Chemistry

Volatile chemistry at Main Endeavour Field (2012)

Volatile chemistry at Main Endeavour Field (2012)

Volatile chemistry for the hydrothermal edifices Sully (blue dots) and Hulk (red dots) located in Main Endeavour Field. As illustrated, the hydrothermal systems in the Bastille complex, where Sully is located, and the northern complex, which hosts Hulk, have continued to have distinct chemical-thermal properties both prior to and following the 1999–2000 events. The implication from these results is that the Bastille complex is fed by a different upflow limb of a convection cell than the northern complex (as illustrated in Figure 2).

MgO from basalt samples at Endeavour (2012)

MgO from basalt samples at Endeavour (2012)

Gray scale bathymetric map showing the location of basalt samples collected on myriad submersible and ROV dive programs, with colored circles indicating the ranges in MgO wt% from recent work by Gill. The most primitive (mafic: > 7.5% MgO) rocks, with highest melt temperatures are in the north were vent fields are more closely spaced. Sasquatch vent fluids also have the highest CO2 concentrations (not affected by diking events), while Mothra, to the south, historically has had the lowest CO2 concentrations (though there has been limited sampling at both fields; Proskurowski et al., 2004).

Lithosphere-to-hydrosphere representation of Endeavour Segment (2012)

Lithosphere-to-hydrosphere representation of Endeavour Segment (2012)

Interdisciplinary lithosphere-to-hydrosphere representation of Endeavour Segment. This image shows the surface bathymetry underlain by multichannel seismic results from Carbotte et al. (2002) and Van Ark et al. (2007). For ease in viewing and graphical representation, the along-axis transect has been moved slightly to the east of the ridge axis; the white dashed line indicates the location of the along-axis survey line within the axial rift.

Silica-chloride content at Bio9 (2012)

Silica-chloride content at Bio9  (2012)

Thermobarometric implications of silica-chloride contents of the Bio9 hydrothermal vent across two eruptive cycles. Measured silica (mmolal) and chloride (molal) data are superposed onto the Fontaine et al. [2009] model to predict temperatures and pressures of equilibration. After each eruption, the vapors are noticeably chloride-poor. The top figure in the inset shows measured exit temperatures (open squares) compared to modeled reaction temperatures (filled squares), derived from temperatures predicted by the silica-chloride model (at left) across the eruptive cycle.

Time-series of dissolved chloride at EPR (2012)

Time-series of dissolved chloride at EPR (2012)

Species (common):
Year: 2012

Silica-chloride time-series of Q vent (2012)

Silica-chloride time-series of Q vent (2012)

Silica-chloride time-series of Q vent from January 2002 to November 2004. Superimposed on the fluid chemical data are fields of temperature and pressure relevant for high chloride fluids, based on experiments of Fournier [1983] and Von Damm et al. [1991], as described in Foustoukos and Seyfried [2007]. For comparison, post-eruptive silica and chloride contents of a Q vent sampled in June 2006 suggest, based on the thermodynamic model of Fontaine et al.

Visualization of the East Pacific Rise (2012)

Visualization of the East Pacific Rise (2012)

Compiled visualization of datasets from the East Pacific Rise (EPR) Integrated Study Site (ISS). At right, ship-based EM300 bathymetry (25-m resolution) shows the axial high between 9°46'N and 9°56'N [White et al., 2006]. A higher resolution bathymetry data set (5-m resolution) collected in 2001 by the autonomous underwater vehicle (AUV) ABE is overlain and shows greater details of the volcanic terrain [Fornari et al., 2004; Escartin et al., 2007].