magmatic and postmagmatic processes in tinmineralizeddec 01, 97· deanorthitization of plagioclase can be identified in thin section from the occurrence of numerous very small mineral inclusions in albitic plagioclase. these inclusions (fluorite, topaz, quartz, sericite, calcite, epidote, etc.) contain cations of the anorthite molecule, and are formed by plagioclasefluid interaction.cited by 0mineralized granitic porphyry of the yangla copper depositthe yangla copper deposit (ycd) is located in the central part of the jinshajiang tectonic belt (jinshajiang metallogenic belt) and is one of the most important copper deposits which has the largescale copper reserves of the northwestern yunnan, china. the ore bodies are strictly controlled by the stratum, pluton, and structure, which are layered, lens, and veinlike within the contact ora g and platinummineralized layer in gabbros of theaug 01, 2· deposition of the mineralized layer is associated in space and time with injections of plagioclasesaturated, primitive magma that mixed with more evolved, resident magma. these events caused efficient partitioning of au and pge into sulfides derived from a large volume of magma, deposition of these sulfides to form the mineralized layer, and subsequent deposition of the overlyingadditional targets eskay mining corp.the eskay rhyolitewillow ridge contact was intercepted by drill hole cbl0506 (figure 9). the interval 28.6633.53 m is a mudstone with sparse flattened black pebbles (< 5 mm). historic assays from this mudstone interval range from 1.001.97 g/t au. rhyolite breccia replaced with semimassive sulphide minerals occurs from 35.5543.07 m.drillhole log metersplagioclase 4555% hornblende 4050% biotite % (very fine grained) unit non mineralized upper contact gradational, lower contact sharp and structural at 66 deg tca transition to lower unit is gradual and marked by a reduction in the abundance of hornblende and the occurrence of pyroxene.leucogabbro mq024 page 2 of barsele minerals corp. projectthe granodiorite is quartzfeldspar phyric and is composed of sericitized plagioclase, quartz, biotite and lesser kfeldspar. (vms) regionally referred to as skelleftestyle. the main mineralized body is approximately 300 metres along strike and 5 to 50 meters in width. g is associated with the basal semimassive arsenopyrite, pyrrhotiteplagioclase feldspar a group of common rockformingoverviewnamesignificanceformationappearanceecologynomenclatureexamplesusesgeologyplagioclase is the name of a group of feldspar minerals that form a solid solution series ranging from pure albite, na(alsi3o8), to pure anorthite, ca(al2si2o8). minerals in this series are a homogenous mixture of albite and anorthite. the names of the minerals in the series are arbitrarily given based upon their relative abundance of albite and anorthite. the minerals of the plagioclase series are listed in the table below along with their relative abundance of albite (ab) and anorthite (an).coexistence of a fluid phase with granitic magmanov 05, 08· textures of plagioclase in the mineralized aplitic veins are different from the idiomorphic textures with sharp plagioclase crystal boundaries that occur in the north granitic body and barren aplitic veins. these textural data suggest that the mineralized aplitic veins were formed from hydrothermal fluid.geology of the mineralized zone of the wanapitei complexmolecular proportion ratio variation diagrams suggest that rocks evolved from a common parent magma that underwent fractionation dominated by olivine and plagioclase. sulphide mineralization (pyrrhotite, chalcopyrite, pentlandite, pyrite) is interstitial to the silicates
emplacement and crystallization histories of cunipgeemplacement and crystallization histories of cunipge sulfidemineralized peridotites in the eagle and eagle east intrusions. differences between the two intrusions were the poikilitic nature of clinopyroxene and the lower abundance of plagioclase in the eagle east intrusion. these differences may be explained by the larger size and thusbiotite types at the detour lake g deposit, canadasep 30, · mineralized zone in the hanging wall of the detour lake deposit, resulting in maﬁc volcanic host rocks with a purplemaroon appearance . on the basis of these ﬁeld relationships, hydrothermal (actinolitebiotiteplagioclaseepidotealmandine calcite quartzplagioclase the mineral plagioclase information andthe