scholarly journals Tracing fluid evolution in sedimentary basins with calcite geochemical, isotopic and U-Pb geochronological data: Implications for petroleum and mineral resource accumulation in the Nanpanjiang Basin, South China

2021 ◽  
Author(s):  
Xiang Ge ◽  
Chuanbo Shen ◽  
Renjie Zhou ◽  
Peng He ◽  
Jianxin Zhao ◽  
...  
Keyword(s):  
Fluid Flow ◽  
South China ◽  
Genetic Model ◽  
Gold Mineralization ◽  
Sedimentary Basins ◽  
Gold Deposits ◽  
Geochemical Data ◽  
Petroleum Migration ◽  
Fluid Evolution ◽  
Flow Activity

Fluid migration in sedimentary basins enable mass and energy transport and play critical roles in geochemical and geodynamical evolution of sedimentary basins. Moreover, reconstructing sedimentary basin fluid evolution from the geological record aids in constraining the evolution of associated petroleum and mineralization systems. As a relict of fluid flow activity, calcite is often a record of fluid flow and therefore can be used to characterize the fluids responsible for its precipitation. Here we study the Nanpanjiang Basin in South China where petroleum reservoirs and Carlin-type gold deposits spatially coincide. Through in situ U-Pb dating and geochemical analysis (87Sr/86Sr, δ18OVienna standard mean ocean water, δ13CVienna Peedee belemnite, rare earth elements) of calcite, this work constrains the key times related to petroleum migration/accumulation and Carlin-type gold mineralization, defines the basin fluid evolution, and proposes a genetic model for petroleum accumulation and gold mineralization within the Nanpanjiang Basin. The U-Pb age (ca. 241.4 Ma) for the gray/black calcite related to bitumen indicates the petroleum migration/accumulation occurred during the Triassic. The U-Pb date (ca. 106−121 Ma) of the white calcite associated with the gold-bearing pyrite, realgar, and fluorite record the lower timing limit of the Carlin-type gold systems. The geochemical data suggest both calcite types are cogenetic but suffered complex evolution with the gray/black calcite precipitating under low temperatures related to the continuous basin burial and the white calcite affected by post formation alteration related to both hydrothermal and meteoric fluids. Combined with the regional tectonic history, the Early Triassic petroleum migration/accumulation and the Early Cretaceous secondary Carlin-type gold mineralization events are considered to be related to the collision between the Indo-China and South China blocks, and the subduction between the Paleo-Pacific and Eurasian plates, respectively.

NOBLE GASES FINGERPRINT THE SOURCE AND EVOLUTION OF ORE-FORMING FLUIDS OF CARLIN-TYPE GOLD DEPOSITS IN THE GOLDEN TRIANGLE, SOUTH CHINA

2020 ◽  
Vol 115 (2) ◽  
pp. 455-469 ◽  
Author(s):  
Xiao-Ye Jin ◽  
Albert H. Hofstra ◽  
Andrew G. Hunt ◽  
Jian-Zhong Liu ◽  
Wu Yang ◽  
...  
Keyword(s):  
South China ◽  
Genetic Model ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Pore Fluid ◽  
Magmatic Fluid ◽  
Metamorphic Fluid ◽  
Independent Evidence ◽  
Golden Triangle ◽  
Carlin Type Gold Deposits

