USGS - science for a changing world

Pacific Coastal & Marine Science Center

A Global Inventory of Natural Gas Hydrate Occurrence

by Keith A. Kvenvolden and Thomas D. Lorenson

home back bottom next

Gas Hydrate Samples - P2b

Map Code: P2b (PDF version)
Reference: Shipboard Scientific Party, 1997, Site 1041: Proceedings, Ocean Drilling Program, Initial Reports, v. 170, p. 153-188.
Geologic Location:
Pacific Ocean
Middle America Trench, an active convergent margin
Offshore from Costa Rica, continental slope
ODP Leg 170, Site 1041
Core/Sample Count: 9 samples
Water Depth: 3306 m
Sediment Depth: 199-259 meters below sea floor (mbsf)
of Gas Hydrate:
"At this site, gas hydrate is mostly concentrated between about 120 and 280 mbsf, the zone of highest TOC content of 1-2.5 wt%. Its primary mode of occurrence is disseminated, with very thin sheets of gas hydrate filling micro-fractures, as indicated by the almost constant salinity and chlorinity in this depth interval."
Analytical Results: The gas-hydrate sample analyzed within this interval (120-280 mbsf) is composed mainly of methane accompanied by amounts of the higher molecular weight hydrocarbons ethane and propane. The volumentric ratio of gas to water ranged from 120 to 140."
Inferred Evidence
for Gas Hydrate:
See Map Code P2a.
home back top next

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: PCMSC Web Team
Content Last Modified: 2001 [poster update 17Nov10 (lzt)]

site P7site P5site P4bsite P4asite P2b