The diatreme, formed as an underground explosion chamber, has been exhumed since formation. Independent technical report for the thorn project, sutlahine river area, british columbia, canada. Geology and mineralization of the peak zone au cuag. Impact breccia definition of impact breccia by the free.
Diatreme brecciahosted epithermal gold deposit at ridge. New mexico geological society guidebook, 61diatremedike complexesst field conference, four corners country, 2010, p. Ar alunite ages from the colquijirca district, ag and. A diatreme, sometimes known as a maardiatreme volcano, is a volcanic pipe formed by a gaseous explosion. Sydney, australia, nov 11, 2010 abn newswire gold anomaly limited asx. A diatreme is a geological structure that forms through a series of volcanic. Impact breccia synonyms, impact breccia pronunciation, impact breccia translation, english dictionary definition of impact breccia. The yanacocha high sulphidation gold district has produced an amazing number of breccia samples. Hydrothermal breccias and veins at the kelian gold mine.
Quartz veins of the first, third and fourth stage are less than 2 m wide. Monchiquites have a groundmass of glass now recrystallized, analcime or. The diatreme is largely composed of minette tuffbreccia with a large wallrock fraction, whereas the dikes are composed of hypabyssal minette. Maardiatreme volcanoes are produced by explosive eruptions that cut deeply into the. Heavy line indicates boundary of cripple creek diatreme. Stratigraphic and structural setting of intrusive breccia diatremes in the white river bull river area, southeastern british columbia article pdf available january 1988 with 70 reads. The unbedded diatreme is dominantly exposed as a massif comprising multiple subvertical columns, interpreted as ephemeralconduit deposits of wellmixed, poorly sorted, composite and juvenile pyroclastrich deposits that truncate marginal layered deposits, plus a. Chemical variations in tetrahedrite tennantite minerals. New insight into the timing and history of diatremedike complexes. Latestage diatreme breccia, dizon porphyry cuau, philippines supergene enrichment. Wilson and head, 2007 an integrated model of kimberlite ascent. Geology of the crater of diamonds state park and vicinity.
The lamprophyre breccia is relatively small, but the margins have produced 2. Erosional remnants consist of a diatreme 170190 m in diameter, of which the central 150 m is wellexposed in a massif featuring 2030mhigh subvertical cliffs, and a 50cmthick basanite dike. Maardiatreme volcanoes, their formation, and their. Round butte is a small but complex miocene diatreme that crops out 190 m below the preeruptive surface, in the southeastern part of the hopi buttes volcanic field. A continued exploration programme has further defined the geology of the tolukuma vein system, verified the resource indicated by newmont, and identified potential for additional mineralisation. The purnama gold deposit in the martabe district smedg. Proceedings of the 47th forum on the geology of industrial. When magma rises up through a crack in the earths crust and makes contact with a shallow body of ground water, rapid expansion of heated water vapor and volcanic gases can cause a. Diatreme article about diatreme by the free dictionary. Near surface zone 0100m in the western basin with several high grade silver intercepts interpreted as a possible flatlying breccia zone. Diatreme breccia from the ortiz gold mine, santa fe county, new mexico by michael thomsen.
A circular volcanic vent produced by the explosive energy of gascharged magmas explanation of diatreme. A diatremehosted gold deposit at montana tunnels, montana. Some diatreme explosions may result from the interaction of hot magma and relatively shallow groundwater. This diatreme was emplaced along the faulted contact between andesitic volcaniclastic rocks, assigned to the late cretaceous elkhorn mountains volcanics, and a sequence of quartz latitic ignimbrites, which are part of the lowland creek volcanics of middle eocene age. Diatreme breccia showing silicification of the within the finely comminuted breccia matrix and vughy silica alteration of porphyritic, interpreted intrusion, fragments, veladero. Principles of igneous and metamorphic petrology second edition. Early miocene volcanism associated with a maardiatreme breccia complex preceded mainstage epithermal gold mineralization at the kelian gold mine.
Rock composed of sharpangled fragments embedded in a finegrained matrix. The author directed this exploration program through the 1990s where his teams discovered multiple individual deposits throughout the district making. A hydrothermal agznpb diatreme breccia, approximately 70m in diameter. Kelian is a large, breccia and veinhosted epithermal sys. The resource at tolukuma hill, designated as zone c, is a mine recoverable 432,000 t at 18. Recognizing that a mineral deposit is hosted by a maardiatreme volcano, and.
Geology and mineralization of the peak zone, a newly. Gravity and magnetic models of the tomahawk diatreme, northern black hills, south dakota. Gold is present in all stages as microscopic inclusions in quartz and sporadically in pyrite. Early miocene volcanism associated with a maardiatreme breccia complex preceded. The rare earth element ree values within this sample were elevated, and an effort was undertaken to identify the source of the ree. Pdf felsic maardiatreme volcanoes host major ore deposits but have been largely ignored in the volcanology literature, especially for the. Diatreme breccias at the kelian gold mine, kalimantan, indonesia. Rdu is pleased to announce that it has signed a binding agreement with a private companymexican to option the 473hectare tarros project. Pdf diatreme breccia from the ortiz gold mine, santa fe. Tell a friend about us, add a link to this page, or visit the webmasters page for free fun content. The mardoux structure is an unconventional maar diatreme in that it was produced mainly by weak explosive activity rather than by. Elie ness, fife, scotland eprints soton university of southampton. The purnama gold deposit in the martabe district of north sumatra, indonesia. Namie breccia crumple breccia mineralisation mineralisation at pipe margin.
