scholarly journals Enhanced processing of magnetic data for delineating lithological boundary and geological structure of the epithermal gold mineralization control system - A case study: Cibaliung Area, Indonesia

2021 ◽  
Vol 882 (1) ◽  
pp. 012047
Author(s):  
Wahyu Eko Junian ◽  
Andri Yadi Paembonan ◽  
Harnanti Y Hutami ◽  
Muhammad Arief Wicaksono
Keyword(s):  
Gold Mineralization ◽  
Geological Structure ◽  
Gold Deposits ◽  
Magnetic Data ◽  
Epithermal Gold ◽  
The West ◽  
Vertical Derivative ◽  
System A ◽  
First Vertical Derivative

Abstract Cibaliung is an area that is traversed by the Au-Ag-Cu mineralization pathway from low to intermediate sulfide epithermal system. The implemented techniques for delineating probable gold deposits by the lithology contact and structures that control epithermal gold mineralization systems in the area include first vertical derivative (FHD), vertical derivative (VD), second vertical derivative (SVD), analytic signal (SA), and tilt angle (TA). The results shows that high continuity of anomaly contrast in the direction of Northwest (NW), North-Northwest (NNW), and North-Northeast (NNE) is presumed to be the target geological structure of the study area. Furthermore, the contrast value of magnetic anomaly represents the lithology contact lies in the direction of the West and the East of the area.

scholarly journals Geophysical prospecting for epithermal gold deposits (a case study from the Maletoivayam gold ore field, Kamchatka Peninsula)

LITOSFERA ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 116-132
Author(s):  
G. V. Gurin
Keyword(s):  
Kamchatka Peninsula ◽  
Ring Structure ◽  
Gold Deposits ◽  
Magnetic Data ◽  
Epithermal Gold ◽  
Geophysical Prospecting ◽  
Electrical Survey ◽  
Altered Zone ◽  
Volcanic Belts

Research subject. The high-sulfidation (HS-type) epithermal gold deposits of the Maletoyvayam ore field, which is located in the volcanic belts of the Kamchatka Peninsula. Materials and methods. The paper presents the results of geophysical and petrophysical studies carried out by “NPP VIRG-Rudgeofizika” (2016–2017 years) in the central part of the Maletoyvayam ore field hosting HS-type gold deposits. Results. The presented case study shows the potential of geophysical prospecting for HS-type epithermal gold deposits located within altered rock areas. On the basis of the conducted magnetic surveys, fragments of a ring structure broken by faults and the hydrothermally altered bodies within the Neogene volcanogenic-sedimentary sequence of the andesite composition were identified. Using the 3D inversion of magnetic data, the shape, size and structure of the hydrothermally altered bodies were estimated. The electrical survey data allowed the hydrothermally altered areas to be differentiated in terms of composition. As a result, zoning of hydrothermally altered areas was conducted, and ore-bearing sites and gold-bearing bodies of monoquartzites in the plan and cross-section were determined. Conclusions. Geophysical techniques for prospecting HS-type epithermal gold deposits are effective in distinguishing important gold-related features within the altered zone thereby facilitating identification of specific drill targets.

Application of high resolution airborne geophysics to epithermal gold exploration in Northeast Queensland and Coromandel, New Zealand

1989 ◽  
Vol 20 (2) ◽  
pp. 99 ◽  
Author(s):  
S.S. Webster ◽  
R.W. Henley
Keyword(s):  
High Resolution ◽  
Regional Scale ◽  
Cost Effective ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Magnetic Data ◽  
Mapping Technique ◽  
Epithermal Gold ◽  
Airborne Geophysics ◽  
Airborne Geophysical Data

High resolution airborne geophysical data over broad areas have been found to optimize exploration for epithermal gold deposits in differing geological environments.Genetic exploration models may be tested in favourable sites by the recognition of geophysical signatures. These signatures reflect structural, lithological and alteration patterns arising from controls on ore deposits and can be applied at regional or detailed scales, using the same data set.At regional scale (e.g. 1:100,000) the magnetic data reflect the regional tectonics and divide the area into domains for the application of appropriate genetic models. At prospect scale (e.g. 1:25,000) the radiometric data allow the extrapolation of poorly outcropping geology to provide a cost-effective mapping technique. The magnetic data can be used to supplement this interpretation or can be used to target deeper sources for direct investigation by drilling.

Laumontitization as an exploration indicator of epithermal gold deposits : A case study of the axi and other epithermal systems in West Tianshan, China

2003 ◽  
Vol 22 (4) ◽  
pp. 289-301 ◽  
Author(s):  
Chen Yanjing ◽  
Bao Jingxin ◽  
Zhang Zengjie ◽  
Chen Huayong ◽  
Liu Yulin
Keyword(s):  
Gold Deposits ◽  
Epithermal Gold

Application of 3D magnetic amplitude inversion to iron oxide-copper-gold deposits at low magnetic latitudes: A case study from Carajás Mineral Province, Brazil

Geophysics ◽  
2015 ◽  
Vol 80 (2) ◽  
pp. B13-B22 ◽  
Author(s):  
Marcelo Leão-Santos ◽  
Yaoguo Li ◽  
Roberto Moraes
Keyword(s):  
Iron Oxide ◽  
Gold Deposits ◽  
Magnetic Data ◽  
Magnetic Latitude ◽  
Amplitude Inversion ◽  
Carajás Mineral Province ◽  
Amplitude Data ◽  
Copper Gold ◽  
Magnetic Amplitude

