrology, 1997, 38:843-876. doi: 10.1093/petroj/38.7.843
Leake B E, Woolley A R, Arps C E S, et al. Nomenclature of amphiboles:Report of the subcommittee on amphiboles of the International Mineralogical Association, Commission on new minerals and mineral names[J]. American Mineralogist, 1997, 61:295-321. doi: 10.1180-minmag.1997.061.405.13/
Reinecke T. Prograde high-to ultrahigh-pressure metamorphism and exhumation of oceanic sediments at Lago di Cignana, Zermattsaas Zone, western Alps[J]. Lithos, 1998, 42:147-189. doi: 10.1016/S0024-4937(97)00041-8
Ravna E J K. The garnet-clinopyroxene Fe2+-Mg geothermometer:an updated calibration[J]. Journal of Metamorphic Geology, 2000, 18(2):211-219. doi: 10.1046/j.1525-1314.2000.00247.x
Ravna E J K, Terry M P. Geothermobarometry of UHP and HP eclogites and schists-an evaluation of equilibria among garnetclinopyroxene-kyanite-phengite-coesite/uartz[J]. Journal of Metamorphic Geology, 2004, 22:579-592. doi: 10.1111/jmg.2004.22.issue-6
Liou J G, Zhang R Y, Ernst W G. High-pressure minerals from deeply subducted metamorphic rocks[J]. Review in Mineralogy, 1998, 37:33-96. http://d.old.wanfangdata.com.cn/NSTLQK/NSTL_QKJJ0210561428/
Zack T, Rivers T, Brumm R, et al. Cold subduction of oceanic crust:implication from a lawsonite eclogite from the Dominican Republic[J]. European Journal of Mineralogy, 2004, 16:909-916. doi: 10.1127/0935-1221/2004/0016-0909
Whitney D L, Davis P B. Why is lawsonite eclogite so rare? Metamorphism and preservation of lawsonite eclogite, Sivrihisar, Turkey[J]. Geological Society of America, 2006, 34(6):473-476.
Whitney D L, Evans B W. Abbreviations for names of rockforming minerals[J]. American Mineralogist, 2010, 95(1):185-187. doi: 10.2138/am.2010.3371
Tsujimori T, Sisson V B, Liou J G, et al. Very-low-temperature record of the subduction process:a review of worldwide lawsonite eclogites[J]. Lithos, 2006, 92:609-624. doi: 10.1016/j.lithos.2006.03.054
Agard P, Labrousse L, Elvevold S, et al. Discovery of Palaeozoic Fe-Mg carpholite in Motalafjella, Svalbard Caledonides:a milestone for subduction-zone gradients[J]. Geology, 2005, 33:761-764. doi: 10.1130/G21693.1
Zhang J X, Meng F C, Wan Y S. A cold Early Palaeozoic subduction zone in the North Qilian Mountains, NW China:petrological and U-Pb geochronological constraints[J]. Journal of Metamorphic Geology, 2007, 25:285-304. doi: 10.1111/jmg.2007.25.issue-3
Du J X, Zhang L F, Bader Z Y, et al. Metamorphic evolution of relict lawsonite-bearing eclogites from the (U)HP metamorphic belt in the Chinese southwestrn Tianshan[J]. Journal of Metamorphic Geology, 2014, 32:575-589. doi: 10.1111/jmg.2014.32.issue-6
云南省地质调查院. 1: 25万澜沧县、勐海县幅区域地质调查报告. 2012.
计量
- 文章访问数:
- HTML全文浏览量: 0
- PDF下载量:
