3 edition of Distribution of gold in porphyry copper deposits found in the catalog.
Distribution of gold in porphyry copper deposits
1988 by U.S. Dept. of the Interior, U.S. Geological Survey in [Reston, Va.?] .
Written in English
|Statement||by Dennis P. Cox and Donald A. Singer|
|Series||U.S. Geological Survey open-file report -- 88-46|
|Contributions||Singer, D. A, Geological Survey (U.S.)|
|The Physical Object|
Intrusive breccias were formed by the emplacement of the biotite diorite into the Panguna Andesite and contain angular andesite fragments set in a matrix of biotite, chalcopyrite, bornite and local free gold. The fracture pattern exhibits a concentric form, modified by the regional NE structural grain, which is exploited by intrusive features such as pebble dykes Clark, If gold is present in the ore-forming solutions, more of it will be deposited in high-temperature porphyry copper-gold deposits where it will be closely associated with bornite. These skarn deposits are truly world class but they are very atypical. Erich U. A CAT has wheels 12 feet high and carries a payload of almost tons.
Chalcopyrite and gold associated with hydrothermal biotite in the Biotite Diorite and Panguna Andesite, iii. Porphyry was extensively used in Byzantine imperial monuments, for example in Hagia Sophia  and in the "Porphyra", the official delivery room for use of pregnant Empresses in the Great Palace of Constantinople. Kawerong Quartz Diorite - the bulk of the intrusion is un-mineralised and occurs to the north-west of the Panguna mine. Biotite Granodiorite and "Feldspar Porphyry", which occupy the low grade central core of the orebody. Metal grades within the breccia bodies decline with depth, and they are cut by dykes of Biuro Granodiorite; Pebble dykes, including one that can be traced laterally in the open pit for x 50 m, exhibit fragment milling and consistent fragment and matrix compositions over considerable distances; Biuro Granodiorite, 3.
If gold is present it will drop out across the temperature spectrum. Arsenopyrite View Larger Image So how do we explore for Porphyry Copper Deposits which are completely covered by barren younger rocks? The upper portions of porphyry copper deposits may be subjected to supergene enrichment. Grasberg and Ertsberg are almost in equator but because there are over 12, feet in elevation they receive snow from time to time as even nearby permanent glacier.
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Copper grades are elevated throughout weak to intense sericite alteration. These alteration types become important in the exploration of porphyry style mineralization as they provide vectors to the mineralization.
I would like to thank Jeff for his generous support in making this presentation possible and Battle Mountain Gold for their generous support for our studies in the Kori Kollo District.
Gold is stripped during the most intense sericite alteration but is unaffected by weaker alteration. Stream sediment anomalies are usually followed up with a regular grid of soil sampling to identify the source of the stream sediments. There is no proper substitute for getting underground and mapping an area in detail but there are other ways of vectoring in on the most prospective areas prior to expanding this boot leather and satellite imagery is one of these tools.
Breccia zones with angular or locally rounded fragments are commonly associated with the intrusives.
Porphyry copper deposits commonly contain hundreds Distribution of gold in porphyry copper deposits book millions of metric tons of ore that averages a fraction of 1 percent copper by weight; although they are low-grade, Distribution of gold in porphyry copper deposits book deposits constitute important sources because they may be worked on a large scale at low cost.
These phases are represented by a series of lithologies which include: Biotite Diorite which comprises the main mass of the apophysis and largely surrounds the Distribution of gold in porphyry copper deposits book Granodiorite and "Feldspar Porphyry" and is a more potassic altered variety of the main Kawerong Quartz Diorite.
Phillips then made a field inspection in Mayconfirmed the similarities, and following stream sediment and ridge and spur soil sampling program, his exploration team delineated a 13 sq km copper anomaly, focused on a m diameter core.
Large porphyry copper deposits are worked in the southwestern United States where molybdenum is produced as a by-productthe Solomon Islands, Canada, Peru, ChileMexico, and other parts of the world.
