Kastern, Mirian; Malone, Mitchell J. (2004): Integrated Ocean Drilling Program, Expedition 301T scientific prospectus; Costa Rica hydrogeology. IODP Management International, College Station, TX, United States, Scientific Prospectus (Integrated Ocean Drilling Program), 301T, 37 pp., georefid:2007-128162

The Costa Rica hydrogeology operation proposes to replace CORK-II downhole instrument strings in holes drilled at Ocean Drilling Program (ODP) Leg 205 Sites 1253 and 1255 (September-November 2002) off Costa Rica. The CORKs are instrumented in a fractured horizon in the oceanic section of the incoming plate and in the decollement zone to investigate fluid flow across the margin and its implications for the seismogenic zone and subduction factory. During Atlantis cruise 11-8 (27 February-7 March 2004) the Alvin was unable to recover the downhole osmotic fluid samplers and miniaturized temperature loggers and was thus unable to deploy the new instrument strings. Apparently, soft debris in the borehole buried the latch, and the limited bottom time, lighter-weight running tools necessary for the Alvin, and limited capacity of the wellhead winch frustrated recovery efforts. These impediments present no significant obstacles to a drillship, as discussed below. Pressure data downloaded from the samplers at Sites 1253 and 1255 record two transient events; evaluation of temperature and fluid chemistry data from the downhole instruments at the two sites is critical to investigating strain or hydrological origins of the pressure events. The osmotic samplers currently installed were designed to collect a time series of samples for fluid and gas analyses over a 2 y period; after 2 y, samples and the information they contain are progressively lost. The temperature loggers will stop recovering data after 6 October 2004. The drillship work proposed here will be done during the transit following Integrated Ocean Drilling Program (IODP) Expedition 301 after the scheduled port call at Astoria, Oregon, en route to the Panama Canal.
West: -86.1100 East: -86.1100 North: 9.3900 South: 9.3900
Expedition: 205
Site: 205-1253
Site: 205-1255
Expedition: 301
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2204/iodp.sp.301T.2004 (c.f. for more detailed metadata)
Data download: application/pdf
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