Pdf the distribution of sedex pbzn deposits through earth history. Sedex cupbzn deposits in the sudbury basin were deposited on the sea floor from fluids in which. Evidence that broken hilltype pbzn deposits are metamorphosed. They are not underlain by a discordant alteration zone or stockwork vent complex that would indicate the path by which ore fluids reached the seafloor. So it supports you at each stage of your supply chain programme. Scribd is the worlds largest social reading and publishing site. Sedimenthosted pbzn deposits contain the worlds greatest lead and zinc resources and dominate world production of these metals. Proterozoic sedimentary exhalative sedex deposits and.
Demo of social compliance documentation kit price 499 usd complete editable social compliance document kit. Sedex deposits are the most important source of lead, zinc and barite, a major. This one covers volcanogenic massive sulfide vms and sedimentary exhalative. The emergence of sedex ores in the rock record at about. They are a chverse group of ore deposits hosted by a wide variety of carbonate and siliciclastic roch that have no obviolls genetic association with igneous activity. Ocean deposits pdf measurements can determine the topography of the ocean floor, and have shown. Mcqueen crc leme, australian national university, canberra, act 0200 and school of rehs, university of canberra, act 2601. Although these two types of deposits have some similarities, particularly ore deposition on or just below the sea floor, sedex deposits differ in that they occur in sedimentary basins formed in intracratonic and epicratonic rift systems large, 1980, are sedimenthosted, and formed by.
Sedimentary exhalative deposits sedex deposits are ore deposits which are interpreted to. Sedimentary exhalative sedex zincleadsilver deposit model by poul emsbo, robert r. In this work, i discuss a classical sedex deposit model for the northwestern cuban pbzn deposits as proposed by carne and cathro 1982. The enormous size of sedex deposits strongly suggests that. Sedex is listed in the worlds largest and most authoritative dictionary database of abbreviations and acronyms. Instead, sedex deposits are products of high pressure and temperature events that cause dewatering and metamorphism of thick piles of accumulated sediments in intracratonic and epicratonic basins leach et al. In others, alteration is less extensive and or carbonaterich large, 1981. Sedimentary exhalative deposits sedex deposits are ore deposits which are interpreted to have been formed by release of orebearing hydrothermal fluids into a water reservoir usually the ocean, resulting in the precipitation of stratiform ore sedex deposits are the most important source of lead, zinc and barite, a major contributor of silver, copper, gold, bismuth and tungsten. So it supports you at each stage of your supply chain programme now and in the future.
Note distal rift related basaltic and felsic volcanic centres. This report draws on previous syntheses and basic research studies of sedimentary exhalative sedex deposits to arrive at the defining criteria, both descriptive and genetic, for sedex type deposits. Object postage can be made at any correios post offices or via collection call. Toward an integrated genetic model for ventdistal sedex deposits d. Base metal deposits in western cuba belong to the sedex type, as defined by carne and cathro 1982. A hypothesized brine reflux flow system responsible for transporting ore fluids is also shown. Sedimentary exhalative deposits sedex deposits are ore deposits that are interpreted to have been formed by release of orebearing hydrothermal fluids into a water reservoir usually the ocean, resulting in the precipitation of stratiform ore gu et al. Sedimentary exhalative sedex deposits are sulfidedominated pbzn ore bodies with sphalerite and galena as the principal ore minerals.
Ncs, obs, ge, we suggest auditors to check with the end client for their preference. Impact of sedimentaryexhalative hydrothermal systems on. In case you need to contract sedex service, contact one of our commercial representatives. Sedimentary exhalative sedex ore deposits are the worlds largest znpb deposits.
