scholarly journals Geology, Geochemistry and Hydrothermal Fluid Characteristics of Low Sulfidation Epithermal Deposit in the Sangon Area, Kokap, Special Region of Yogyakarta

2017 ◽  
Vol 2 (1) ◽  
pp. 48
Author(s):  
Pranayoga Pramumijoyo ◽  
Arifudin Idrus ◽  
I Wayan Warmada ◽  
Kotaro Yonezu
Keyword(s):  
Normal Fault ◽  
Wall Rock ◽  
Geological Condition ◽  
Alteration Zones ◽  
Quartz Veins ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Wall Rock Alteration ◽  
Low Sulfidation ◽  
Special Region

On the basis of the previous studies and reconnaissance survey in the studyarea covering Sangon, Kalirejo, Kokap Sub-district, Kulon Progo Regency, Special Region of Yogyakarta, it reveals some facts of the occurrence of quartz veins with massive, crustiform, comb, drusy cavity, saccharoidal, granular, and reniform/mammillated textures, the appearance of lattice bladed barite and hydrothermal breccia veins. Referring to those characteristics, the deposit type in the study area is interpreted to be low sulfidation epithermal type. This study is aimed to understand and characterize the geological condition, rock and ore geochemistry and the mineralizing fluids. The alteration and ore mineralization are almost observed in entire rock units particularly the intrusive andesite 1. Their formation is controlled by the tension fractures (NW–SE and NE–SW) which associate with sinistral strike slip faults (NE–SW), dilational jog (NNW–SSE), oblique normal fault (WNW–ESE), and predictable normal fault at the NE of study area (NW–SE). The alteration zones are developed to be silica-clay (quartz-illite-kaolinite-kaolinite/smectite), argillic (smectite-illite/smectite), and propylitic (chlorite-calcite±epidote). The precipitationof ore minerals is controlled by boiling, mixing, and wall-rock alteration, and canbe found in the quartz veins (quartz-adularia-sericite) and disseminated in the alteration zones, which their high variability is only can be found in the quartz veins, including pyrite, sphalerite, chalcopyrite, galena, marcasite, and arsenopyrite. Based on the ICPAES measurement of 5 quartz vein samples, the Cu, Zn, Pb, and As grade reach about 5,171 ppm, 8,995 ppm, 6,398 ppm, 34.1 ppm, and 1,010.5 ppm, respectively. Gold is not detected. Fluid inclusion microthermometric analysis shows Th of 242.1–257.6 °C and salinity of 1.57–3.87 wt.% NaCl equiv., which indicate a depth below the paleosurface of 384–516 m, and pressure of 101.7–136.6 bar. The ore deposit in the study area is interpreted to be a deep basemetal low sulfidation epithermal type. Gold might be depleted in this epithermal type.

scholarly journals Origin of the Kyaukmyet Low-Sulfidation Epithermal Gold Prospect, Monywa District, Central Myanmar

2021 ◽  
Vol 54 (1E) ◽  
pp. 1-18
Author(s):  
Toe Oo ◽  
Agung Harijoko ◽  
Lucas Setijadji
Keyword(s):  
Magmatic Fluid ◽  
Epithermal Gold ◽  
Quartz Veins ◽  
Mineral Assemblages ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Alteration Minerals ◽  
Homogenization Temperatures ◽  
Low Sulfidation

The Kyaukmyet prospect is one of the principal epithermal gold prospects in the Monywa District, Central Myanmar; its gold- and base metal-bearing quartz veins contain around 3 g/t gold. Ore minerals are mainly hosted by volcanic and volcaniclastic rocks of the Late Oligocene to Middle Miocene Magyigon Formation. The distribution of magmatic intrusions in the area is controlled by ENE-WSW trending faults; these faults are likely related to ore mineralization. Common ore minerals at the Kyaukmyet prospect include pyrite, sphalerite, galena, chalcopyrite, and electrum. They occur in mineralized crustiform-textured brecciated quartz veins and banded (colloform) and massive quartz veins. Mineralized rock is accompanied by silicification and propylitic and argillic alterations. The alteration mineral assemblages include quartz, adularia, calcite, chlorite, illite/smectite, sericite, and illite. Fluid inclusions in the quartz veins have homogenization temperatures ranging from 148 °C to 304 °C and salinities from 0.35 wt % to 2.75 wt % NaCl equiv. The quartz in the mineralized quartz veins was most likely precipitated at a depth ranges165-256 m below the paleosurface. The precipitation of gold at the Kyaukmyet prospect may have been formed by mixing large amounts of meteoric fluid with small amounts of magmatic fluid. The coexistence of liquid-rich and vapor-rich inclusions and presence of adularia and bladed calcite indicate that fluid boiling is caused the main mechanism of ore formation. The vein textures, ore mineral assemblages, alteration minerals and fluid inclusion data suggest that the Kyaukmyet prospect is a polymetallic low-sulfidation epithermal gold deposit.

