Search results for "Fracture zone"
showing 3 items of 3 documents
Sources, degassing, and contamination of CO2, H2O, He, Ne, and Ar in basaltic glasses from Kolbeinsey Ridge, North Atlantic
2005
Abstract New volatile data (CO2, H2O, He, Ne, and Ar) are presented for 24 submarine basaltic glasses from the Kolbeinsey Ridge, Tjornes Fracture Zone and Mohns Ridge, North Atlantic. Low CO2 and He contents indicate that magmas were strongly outgassed with the extent of degassing increasing toward the south, as expected from shallower ridge depths. Ne and Ar are significantly more abundant in the southernmost glasses than predicted for degassed melt. The strong atmospheric isotopic signal associated with this excess Ne and Ar suggests syn- or posteruptive contamination by air. Degassing, by itself, cannot generate the large variations in δ13C values of dissolved CO2 or coupled CO2-Ar varia…
Tomography Application to Complex Seismic Data of the Tjornes Fracture Zone (Iceland)
2014
The Tjornes Fracture Zone (TFZ) is an active seismic zone in Northeast Iceland. It plays a key role to understand the geodynamic movement and location of tectonic plates. However the seismic experiment can not be performed close to earthquake sources, because sources are mainly located in the Greenland Sea. The unusual geological structure of TFZ and the limited conditions of an experiment lead to significant deviations between real observations and the values that are calculated in accordance with theoretical models. Consequently, there is a loss of adequacy and stability of tomography systems. Outcomes of the method, which takes into account this problem, are analyzed in the present chapt…
First gas and thermal measurements at the frequently erupting Gamalama volcano (Indonesia) reveal a hydrothermally dominated magmatic system
2020
Abstract The first gas and thermal measurements at the summit of the Gamalama volcano indicate that the system is dominated by hydrothermal processes. This is highlighted by the prevalence of H2S over SO2 (H2S/SO2 = 2–8), a high CO2/SO2 ratio (76–201), and a low heat transfer (3.0 MW) to the surface. A relative variation in gas composition is observed along the degassing fracture zone, possibly due to partial S scrubbing. Despite this surface hydrothermal signature, the system exhibits high gas equilibrium temperatures (425–480 °C), indicating that fluids are not exclusively derived from a boiling hydrothermal aquifer, but also sourced by cooling and crystallizing basaltic magma at deep tha…