Publication Date:
2020-01-13
Description:
The understanding of the relationship between the geochemistry of fluids circulating during
travertine deposition and the presence of active faults is crucial for evaluating the seismogenetic potential
of an area. Here we investigate travertines from Pamukkale and Reşadiye (Turkey), sited in seismic regions
and next to thermal springs. These travertines formed ~24,500–50,000 (Pamukkale) and ~240–14,600 years
(Reşadiye) BP. We characterize fluid inclusions (FIs) and studied concentration of H2O, CO2, O2 + N2,
and 3He, 4He, 20Ne, and 40Ar, and bulk composition (trace elements and δ13C‐δ18O). FIs from both localities
are mainly primary with low salinity and homogenization temperature around 136–140 °C. H2O is the major
component followed by CO2, with the highest gas content measured in Pamukkale travertines.
Concentrations of Ne‐Ar together with O2 + N2 indicate that travertines from both areas precipitated from
atmosphere‐derived fluids. The 3He/4He is 0.5–1.3 Ra in Pamukkale and 0.9–4.4 Ra in Reşadiye. Samples
with R/Ra 〉 1 are modified by cosmogenic 3He addition during exposure to cosmic rays. Excluding these
data, FIs of Reşadiye are mostly atmosphere‐derived. This implies a shallow formation where the circulation
was dominated by meteoric waters, which is consistent with their young age. Instead, FIs of Pamukkale
show mixing of mantle‐, crustal‐, and atmosphere‐derived He, indicating that these travertines formed in
lithospheric fractures. Based on the δ13CCO2 and δ18O of bulk rocks, we infer that travertines formed
involving crustal‐ (mechanochemical rather than organic) and mantle‐derived CO2. Trace elements of
Pamukkale and Reşadiye show comparable rare earth element patterns. We conclude that travertines
formed in response of seismogenetic activity.
Description:
Published
Description:
5473-5498
Description:
2T. Deformazione crostale attiva
Description:
7T. Variazioni delle caratteristiche crostali e precursori sismici
Description:
6A. Geochimica per l'ambiente e geologia medica
Description:
JCR Journal
Keywords:
travertine
;
fluid inclusions
;
noble gas
;
Pamukkale
;
Reşadiye
;
seismogenetic activity
;
geochemistry
;
d13C and d18O
;
Sold Earth
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
