Metallogeny of the Baiyangping Lead-Zinc Polymetallic Ore Concentration Area, Northern Lanping Basin of Yunnan Province, China

The Lanping Basin in the Nujiang-Lancangjiang-Jinshajiang （the Sanjiang） area of northeastern margin of the Tibetan Plateau is an important part of eastern Tethyan metallogenic domain. This basin hosts a number of large unique sediment-hosted Pb-Zn polymetallic deposits or ore districts, such as the Baiyangping ore concentration area which is one of the representative ore district. The Baiyangping ore concentration area can be divided into the east and west ore belts, which were formed in a folded tectogene of the India-Asia continental coUisional setting and was controlled by a large reverse fault. Field observations reveal that the Mesozoic and Cenozoic sedimentary strata were outcropped in the mining area, and that the orebodies are obviously controlled by faults and hosted in sandstone and carbonate rocks. However, the oreforming elements in the east ore belt are mainly Pb-Zn -Sr-Ag, while Pb-Zn-Ag-Cu-Co elements are dominant in the west ore belt. Comparative analysis of the C-O-Sr-S-Pb isotopic compositions suggest that both ore belts had a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata; the ore- forming fluids were originated from formation water and precipitate water, which belonged to basin brine fluid system; sulfur was from organic thermal chemical sulfate reduction and biological sulfate reduction; the metal mineralization material was from sedimentary strata and basement, but the difference of the material source of the basement and the strata and the superimposed mineralization of the west ore belt resulted in the difference of metallogenic elements between the eastern and western metallogenic belts. The Pb-Zn mineralization age of both ore belts was contemporary and formed in the same metaliogenetic event. Both thrust formed at the same time and occurred at the Early Oligocene, which is consistent with the age constrained by field geological relationship.

Zinc, copper, and strontium isotopic variability in the Baiyangping Cu–Pb–Zn–Ag polymetallic ore field, Lanping Basin, Southwest China

The Baiyangping Cu-Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt,between the Jinshajiang-Ailaoshan and Lancangjiang faults,and the deposit can be divided into eastern and western ore zones.Based upon microscope observation of ore minerals and analysis of zinc,copper,and strontium isotope composition,we conclude that:(1)the zinc isotopic compositions of sphalerite from the eastern and western ore belt of the Baiyangping polymetallic ore deposits are enriched in both the heavy(-0.09‰ to+0.15‰) and light(-0.19‰ to-0.01‰)zinc isotopes.Rayleigh fractionation is likely the additional factor controlling the observed temporal and spatial variations in zinc isotopes in the two studied ore zones.The zinc isotopic composition in the Baiyangping polymetallic Pb-Zn deposits may have the same fractionation as that of magmatic-hydrothermal,VHMS,SEDEX,and MVT deposits,as demonstrated by geological and other geochemical evidence;(2) the range of δ^(65)Cu in massive tetrahedrite is from-0.06‰ to+0.12 ‰ that relates to the early stages of ore-formation,which are higher than that of venial chalcopyrite(from-0.72‰ to-0.07‰)formed at a late ore-forming stage in the western ore belt.Different ore-forming stages and alteration or leaching processes are likely the main factors controlling the observed variations in copper isotopes in the western ore zone;(3) the ^(87)Sr/^(86)Sr value of hydrothermal calcite in eastern(0.7080-0.7093) and western(0.7085-0.7113) ore belt suggested that mineralization of early calcite,with^(87)Sr/^(86)Sr values much higher than in ancient Late Triassic seawater,may be related to recrystallization from a radiogenic Sr-rich or silicifying fluid,either from the strata that the ore-forming fluid flows through or from other fluids.

Ore-forming material sources of the Baiyangping Cu-Co-Ag polymetallic deposit in the Lanping Basin,western Yunnan Province

The ore-forming material sources of the Baiyangping copper-cobalt-silver polymetallic deposit have been studied in view of the S, Pb, C, O and H isotopic characteristics and the ratio of Co/Ni of cobaltite. The results showed that sulfur in metallic sulfides may have come from a mixed sulfur-source consisting of the sulfur-source from metamorphic rocks in the basin basement with basic volcanic rocks and the sulfur-source from basin sulfates; lead in the ores was provided by the sedimentary rocks and basement rocks; CO2 in ore-forming fluids was derived from thermolysis of altered and normal marine facies carbonates and decarboxylation of sedimentary organic matter respectively; the ore-forming fluids belong to the SO4-Cl-Na-Ca-type basin thermal brines derived from paleo-meteoric waters; cobalt in the deposit may also be derived from the metamorphic rocks in the basin basement with basic volcanic rocks.

