The cd pbzn deposits occur in passive margins, backarcs and continental rifts, and sag basins, which are tectonic settings that, in some cases, are transitional into one another. Sedimentary exhalative deposits sedex deposits are ore deposits which are interpreted to. Sedimentary exhalative origin for magnetite deposits of the new jersey highlands. The genesis of such economic deposits has been problematic. Sedimentary exhalative origin for magnetite deposits of the. Such biogeochemical cycles are important in geology because they affect many minerals. Shale basins, sulfurdeficient ore brines and the formation. Mechanical deposition of sedimentary mineral deposits in some cases, the ore mineral, on account of its resistance to weathering and its hardness, survived the destruction of many of the rock minerals. Proterozoic sedimentary exhalative sedex deposits 171 sulfate. However, geochron ages of the footwall mineralization are scarce.
Click download or read online button to get mineral deposits and earth evolution book now. Shah purpose the objective of this report is to develop a model for sedex deposits based on processes critical to their formation. 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. According to the mechanism of sedimentary exhalative mineralization, the sedimentary layer is formed as seabed sediments. Oct 17, 2001 a majority of the worlds sedimenthosted exhalative sedex leadzinc deposits are ventdistal.
Nov 03, 2014 ore deposit is a natural concentration of one or more minerals within the host rock. Metal sulfi des in most proterozoic deposits have yielded broad ranges of predominantly positive d34s values traditionally attributed to bacterial sulfate reduction. Metal sulfi des in most proterozoic deposits have yielded broad. Sedimentary rocks and their processes lakehead university. Sedimentary exhalative cuznpb deposits of the guaniguanico terrane, western cuba. For example, if the mode of transport is by sliding down a slope, the deposits that result are generally chaotic in nature, and show a wide variety of particle sizes.
Gold in sedex deposits gold in 2000 geoscienceworld books. Sedimentary exhalative deposits is part of wikiproject geology, an attempt at creating a standardized, informative, comprehensive and easytouse geology resource. Emsbo, poul, 2009, geologic criteria for the assessment of sedimentary exhalative sedex znpbag deposits. Much of our knowledge of the evolution of life on earth derives from fossils preserved in sedimentary rocks.
The latong sulfide ore deposits posses pb isotope ratio of 206pb204pb 19. Sedimentary exhalative sedex deposits are sulfidedominated pbzn ore bodies with sphalerite and galena as the principal ore minerals. The deposits found in other parts of the world are products of diverse, wellrecognized, hydrothermal systems e. 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. Proterozoic sedimentary exhalative sedex deposits 171 sulfate sul. The framework for the model development is a mineral systems. According to the mechanism of sedimentaryexhalative mineralization, the sedimentary layer is. Sedimentary exhalative sedex ore deposits are the worlds largest znpb deposits. A new genetic model for sedimentary exhalative ore deposits sedimentaryexhalative sedex deposits are one of the most. This report draws on previous syntheses as well as on topical studies of deposits in sedex basins to determine the characteristics and processes that produced sedex deposits. Ore deposits in an evolving earth download ebook pdf, epub. Dear colleagues, this special issue of minerals, entitled sedimentary ore 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. Impact of sedimentaryexhalative hydrothermal systems on.
C this article has been rated as cclass on the projects quality scale. Klein summary of relevant geologic, geoenvironmental, and geophysical information deposit geology. Sedimentary exhalative how is sedimentary exhalative. The model that best accounts for the geological and geochemical features of the massive sulfides in the ipb involves the flow of basinal brines expelled from or circulating through the pq group, in a scheme similar to that envisaged for many sedimentary exhalative deposits e. Geologic criteria for the assessment of sedimentary.