The host-rock is progressively altered by the hydrothermal fluids that pas through it. Grunsky, Karen D. Mineralized veins are often only a millimeter or two across but the grade comes from the high density of the veinlets.
Phase equilibrium constraints for solutions with geologically reasonable reduced sulfur contents indicate that high-temperature porphyry copper-gold deposits will contain bornite and magnetite, whereas lower temperature deposits whether primary or overprinted by phyllic alteration will contain chalcopyrite and pyrite.
The driver probably barely noticed when he drove over this SUV everything about porphyry deposits is big. This primary mineralizing event yield only low grade mineralization, grades of 0.
The West Zone outcrops, while the East Zone, which extends to a depth of at least m, is unconformably overlain by a sequence of Late Cretaceous to Eocene sedimentary and volcanic rocks. Thesis, The University of Utah X p. Existing hydrothermal solutions can be studied at hot springs, in subsurface brine reservoirs such as those in the Imperial Valley of California, the Cheleken Peninsula on the eastern edge of the Caspian Sea in Turkmenistan, in oil-field brines, and in submarine springs along the mid-ocean ridge.
Now although primary porphyry mineralization generally has pretty modest grades subsequent weathering and erosion of the porphyry may pretty high grade secondary deposits of copper just below the water table. Theme Session on Transition between porphyry copper and epithermal systems.
Fossil hydrothermal solutions can be studied in fluid inclusionswhich are tiny samples of solution trapped in crystal imperfections by a growing mineral. Some of the most famous, found in Japan and called kuroko deposits, yield ores that contain as much as 20 percent combined copper, lead, and zinc by weight, plus important amounts of gold and silver.
Satellite imagery as with most forms of geophysics usually generates a large number of false anomalies as well as a few real ones sorting out the truth from the false is largely a matter of experience and then field checking. The rock on the bottom right has suffered this potassic alteration; pink-orange mineral is potassium feldspar.
This is a photo from the edge of the pit and you can start to get an idea of the scale for the trucks climbing up the whole roads within the pit but you only really get a full understanding of the scale when you see one of those trucks standing next to a normal SUV. These breccia zones are typically hydrothermal in nature, and may be manifested as pebble dikes.Regardless of this uncertainty, the mode for the Cu/Au ratio distribution in Fig.
2 and Table 1 is about 40, suggesting that this should be the division between gold-rich and gold-poor deposits. Definition of porphyry copper–gold deposits should be based on both copper and gold grades for several galisend.com by: Preface --An overview of the world's porphyry and other hydrothermal copper & gold deposits, and their distribution / T.
Michael Porter --General --Major regional factors favoring large size, high hypogene grade, elevated gold content and supergene oxidation and enrichment of porphyry copper deposits / Richard H Sillitoe --Factors influencing. This book will be appreciated by students, teachers and professional geologists for its clarity of expression and scholarship of content.' Noel C.
White - Consulting Economic Geologist and Honorary Research Professor, CODES, University of Tasmania 'If you’ve been searching for a modern textbook on metallic ore deposits, this is a good galisend.com: John Ridley.Gold-Distribution of Pdf in Porphyry Copper Deposits By Dennis P.
Cox and Donald A. Singer Abstract Analysis of 55 porphyry copper deposits demon-strates a continuum between porphyry copper-gold.Preface --An overview of the world's porphyry and other hydrothermal copper & gold deposits, and their distribution / T.
Michael Porter --General --Major regional factors favoring large size, high hypogene grade, elevated gold content and supergene oxidation and enrichment of porphyry copper deposits / Richard H Sillitoe --Factors influencing.A brief discussion of the porphyry copper subtypes is in the Appendix.
Associated Deposit Types Ebook variety of deposit types are spatially, if not genetically, related to porphyry copper mineralization, including skarns, polymetallic veins and replacements, and epithermal veins. Copper skarn deposits occur near many porphyry copper host intru.