scholarly journals Geological mapping and mineral prospectivity using remote sensing and GIS in parts of Hamissana, Northeast Sudan

2021 ◽  
Vol 11 (3) ◽  
pp. 1123-1138
Author(s):  
Mohamed Taha AlMakki Mohamed ◽  
Latifa Shaheen Al-Naimi ◽  
Tochukwu Innocent Mgbeojedo ◽  
Chidiebere Charles Agoha
Keyword(s):  
Remote Sensing ◽  
Gold Mineralization ◽  
Principal Component ◽  
Original Data ◽  
Wall Rock ◽  
Geological Mapping ◽  
Landsat 8 ◽  
Alteration Zones ◽  
Wall Rock Alteration ◽  
Rock Alteration

AbstractIn recent years, various geological activities and different mineral prospecting and exploration programs have been intensified along the Red Sea hills in order to elucidate the geological maps and to evaluate the mineral potentials. This study is therefore aimed at testing the viability of using remote sensing and geographic information system (GIS) techniques for geological mapping and prospecting for gold mineralization in the area. The study area is located in northeast Sudan and covers an area of about 1379 km2. Different digital image processing techniques were applied to Landsat 8 Operational Land Imager image in order to increase the discrimination between various lithological units and to delineate wall rock alteration which represents target zones for gold mineralization. Image sharpening was performed to enhance the spatial resolution of the images for more detailed information. Contrast stretching was applied after the various digital processing procedures to produce more interpretable images. The principal component analysis transformations yielded saturated images and resulted in more interpretable images than the original data. Several ratio images were prepared, combined together and displayed in RGB color composite ratio images. This process revealed the existence of alteration zones in the study area. These zones extend from the northeast to the southwest in the acid meta-volcanic and silica barite rocks. The enhanced satellite images were implemented in the GIS environment to facilitate the final production of the geological map at scale 1:400,000. X-ray fluorescence analyses prove that selected samples taken from the wall rock alteration zones are gold-bearing.

scholarly journals Magmatic-Hydrothermal Processes of Vein-Type Haman-Gunbuk-Daejang Copper Deposits in the Gyeongnam Metallogenic Belt in South Korea

2021 ◽  
Vol 9 ◽  
Author(s):  
Tong Ha Lee ◽  
Jung Hun Seo ◽  
Bong Chul Yoo ◽  
Bum Han Lee ◽  
Seung Hee Han ◽  
...  
Keyword(s):  
Fluid Inclusions ◽  
Hydrothermal Activity ◽  
Hydrothermal Conditions ◽  
Copper Deposits ◽  
Quartz Veins ◽  
Calcite Veins ◽  
Vein Type ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Shale Formation