Abstract Precise constraints on the source and evolution of ore-forming fluids of Carlin-type gold deposits in the Golden Triangle (south China) are of critical importance for a better understanding of the ore genesis and a refined genetic model for gold mineralization. However, constraints on the source of ore fluid components have long been a challenge due to the very fine grained nature of the ore and gangue minerals in the deposits. Here we present He, Ne, and Ar isotope data of fluid inclusion extracts from a variety of ore and gangue minerals (arsenian pyrite, realgar, quartz, calcite, and fluorite) representing the main and late ore stages of three well-characterized major gold deposits (Shuiyindong, Nibao, and Yata) to provide significant new insights into the source and evolution of ore-forming fluids of this important gold province. Measured He isotopes have R/RA ratios ranging from 0.01 to 0.4 that suggest a maximum of 5% mantle helium with an R/RA of 8. The Ne and Ar isotope compositions are broadly comparable to air-saturated water, with a few analyses indicating the presence of an external fluid containing nucleogenic 38Ar and radiogenic 40Ar. Plotted on the 20Ne/4He vs. helium R/RA and 3He/20Ne vs. 4He/20Ne diagrams, the results define two distinct arrays that emanate from a common sedimentary pore fluid or deeply sourced metamorphic fluid end-member containing crustal He. The main ore-stage fluids are interpreted as a mixture of magmatic fluid containing mantle He and sedimentary pore fluid or deeply sourced metamorphic fluid with predominantly crustal He, whereas the late ore-stage fluids are a mixture of sedimentary pore fluid or deeply sourced metamorphic fluid bearing crustal He and shallow meteoric groundwater containing atmospheric He. Results presented here, when combined with independent evidence, support a magmatic origin for the ore-forming fluids. The ascending magmatic fluid mixed with sedimentary pore fluid or deeply sourced metamorphic fluid in the ore stage and subsequently mixed with the meteoric groundwater in the late ore stage, eventually producing the Carlin-type gold deposits in the Golden Triangle.

scholarly journals Genesis of the Late Cretaceous Longquanzhan Gold Deposit in the Central Tan-Lu Fault Zone, Shandong Province, China: Constraints from Noble Gas and Sulfur Isotopes

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 250
Author(s):  
Chuanpeng Liu ◽  
Wenjie Shi ◽  
Junhao Wei ◽  
Huan Li ◽  
Aiping Feng ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Fault Zone ◽  
Late Cretaceous ◽  
Genetic Model ◽  
Gold Mineralization ◽  
Sulfur Isotopes ◽  
Noble Gas ◽  
Gold Deposits ◽  
Shandong Province ◽  
Magma Sources

The Longquanzhan deposit is one of the largest gold deposits in the Yi-Shu fault zone (central section of the Tan-Lu fault zone) in Shandong Province, China. It is an altered-rock type gold deposit in which ore bodies mainly occur at the contact zone between the overlying Cretaceous rocks and the underlying Neoarchean gneissic monzogranite. Shi et al. reported that this deposit formed at 96 ± 2 Ma using pyrite Rb–Sr dating method and represents a new gold mineralization event in the Shandong Province in 2014. In this paper, we present new He–Ar–S isotopic compositions to further decipher the sources of fluids responsible for the Longquanzhan gold mineralization. The results show that the δ34S values of pyrites vary between 0.9‰ and 4.4‰ with an average of 2.3‰. Inclusion-trapped fluids in ore sulfides have 3He/4He and 40Ar/36Ar ratios of 0.14–0.78 Ra and 482–1811, respectively. These isotopic data indicate that the ore fluids are derived from a magmatic source, which is dominated by crustal components with minor mantle contribution. Air-saturated water may be also involved in the hydrothermal system during the magmatic fluids ascending or at the shallow deposit site. We suggest that the crust-mantle mixing signature of the Longquanzhan gold deposit is genetically related to the Late Cretaceous lithospheric thinning along the Tan-Lu fault zone, which triggers constantly uplifting of the asthenosphere surface and persistent ascending of the isotherm plane to form the gold mineralization-related crustal level magma sources. This genetic model can be applied, to some extent, to explain the ore genesis of other deposits near or within the Tan-Lu fault belt.

scholarly journals Typomorphic Features of Placer Gold from the Billyakh Tectonic Melange Zone of the Anabar Shield and Its Potential Ore Sources (Northeastern Siberian Platform)

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 281
Author(s):  
Boris Gerasimov ◽  
Vasily Beryozkin ◽  
Alexander Kravchenko
Keyword(s):  
Native Gold ◽  
Gold Mineralization ◽  
Coarse Fraction ◽  
Gold Deposits ◽  
Primary Sources ◽  
The Arctic ◽  
Geochemical Data ◽  
Placer Gold ◽  
Anabar Shield ◽  
Tectonic Mélange

