The University of Southampton
University of Southampton Institutional Repository

Skarn formation and tin enrichment during regional metamorphism: The Hämmerlein polymetallic skarn deposit

Skarn formation and tin enrichment during regional metamorphism: The Hämmerlein polymetallic skarn deposit
Skarn formation and tin enrichment during regional metamorphism: The Hämmerlein polymetallic skarn deposit
The Hämmerlein Sn-rich polymetallic skarn deposit (Erzgebirge, Germany), which is hosted by Variscan schists and gneisses, includes garnet, amphibole, pyroxene, and magnetite skarns that formed during regional metamorphism at ~340 Ma. The skarn deposit was overprinted during the intrusion of the ca. 320 Ma Eibenstock granite. Tin was introduced into the system during regional metamorphism at 340 Ma (Sn mostly hosted in silicate minerals) and after the intrusion of the Eibenstock granite at c. 320 Ma (Sn hosted in cassiterite). The emplacement of late stage melts of the Eibenstock granite also resulted in the formation of cassiterite-quartz veins in the schists hosting the Hämmerlein skarns and at some distance in the formation of several cassiterite greisen. Major, trace, and rare earth element data of the skarn units and their hosts rocks demonstrate that skarns formed from impure carbonates with variable proportions of silicate minerals. Depending on the original modal compositions of the skarns and their host rocks, the mineralizing fluid selectively added and removed elements, which resulted for the skarns and the schist ore in a general enrichment in Sn, In, Cu, and W and a noticeable depletion in Al and Sr. The Sr, Nd, and Pb isotopic composition of the skarns, schists, and gneisses resembles those of the metamorphic rocks of the Erzgebirge rather than those of the granites, possibly indicating that the geochemical signature of granite-derived fluids had been severely altered during fluid-rock interaction before these fluids reached the skarns, schists, and gneisses. Similarly, the Li and B isotopic composition of the skarn samples reflects the likely range of possible source rocks for metamorphic fluids, rather than the composition of the granite-derived fluid. In contrast, the Li and B signature of greisen samples shows a variable mixture of material derived from the granite and the metasedimentary rocks, respectively. Our data show that a first Sn enrichment took place when the Paleozoic sedimentary rocks were affected by regional metamorphism at ca. 340 Ma. Fluids derived from these siliciclastic sedimentary protoliths mobilized and transported Sn and Fe. These fluids reacted with the impure carbonates, resulting in decarbonation and the formation of calc-silicate minerals and biotite in the various skarn types. The changing fluid composition as well as the incorporation of Fe in skarn silicates and formation of Fe-oxides resulted in the incorporation of Sn into silicate minerals. During or after the emplacement of the Eibenstock granite, the original skarn was to a variable extent retrogressed and Sn was released from Sn-bearing calc-silicates and biotite. During this event additional Sn was added to the skarn and the hosting schists. Released Sn and newly added Sn precipitated as cassiterite.
Hammerlein, Erzgebirge, Tin, Skarn, Greisen, Lithium, boron
0024-4937
Lefebvre-Desanois, Marie
b9ca8d27-8ab9-4a72-b4e4-39defc53aa85
Romer, Rolf L.
4b7f8a1e-0f1f-48fc-870c-6febe58617fd
Glodny, Johannes
02581e85-51ed-4be8-a816-c2334bbb4459
Roscher, Marco
a750f923-bae8-4a0b-ad22-9c0d81b53467
Lefebvre-Desanois, Marie
b9ca8d27-8ab9-4a72-b4e4-39defc53aa85
Romer, Rolf L.
4b7f8a1e-0f1f-48fc-870c-6febe58617fd
Glodny, Johannes
02581e85-51ed-4be8-a816-c2334bbb4459
Roscher, Marco
a750f923-bae8-4a0b-ad22-9c0d81b53467

Lefebvre-Desanois, Marie, Romer, Rolf L., Glodny, Johannes and Roscher, Marco (2019) Skarn formation and tin enrichment during regional metamorphism: The Hämmerlein polymetallic skarn deposit. Lithos, 348–349, [105171]. (doi:10.1016/j.lithos.2019.105171).

Record type: Article

Abstract

The Hämmerlein Sn-rich polymetallic skarn deposit (Erzgebirge, Germany), which is hosted by Variscan schists and gneisses, includes garnet, amphibole, pyroxene, and magnetite skarns that formed during regional metamorphism at ~340 Ma. The skarn deposit was overprinted during the intrusion of the ca. 320 Ma Eibenstock granite. Tin was introduced into the system during regional metamorphism at 340 Ma (Sn mostly hosted in silicate minerals) and after the intrusion of the Eibenstock granite at c. 320 Ma (Sn hosted in cassiterite). The emplacement of late stage melts of the Eibenstock granite also resulted in the formation of cassiterite-quartz veins in the schists hosting the Hämmerlein skarns and at some distance in the formation of several cassiterite greisen. Major, trace, and rare earth element data of the skarn units and their hosts rocks demonstrate that skarns formed from impure carbonates with variable proportions of silicate minerals. Depending on the original modal compositions of the skarns and their host rocks, the mineralizing fluid selectively added and removed elements, which resulted for the skarns and the schist ore in a general enrichment in Sn, In, Cu, and W and a noticeable depletion in Al and Sr. The Sr, Nd, and Pb isotopic composition of the skarns, schists, and gneisses resembles those of the metamorphic rocks of the Erzgebirge rather than those of the granites, possibly indicating that the geochemical signature of granite-derived fluids had been severely altered during fluid-rock interaction before these fluids reached the skarns, schists, and gneisses. Similarly, the Li and B isotopic composition of the skarn samples reflects the likely range of possible source rocks for metamorphic fluids, rather than the composition of the granite-derived fluid. In contrast, the Li and B signature of greisen samples shows a variable mixture of material derived from the granite and the metasedimentary rocks, respectively. Our data show that a first Sn enrichment took place when the Paleozoic sedimentary rocks were affected by regional metamorphism at ca. 340 Ma. Fluids derived from these siliciclastic sedimentary protoliths mobilized and transported Sn and Fe. These fluids reacted with the impure carbonates, resulting in decarbonation and the formation of calc-silicate minerals and biotite in the various skarn types. The changing fluid composition as well as the incorporation of Fe in skarn silicates and formation of Fe-oxides resulted in the incorporation of Sn into silicate minerals. During or after the emplacement of the Eibenstock granite, the original skarn was to a variable extent retrogressed and Sn was released from Sn-bearing calc-silicates and biotite. During this event additional Sn was added to the skarn and the hosting schists. Released Sn and newly added Sn precipitated as cassiterite.

This record has no associated files available for download.

More information

Accepted/In Press date: 10 August 2019
e-pub ahead of print date: 14 August 2019
Keywords: Hammerlein, Erzgebirge, Tin, Skarn, Greisen, Lithium, boron

Identifiers

Local EPrints ID: 449752
URI: http://eprints.soton.ac.uk/id/eprint/449752
ISSN: 0024-4937
PURE UUID: 00e204fd-3145-451c-bc7c-7fba3502aac4
ORCID for Marie Lefebvre-Desanois: ORCID iD orcid.org/0000-0002-3173-3114

Catalogue record

Date deposited: 15 Jun 2021 16:33
Last modified: 17 Mar 2024 04:07

Export record

Altmetrics

Contributors

Author: Marie Lefebvre-Desanois ORCID iD
Author: Rolf L. Romer
Author: Johannes Glodny
Author: Marco Roscher

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×