Sedex deposits are the most important source of lead, zinc and barite, a major contributor of. Sedimentary textural characteristics like rounding and sorting are clues to depositional environments. Illustrate the common structures and textures in sedimentary rocks. Some sediments and sedimentary rocks are resources in their own right, or contain resources. A new genetic model for sedimentary exhalative ore deposits. These deposits were located mainly in the terreno guerrero gt 2, and most of these deposits are of. Times of metalrich brine discharge into ancient ocean basins, associated with the formation of sedimentary exhalative sedex znpbba ore deposits, coincided with shortduration positive excursions spikes in the global marine sr isotope record.
While these spikes are unexplained by conventional oceanic models, chronostratigraphic correlations, combined with mass balance evidence and. Stratiform and stratabound znpbag deposits in australia. Note distal rift related basaltic and felsic volcanic centres. Mineral deposits and earth evolution download ebook pdf. Sedimentaryexhalative deposits are formed in the sea, so the genetic study of this kind of deposit can be combined with the principles of sedimentology ruffell et al. In this paper, we do not discuss sandstone pb, sandstonehosted pb, or pbzn vein districts, such as freiberg, germany, and coeur dalene, united states, because these deposits are highly restricted. You will be redirected to the full text document in the repository in a few seconds, if not click here. Sedimentary structures and fossils also are useful for interpreting depositional history. Geochemical evidences of sedimentaryexhalative origin of. Studies of the tectonic, sedimentary, and fluid evolution of modern and ancient sedimentary basins have also been used to select defining criteria. Pdf the koushk zinclead deposit in the central part of the. Previously, the timing of massive sulfide deposits was estimated by dating the minerals in the stratabound sulfide orebody 2125. A new genetic model for sedimentary exhalative ore deposits sedimentary exhalative sedex deposits are one of the most important types of metal ore deposits.
Discuss the concept of rounding in sedimentary rocks d. Peter matt, a wayne powell, a richard volkert, b matthew gorring, c al johnson a. Sedimentary exhalative deposits are formed in the sea, so the genetic study of this kind of deposit can be combined with the principles of sedimentology ruffell et al. The sulfur cycle is the collection of processes by which sulfur moves between rocks, waterways and living systems. Shale basins, sulfurdeficient ore brines and the formation of exhalative base metal deposits. Heavy isotopic signatures are often ascribed to fractionation within closed or partly closed local. Sulphide, carbonate, oxide, and silicatepredominant if is present. 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. Sedimentary exhalative sedex zincleadsilver deposit model by poul emsbo, robert r. Thus, the oremineral was deposited, without being chemically.
Sedex deposits are well known for the large amounts of sulfur they contain, which is present in proterozoic examples almost exclusively as pyrite, base metal sul. Author links open overlay panel fernando tornos a christoph a. 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. Ore deposits in an evolving earth download ebook pdf. Special publication of the society for geology applied to. Ppt sedex deposits powerpoint presentation free to. Sedimentary exhalative origin for magnetite deposits of. Pdf proterozoic sedimentary exhalative sedex deposits and.
Irishtype zinclead deposits represent a distinctive subclass of the carbonatehosted zinclead deposit family, having geological features and genetic models that are hybrids between sedimentary exhalative sedex. Apr 30, 20 irishtype zinclead deposits represent a distinctive subclass of the carbonatehosted zinclead deposit family, having geological features and genetic models that are hybrids between sedimentary exhalative sedex. Sedimentary exhalative deposits sedex what are sedex deposits. Diagrammatic cross section showing mineral zoning in sedimentary exhalative znpb deposits from briskey, 1986. Preliminary description of the origin of a sedimentary exhalative. A majority of the worlds sedimenthosted exhalative sedex leadzinc deposits are ventdistal. Mineralogy, bulk and rare earth element geochemistry of. Although the specifics of this deposit type are complex goodfellow et al. Brine reflux systems may produce multiple sedex deposits over periods 1 my. Textures of clastic sedimentary rocks when sediment is transported and deposited, it leaves clues to the mode of transport and deposition. Another submarine syngeneic sulphide deposits the sedimentary exhalative or sedex deposit. The most widely applied genetic model involves sedimentary exhalative sedex processes, where a sulfidic euxinic water column provides the in situ trap for hydrothermally vented metalbearing fluids.