Precambrian shields and outcropped Precambrian rock complexes in the Arctic may serve as the most important sources of various types of mineral raw materials, including gold. The gold potential of the Anabar shield in the territory of Siberia has, thus far, been poorly studied. A number of primary and placer gold occurrences have been discovered there, but criteria for the prediction of and search for gold mineralization remain unclear. The main purpose of this paper was to study the typomorphic features of placer gold in the central part of the Billyakh tectonic mélange zone in the Anabar shield and to compare them to mineralization from primary sources. To achieve this, we utilized common methods for mineralogical, petrographic, and mineragraphic analyses. Additionally, geochemical data were used. As a result of this investigation, important prospecting guides were identified, and essential criteria for the prediction of and search for gold deposits were elucidated. The characteristics of the studied placer gold were specific for gold derived from a proximal provenance. These characteristics included the poor roundness of the native gold grains, a cloddy–angular and dendritic form, an uneven surface, and a high content of coarse-fraction native gold (0.5–2 mm), which was as high as 24% of the volume of analyzed native gold. In addition, we conducted a study on the mineralogical features of the gold-sulfide mineralization that was disseminated throughout a small exposure area of paleo-Proterozoic para- and orthogneisses in the Anabar shield basement. A comparison of mineral inclusions in the coarse-fraction native gold and mineral assemblages in the ore deposits showed that one of the possible primary sources for placer gold might be small bodies of metasomatically altered orthogneisses associated with large granitoid plutons.

Magnetic modeling of iron oxide copper-gold mineralization constrained by 3D multiscale integration of petrophysical and geochemical data: Cloncurry District, Australia

2013 ◽  
Vol 1 (1) ◽  
pp. T63-T84 ◽  
Author(s):  
James R. Austin ◽  
Phillip W. Schmidt ◽  
Clive A. Foss
Keyword(s):  
Iron Oxide ◽  
Gold Mineralization ◽  
Signal Amplitude ◽  
Gold Deposits ◽  
Geochemical Data ◽  
Geophysical Investigation ◽  
Structural Controls ◽  
Breccia Pipe ◽  
Copper Gold

Magnetite-rich iron oxide copper-gold deposits (IOCGs) are geologically and geochemically complex and present major challenges to geophysical investigation. They often sit beneath significant cover, exhibit magnetic remanence, and suffer from self-demagnetization effects. Because remanence in magnetite-bearing drill core samples is commonly overprinted by drilling, in situ natural remanent magnetization is difficult to measure accurately, and thus IOCGs cannot be modeled definitively using geophysics alone. We examined structural controls on a magnetite-rich IOCG in northwest Queensland and the relationships between structure, alteration, Fe oxides, and mineralization at core to deposit scale. Magnetite within the deposit has a multidomain structure, and thus it would commonly have an in situ magnetization parallel to the earth’s field. In contrast, pyrrhotite has a pseudosingle-domain structure and so it is the predominant carrier of stable remanence within the ore system. Geophysical lineament analyses are used to determine structural controls on mineralization, geophysical filters (e.g., analytic signal amplitude) are used to help define structural extent of the deposit, and basement geochemistry is used to map mineral footprints beneath cover. These techniques identified coincident anomalies at the intersection of north and northwest lineaments. Leapfrog™ interpolations of downhole magnetic susceptibility and Cu, Au, and Fe assay data were used to map the distribution of magnetite, copper, gold, and sulfur in 3D. The analysis revealed that Cu and Au mineralization were coupled with the magnetite net-vein architecture, but that Cu was locally enriched in the east–northeast-trending demagnetized zone. The results from this suite of geophysical, petrophysical, and geochemical techniques were integrated to constrain modeling of the Brumby IOCG. Brumby can be described as a breccia pipe sitting at the intersection of north-striking, east-dipping, and northwest-striking, southeast-dipping structures that plunges moderately to the south–southeast. The breccia pipe was overprinted by a relatively late net-vein magnetite breccia and crosscut by a later, magnetite-destructive, east–northeast-striking fault.