^(40)Ar-^(39)Ar Dating of Quartz from Ore in the Baiyangping Cu-Co Polymetallic Ore-Concentrated Area, Lanping Basin, Yunnan

Ar- 39Ar fast neutron activation age spectrum of quartz in ore collected from the Baiyangping Cu-Co polymetallic ore-concentrated area, Lanping Basin, is saddle-shaped. The plateau age, minimum appearance age and isochron age shown on the spectra are 56.53± 0.43 Ma, 55.52± 1.78 Ma and 55.90± 0.29 Ma respectively. The age data are consistent with each other within 1σ uncertainties. Because the given initial 40Ar/ 36Ar value of 294.7± 1.14 is very close to Nier’s value ( 295.5±5), both plateau and isochron ages may be considered as the forming time of quartz. So the age of 55.90- 56.53 Ma represents the forming age of ore deposits. It is obvious that the ore deposits were formed during the Early Himalayan period.

Giant Mineral Deposits and Their Geodynamic Setting in the Lanping Basin, Yunnan, China

There are giant mineral deposits, including the Jinding Zn-Pb and Baiyangping Ag-Co-Cu, and otherimportant mineral deposits (e.g., Baiyangchang Ag-Cu, Jinman Cu deposits, etc.) in the Lanping Mesozoic-Cenozoic Basin, Yunnan Province, China. The tabular ore-bodies and some veins hosted in terrestrial clastic rocks of the Mesozoic-Cenozoic age and no outcropping of igneous rocks in the giant deposits lead to the proposal of syngenetic origin, but the giant mineral deposits are not stratabound (e.g. MVT, sandstone- and Sedex-type). They formed in a continental red basin with intense crust movement. The mineralization is controlled by structures and lithology and occurs in different strata, and no sedimentary nature and no exhalative sediments are identified in the deposits. The deposits show some relations with organic matter (now asphalt and petroleum) and evaporates (gypsum). The middle-low-temperature (mainly 110℃ to 280℃) mineralization took place at a depth of about 0.9 km to 3.1 km during the early Himalayan (58 to 67 Ma). The salinity of ore-forming fluids is surprisingly low (1.6% to 18.0 wt% (NaCl)eq). Affected by the collision of the Indian and Eurasian plates, the mantle is disturbed under the Lanping Basin. The large-scale mineralization is closely linked with the geodynamics of the crust movement, the mantle and mantle-flux upwelling and igneous activity. Giant mineral deposits and their geodynamic setting are unique in the Lanping Basin.

The Electrical Conductivity Structure of the Lanping–Simao Basin and its Implications for Mineralization

Objective The Lanping-Simao Basin in western Yunnan, located in the southeastern margin of the Tibetan Plateau, is tectonically in the transition zone between the Gondwana and Eurasia tectonic domains. It is also the frontier zone of northeastern extrusion of the Indochina Plate towards the Eurasia Plate as well as the escape zone for the deep material. The middle axial tectonic zone, also known as the Lanping-Simao Fault （LSF） in previous study, is a giant intraplate tectonic belt composed of a series of narrow uplift belt, rupture depression zone, metamorphic belt, alteration belt and marginal fracture system, which were formed by the compressional uplift of the central depression of the Lanping-Simao Basin. This tectonic unit controls the geological evolution, seismic activity, hot spring distribution and ore formation of the LanpingSimao Basin since the Mesozoic and Cenozoic.

Tectonic Setting and Nature of the Provenance of Sedimentary Rocks in Lanping Mesozoic-Cenozoic Basin: Evidence from Geochemistry of Sandstones

The geochemical composition of sandstones in the sedimentary basin is controlled mainly by the tectonic setting of the provenance, and it is therefore possible to reveal the tectonic setting of the provenance and the nature of source rocks in terms of the geochemical composition of sandstones. The major elements, rare\|earth elements and trace elements of the Mesozoic\|Cenozoic sandstones in the Lanping Basin are studied in this paper, revealing that the tectonic settings of the provenance for Mesozoic\|Cenozoic sedimentary rocks in the Lanping Basin belong to a passive continental margin and a continental island arc. Combined with the data on sedimentary facies and palaeogeography, it is referred that the eastern part of the basin is located mainly at the tectonic setting of the passive continental margin before Mesozoic, whereas the western part may be represented by a continental island arc. This is compatible with the regional geology data. The protoliths of sedimentary rocks should be derived from the upper continental crust, and are composed mainly of felsic rocks, mixed with some andesitic rocks and old sediment components. Therefore, the Lanping Mesozoic\|Cenozoic Basin is a typical continental\|type basin. This provides strong geochemical evidence for the evolution of the paleo\|Tethys and the basin\|range transition.