Strong hydrothermal alteration modifies rock physical properties in iron oxide-copper-gold deposits (IOCGs) and may result in characteristic signatures detectable in geophysical surveys. Magnetic data are commonly used in characterizing orebodies, and 3D inversions are often used to assist in interpretations. In areas with strong remanence and self-demagnetization, the total magnetization can have directions different from the inducing field direction. This deviation precludes the use of traditional inversion methods. Magnetic amplitude inversion offers one solution to this challenge because the amplitude data are weakly dependent on the magnetization direction. In addition, the low magnetic latitude also imposes difficulty in amplitude data calculation due to the instability in the component conversion in the wavenumber domain. To formulate a practical approach, we present a case study on applying the magnetic amplitude inversion to the Furnas southeast IOCG deposit at the low magnetic latitude in Carajás Mineral Province, Brazil, and demonstrate that the approach can reliably recover an interpretable distribution of effective magnetic susceptibility and identify massive magnetite from hydrothermal alterations associated with the high-grade ore.

scholarly journals GEOLOGY AND ORE MINERALISATION OF NEOGENE SEDIMENTARY ROCK HOSTED LS EPITHERMAL GOLD DEPOSIT AT PANINGKABAN, BANYUMAS REGENCY, CENTRAL JAVA, INDONESIA

2015 ◽  
Vol 7 (2) ◽  
pp. 75
Author(s):  
Arifudin Idrus ◽  
Fahmi Hakim ◽  
I Wayan Warmada ◽  
Mochammad Aziz ◽  
Jochen Kolb ◽  
...  
Keyword(s):  
Base Metal ◽  
Gold Mineralization ◽  
Early Stage ◽  
Gold Deposits ◽  
Epithermal Gold ◽  
Central Java ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Miners

Low suphidation (LS) epithermal gold deposits were recently found in the Paningkaban area, Central Java province, Indonesia, with more than five hundred artisanal gold miners currently operating in the area. This study is aimed to understand the geological factors controlling the gold mineralization and to characterize the alteration and ore mineralogy of the deposit. Several epithermal veins/veinlets trending N–S, NW–SE, and NE–SW are hosted by Tertiary turbiditic volcanoclastic sedimentary rocks of the Halang formation. This formation is composed of looping gradation of sandstone and siltstone units. Pre- and syn-mineralization structures such as extension joints, normal sinitral fault and sinitral fault control the gold mineralization. Fault movements formed dilational jogs manifested by NW-SE-trending en-echelon tension gash veins. Four main alteration zones are identified: (a) phyllic, (b) argillic, (c) sub propylitic and (d) weak subpropylitic. Ore minerals consist of native gold, electrum, native silver, pyrite, chalcopyrite, sphalerite, galena, arsenopyrite, cubanite, marcasite, covellite and tennantite, which are commonly associated withargillic alteration. Vein structures such as massive, swarm and low angle veins, stockwork and veins dispersed in diatreme breccia are present. Normal banded, cockade, crustiform, bladed carbonates as well as, comb and saccharoidal features are the typical vein textures. It is noteworthy that the veins are basically composed of carbonate with minor quartz at gold grades of up to 83 g/t Au. Based on the vein structures and textures, four stages of ore mineralization were developed consisting of (a) early stage (fluidized breccia and quartz vein), (b) middle stage (carbonate base metal), (c) late stage (late carbonate), and supergene stage. Gold mineralization originated mainly during middle and late stages, particularly in association with cockade, crustiform, bladed carbonate base metal veins. Based on those various features, the LS epithermal deposit in the study area is categorized as carbonate-base metalgold mineralization type.

Mineralization, antiforms and crustal extension in andesitic arcs

1994 ◽  
Vol 131 (2) ◽  
pp. 231-242 ◽  
Author(s):  
A. H. G. Mitchell ◽  
J. C. Carlile
Keyword(s):  
Gold Mineralization ◽  
Porphyry Copper ◽  
Geothermal Gradient ◽  
Gold Deposits ◽  
Hydrothermal Fluids ◽  
Plate Motion ◽  
Epithermal Gold ◽  
Crustal Extension ◽  
Copper Mineralization ◽  
High Level

AbstractThe distribution and stratigraphic position of porphyry copper and epithermal gold deposits in andesitic arcs of the western Pacific and eastern Europe suggest that porphyry copper and epithermal vein deposits of adularia–sericite type develop successively under different stress regimes in an evolving arc, rather than being genetically related as commonly supposed. Absence of coeval high-level stocks in the root zones of many adularia-sericite deposits suggests that circulation of the dominantly meteoric hydrothermal fluids is not driven by shallow intrusions. The location of several world-class deposits on basement geanticlines, and on more localized antiforms of which at least one has been interpreted as a metamorphic core complex, implies that elevation of the arc, emplacement of magmatic sills at depth and adularia–sericite type gold mineralization are genetically related to subduction-induced crustal extension. Ascent of deep hydrothermal fluids, predominantly meteoric but with a metamorphic or magmatic component, may be controlled by regional low-angle structures at depth, analogous to those inferred for some mesothermal gold deposits. Mineralization at shallow (epithermal) depths in high-angle structures largely reflects the high geothermal gradient and mixing of deep fluid with cool meteoric water in or at the base of the permeable volcanic cover. Andesitic magmatism may resume following porphyry copper mineralization, adularia–sericite epithermal gold mineralization, or continued extension to form a ‘back arc’ spreading system, depending on the relative plate motion.

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