Supergene oxidation of epithermal gold-silver mineralization in the Deseado massif, Patagonia, Argentina: response to subduction of the Chile Ridge

Supergene oxidation of epithermal gold-silver mineralization in the Deseado massif, Patagonia,... Radiometric ages for supergene alunite and jarosite effectively date the oxidation of former concentrations of pyrite and any associated sulfide minerals. These K-bearing sulfate minerals, formed under low-pH conditions, are uncommon supergene products in low-sulfidation epithermal deposits because of the general paucity of pyrite for acid generation. For this reason, the age of supergene oxidation—locally to depths of 200 m or more—in the epithermal Au-Ag deposits of the Deseado massif, located in the extra-Andean foreland of Patagonia, southern Argentina, has remained unknown. Although, theoretically, the oxidation could have taken place anytime between the Late Jurassic, when the Au-Ag mineralization formed, and Pleistocene, K-Ar ages for alunite and jarosite from two widely separated and unusually pyritic, Ag-bearing hydrothermal breccias (Lejano and Libanesa) show it to have been mid-Miocene, 13.8 ± 1.8 Ma. This is the time when the Deseado massif underwent appreciable regional-scale tectonic uplift and valley incision, following ~ 140 myr during which the region was topographically subdued and the site of either fluvio-lacustrine or shallow- marine sedimentation. The uplift, combined with increasing aridity due to the orographic rain shadow caused by growth of the Patagonian Andes to the west and enhanced by global cooling, would have depressed regional http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Mineralium Deposita Springer Journals

Supergene oxidation of epithermal gold-silver mineralization in the Deseado massif, Patagonia, Argentina: response to subduction of the Chile Ridge

Loading next page...
 
/lp/springer_journal/supergene-oxidation-of-epithermal-gold-silver-mineralization-in-the-yGgk8ODcfu
Publisher
Springer Journals
Copyright
Copyright © 2018 by Springer-Verlag GmbH Germany, part of Springer Nature
Subject
Earth Sciences; Geology; Mineral Resources; Mineralogy
ISSN
0026-4598
eISSN
1432-1866
D.O.I.
10.1007/s00126-018-0814-4
Publisher site
See Article on Publisher Site

Abstract

Radiometric ages for supergene alunite and jarosite effectively date the oxidation of former concentrations of pyrite and any associated sulfide minerals. These K-bearing sulfate minerals, formed under low-pH conditions, are uncommon supergene products in low-sulfidation epithermal deposits because of the general paucity of pyrite for acid generation. For this reason, the age of supergene oxidation—locally to depths of 200 m or more—in the epithermal Au-Ag deposits of the Deseado massif, located in the extra-Andean foreland of Patagonia, southern Argentina, has remained unknown. Although, theoretically, the oxidation could have taken place anytime between the Late Jurassic, when the Au-Ag mineralization formed, and Pleistocene, K-Ar ages for alunite and jarosite from two widely separated and unusually pyritic, Ag-bearing hydrothermal breccias (Lejano and Libanesa) show it to have been mid-Miocene, 13.8 ± 1.8 Ma. This is the time when the Deseado massif underwent appreciable regional-scale tectonic uplift and valley incision, following ~ 140 myr during which the region was topographically subdued and the site of either fluvio-lacustrine or shallow- marine sedimentation. The uplift, combined with increasing aridity due to the orographic rain shadow caused by growth of the Patagonian Andes to the west and enhanced by global cooling, would have depressed regional

Journal

Mineralium DepositaSpringer Journals

Published: Jun 7, 2018

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off