The role of dense brines in the formation of ventdistal. This report draws on previous syntheses and basic research studies of sedimentary exhalative sedex deposits to arrive at the defining criteria, both descriptive and genetic, for sedextype deposits. By comparing both deposits,it is found that there are some similarities,such as the oreforming fluid power. Times of metalrich brine discharge into ancient ocean basins, associated with the formation of sedimentaryexhalative sedex znpbba ore deposits, coincided with shortduration positive excursions spikes in the global marine sr isotope record. Whether your supply chain includes 100s or s of suppliers, sedex advance scales to meet your needs. Gold in sedex deposits gold in 2000 geoscienceworld. Alteration is more subtle due to lower temperature of ore fluid typically just carbonate. The workers committee exists in theory but does not appear to function. Metal sulfi des in most proterozoic deposits have yielded broad ranges of predominantly positive d34s values traditionally attributed to bacterial sulfate reduction. Rich accumulations of lead, zinc and silver are found in the ore minerals sphalerite zinc sulfide and galena lead sulfide deposited between thin layers of marine sand, silt and mud in sedimentary basins. Although the specifics of this deposit type are complex goodfellow et al.
Sedex deposits 1 sedex deposits sedimentary exhalative 2 sedex ore 3 znpb reserves and production by deposit type 4 grade and tonnage of all sedex deposits 5 grade and tonnage of some sedex deposits 6 sedex deposits of the selwyn basin 7 tom sedex deposit, yukon 15. Sedex deposits are marked by stratiform, sedimenthosted znpbsul. Part 7 of an 11 part series introducing ore deposit geology to nontechnical people. Geological survey scientific investigations report 20105070n, 57 p. Meggen znpb sulfide and barite deposit, germany, is a classic example of a sedex deposit. While these spikes are unexplained by conventional oceanic models, chronostratigraphic correlations, combined with mass balance evidence and. Chapter 218 the distribution of sedex pbzn deposits through e arth histor y. A majority of the worlds sedimenthosted exhalative sedex leadzinc deposits are ventdistal. Brine reflux systems may produce multiple sedex deposits over periods 1 my. Another submarine syngeneic sulphide deposits the sedimentary exhalative or sedex deposit. Large 1983 describes more subtle types of alteration near some deposits, including increased. More single large deposits spaced very far apart 2050km in belts. Origin of a giant orebody at navan, ireland nature. Sangster the original version of this article unfortunately contained a mistake.
Sedimentary exhalative sedex usgs publications repository. Pyrite trace element haloes to northern australian sedex. Shah purpose the objective of this report is to develop a model for sedex deposits based on processes critical to their formation. Volcanogenic massive sulfide ore deposit wikipedia.
Volcanogenic massive sulfide ore deposits, also known as vms ore deposits, are a type of metal sulfide ore deposit, mainly copperzinc which are associated with and created by volcanicassociated hydrothermal events in submarine environments these deposits are also sometimes called volcanichosted massive sulfide vhms deposits. The type of sedimentary basin from which the ore fluids are derived, and the lithologies contained within the basin, control these differences in fluid chemistry. Sedex certification supplier ethical data exchange a smeta audit sedex certification supplier ethical data exchange program is an electronic framework intended to help organizations improve ethical execution of their inventory network. To form sedex deposits, you require the deep sedimentary basins so distribution is more limited than that of vms deposits, however they are still found on all continents and there are about 125 sedex deposits on note, and these are marked in red on the map. Pdf the distribution of sedex pbzn deposits through earth. Pbzn sedex deposits and their copper stockwork roots. They are grouped together in the santa luciamatahambre metallogenic district fig.
Comparative study on sedex deposits and vms deposits. Sedex sedimentary exhalative deposits are one of several types of sedimenthosted leadzinc deposits. Sedex deposits the many details of sedimentary exhalative sul. Sulphur isotopic data from pyrite and chalcopyrite indicate a biogenic and magmatic origin, at least for part of the cuban sulphides.