Haman, Gunbuk, and Daejang deposits are neighboring vein-type hydrothermal Cu deposits located in the SE part of the Korean Peninsula. These three deposits are formed by magmatic-hydrothermal activity associated with a series of Cretaceous granodioritic intrusions of the Jindong Granitoids, which have created a series of veins and alterations in a hornfelsed shale formation. The copper deposits have common veining and alteration features: 1) a pervasive chlorite-epidote alteration, cut by 2) Cu-Pb-Zn-bearing quartz veins with a tourmaline-biotite alteration, and 3) the latest barren calcite veins. Chalcopyrite, pyrite, and pyrrhotite are common ore minerals in the three deposits. Whereas magnetite is a dominant mineral in the Haman and Gunbuk deposits, no magnetite is present, but sphalerite and galena are abundant in the Daejang deposit. Ore-bearing quartz veins have three types of fluid inclusions: 1) liquid-rich, 2) vapor-rich, and 3) brine inclusions. Hydrothermal temperatures obtained from the brine inclusion assemblages are about 340–600, 250–500, and 320–460°C in the Haman, Gunbuk, and Daejang deposits, respectively. The maximum temperatures (from 460 to 600°C) recorded in the fluid inclusions of the three deposits are higher than those of the Cu ore precipitating temperature of typical porphyry-like deposits (from 300 to 400°C). Raman spectroscopy of vapor inclusions showed the presence of CO2 and CH4 in the three deposits, which indicates relatively reduced hydrothermal conditions as compared with typical porphyry deposits. The Rb/Sr ratios and Cs concentrations of brine inclusions suggest that the Daejang deposit was formed by a later and more fractionated magma than the Haman and Gunbuk deposits, and the Daejang deposit has lower Fe/Mn ratios in brine inclusions than the Haman and Gunbuk deposits, which indicates contrasting redox conditions in hydrothermal fluids possibly caused by an interaction with a hosting shale formation. In brines, concentrations of base metals do not change significantly with temperature, which suggests that significant ore mineralization precipitation is unlikely below current exposure levels, especially at the Haman deposit. Ore and alteration mineral petrography and fluid inclusions suggest that the Haman deposit was formed near the top of the deep intrusion center, whereas the Gunbuk deposit was formed at a shallower intrusion periphery. The Daejang deposit was formed later at a shallow depth by relatively fractionated magma.

scholarly journals SILVER-GOLD FORMATION TYPE ORE MINERALIZATION IN TAJIKISTAN

2018 ◽  
Author(s):  
Ф.А. Файзиев ◽  
А.Р. Файзиев
Keyword(s):  
Silver Sulfide ◽  
Ore Formation ◽  
Gold Ore ◽  
Quartz Veins ◽  
Multi Stage ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Formation Type ◽  
High Silver ◽  
Subsurface Formation

Серебро-золоторудный формационный тип минерализации в Таджикистане известен в пределах Табошар-Канджольского рудного узла (Карамазар) и на Памире. В Карамазаре к этому типу относятся месторождения Школьное, Четсу и Караулхона, а на Памире рудопроявления Сассык, Лянгар, Бугучиджилга, Курустык и др. Серебро-золоторудный формационный тип представлен убогосульфидными кварц-золоторудными жилами с высоким содержанием серебра. Рудные минералы представлены пиритом, тетраэдритом, халькопиритом, пираргиритом, фрейбергитом, миаргиритом, самородным золотом, электрумом и кюстелитом. Формационными особенностями этого типа являются предрудная пропилитизация, синрудная березитизация, многостадийный характер минерализации, простой минеральный состав, крайне неравномерное распределение серебра и золота, а также близповерхностное образование золота и его низкопробность. Продуктивное оруденение в них образовалось при сравнительно низких температурах (300–150ο) и давлениях (500 бар и ниже). Silver-gold ore-formation type mineralization in Tajikistan known within Taboshar-Kanjol – ore unit (Karamazar) and the Pamirs. The most known deposits KaramazarScholnoe, Chetsy and Karaulhona and the Pamirs to this type of ore can be attributed Sassyk, Langar, Buguchidzhilga, Kurustyk. Silver-gold ore-formation type is represented by poorly-high silver sulfide-quartz veins of gold mining. The ore minerals are pyrite, tetrahedrite, chalcopyrite, pyrargyrite, freibergite, miargyrite, native gold, electrum and kyustelitе. Formational peculiarities of this type are pre-ore propylitization, sin-ore beresitization, multi-stage nature of the mineralization, simple mineral composition, extremely uneven distribution of silver and gold, as well as subsurface formation of gold and its sleaze. Productive mineralization formed there in at relatively low temperatures (300–150ο) and pressures (500 bar or less).

scholarly journals The Distribution of Precious Metals in High-Grade Banded Quartz Veins from Low-Sulfidation Epithermal Deposits: Constraints from µXRF Mapping

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 740 ◽  
Author(s):  
Erik Tharalson ◽  
Thomas Monecke ◽  
T. Reynolds ◽  
Lauren Zeeck ◽  
Katharina Pfaff ◽  
...  
Keyword(s):  
Precious Metals ◽  
Thermal Waters ◽  
High Grade ◽  
Epithermal Deposits ◽  
Quartz Veins ◽  
Ore Minerals ◽  
Low Sulfidation ◽  
Hand Specimen ◽  
Black Color ◽  
Representative Samples