Basin Fluid Mineralization during Multistage Evolution of the Lanping Sedimentary Basin,Southwestern China

The Lanping sedimentary basin has experienced a five-stage evolution since the late Paleozoic： ocean-continent transformation （late Paleozoic to early mid-Triassic）; intracontinental rift basin （late mid-Triassic to early Jurassic）; down-warped basin （middle to late Jurassic）; foreland basin （Cretaceous）; and strike-slip basin （Cenozoic）. Three major genetic types of Ag-Cu polymetallic ore deposits, including the reworked hydrothermal sedimentary, sedimentary-hydrothermally reworked and hydrothermal vein types, are considered to be the products of basin fluid activity at specific sedimentary-tectonic evolutionary stages. Tectonic differences of the different evolutionary stages resulted in considerable discrepancy in the mechanisms of formation-transportation, migration direction and emplacement processes of the basin fluids, thus causing differences in mineralization styles as well as in genetic types of ore deposit.

EVOLUTION OF ORE-FORMING FLUIDS AND Ag-Cu POLYMETAL MINERALIZATION IN THE LANPING BASIN, YUNNAN

The Lanping Mesozoic—Cenozoic sedimentary basin, situated in the Middle section of the “Sanjiang" (Nujiang—Lancangjiang—Jinshajiang) area in the east margin of the Tibet plateau, is well known for its large production of base\|metal sulphide deposits. The worldwide famous super\|large Jinding Pb\|Zn deposit is located in the middle of the basin. The evolution history of the Lanping basin since Mesozoic can be divided into six stages, i.e., ①active continental marginal basin (T 1—T 2); ②back\|arc rift basin (T 3—J 1); ③intracontinental depressive basin (J 2—J 3); ④foreland basin (K); ⑤strike\|slipping and mutual thrusting (E 1—E 3); and ⑥strike\|slipping and pull\|apart basin (N 1\|present). Three main types of Ag\|Cu polymetal deposits are recognized in the basin. Deposits of sedimentary exhalation\|hydrothermal reworking origin (type Ⅰ) are hosted chiefly in limestones, dolomitic limestones, and siliceous rocks of the Upper Triassic Sanhedong Formation (T 3 s ) in Sanshan area. Deposits formed through normal chemical sedimentation in closed to semi\|closed environments (type Ⅱ; e.g., Jinman and Baiyangchang) during the depressive and foreland basin stages occur in various horizons of Jurassic and Cretaceous ages. Hydrothermal reworking on deposits of this type during the Himalayan period are locally pronounced, especially in the west margin of the basin near the Lancangjiang thrust fault. The third deposit type in the basin (type Ⅲ; e.g., Baiyangping and Fulongchang) is the Ag\|bearing tetrahedrite vein deposits occurring almost in all Mesozoic—Cenozoic strata, especially in the Cretaceous. Ore minerals formed during synsedimentary periods of types Ⅰ and Ⅱ are relatively simple and dominated by chalcopyrite and bornite, though sphalerite, galena, pyrite, tetrahedrite and pyrite are also present. In the deposits of type Ⅲ as well as in the ores formed during the hydrothermal reworking period in deposits of type Ⅰ and Ⅱ, ore minerals are extremely complicated and characterized by predominant Ag\|bearing tetrahedrite and other complex sulfosalts of Cu\|Ni\|Co\|Fe\|As\|S and Cu\|Bi\|S series. The associated gangue minerals are mainly quartz, siderite, Fe\|dolomite, barite, and celestite.

