Time-series geochemical and tracer injection recovery data from the deep (basaltic) crustal fluids from IODP Holes 1301A/1362B on the eastern flank of Juan de Fuca Ridge
Abstract
Integrated Ocean Drilling Program borehole CORK (Circulation Obviation Retrofit Kit) observatories provide invaluable opportunities to study the deep biosphere. In order to draw large volumes of fluids from crustal aquifers to seafloor, we developed an autonomous sensor and fluid sampling system, GeoMICROBE (Cowen et al., 2012). GeoMICROBE's Major components include a positive displacement primary pump, a primary valve manifold system, sensors (e.g., fluid flow rate, temperature, dissolved O2, electrochemistry-voltammrtry analyzer), 24-48 port in situ filtration and fluid collection system, computerized controller, six 24V-40A batteries and wet-mateable (ODI) communications with submersibles. This sampling system has been successfully deployed at IODP Hole 1301A in 2010 on the eastern flank of Juan de Fuca Ridge. The GeoMICROBE was successfully recovered in the summer of 2011. However, due to the narrow inner diameter of the fluid delivery line (1/4''), the batteries were exhausted and only half of the preprogrammed sampling procedures were accomplished. After quick turn-around the GeoMICROBE was redeployed at nearby CORK 1362B for Summer, 2012 recovery. CORKs 1301A and 1362B are only ~800 m apart and both penetrate to ~40-50m into the basement. Unlike CORK 1301A, the fluid deliver line installed on CORK 1362B has 1/2'' inner diameter. The much lower resistance allows us to pump the fluids up with reduced power consumption. A conservative power consumption model was made to ensure that enough battery power would be available to complete the twelve monthly samplings. Monthly, following extensive flushing ~3 L of fluid was passed through a 0.2 μm polycarbonate filter. The filter holder was pre-charged with 6% glutaraldehyde. Also, monthly whole fluid samples were collected and stored in an acid-washed 500mL Tedlar bag. The whole fluid will be used for analysis of colloidal (Microspheres) and dissolved tracers injected into the upper crust in August 2010 as well as major ions, nutrients, total alkalinity, total organic carbon and total dissolved organic carbon. Here, we will present initial results of tracter recoveries, in situ measurements and shore-based geochemical analysis of the whole fluid samples collected by the GeoMICROBE. The data and their implications will be discussed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMOS24B..06C
- Keywords:
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- 0452 BIOGEOSCIENCES / Instruments and techniques;
- 1895 HYDROLOGY / Instruments and techniques: monitoring;
- 4277 OCEANOGRAPHY: GENERAL / Time series experiments;
- 4294 OCEANOGRAPHY: GENERAL / Instruments and techniques