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| Titel |
Tracing Origin of sulfur in hydrothermal system of Eastern Taiwan |
| VerfasserIn |
Hsiao-Yuan Hsu, Chen-Feng You, Chuan-Hsiung Chung, Suresh Kumar Aggarwal |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250130739
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| Publikation (Nr.) |
 EGU/EGU2016-11039.pdf |
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| Zusammenfassung |
| Multiple sulfur isotope results and sulfate concentrations are reported for different
hydrothermal system in many countries. However, Taiwan is a seismically active country with
plenty of hot spring resources, but only a few studies discuss about sulfur isotopes of them.
No exhaustive study has been done to explain the high concentration and origin of sulfur in
hydrothermal system of Taiwan, and chemical reaction between sulfide and sulfate.
The true sulfur speciation in geothermal waters is difficult to preserve in samples
for laboratory analysis. However, isotopic analysis is possible for the two species
SO42− and S2O32−, together. Analysis of other species was also carried out for a
possible study to understand the inter-conversion mechanism of sulfur species, and
transport of other elements in aquifers, along with sulfur cycling in hydrothermal
system of Taiwan. Fifteen samples, hot spring (5) and river water (10) were collected
from East Taiwan and 5 hot spring samples were also collected from Japan for
comparison.
The samples were pre-concentrated and subjected to separation with anion exchange resin
AGI-X8 and isotopic analysis with MC-ICPMS. The anions and cations were determined by
Ion chromatography and ICP-OES, respectively. Samples from western Japan have been
defined as Na–Cl type ground water and originate from ’fossil seawater’ entrapped in the
formations. The K/Cl and SO4/Cl ratios in hot spring water samples lie into a range between
rain water and sea water. The Br/Cl ratios in hot spring water samples were close to
that of sea water line, and could be distinguished from river water samples. Trace
elements Li and B were high in hot spring samples from eastern Taiwan. This can be
due to strong weathering in groundwater system. δ34S values in most of the hot
spring samples were in the range between 15.74-24.87 ‰ which is close to δ34S in
seawater(+21 ). However, δ34S in samples from Zhiben (Taiwan) and Kurama (Japan) were
-1.50‰ and -3.17 ‰ respectively. The lighter sulfur isotope ratios indicate the
reduction of sulfate, probably by bacteria, because of domestic contamination in the
groundwater system in these two hot spring resorts. The data on major elements and sulfur
isotopes showed that the river water samples, which were collected near hot spring
wells, were influenced by the hot springs. Based on the water chemistry of end
members i.e., Br/Cl, Na/Cl, K/Cl and SO4/Cl and sulfur isotope signatures, most of
the samples were considered to be mixture of rain water and sea water (or brine). |
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