Timing and duration of hydrothermal activity at the Los Bronces porphyry cluster: an update
Author
dc.contributor.author
Deckart, Katja
Author
dc.contributor.author
Silva, W.
es_CL
Author
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Spröhnle, C.
es_CL
Author
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Vela, I.
es_CL
Admission date
dc.date.accessioned
2015-01-07T19:07:09Z
Available date
dc.date.available
2015-01-07T19:07:09Z
Publication date
dc.date.issued
2014
Cita de ítem
dc.identifier.citation
Miner Deposita (2014) 49:535–546
en_US
Identifier
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DOI 10.1007/s00126-014-0512-9
Identifier
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https://repositorio.uchile.cl/handle/2250/126978
General note
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Artículo de publicación ISI
en_US
Abstract
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New geochronological data from the Los Bronces
cluster of the Río Blanco-Los Bronces mega-porphyry Cu-Mo
district establish a wide range of magmatism, hydrothermal
alteration, and mineralization ages, both in terms of areal
extent and time. The northern El Plomo and southernmost
Los Piches exploration areas contain the oldest barren porphyritic
intrusions with U-Pb ages of 10.8±0.1 Ma and 13.4±
0.1 Ma, respectively. A hypabyssal barren intrusion adjacent
northwesterly to the main pit area yields a slightly younger age
of 10.2±0.3 Ma (San Manuel sector, U-Pb), whereas in the
Los Bronces (LB) open-pit area, the present day mineral
extraction zone, porphyries range from 8.49 to 6.02 Ma (UPb).
Hydrothermal biotite and sericite ages are up to 0.5 Ma
younger but consistent with the cooling of the corresponding
intrusion events of each area. Two quartz-molybdenite B-type
veins from the LB open pit have Re-Os molybdenite ages of
5.65±0.03 Ma and 5.35±0.03 Ma consistent with published
data for the contiguous Río Blanco cluster. The San Manuel
exploration area within the Los Bronces cluster, located about
1.5–2 km southeast of the open-pit extraction zone, shows
both the oldest hydrothermal biotite (7.70±0.07 Ma;
40Ar/39Ar) and breccia cement molybdenite ages (8.36±
0.06 Ma; Re-Os) registered in the entire Río Blanco-Los
Bronces district. These are also older than those reported from
the El Teniente porphyry Cu(-Mo) deposit, suggesting that
mineralization in the late Miocene to early Pliocene porphyry
belt of Central Chile commenced 2 Ma before the previously
accepted age of 6.3 Ma.
en_US
Patrocinador
dc.description.sponsorship
This study has been financed by Anglo American
Chile.