High-grade ore zones in low-sulfidation epithermal deposits are commonly associated with the occurrence of banded quartz veins. The ore minerals in these veins are heterogeneously distributed and are mostly confined to ginguro bands, which can be identified in hand specimen based on their distinct dark gray to black color. Micro-X-ray fluorescence element maps obtained on representative samples of banded quartz veins show that Au occurs together with Ag minerals in some of the ginguro bands, but Au can also be present in quartz bands that are light gray to white and cannot be macroscopically distinguished from barren bands. The occurrence of compositionally distinct ginguro and gankin bands, the latter being a new term coined here for colloform quartz bands containing primarily electrum or native gold, can be explained by temporal changes in the composition of the ore-forming thermal waters or variations in the conditions of ore deposition. Textural relationships, including the dendritic shape of ore minerals that appear to have grown in a matrix of silica microspheres, suggest that the ginguro and gankin bands have formed as a result of rapid deposition associated with vigorous boiling or flashing of the thermal waters.

scholarly journals The Ag- and Au-bearing phases in the Escondida epithermal vein, Cerro Moro deposit, Santa Cruz, Argentina

2020 ◽  
Vol 58 (2) ◽  
pp. 191-201 ◽  
Author(s):  
Ana C. Mugas Lobos ◽  
María Florencia Márquez-Zavalía ◽  
Laura B. Hernández
Keyword(s):  
Partial Substitution ◽  
Critical Element ◽  
Santa Cruz ◽  
Epithermal Deposits ◽  
Fine Grained ◽  
Quartz Veins ◽  
Epithermal Mineralization ◽  
Ore Minerals ◽  
The Usa ◽  
Low Sulfidation

ABSTRACT The Cerro Moro deposit is located at 48°5′55″S, 66°39′1.6″W and 100 m.o.s.l. in Santa Cruz province, southern Argentina. It is a low sulfidation Au-Ag epithermal mineralization hosted by numerous NW–SE structurally controlled quartz veins developed in close spatial and temporal proximity to the products of Jurassic extension and magmatism. The Escondida vein is the most significant mineralized structure, as it hosts the base metal-rich and Au-Ag high grade mineralization. In this vein and the Zoe ore-shoot, ore minerals are abundant (sphalerite, galena, chalcopyrite, acanthite, and less abundant pyrite and marcasite) and frequently related to dark grey, fine-grained quartz with massive, porous, crustiform, and banded textures; variable quantities of fine-grained flakes of muscovite are locally present. The Ag- and Au-bearing mineral association is represented by acanthite, argyrodite, polybasite, pearceite, stromeyerite, mckinstryite, and jalpaite. Abundant acanthite occurs commonly associated with gold and silver; copper enrichments were detected and interpreted as nanoinclusions of Cu-bearing minerals. The occurrence of Se- and Te-enriched minerals (acanthite, argyrodite, polybasite, pearceite, stromeyerite, and mckinstryite), rather than silver selenides and/or tellurides, indicates the presence of reduced mineralizing fluids and may be ascribed to partial substitution of S by Se or Te. Polybasite and pearceite were differentiated by their chemistry. Although the presence of argyrodite in epithermal deposits with silver sulfosalts is relatively common, this first mention in Cerro Moro is highly encouraging for exploration for germanium, a critical element, which is also considered strategic by countries such as the USA and China.

scholarly journals Factor analyses of transformed geochemical compositional data of meme river stream sediment, Lokoja, north central Nigeria

2021 ◽  
Vol 9 (1) ◽  
pp. 19
Author(s):  
Ngozi-Chika C.S ◽  
Olorunyomi A. E. ◽  
Echetema H. N. ◽  
Ibrahim O.I
Keyword(s):  
Compositional Data ◽  
Correlation Coefficients ◽  
Sedimentary Basins ◽  
Crystalline Rocks ◽  
Spearman Correlation ◽  
North Central ◽  
Quartz Veins ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Clastic Sedimentary

