Porphyry Deposits&lt;subtitle&gt;Characteristics and Origin of Hypogene Features&lt;/subtitle&gt;

Seedorff, Eric; Dilles, John H.; Proffett, John M.; Einaudi, Marco T.; Zürcher, Lukas; Stavast, William J. A.; Johnson, David A.; Barton, Mark D.; Hedenquist, Jeffrey W.; Thompson, John F.; Goldfarb, Richard J.; Richards, Jeremy P.

doi:10.5382/av100.10

Cited by 302 publications

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“…On the other hand, the significant uncertainty in applying the biotite thermometer may be due to the alteration, disequilibrium, local equilibrium, or re-equilibration of biotite following peak temperature conditions (Henry et al, 2005). Of note, such processes generally occur in porphyry copper systems, especially when there is alkali exchange during magmatic to hydrothermal transition (potassic alteration, Seedorff et al, 2005). However, evaluation of whether disequilibrium or local equilibrium occurred is traced by checking the chemical variation by analyzing points of biotite samples (Mercer and Reed, 2013), but the fact is that the homogeneous biotites may be out of equilibrium.…”

Section: Analyzing Proceduresmentioning

confidence: 99%

“…On the other hand, the presence of amphibole typically implies low Al rocks that can be another problem for using a titanium-in-biotite thermometer. Moreover, during the temperature dropping of porphyry copper systems, destabilization of biotite by decreasing the activity of K 2 SO 4 under intermediate aK + / aH + conditions may lead to the formation of chlorite (Seedorff et al, 2005). This is reported in many porphyry copper systems (e.g., Altar porphyry Cu-Au deposit, Andes Cordillera of San Juan; Maydagan et al, 2016; Meiduk and Iju porphyry copper systems, Urumieh-Dokhtar magmatic arc; Rezaei, 2017).…”

Section: The Availability Of Mineralogical Requisites Ofmentioning

confidence: 99%

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Titanium‐in‐biotite thermometry in porphyry copper systems: Challenges to application of the thermometer

Rezaei

Zarasvandi

2019

Resource Geology

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Empirical geothermometer dealing with Ti solubility in the Fe‐Mg biotites was originally proposed for biotites in graphitic, peraluminous metapelites containing ilmenite or rutile that equilibrated roughly at 4–6 kbar. Given that biotites are abundant in the porphyry copper systems, this geothermometer has frequently been used for the determination of magmatic–hydrothermal temperatures in the porphyry copper systems. Common associations of porphyry copper deposits (PCDs), that is, low Al content of biotite, biotite chloritization (causes the biotite to become more magnesian and to lose Ti), and biotite formation by amphibole replacement, as well as disequilibrium, local equilibrium, or re‐equilibration of biotites, especially through potassic alteration, may provide significant uncertainty in the temperatures estimated a by Ti‐in‐biotite geothermometer. In addition, besides the calibration range of thermometer for pressure (400–600 MPa), the temperatures of major sulfide precipitation in PCDs (>~400°C) does not fit with the temperature range of thermometer calibration (480–800°C). Worth noting, as confirmed by fluid inclusion data in the Sarkuh PCD, regardless of presence of mineralogical requirements, obtained temperatures of sulfide mineralization using Ti in biotite thermometer could be overestimated. This may be due to the difference between general conditions of sulfide mineralization and calibration range of Ti in the biotite thermometer for pressure and temperature, as well as the metaluminous nature of biotites in PCDs.

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Section: Analyzing Proceduresmentioning

confidence: 99%

Section: The Availability Of Mineralogical Requisites Ofmentioning

confidence: 99%

Titanium‐in‐biotite thermometry in porphyry copper systems: Challenges to application of the thermometer

Rezaei

Zarasvandi

2019

Resource Geology

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“…Mineralization comprises: (a) porphyry-type quartz stockworks (A-and D-type veins according to Seedorf et al [35] in the microgranite porphyry and partly in the monzodiorite; (b) sulphide disseminations hosted in both magmatic rocks; and (c) base metal veins (E-type veins), which crosscut the previous styles of mineralization. Table 2).…”

Section: Mineralization and Alterationmentioning

confidence: 99%

A New Porphyry Mo Mineralization at Aisymi-Leptokarya, South-Eastern Rhodope, North-East Greece: Geological and Mineralogical Constraints