Provenance and salt structures of gypsum formations in Pb-Zn ore-bearing Lanping basin,Southwest China

Large-scale gypsum rocks associated with world-class Pb-Zn ore formations are widely distributed in the Lanping Basin,Sowthwest China.Geochemical studies alongside field investigations were conducted in this study to determine the source and evolutionary processes of the gypsum rocks in this area.The gypsum sequences in the Lanping Basin developed in two formations:the Triassic Sanhedong Formation and the Paleogene Yunlong Formation.The gypsum hosted in the former displays a primary thick-banded structure withδ34SV-CDT values in the range of 14.5‰−14.8‰.Combined with the 87Sr/86Sr values(0.707737−0.707783)of limestone,it can be suggested that the Sanhedong Formation is of marine origin.In contrast,the gypsum from the Paleogene Yunlong Formation is characterized by the dome,bead and diapiric salt structures,wider range of both 87Sr/86Sr(0.707695−0.708629)andδ34SV-CDT values(9.6‰−17‰),thus indicating a marine source but with the input of continental materials.The initial layered salt formations were formed by chemical deposition in a basin and were later intensely deformed by collisional orogeny during the Himalaya period.As a result,variable salt structures were formed.We hereby propose an evolutionary model to elucidate the genesis of the gypsum formations in the Lanping Basin.

Cenozoic evolution of tectono-fluid and metallogenic process in Lanping Basin, western Yunnan Province, Southwest China: Constraints from apatite fission track data

Since the Mesozoic, abundant metal and salt deposits have been formed in the Lanping Basin, western Yunnan Province, Southwest China, constituting a well-known hydrothermal ore belt in China. Most of the deposits are meso-epithermal hydrothermal deposits. This paper preliminarily deals with the mineralization ages of hydrothermal deposits in the Lanping Basin by using the apatite fission track method, and integrates the spatial distribution of the deposits and their regional geological backgrounds, to give the preliminary viewpoints as follows: (1) the apatite fission track ages acquired range from 19.9 Ma to 52.8 Ma, much younger than those of their host strata, so they may be considered to be mineralization ages, which represent the late mineralization period; (2) the apatite fission track ages tend to become younger from the west to the middle of the basin, indicating that the latest evolution of tectono-fluid and/or metallogenic processes of the middle basin ended later than that in the west; (3) in the Paleogene, most of the Cu deposits were formed in the western part of the basin; (4) the major metallogenic processes occur between the Paleogene and the Neogene, because the eastern and western edges of the basin were subducted into and collided with its bilateral continental blocks, respectively, and the central fault was strongly activated, which led to the processes of large-scale ore-forming fluids, and their differentiation and transport because of the variation of their physical and chemical properties. Having been squeezed and uplifted, the Lanping Basin became an intermontane basin that contains many kinds of fluid traps resulting in the formation of different types of ore deposits (for example, Pb-Zn, Cu, Ag) of different scales in the middle of the basin. Simultaneously, the fluids with volatile elements such as Hg, Sb and As were transported upwards along the central fault system and diffused into its subordinate fractures, thus leading to the metallogenic processes of Hg, Sb and As in the eastern composite anticline of the Lanping Basin; (5) and later, these ore deposits experienced reformation and oxidization. To summarize,deep giant faults were active in the basin, and metallogenic processes were constrained by the evolution of tectono-fluids in the Lanping Basin. Simultaneously, the occurrence of the metallogenic processes made the nature of fluid and the structural environment change, which led to returning and recycling of the fluids. Multi-stage and zonational metallogenic processes are the characteristics of the ore deposits in the Lanping Basin.

Fault Zone Fluid Deep-penetrating Techniques for Potash Deposit Prediction in Lanping-Simao Basin,Yunnan,South China

In China,the strategic resource potash is suffering from severe shortages,and the ancient marine solid potash locating is still a problem of long impregnability.Till now,only the Mengyejing Potash Deposit was found