Geochemical mapping using stream sediments from MRDB, north-central, Nigeria was undertaken towards obtaining multivariate association patterns reflecting the presence of ore mineralization in Lokoja region. The area is underlain by Precambrian crystalline rocks within the Benin-Nigeria Shield and clastic sedimentary rocks of Bida Basin (one of Nigeria inland sedimentary basins). The basement crystalline rocks have been known as a source of ore minerals in Nigeria. The major lithological units are cut by the Meme river watershed which have deposited in their tributaries, large quantities of alluvial and eluvial deposits formed during an extensive period of weathering and surficial processes. The PC analysis was performed on clr-transformed of Meme sediment geochemical compositional data of selected ore forming elements in the hope of obtaining geochemical information that could elucidate on the inferred ore mineralization of the region. The eight PCs explain about 93% of the total variance. The positive and negative loadings of PCs indicated the presences of oxides, sulphides, REEs and gems mineralisation in the region. Further interrogation of Spearman correlation of ilr transformed data with respect to the PC loadings indicated  well developed relationship between Sr and V (0.55), Mn and Pb (0.89), Mn and Ta (0.77), Mn and Nb (0.78), Nb vs Ta (0.98), Rb and Cr (0.59), In and As (0.64), Pb and Ga (0.78), Sb and Au (0.52), Ba and Cr (0.50). The elemental association suggests that they are either indicator of their own mineralization or are suitable pathfinders to pertinent minerals in Lokoja region. The negative correlation between Fe with other ore elements indicated that the Fe is from both proximal and dextral sources probably due to many Fe formations and mineralisation (goethite, haematite± siderite – bearing sedimentary ironstone formations in the region). The high Spearman correlation coefficients between Mn, Nb and Ta inferred that these ore elements are from the proximal sources because they are reliable pathfinders to pertinent oxides mineralisation in the region. Inferred proximal mineralisation in the region include beryl, topaz, columbite, quartzofeldspathic and quartz veins with anomalous concentration of Au as well as industrial minerals which are artisanally mined in places for industrial purposes. 

Ore Mineralogy of the Louvem Copper Deposit Val d'Or, Quebec

1972 ◽  
Vol 9 (12) ◽  
pp. 1596-1611 ◽  
Author(s):  
Jayanta Guha ◽  
Richard Darling
Keyword(s):  
Copper Deposit ◽  
Wall Rock ◽  
Textural Features ◽  
Ore Deposit ◽  
Ore Body ◽  
Ore Minerals ◽  
Wall Rock Alteration ◽  
Ore Mineralogy ◽  
Rock Alteration ◽  
Host Rocks

Microscopic study of samples from the Louvem copper deposit shows that the principal ore minerals are pyrite, chalcopyrite, and sphalerite and the accessory ore minerals are rutile, tetradymite, two unidentified tellurides, cobaltite, molybdenite, galena, and four optically distinct phases having compositions along the digenite–bornite tie line.The Louvem ore body is a pipe-shaped mass of mineralized rhyolitic tuff and agglomerate that is conformable with enclosing volcanic and pyroclastic rocks. The ore body is zoned, with a copper-rich core and pyrite-rich margins. Wall-rock alteration spatially related to the ore deposit suggests that it was formed by replacement of porous tuffaceous host rocks by a hydrothermal fluid. Textural features of the ore indicate that it was subjected to post-emplacement thermal metamorphism.

Characteristics of Lead and Zinc Polymetallic Deposit and Wall Rock Alteration Zoning in Luziyuan, Yunnan

2013 ◽  
Vol 734-737 ◽  
pp. 52-55
Author(s):  
Lei Zeng ◽  
Ming Guo Deng ◽  
Chang Liang Lv ◽  
Wei Liu
Keyword(s):  
Wall Rock ◽  
Geological Investigation ◽  
Polymetallic Deposit ◽  
Ore Body ◽  
Lead And Zinc ◽  
Alteration Zoning ◽  
Ore Mineralization ◽  
Wall Rock Alteration ◽  
Lead Zinc ◽  
Rock Alteration

The lead and zinc polymetallic deposit in LuziYuan is an ultra-large type skarn deposit. The ore body originated from the interlayer crushed zone between the second and thrid section of stratum marble and slate (schist) interbedding of upper Cambrian series Shahechang group, the wall rock alteration is intensice in the diggings, and the alteration zoning is obvious. Through field geological investigation and data analysis, based on the petrography of alterated rocks and combined with catalog information of drilling, the wall rock alteration in the diggings of LuziYuan is divided into four alteration zones,which are in sequence: carbonate-quartz-chloritization zone; carbonate-quartz-skarn lithification zone; skarn-lead zinc ore mineralization zone; and skarn-pyritization zone. The forming of ore body is related to alterations such as skarn lithification, silicification, marmarization, magnetite, etc.

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