 |
| Titel |
Source of ore-forming fluids of the Tianbaoshan Pb-Zn deposit, Southwest
China: constrains from C-O, S, and He-Ar isotopes |
| VerfasserIn |
Jian Wang, Jun Zhang, Wenbin Zhong |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250126867
|
| Publikation (Nr.) |
 EGU/EGU2016-6656.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Sichuan-Yunnan-Guizhou (SYG) metallogenic province is one of the most important
areas for Pb-Zn resources in China. The metallogenic sources of these Pb-Zn deposits have
long been debated. In this study, we provide integrated C-O-S-He-Ar isotopic data of the
typical Tianbaoshan Pb-Zn deposit, with an aim to constrain the sources of ore-forming
fluids.
The Tianbaoshan deposit a large-sized Pb-Zn deposit in SYG metallogenic province,
Southwest China. The proven resources include 2.6 Mt metals of Zn+Pb with average
grades of 10.09% Zn and 1.50% Pb. The orebodies are hosted within the carbonates
of the Ediacaran Dengying Formation. Ore minerals consist mainly of sphalerite,
galena, chalcopyrite, and pyrite. Gangue minerals are dominated by calcite and
dolomite.
The calcite samples from the Tianbaoshan deposit yield homogeneous δ13CV −PDBvalues of
-1.70‰ to -1.60‰ (average -1.63), with δ18OV −SMOW values ranging from 12.9‰ to
15.2‰ (average 14.4). The C-O isotopic data suggest the hydrothermal fluids may be
originated from a mixed source involving both mantle and carbonate wall rocks. The δ34S
values of the sphalerite, galena and chalcopyrite samples vary from 3.32‰ to 5.71‰
-0.36‰ to 1.31‰ and 4.5‰ to 4.7‰ respectively, indicating a magmatic source for sulfur.
The 3He/4He ratios of chalcopyrite samples range from 0.01 to 0.32 Ra which is slightly
higher than the crustal ratios (0.05 Ra), but obviously lower than that of mantle fluids (6 to 9
Ra). The 40Ar/36Ar ratios range from 345.0 to 669.1, which are slightly higher than that of air
(298.5). The He-Ar isotopic compositions suggest that the ore-forming fluids are
dominantly derived from the crust, with litter contamination from mantle-derived
fluids.
In combination with the C-O, S, and He-Ar isotopic data, we propose the ore-forming
fluids of the Tianbaoshan deposit were derived by mixing of crustal and mantle fluids. And
the metallogenic process may be genetically related to the magmatism in this area. |
|
|
|
|
|
|