The Velardena Zn-(Pb-Cu) skarn-epithermal deposits, central-northern Mexico: New physical-chemical constraints on ore-forming processes
Por:
Jimenez-Franco, Abigail, Canet, Carles, Alfonso, Pura, Gonzalez-Partida, Eduardo, Rajabi, Abdorrahman, Escalante, Edgar
Publicada:
1 ene 2020
Categoría:
Earth and planetary sciences (miscellaneous)
Resumen:
The Velardena raining district is economically the most important of
Durango state. The ore deposits occur in different skarn zones developed
within the intrusive contact between Mesozoic limestones and Eocene
granitic stocks and dikes. The most important ore deposits are related
to the Santa Maria dike and Reyna de Cobre porphyritic stock (separated
front each other by 10 km). They occur as irregularly shaped replacement
masses developed near the intrusive contact and have a skarn paragenesis
dominated by talc:-silicates and sulfides. The mineral assemblages show
replacement textures and are dominated by calcic clinopyroxene
(Di(97-53)Hd(12-02)Jh(01-01)) and garnet (Ad(100-57)Grs(43-00)) in the
exoskarn, with wollasuinite particularly abundant in the endoskarn.
Hydrous silicates are actinolite, epidote, and chlorite, whereas
sulfides include pyrite, sphalerite, pyrrhotite, galena, chalcopyrite,
and sulfosalts. Scheelite, hematite, quartz, and calcite are also
present. According to sphalerite geobarometry, the skarns Formed at
hypabyssal depths (similar to 3-4 km). They developed by a succession of
replacive mineralizing events, including (a) a prograde stage at
temperatures from >= 470 to 335 degrees C in conditions of low f (CO2),
followed by (b) a retrograde stage From 335 to 220 degrees C. There was
a general increase in f (O-2), accompanying the temperature decline
during the Formation of the system, which accounts for a process of
mixing with cooler, oxidizing, and dilute water. During the retrograde
stage, wollastonite, calcic garnet and clinopyroxene formed. On the
other hand, hydrous silicates, sulfides, sulfosalts, scheelite, and
hematite crystallized during the retrograde stage. Skarn mineralization
is crosscut by veins of calcite, fluorite, adularia, and sphalerite. The
vein mineralization formed at temperatures below 200 degrees C. The
different ore deposits of Velardena constitute a telescoped
skarn-epith-ermal mineral system.
Filiaciones:
Jimenez-Franco, Abigail:
Univ Barcelona, Dept Min Petrol & Geol Aplicada, Marti & Franques S-N, Barcelona 08028, Catalunya, Spain
Univ 8 Barcelona, Inst Nanociencia & Nanotecnol, IN2UB Fac Quim, Av Diagonal 645, Barcelona 08028, Catalunya, Spain
Univ Nacl Autonoma Mexico, Posgrad Ciencias Tierra, Ciudad Univ, Coyoacan 04510, Cdmx, Mexico
Canet, Carles:
Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Ciudad Univ, Coyoacan 04510, Cdmx, Mexico
Univ Nacl Autonoma Mexico, Inst Geofis, Ciudad Univ, Coyoacan 04510, Cdmx, Mexico
Alfonso, Pura:
Univ Politecn Cataluna, Dept Engn Minera Ind & TIC, Av Bases Manresa 61-73, Barcelona 08242, Spain
Gonzalez-Partida, Eduardo:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Campus Juriquilla, Santiago De Queretaro 76230, Mexico
Rajabi, Abdorrahman:
Univ Tehran, Sch Geol, Coll Sci, 16th Azar St,Enghelah Sq, Tehran, Iran
Escalante, Edgar:
Ind Penoles, Prolongac Comonfort S-N, Torreon 27370, Coahuila, Mexico
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