THE EVOLUTION OF LANPING RIFT BASIN FROM LADINIAN IN MIDDLE TRIASSIC EPOCH TO EARLY JURASSIC EPOCH

Lanping basin was a massif (land massif) in late Palaeozoic Era. The ocean of Jinshajiang separated it from Yangtze plate in east. Lancangjiang ocean separated it from Yunnan—Tibet plate in west. From late Permian Epoch, the oceanic crust of Jinshajiang subduced the west from east, the one of Lancangjiang down went the east from west, and then the Yunnan—Tibet ancient land gradually closed to the Yangtze. In the end of the Permian Period, two continents and Lanping plate touched together, and the evolution history of the Paleotethys was end. Hercynian orogenic belt in the east and west sides of Lanping had volcanic rock colliding in early—middle Triassic Epoch. In Ladinian in middle Triassic and Carnian in late Triassic, the north side of Lanping basin formed the serial volcanic rock of spilite—quartz keratophyre because mantle\|derived magma causing by delamination rose and mixed with the constituent of continental crust. The volcanic rock overlapped the middle Triassic and late Palaeozoic stratum in angular unconformity. It was the feature of double peak or evolution from the basic to the acid. The race element distribution of volcanic rock was same as the one of tholeiite in island and inter\|arc basin. The rate of lead isotope of the volcanic rock was much higher. These points all distributed above the NHRL in Pb\|Pb. This indicated that the Pb of volcanic rock was the mantle\|derived magma mixed with crust one. The large\|area progression in Lanping rift basin begun in late Carnian.. The east side in Lanping basin developed the sedimentary system that was granule gravel (grit) rock in border facies—limestone in beach facies—black shale, and the middle had black shale, banded siliceous rock, brecciform limestone in late Carnian to Norian. The geochemistry research of siliceous rock showed that the genesis of the chert was hot water. The development of brecciform limestone was related with action of central\|axis rift. The Lanping rift basin went into consuming stage in Rhaetian Epoch of the late Triassic. The basin developed clastic rock bearing coal of continental\|oceanic alternation facies. In early Jurassic, the sedimentary area atrophied further, and the fine lacustrine sediment whose thickness was not great developed in the east of central\|axis. The west stratum of the basin in late Triassic Epoch touched directly with the one in middle Jurassic. Lanping basin was going into another evolution stage that was down\|warped basin.

The development of mine digitization information system and its application to the Lanping Pb-Zn mine

To compile the software package of the mine digitization information system in terms of the principle and methods of mathematics geology and geographic information system using computer languages such as VB and Matlab,this paper introduces the function composition and operating environment of this information system,and illustrates the function and effectiveness of the software package as exemplified by the Lanping Pb-Zn mine,Yunnan Province.

TECTONIC SETTING OF ORGANIC MINERALIZATION IN THE LANPING-SIMAO BASIN,WESTERN YUNNAN, SW CHINA

The Tertiary is the main mineralization period in the Lanping-Simao Basin.The deposits are rich in organic matter and the organie matter takes part in the metal and nonmetal mineralization process. The organic mineralization is controlled by the tectonic setting.Different tectonic setting results in different mineralization and type of organic matters.

Geology and isotopic composition of helium,neon,xenon and metallogenic age of the Jinding and Baiyangping ore deposits,northwest Yunnan,China

Both the Jinding and Baiyangping ore deposits developed in the Lanping basin, which is a Mesozoic-Cenozoic terrestrial clastic sedimentary basin. Their occurrences can easily lead many people to compare them with the Pb-Zn deposit hosted in sedimentary rocks, such as Mississippian Valley-, Sedex- and sandstone-type Pb-Zn deposits. However, the Lanping basin developed in the settings of strong tectonic activity of the continental crust, which could cause an effective material exchange between the lower crust and the upper mantle. The orebodies are clearly tectonically controlled without syngenetic features, which probably represents a new type of the sedimentary rock-hosted Pb-Zn deposit. The isotopic compositions of noble gases in ore-forming fluids indicate that 2%32% of helium (3He/4He = 0.19 Ra1.97 Ra) is derived from the mantle, 50.1% of neon (20Ne/22Ne = 10.4510.83; 21Ne/22Ne = 0.03) from the mantle, and considerable amount of xenon (129Xe/130Xe = 5.846.86; 134Xe/130Xe = 2.262.71) from the mantle, which show that mantle fluids played an important role in the ore formation. The ore-forming age of 6760 Ma obtained by Re-Os and 40Ar-39Ar dating methods is later than the host rock, which is coeval with the Himalayan alkali magmatism of the mantle source and mantle-crust source. In this paper, the mineralization of the Jinding and Baiyangping ore deposits is considered to be related to the mantle fluids which move upward with the magma or along the deep faults, and mix with the meteoritic brine in the crust to result in large-scale deposition.

