Petrochemical...as an example_Jianzhao Yin.pdf

ORIGINAL ARTICLEPetrochemical eigenvalues and diagrams for the identificationof metamorphic rocks protolith,taking the host rocksof Dashuigou tellurium deposit in China as an exampleJianzhao Yin1Shoupu Xiang2Yuhong Chao3Yuhan Yin4Hongyun Shi5Received:29 March 2022/Revised:28 October 2022/Accepted:3 November 2022/Published online:5 December 2022 The Author(s),under exclusive licence to Science Press and Institute of Geochemistry,CAS and Springer-Verlag GmbH Germany,part ofSpringer Nature 2022Abstract The Dashuigou tellurium deposit is the worldsonly known independent tellurium deposit.By restoringmetamorphic rocks protolith,we seek to understand notonly the development and evolution trajectory of the regionbut also the origin of the relevant deposits.While there aremany ways to restore metamorphic rocks protolith,wetake the host metamorphic rocks of Dashuigou telluriumdeposit and leverage various petrochemical eigenvaluesand related diagrams previously proposed to reveal thedeposits host metamorphic rocks protolith.The petro-chemical eigenvalues include molecular number,Nigglisvalue,REE parity ratio,CaO/Al2O3ratio,Fe3+/(Fe3+-+Fe2+)ratio,chondrite-normalized REE value,loga-rithmic REE value,various REE eigenvalues includingscandium,Eu/Sm ratio,total REE amount,light and heavyREEs,dEu,Eu anomaly,Sm/Nd ratio,and silicon isotoped30SiNBS-28%,etc.ThepetrochemicalplotsincludeACMs,100 mg-c-(al+alk),SiO2-(Na2O+K2O),(al+fm)-(c+alk)versus Si,(FeO+Fe2O3+TiO)Al2O3MgO,c-mg,Al2O3(Na2O+K2O),chondrite-normalizedREE model,La/Yb-REE,and Sm/Nd ratio,etc.On thebasis of these comprehensive analyses,the following con-clusions are drawn,starting from the many mantle-derivedtypes of basalt developed in the study area of differentgeological ages,combined with the previously publishedresearch results on the deposits fluid inclusions and sulfurand lead isotopes.The deposit is formed by mantledegassing in the form of a mantle plume in the late Yan-shanian orogeny.The degassed fluids are rich in nano-scalesubstances including Fe,Te,S,As,Bi,Au,Se,H2,CO2,N2,H2O,and CH4,which are enriched by nano-effect,andthen rise to a certain part of the crust in the form of mantleplume along the lithospheric fault to form the deposit.Theultimate power for tellurium mineralization was from H2flow with high energy,which was produced through radi-ation from the melted iron of the Earths outer core.The H2flow results in the Earths degassing,as well as the mantleand crusts uplift.Keywords Petrochemical diagrams and eigenvalue Protolith Metamorphic rock Independent telluriumdeposit Host rock The mantle plume Jianzhao YShoupu XYuhong CYuhan YHongyun S1College of Earth Sciences,Jilin University,2199 JiansheStreet,Changchun 130061,China2Silvercorp Metals Inc,Suite 601-Building 1,China ViewMansion,#A2 East GongTi Road,Chaoyang District,Beijing 100027,China3Engineering Geology Brigade of Jiangxi Bureau of Geology,658 Jiefangxilu Road,Nanchang 330002,Jiangxi Province,China4Xuchang Electrical Vocational College,Xuchang 461000,China5Orient Resources Ltd,9280 Kirkmond Crescent,Richmond,B.C V7E 1M8,Canada Acta Geochim(2023)42(1):103124https:/doi.org/10.1007/s11631-022-00583-61 IntroductionAs the only identified independent tellurium deposit in theworld(Yin 1996a,b),the Dashuigou tellurium deposit hasaroused widespread curiosity from domestic geologists inChina since its discovery in 1992.There exist divergentopinions on the origin of both the ore-forming elementsand the Dashuigou tellurium deposit itself(Cao et al.1994,1995;Luoetal.1994,1996;Chenetal.1994a,b,1996;Yin 1996a,b;Yin and Shi 2019;Wanget al.2000).Yin(1996a,b),Yin and Shi(2019),one of the authors ofthis paper,proposed that scattered elements including tel-lurium and bismuth originated from the deep Earth,mainlythrough the mantles degassing in the form of a mantleplume or hot spot,and enriched through nano-effect.This paper attempts to further prove the close relation-ship between the upper mantle and the origin of thedeposit,that is,the causal relationship between its forma-tion and mantle degassing in the form of a mantle plume,from the perspective of the protoliths origin of thedeposits metamorphic host rocks.More importantly,thispaper focuses on various petrochemical diagrams andnumerous eigenvalues for the protoliths restoration of themetamorphic rocks.The authors hope that this articlespublication will aid in the efforts of others who are engagedin similar metamorphic rock research.2 Regional geology and geophysics2.1 GeneralNestling in the convergence between the Indian,Eurasian,and Pacific Plates,the Dashuigou tellurium deposit islocated in the transitional belt between the Yangtze Plat-form and Songpan-Ganzi folded belt(Fig.1).Geophysicaldata indicates that the upper mantle below the regionuplifts obviously(Luo et al.1994,1996;Yin 1996a).Thearea possesses high heat flow.There is also a low-velocityand low-resistivity zone in the middle crust that is inter-preted as a decollement.It is also a gravity g