Abstract
Application of hornblende thermobarometry and fluid inclusion studies to the Palaeoproterozoic (1.7 Ga) basement rocks from Maddhapara, NW Bangladesh, provide information on the pressure and temperature (P-T) conditions of crystallization, the emplacement depth and composition of magmatic fluid. The basement rocks are predominantly diorite or quartz diorite with a mineral assemblage of plagioclase, hornblende, biotite, quartz, K-feldspar, titanite, and secondary epidote and chlorite. The calculated P-T conditions of the dioritic rocks are 680-725 °C and 4.9-6.4 kbar, which probably correspond to crystallization conditions. Fluid inclusion studies suggest that low- to medium-salinity (0-6.4 wt.% NaCleq) H2O-rich fluids are trapped during the crystallization of quartz and plagioclase. The isochore range calculated for primary aqueous inclusions is consistent with the P-T condition obtained by geothermobarometry. The basement rocks likely crystallized at a depth of ∼17-22 km, with a minimum average exhumation rate of ∼12-15 m/Ma during Palaeoproterozoic to Lopingian time. Such slow exhumation indicates low relief continental shield surface during this period.
| Original language | English |
|---|---|
| Pages (from-to) | 731-739 |
| Number of pages | 9 |
| Journal | Journal of Asian Earth Sciences |
| Volume | 34 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - May 20 2009 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Earth-Surface Processes
- Geology
Cite this
}
Geothermobarometry and fluid inclusions of dioritic rocks in Bangladesh : Implications for emplacement depth and exhumation rate. / Hossain, Ismail; Tsunogae, Toshiaki; Rajesh, H. M.
In: Journal of Asian Earth Sciences, Vol. 34, No. 6, 20.05.2009, p. 731-739.Research output: Contribution to journal › Article
TY - JOUR
T1 - Geothermobarometry and fluid inclusions of dioritic rocks in Bangladesh
T2 - Implications for emplacement depth and exhumation rate
AU - Hossain, Ismail
AU - Tsunogae, Toshiaki
AU - Rajesh, H. M.
PY - 2009/5/20
Y1 - 2009/5/20
N2 - Application of hornblende thermobarometry and fluid inclusion studies to the Palaeoproterozoic (1.7 Ga) basement rocks from Maddhapara, NW Bangladesh, provide information on the pressure and temperature (P-T) conditions of crystallization, the emplacement depth and composition of magmatic fluid. The basement rocks are predominantly diorite or quartz diorite with a mineral assemblage of plagioclase, hornblende, biotite, quartz, K-feldspar, titanite, and secondary epidote and chlorite. The calculated P-T conditions of the dioritic rocks are 680-725 °C and 4.9-6.4 kbar, which probably correspond to crystallization conditions. Fluid inclusion studies suggest that low- to medium-salinity (0-6.4 wt.% NaCleq) H2O-rich fluids are trapped during the crystallization of quartz and plagioclase. The isochore range calculated for primary aqueous inclusions is consistent with the P-T condition obtained by geothermobarometry. The basement rocks likely crystallized at a depth of ∼17-22 km, with a minimum average exhumation rate of ∼12-15 m/Ma during Palaeoproterozoic to Lopingian time. Such slow exhumation indicates low relief continental shield surface during this period.
AB - Application of hornblende thermobarometry and fluid inclusion studies to the Palaeoproterozoic (1.7 Ga) basement rocks from Maddhapara, NW Bangladesh, provide information on the pressure and temperature (P-T) conditions of crystallization, the emplacement depth and composition of magmatic fluid. The basement rocks are predominantly diorite or quartz diorite with a mineral assemblage of plagioclase, hornblende, biotite, quartz, K-feldspar, titanite, and secondary epidote and chlorite. The calculated P-T conditions of the dioritic rocks are 680-725 °C and 4.9-6.4 kbar, which probably correspond to crystallization conditions. Fluid inclusion studies suggest that low- to medium-salinity (0-6.4 wt.% NaCleq) H2O-rich fluids are trapped during the crystallization of quartz and plagioclase. The isochore range calculated for primary aqueous inclusions is consistent with the P-T condition obtained by geothermobarometry. The basement rocks likely crystallized at a depth of ∼17-22 km, with a minimum average exhumation rate of ∼12-15 m/Ma during Palaeoproterozoic to Lopingian time. Such slow exhumation indicates low relief continental shield surface during this period.
UR - http://www.scopus.com/inward/record.url?scp=60649117924&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=60649117924&partnerID=8YFLogxK
U2 - 10.1016/j.jseaes.2008.10.010
DO - 10.1016/j.jseaes.2008.10.010
M3 - Article
VL - 34
SP - 731
EP - 739
JO - Journal of Asian Earth Sciences
JF - Journal of Asian Earth Sciences
SN - 1367-9120
IS - 6
ER -