Geochemical Constraints on the Origin and Evolution of Spring Waters in the Changdu-Lanping-Simao Basin, Southwestern China

Chemical and isotopic data were measured for 51 leached brine springs in the Changdu-Lanping-Simao Basin(CD-LP-SM),China.The predominance of Cl and Na,saturation indices of carbonate minerals,and Na/Cl and Ca/SO4 ratios of^1 suggest that halite,sulphate,and carbonate are the solute sources.Integration of geochemical,δ18 O,andδD values suggests that springs are mainly derived from meteoric water,ice-snow melt,and water-rock interactions.B concentrations range from 0.18 to 11.9 mg/L,withδ11 B values of-4.37‰to+32.39‰,indicating a terrestrial source.Theδ11 B-B relationships suggest B sources of crustal origin(marine carbonates with minor crust-derived volcanics);we did not identify a marine or deep mantle origin.Theδ11 B values of saline springs(+4.61‰to+32.39‰)exceed those of hot(-4.37‰to+4.53‰)and cold(-3.47‰to+14.84‰)springs;this has contributed to strong water-rock interactions and strong saturation of dissolved carbonates.Conversely,the global geothermalδ11 B-Cl/B relationship suggests mixing of marine and non-marine sources.Theδ11 B-Cl/B relationships of the CD-LP-SM are similar to those of the Tibet geothermal belt and the Nangqen Basin,indicating the same B origin.These differ from thermal waters controlled by magmatic fluids and seawater,suggesting that B in CD-LP-SM springs has a crustal origin.

滇西兰坪金顶超大型铅锌矿床围岩微量元素地球化学特征及其意义

滇西兰坪盆地是三江成矿带的重要组成部分,金顶铅锌矿是区内重要的超大型矿床。为了查明金顶超大型铅锌矿床的成矿物质来源,对金顶矿区围岩样品进行微量元素地球化学分析。结果显示,稀土总量接近大陆上地壳的平均稀土元素总量值,轻稀土元素相对富集、重稀土元素相对亏损,呈明显的右倾型,具有显著的Eu负异常。微量元素特征显示Cu的平均含量为24.4×10^(-6),未发生明显富集迁移。Pb、Zn平均含量随矿体距离远近变化较大(Pb含量为2.9×10^(-6)~24.7×10^(-6),平均含量为13.1×10^(-6);Zn含量为8.8×10^(-6)~236.0×10^(-6),平均含量为76.6×10^(-6)),与矿体距离呈现出明显的相关性,距离矿体越近,含量越高。稀土元素特征及微量元素相关关系分析表明,矿区围岩古近纪云龙组地层不是提供成矿物质的矿源层。矿区石膏锶、硫同位素地球化学性质显示金顶矿区的石膏为晚三叠世三合洞组蒸发沉积型,且在适当的成矿温度条件下(150~300℃),石膏会发生热化学还原作用(TSR),为金属硫化物矿床提供硫源。

二维初至波层析成像揭示的兰坪盆地—扬子西缘浅层地壳结构

兰坪盆地—扬子西缘位于青藏高原东南缘,在地质构造上属特提斯-喜马拉雅强烈挤压、碰撞造山带的东部,兼跨华南板块与古冈瓦纳板块两大构造单元。其浅层地壳是记录地壳形变、岩浆作用与成矿作用的重要载体。本文利用兰坪盆地—扬子西缘220km长的深反射地震剖面的初至波(Pg震相)数据,通过层析成像反演方法,获得了测线下方4km以浅的上地壳浅层P波速度结构。成像结果显示,兰坪盆地沉积厚度从西到东逐渐减薄,扬子块体西缘东部表现出“两侧厚中间薄”的特点;兰坪盆地内有多组逆冲断裂,金沙江断裂与程海断裂近乎垂直;金顶铅锌矿的形成可能与底部热隆有关,北衙金矿下方结晶基底向上突起,推测由岩浆上涌所致。

滇西兰坪盆地膏盐微量元素、同位素地球化学特征及意义

滇西兰坪盆地中多数金属矿床伴生大量膏盐体,为了探讨膏盐体与金属成矿关系,对膏盐体进行了微量元素和同位素地球化学分析。发育在云龙组中呈层状黑色石膏稀土总量,δEu(0.87)和δCe(0.95),^(87)Sr/^(86)Sr(0.708629~0.710189),δ^(34)S_(V-CDT)(9.6‰~+11.9‰)与区域云龙组地层地球化学特征相近;分布在云龙组地层中呈蘑菇状、指状侵入的块状石膏的稀土总量,δEu(0.65)和δCe(0.85),^(87)Sr/^(86)Sr(0.707695~0.708127),δ^(34)S_(V-CDT)(+12.6‰~+15.4‰)与晚三叠世三合洞组碳酸盐岩的地球化学特征相近。结合微量元素和同位素地球化学分析,兰坪盆地的Sr、Cu、Pb和Zn等成矿元素主要来源于热卤水对地层的淋滤和萃取,成矿元素S主要为沉积地层中的硫酸盐热化学还原的产物。