Low sulphidation epithermal auag deposits are characterised by neutral wall rock alteration assemblages dominated by illitic clays, although acidic waters collapsing from near surfical acid sulphate caps deposit kaolin within some ore assemblages below. Province of british columbia mineral resources divisionministry of energy, mines and geological survey branchpetroleum resourceshon. Hydrothermal breccias and veins at the kelian gold mine, kalimantan, indonesia. The diatreme consists of volcanic breccias and phonolites and lamprophyre breccias. Vughy silica alteration of a lapilli tuff, del carmen. Maar diatreme volcanoes, their formation, and their setting in hardrock or softrock environments volker lorenz institut fur geologie, universitat wurzburg, pleicherwall 1, d97070 wurzburg, germany abstract. Only breccia veins of the second stage are up to 10 m wide. It is interpreted that the emplacement of the later diatreme breccia was responsible for this fracturing and brecciation in.
Independent technical report for the thorn project. Unbedded diatreme deposits reveal maardiatremeforming. Scribd is the worlds largest social reading and publishing site. The diatreme consist of a mixture of breccia which is a sedimentary rock composed. Early miocene volcanism associated with a maardiatreme breccia complex preceded mainstage epithermal gold mineralization at the kelian gold mine, kalimantan, indonesia. The cunningham hill deposit at ortiz was hosted in a diatreme volcanic vent breccia. The deep root system of ship rock, an exhumed oligocene maardiatreme complex, has not been resolved. The tolukuma gold silvervein system, papua new guinea. Pdf diatreme breccias at the kelian gold mine, kalimantan. The collective shumagin vein system commonly has completely replaced andor destroyed the footwalldiatreme.
Consistent with their high fluid content, outgassing took place at great depth, and emplacement was achieved rapidly along hydraulically driven cracks from depths of the order of 50 to more than 150 kms. Pt 5 breccias workshop free download as powerpoint presentation. Principles of igneous and metamorphic petrology second. Repetitive diatreme explosions formed two major breccia necks at cripple creek over 3,000 feet deep. Standing rocks east, hopi buttes, navajo nation, usa. Porphyry introduction1achf seg10lombok magma clastic rock. The term diatreme has been applied more generally to any concave body of broken rock or tuff breccia, generally formed by explosive or hydrostatic forces, whether or not it is related to volcanism. Read unconventional maar diatreme and associated intrusions in the soft sedimenthosted mardoux structure gergovie, france, bulletin of volcanology on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Wholerock chemical composition of host rocks and recently acquired kar age of hydrothermal mineral of the coo epithermal gold deposit in mindanao island of the philippines are herein reported.
The sheahan diamond literature reference compilation is compiled by patricia sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcements called the sheahan diamond literature service that is distributed as a free pdf to a list of followers. When magma rises up through a crack in the earths crust and makes contact with a shallow body of ground water, rapid expansion of heated water vapor and volcanic gases can cause a series of explosions. Wholerock geochemistry of host rocks and kar age of. Subsurface phreatic explosions occurred around the margins of the diatreme breccia complex, focusing hightemperature fluid flow and generating several large. Targets include sediment hosted gold, silvergoldleadzincbearing diatremebreccia, goldsilvercopper veins and. January 24, 2014 geology and mineralization of the peak zone au cuag deposit, tetlin project, alaska. Alkali basaltic diatremes such as elie ness fife, scotland expose a range of. Geophysical strategies for kimberlite exploration in northern canada power, m.
Transition zone between the upper diatreme and lower. Maardiatreme volcanoes are produced by explosive eruptions that cut deeply into the country rock. A diatreme, sometimes known as a maar diatreme volcano, is a volcanic pipe formed by a gaseous explosion. The country rock is the upper cretaceous mancos shale. Geophysical strategies for kimberlite exploration in. Textures present within the main phase of the tuzo kimberlite that include hypabyssal kimberlite, tuffisitic kimberlite breccia and gradational. Diatreme definition of diatreme by the free dictionary. Using gravity for subsurface imaging at ship rock, new mexico. Goa is pleased to announce that the companys maiden drilling program at the potentially world class crater mountain gold project is on track to commence on 21st november 2010. Carbonatitic magmatism of the monteregian hills by david lentz 1, nelson eby 2, serge lavoie 3, and adrian park 1 1. There are three eruptive subbasins to this diatreme one in the north, one in the south, and one in the southwest. A bulkminable, goldsilver deposit at montana tunnels, southwestern montana, is located in the central part of a diatreme. In the sulphide zone gold is present as free grains and within enargite. Because ship rock is composed of almost all minette tuffbreccia, and not a large amount of slumpedin wallrock, it is thought by those who support the diatreme model that the abovesurface feature is at middiatreme, and therefore at least.
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