plagioclase series is a group of related feldspar minerals that essentially have the same formula but vary in their percentage of sodium and calcium. albite and anorthite are the end members of the series, with the intermediary minerals oligoclase, andesine, labradorite, and bytownite. the acclaimed dana's system of mineralogy lists the intermediary members as individual minerals, whereas the ima does not recognize them as individual mineralalbite na al si 3 o 8rapid crystallization of preciousmetalmineralized layersapr , · plagioclase sr concentrations mostly range between 250 and 500 ppm, and barium (ba) and rubidium (rb) concentrations are consistently <1 ppm.cited by 8research roundup new findings on crystallization inapr 30, · isotopic heterogeneity is present between plagioclase crystals, between clinopyroxene and plagioclase and within plagioclase crystals throughout the studied section. on the basis of these observations, we demonstrate that platinumgroup element mineralization formed by repeated smallvolume reactive melt percolation events.plagioclase plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more properly known as the plagioclase feldspar series. this was first shown by the german mineralogist johann friedrich christian hessel (9672) in 26.crystal class pinacoidal (1), (same hm symbol)geoi lecture notes igneous rocksa plagioclase consisting of a mixture of 60% anorthite and 40% albite is therefore an60. a rock consisting of over 90% plagioclase (therefore less than 10% mafic minerals) is an "anorthosite". anorthorsite is very common in the adirondacks and in the lunar highlands.united states department of the interior cecil d.biotiteplagioclasequartz gneiss ___ 4 orthogneiss.. 5 carbonaceous metasedimentary rocks ~_____ 5 mineralized zones may have formed directly from an aqueous phase that evolved during final crystallization of the granite complex and escaped along crosscutting faults.
24. magmatic resorption versus subsolidusplagioclase, approaching a granite composition in the core of the pluton. and si (quartz) in the upper levels, along with disseminated copper sulfides in the . 3 mineralized zone. all mineral replacements (resorptions) were postulated to occur at temperatures above the solidus because the kfeldspar is orthoclase rather thanfeldspars, exsolution, zoning, and twinningsodic plagioclase) is indicative of late reaction with foreign crystals with magma or possibly metamorphism. oscillatory zoning (see figure 1)is a large number of thin shells of different compositions. the cause is uncertain. feldspars are either monoclinic (sanidine,chemical composition of rockforming minerals inwithin the study area, kfeldspar has a narrow compositional range (89.491% or), whereas plagioclase spans a wide range (4.470.07% an). in all of the investigated samples, t ab = t an = t or, suggesting that magmatic equilibrium between the coexisting plagioclase and kfeldspar was maintained. igneous amphibole phenocrysts from hypabyssalu.s. department of the interior u.s. geologicalporphyry intrusions that are spatially associated with mineralized breccias located at the national belle mine, near red mountain pass, yield slightly discordant kar dates of .9±0.6 and 24.0±0.7 ma, respectively (hon and plagioclase, quartz, biotite, hypersthene, augite, magnetite, apatite, and zircon.published division geology and resources33. mineralized metabasalt (greenstone) albemarle county donated by luck stone corporation, charlottesville plant grayishgreen, to darkyellowishgreen, ﬁnegrained, schistose metabasalt. composed of chlorite, actinolite, albite, epidote, quartz, and magnetite. fractured zone is ﬁlled with pink plagioclase,skarnhosted mineralization in paleozoic rocksmineralized skarn is 36 feet, nil au, 0.24 oz/t ag, 1.% pb, 0.03% cu, 2.43% zn (table 3iii). the skarn appears to have developed at relatively high temperature prior to base metal mineralization and was subsequently mineralized during stages of declining temperature and surges of hydrothermal activity.geological report on the maybrun mine propertythe base or footwall aphyric basalts in the mine sequence are nonmineralized. i the ore zones are confined to a second type of basalt characterized by altered plagioclase phenocrysts. the ore (cuau) is common in small pillow parts of the plagioclasephyric flow units. two flows, ii and iii, are considered exploration or development targets.