scholarly journals Occurrences and Characteristics of Gold Mineralization in Rampi Block Prospect, North Luwu Regency, South Sulawesi Province, Indonesia

2016 ◽  
Vol 1 (2) ◽  
pp. 63 ◽  
Author(s):  
Arifudin Idrus ◽  
Suaib Mansur ◽  
Ahmad Ahmad ◽  
Rahmayuddin Rahmayuddin ◽  
Abdul Abdul
Keyword(s):  
Research Method ◽  
Genetic Model ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Quartz Veins ◽  
South Sulawesi ◽  
Supergene Enrichment ◽  
Systematic Exploration ◽  
Ore Mineralization ◽  
Gold Grade

This study is aimed to identify the occurences, characterisatics and genetic type of gold mineralization, and to elucidate the preliminary gold potential in the study area. Research method includes field observation of prospect geology, hydrothermal alteration and ore mineralization. Laboratory analysis consists of petrography, ore microscopy and ore chemistry. Geologically, quartz ± gold veins were found in Rampi block prospect, which are mainly hosted by metamorphic and metasediment rocks. The quartz veins has structurally segmented with massive, brecciated and laminated textures. Orientation and distribution of veins is controlled by NW–SE and NE–SW trending structures. Sulfides are present with minor abundance (<1 %). Pyrite is obviously observed and partially oxidized. Arsenopyrite and stibnite are minor, while basemetal (Pb, Zn) sulfides are very rare. Gold mineralization occurred in quartz veins and closely related to silica-clay and silicic alteration. Gold grade varies from 0.1 to 11 ppm Au (29 samples). Quartz veins contained high gold grade (>9 ppm) commonly show laminated and brecciated texture and has been undergone a supergene enrichment. According to several characteristics above, gold deposit in Rampi block prospect tends to meet the criteria of orogenic/mesothermal gold type (cf. Groves et al., 2003). The deposit shares similarities with Awak Mas prospect, which is already confirmed to be a mesothermal type in Luwu district (cf. Querubin and Walters, 2011). Therefore, discoveries of economic mesothermal gold deposits are still open in the metamorphic terrains, and thus, it requires a systematic exploration based on the genetic model of the deposit.

Chapter 35: Gold Deposits of the Jiaodong Peninsula, Eastern China

2020 ◽  
pp. 753-774
Author(s):  
Kun-Feng Qiu ◽  
Richard J. Goldfarb ◽  
Jun Deng ◽  
Hao-Cheng Yu ◽  
Zong-Yang Gou ◽  
...  
Keyword(s):  
South China ◽  
North China ◽  
Gold Mineralization ◽  
Eastern China ◽  
Gold Deposits ◽  
Fault System ◽  
South China Block ◽  
North China Block ◽  
The North ◽  
Basement Rocks

Abstract The Jiaodong gold province, within the eastern margin of the North China block and the translated northeastern edge of the South China block, has a stated premining gold resource exceeding 4,500 metric tons (t). It is thus one of the world’s largest gold provinces, with a present cumulative annual production estimated at 60 t Au. More than 90% of the Jiaodong gold resource is hosted by batholiths and related bodies of the Linglong (ca. 160–145 Ma) and, to a lesser degree, Guojialing (ca. 130–122 Ma) suites. The intrusions were emplaced into high-grade metamorphic basement rocks of the Precambrian Jiaobei (North China block) and Sulu (South China block) terranes during a 70-m.y.-period of lithospheric delamination, extensional core complex formation, and exhumation. The deposits are located about 20 to 200 km to the east of the continental-scale NNE-striking Tancheng-Lujiang (Tan-Lu) strike-slip fault system. They occur along a series of more regional NNE- to NE-striking brittle and ductile-brittle faults, which appear to intersect the Tan-Lu main structure to the southwest. This system of early to middle Mesozoic regional thrust faults, reactivated during Cretaceous normal motion and ore formation, tends to occur along the margins of the main Linglong batholiths or between intrusions of the two suites of granitoids. Orebodies are mainly present as quartz-pyrite veins (Linglong-type) and as stockwork veinlets and disseminated mineralization (Jiaojia-type). The two mineralization styles are transitional and may be present within the same gold deposit. The ca. 120 Ma timing of gold mineralization correlates with major changes in plate kinematics in the Pacific Basin and the onset of seismicity along the Tan-Lu fault system, with the enormous fluid volumes and associated metal being derived from sediment devolatilization above the westerly subducting Izanagi slab.