et al. 2018

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A new porphyry Mo prospect has been discovered in the Aisymi-Leptokarya area, along the southern margin of the Byala Reka-Kechros metamorphic dome, south-eastern (SE) Rhodope metallogenic zone. The study area is dominated by an Oligocene felsic dike complex, which hosts the porphyry Mo mineralization and intrudes into upper Eocene sandstones-marls and the Leptokarya monzodiorite pluton. The Aisymi-Leptokarya felsic dike complex displays a rhyodacitic to dacitic composition with post-collisional affinities. The porphyry Mo mineralization occurs in the form of porphyry-style quartz stockworks in the felsic dike complex associated with potassic alteration characterized by hydrothermal K-feldspar. The ore minerals consist mainly of pyrite, molybdenite, kesterite, bismuthinite and galena within both the stockwork and the rock matrix. Bulk ore analyses indicate enrichment in Mo (up to 215 ppm), Se (up to 29 ppm), Bi (up to 8 ppm) and Sn (up to 14 ppm) in the porphyry quartz veins. Late-stage, north-east (NE-) and north-west (NW-)trending milky quartz intermediate-sulfidation epithermal veins with base metals, crosscut previous vein generations and are characterized by Ag, Sn and Te anomalies. The Aisymi-Leptokarya porphyry Mo prospect is set in a back-arc geotectonic regime and shares similarities to other post-subduction porphyry molybdenum deposits elsewhere. These deposits are characterized by fluids with low CO 2 /H 2 O, F/Cl and K/Na ratios and a low Rb-Nb and moderate to high Sr signature. They were originally described from the Endako deposit, British Columbia, Canada [5]; (2) Climax-type (or low-fluorine) is rift related. This deposit type is characterized by a high F/Cl ratio and significant variations in their CO 2 /H 2 O and K/Na ratios [6]. They also display high Rb-Nb geochemical signatures; (3) Dabie-type was recently described by Mi et al. [7] named after the Dabie Shan orogenic belt, China and occurs in collision to post-collision environments. These deposits are genetically linked to high-K calc-alkaline to shoshonitic magmas, in syn-to post-collisional tectonic settings and are related to fluids with high CO 2 /H 2 O, F/Cl and K/Na ratios. The class is originally represented by the giant Qian'echong Mo deposit, east China [7]. Alteration patterns in porphyry Mo deposits usually comprise an internal zone dominated by potassic alteration, which grades outwards into silicic/sericitic, propylitic and more distally to argillic assemblages [8][9][10].The Thrace metallogenic province in NE Greece hosts a number of mineralization types including porphyry, high/intermediate-sulfidation, epithermal and other intrusion related systems, containing significant amounts of precious and critical metals [11][12][13]. Among them, many porphyry-type deposits are enriched in molybdenum, along with other commodities (e.g., Cu, Au, Re). Characteristic examples are the Pagoni Rachi, Konos, Myli, Maronia and Melitena deposit/prospects [11][12][13][14][15][16].A new porphyry Mo prospect was recently discovered [17] in the po...

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“…The stockwork ores occur within the sericitic-chloritic zone. The Xiaoxinancha Au-Cu deposit can be classified to the porphyry Au-Cu deposit according to the classification scheme (Seedorff et al, 2005).…”

Section: Deposit Typementioning

confidence: 99%

Two periods of mineralization in Xiaoxinancha Au–Cu deposit, NE China: evidences from the geology and geochronology

et al. 2014

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The Xiaoxinancha Au–Cu deposit is located at the eastern segment of the Tianshan–Xingmeng orogenic belt in northeast China. The deposit includes porphyry Au–Cu orebodies, veined Au–Cu orebodies and veined Mo mineralizations. All of them occur within the diorite intrusion. The Late Permian diorite, Late Triassic granodiorite, Early Cretaceous granite and granite porphyry are developed in the ore area. The studies on geological features show that the porphyry Au–Cu mineralization is related to the Late Permian diorite intrusion. New geochronologic data for the Xiaoxinancha porphyry Au–Cu deposit yield Permian crystallization zircon U–Pb age of 257 ± 3 Ma for the diorite that hosts the Au–Cu mineralization. Six molybdenite samples from quartz + molybdenite veins imposed on the porphyry Au–Cu orebodies yield an isochron age of 110.3 ± 1.5 Ma. The ages of the molybdenites coeval to zircon ages of the granite within the errors suggest that the Mo mineralization was genetically related to the Early Cretaceous granite intrusion. The formation of the diorite and the related Au–Cu mineralization were caused by the partial melting of the subduction slab during the Late Palaeozoic palaeo‐Asia Ocean tectonic stage. The Re contents and Re–Os isotopic data indicate that the crustal resource is dominated for the Mo mineralization during the Cretaceous extensional setting caused by the roll‐back of the palaeo‐Pacific plate. Copyright © 2014 John Wiley & Sons, Ltd.

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Porphyry Deposits<subtitle>Characteristics and Origin of Hypogene Features</subtitle>

Cited by 302 publications

References 0 publications

Titanium‐in‐biotite thermometry in porphyry copper systems: Challenges to application of the thermometer

Titanium‐in‐biotite thermometry in porphyry copper systems: Challenges to application of the thermometer

A New Porphyry Mo Mineralization at Aisymi-Leptokarya, South-Eastern Rhodope, North-East Greece: Geological and Mineralogical Constraints

Two periods of mineralization in Xiaoxinancha Au–Cu deposit, NE China: evidences from the geology and geochronology

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