For example, if the mode of transport is by sliding down a slope, the deposits that result are generally chaotic in nature, and show a. Massive sulfide zn deposits in the proterozoic did not. Download ore deposits in an evolving earth or read online books in pdf, epub, tuebl, and mobi format. 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. Pdf geology, ore facies and sulphur isotopes of the koushk vent. Sedimentary exhalative sedex zincleadsilver deposit model. Massive sulphides are spatially and temporally associated with iron formation if and other hydrothermal sedimentary rocks in the vicinity of the brunswick no. Although the matahambre sedimentary exhalative base metal deposit is an important past producer, no sedimentary exhalative deposits are currently being mined in the greater antilles. Ore deposit is a natural concentration of one or more minerals within the host rock. Biochemical cycles are also important for life because sulfur is an essential element, being a constituent of many proteins and cofactors, and sulfur compounds can be used as oxidants or.
Read geochemical evidences of sedimentaryexhalative origin of the shalehosted pgeagauzncu occurrences of the prades mountains catalonia, spain. Jan 10, 2017 submarine exhalative sedex base metal deposits schematic sketch of the geological setting of an exhalative sedimentary sedex sulphide barite ore deposit in a black shale basin. Pdf proterozoic sedimentary exhalative sedex deposits. Proterozoic sedimentary exhalative sedex deposits and links to. The major defining features of the northern australian. Sedimentary exhalative sedex usgs publications warehouse. Sedex deposits account for more than 50 percent of the worlds zinc and lead reserves and furnish more than 25 percent of the worlds production of these two metals. Draft 1 1 sedimentary exhalative origin for magnetite deposits of the new jersey 2 highlands 3 peter matt, wayne powell, richard volkert, matthew gorring and al johnson 4 5 abstract 6 the new jersey highlands and contiguous hudson new york highlands host hundreds of 7 small, workedout magnetite mines, and the major zincoxide deposits of franklin and sterling.
This site is like a library, use search box in the widget to get ebook that you want. 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. Submitted papers must make a significant contribution to the field of study and must place the. For example, desert sand dune deposits are well sorted and well rounded, whereas glacial deposits are poorly sorted. The absence of a vent complex, together with sulfide mineral replacement of host rock mineral assemblages has led several investigators to. Longitudinal cross section showing development of supergene zone and ironrich gossan based on elura deposit, australia. Click download or read online button to get ore deposits in an evolving earth book now. If you would like to participate, you can choose to edit this article, or visit the project page for more information. The second subtype of sedimenthosted pbzn deposits is.
Zncu mineralisation in cuba is hosted in the silicic lastic sedimentary rocks of the san cayetano. Mineralization of rare earths, platinum and gold in a. However, recent work in nevada has demonstrated that the host rocks of midtertiary carlintype gold deposits also contain devonian sedex mineralization, which is significant because these deposits will be mined for gold and not znpb or barite emsbo et al. Download as ppt, pdf, txt or read online from scribd. Proterozoic sedimentary exhalative sedex deposits and links. 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. Volume 247, issues 12, 15 january 2008, pages 195207. Of these, the deposits in southern china are remarkably simi. Describe the mode of formation of the sedimentary rocks b. Proterozoic sedimentary exhalative sedex deposits and. Sedimentaryexhalative sedex deposits are one of the most important types of metal ore deposits. The exhalative sediments linked to the volcanic exhalative. Origin, exploitation, paleoenvironmental significance, is dedicated to those metalliferous ore deposits that owe their origin to a combination of marine and terrestrial sedimentary processes chemical, biochemical, organic, detrital, as. Please note that the content of this book primarily consists of articles available from wikipedia or other free sources online.
1631 955 1369 671 712 787 36 613 363 894 1222 650 1234 893 619 1532 1620 1476 1205 91 125 203 1250 519 140 173 792 1173 785 1487 623 1063 1291 400 1132