Chapter 16: Giant Carlin-Type Gold Deposits of the Cortez District, Lander and Eureka Counties, Nevada

2020 ◽  
pp. 335-353
Author(s):  
Mark A. Bradley ◽  
L. Page Anderson ◽  
Nathan Eck ◽  
Kevin D. Creel
Keyword(s):  
Great Basin ◽  
Genetic Model ◽  
Gold Mineralization ◽  
Late Eocene ◽  
Gold Deposits ◽  
Gold Deposition ◽  
Lower Paleozoic ◽  
Fine Grained ◽  
Siliciclastic Rocks ◽  
Carlin Type Gold Deposits

Abstract The Cortez district is in one of the four major Carlin-type gold deposit trends in the Great Basin province of Nevada and contains three giant (&gt;10 Moz) gold orebodies: Pipeline, Cortez Hills, and Goldrush, including the recently discovered Fourmile extension of the Goldrush deposit. The district has produced &gt;21 Moz (653 t) of gold and contains an additional 26 Moz (809 t) in reserves and resources. The Carlin-type deposits occur in two large structural windows (Gold Acres and Cortez) of Ordovician through Devonian shelf- and slope-facies carbonate rocks exposed through deformed, time-equivalent lower Paleozoic siliciclastic rocks of the overlying Roberts Mountains thrust plate. Juxtaposition of these contrasting Paleozoic strata occurred during the late Paleozoic Antler orogeny along the Roberts Mountains thrust. Both upper and lower plate sequences were further deformed by Mesozoic compressional events. Regional extension, commencing in the Eocene, opened high- and low-angle structural conduits for mineralizing solutions and resulted in gold deposition in reactive carbonate units in structural traps, including antiforms and fault-propagated folds. The Pipeline and Cortez Hills deposits are located adjacent to the Cretaceous Gold Acres and Jurassic Mill Canyon granodioritic stocks, respectively; although these stocks are genetically unrelated to the later Carlin-type mineralization event, their thermal metamorphic aureoles may have influenced ground preparation for later gold deposition. Widespread decarbonatization, argillization, and silicification of the carbonate host rocks accompanied gold mineralization, with gold precipitated within As-rich rims on fine-grained pyrite. Pipeline and Cortez Hills also display deep supergene oxidation of the hypogene sulfide mineralization. Carlin-type mineralization in the district is believed to have been initiated in the late Eocene (&gt;35 Ma) based on the age of late- to postmineral rhyolite dikes at Cortez Hills. The Carlin-type gold deposits in the district share common structural, stratigraphic, alteration, and ore mineralogic characteristics that reflect common modes of orebody formation. Ore-forming fluids were channeled along both low-angle structures (Pipeline, Goldrush/Fourmile) and high-angle features (Cortez Hills), and gold mineralization was deposited in Late Ordovician through Devonian limestone, limy mudstone, and calcareous siltstone. The Carlin-type gold fluids are interpreted to be low-salinity (2–3 wt % NaCl equiv), low-temperature (220°–270°C), and weakly acidic, analogous to those in other Carlin-type gold deposits in the Great Basin. The observed characteristics of the Cortez Carlin-type gold deposits are consistent with the recently proposed deep magmatic genetic model. Although the deposits occur over a wide geographic area in the district, it is possible that they initially formed in greater proximity to each other and were then spatially separated during Miocene and post-Miocene regional extension.