Ocean deposits pdf ocean deposits pdf ocean deposits pdf download. Pdf proterozoic sedimentary exhalative sedex deposits. Submarineexhalative sedex base metal deposits schematic sketch of the geological setting of an exhalative sedimentary sedex sulphide barite ore deposit in a black shale basin. These unique features also are found to harbor a diverse array of. Ppt sedex deposits powerpoint presentation free to. Pdf the distribution of sedex pbzn deposits through. Sedex deposits are distinct from the volcanichosted massive sulfide deposits described by huston 2000. Pdf proterozoic sedimentary exhalative sedex deposits and. Proterozoic sedimentary exhalative sedex deposits and links to evolving global ocean chemistry core reader. Distal mnbearing sediments were deposited in seawater in which. Sedex deposits are closely associated with underlying hyrdrothermal feeder zone hydrothermal alteration not well documented or mapped extends for hundreds of meters into the pre and postore sedimentary sequence and up to several kilometers laterally from the deposit. Selected bht characteristics compared to those of sedex deposits. Encyclopedia of life support systems eolss deposits either to the present earths surface i. Some sedex deposits with ore textures that mimic synsedimentary textures were formed by replacement processes below the sea floor e.
Conversely, sedex deposits with continental affinity lie in the complex. First, siderite is a component of several important sedex deposits and may be unreported in others. It is constantly evolving in line with the latest risks and our members feedback. These are very familiar in genesis to the vms deposits except they are not primarily driven by intrusions below but are instead products of dewatering and metamorphism of thick piles of accumulated sediments in ocean basins hence the sed part of the name, the exhalative portion of the name. Geology of basemetal deposits encyclopedia of life.
Essential geologic, chemical, physical, and mass balance constraints on sedex ore formation that must be accounted for in any. This research presents results from a systematic laser ablationicpms investigation of the trace metal content of sedimentary pyrite associated with two northern australian proterozoic sedimenthosted zn deposits. The worldclass howards pass sedex znpb district, selwyn. The importance of oxidized brines for the formation of.
Typical setting is passive marginfailed riftsag basin. Total 140 files quick download in editable form by edelivery chapter1. Proterozoic sedimentary exhalative sedex deposits and links to. Heavy isotopic signatures are often ascribed to fractionation within closed or partly closed local. In order to distinguish the difference between sedex deposits and vms deposits,the authors compare both deposits systematically from the aspects of metallotectonic background,orecontrolling factors,metallogenic model,material sources,deposit geological features,etc. What are the differences between sedex and vms deposits and how the vms and sedex deposits fit into the overall scheme of things. The absence of a vent complex, together with sulfide mineral replacement of host rock mineral assemblages has led several investigators to.
Sedex paper 2016 the relationship of sedex deposits to. The distribution of sedex pbzn deposits through earth history. Sedimentary exhalative sedex zincleadsilver deposit model. You remember that nature concentrates the metals by a process of partially melting crustal rocks at depth, letting the metal rise through the crust and cool, dumping the valueless material such as feldspar and amphibole on the way and concentrating the really useful. In some deposits, silicification is the dominant or only alteration meggen, germany and red dog, alaska. Sedimentary exhalative deposits abbreviated as sedex from sedimentary exhalative are ore deposits which are interpreted to have been formed by release of orebearing hydrothermal fluids into a water reservoir usually the ocean, resulting in the precipitation of stratiform ore. Although the benue trough leadzincbarium deposits may be considered a clastic rock dominated leadzincbarium deposit. A nmge of orefortl1ing processes in a vmiety of geologic and tectonic environments created these.
The host rocks of the deposits are gritstones, sandstones and black shales, with no igneous rocks involved. The framework for the model development is a mineral systems. Metal sulfi des in most proterozoic deposits have yielded broad. Preliminary description of the origin of a sedimentary. A twofold subdivision for stratiform sedimenthosted pbzn sedimentary exhalative, sedex deposits is proposed, based on fundamental differences in the chemistry of the mineralizing brines. The style of znpb mineralization in each deposit is identical, and the rocks that host the deposits are assumed to be of the same age. Introduction ore deposits are crustal concentrations of useful elements that can be exploited at a pro. Sedex, or sedimentary exhalative deposits, are ore deposits formed when hydrothermal fluids enter a water reservoir, such as an ocean, and precipitate minerals. Studies of the tectonic, sedimentary, and fluid evolution of modern and ancient sedimentary basins have also been used to select defining criteria.
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