scholarly journals The Role of Manganese as a Controller for Gold Mineralization

2019 ◽  
Author(s):  
Ricardo A. Valls ◽  
Jorge Cruz Martín
Keyword(s):  
Genetic Model ◽  
Gold Mineralization ◽  
Hydrothermal Process ◽  
Significant Negative Correlation ◽  
Geochemical Data ◽  
San Jose ◽  
Quartz Veins ◽  
The North ◽  
Binary Correlation ◽  
Altered Zone

The San José de Las Malezas quartz-gold deposit is located on the North side of the Cuban Ophiolitic Complex, within the Structural-Facial Zone "Zaza", Province of Villa Clara, Cuba. In the area of the deposit there is a well developed listwanite zone that begins with (i) massive and relatively little altered serpentinites that pass into (ii) iron-altered serpentinites which are in gradational contact with (iii) completely carbonatized rocks and (iv) a core of silicified rocks and quartz veins. Copper and gold mineralization are associated with these quartz bodies, but binary correlation analysis of geochemical data suggests that the ores are genetically independent of one another. In concordance with the proposed genetic model supported by thermodynamic calculations and field observations, copper is thought to be introduced by a hydrothermal process, whereas gold was leached from the serpentinites. The evolution of manganese minerals from anaerobic to aerobic species provoked a reducing environment which difficulted the precipitation of gold and other ores inside and near the serpentinites. Accordingly, a significant negative correlation between gold and manganese in similar areas of hydrothermally altered serpentinites, may be good indicators of possible gold concentrations. The mechanical transportation of very small and thin scales of native gold from the serpentinites by the fluids is also suggested as a possible mechanism to explain the presence of this kind of scales inside the iron-altered zone.

scholarly journals Geology and Geochemistry of Selected Gold Deposits in the Ailaoshan Metallogenic Belt, China: Origin of Ore-Forming Fluids

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1276
Author(s):  
Yang Li ◽  
Denghong Wang ◽  
Chenghui Wang ◽  
Yan Sun ◽  
MIMA Pu-chi
Keyword(s):  
Host Rock ◽  
Large Scale ◽  
Gold Mineralization ◽  
Mining Area ◽  
Gold Deposits ◽  
Pb Isotopes ◽  
Late Triassic ◽  
Geochemical Data ◽  
Continental Scale ◽  
Metallogenic Belt

The formation of the Ailaoshan metallogenic belt was the result of: the Neoproterozoic super mantle plume, the Indosinian and South China blocks in the Late Triassic after the Paleo-Tethys Ocean closure, and Oligocene-Eocene continental-scale shearing related to the India-Eurasia collision. It is one of the most important Cenozoic gold ore province in the world. In this paper, the geological characteristics, isotopic geochemistry, and geochemical data of ore-forming fluids of four large-scale gold deposits in the Ailaoshan metallogenic belt (Mojiang Jinchang, Zhenyuan Laowangzhai, Yuanyang Daping, and Jinping Chang’an) are comprehensively compared. The features of host-rock alteration, metallogenetic periods and stages, geochronology, fluid inclusion, and C-H-O-S-Pb isotopes of gold deposits are summarized and analyzed. The gold mineralization in the Ailaoshan metallogenic belt occurred mostly in 50–30 Ma, belonging to the Himalayan period. The gold mineralization is closely related to silicification, argillation, carbonation, and pyritization due to the strong mineralization of hydrothermal fluid, the development of alteration products, and the inconspicuous spatial zonation of alteration types. The ore-forming fluid is mainly composed of mantle fluid (magmatic water) and metamorphic fluid (metamorphic water). The ore-forming materials of the Jinchang, Chang’an, and Laowangzhai gold deposits mainly originate the host-rock strata of the mining area, and the carbon is more likely to from marine carbonate. The carbon in the Daping gold deposit from the original magma formed by the partial melting of the mantle. Pb isotopes have characteristics of crustal origin, accompanied by mixing of mantle-derived materials and multisource sulfur mixing, and are strongly homogenized.

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