Geothermal state of DSDP Hole 333A, 395A and 534A; results from the DIANAUT Program

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doi: 10.1029/92GL00333
Author(s): Gable, Robert; Morin, Roger H.; Becker, Keir
Author Affiliation(s): Primary:
BRGM, Orleans, France
Other:
U. S. Geol. Surv., United States
Rosenstiel Sch. Mar. and Atmos. Sci., United States
Volume Title: Geophysical Research Letters
Source: Geophysical Research Letters, 19(5), p.505-508. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276 CODEN: GPRLAJ
Note: In English. 15 refs.; illus. incl. 1 table
Summary: Heat-flow values determined from the DIANAUT program provide insight into the geothermal state of three DSDP holes situated on the western flank of the Mid-Atlantic Ridge. Very low values (20 mW/m2 max.) observed in 3.5-m.y.-old crust at Hole 333A decrease with depth and indicate persistent basement cooling due to cold water circulation in the porous level of the upper oceanic crust. Cold ocean bottomwater continues to invade the upper level of fractured 7.3-m.y.-old basement at Hole 395A, but temperature v. time records show large-scale temperature fluctuations, probably associated with borehole convection, at 500 mbsf and stable temperatures, probably indicating a slow return to thermal equilibrium, at 600 mbsf. The 154-m.y.-old crust at Hole 534A exhibits a relatively steady thermal state with a heat flow close to theoretical values for a conductively cooling plate; small variations in the thermal gradient recorded in this well probably represent very slow and subtle movement of borehole fluids. The close comparison of these latest results with those obtained several years previously, demonstrates the presence of relatively stable thermal regimes. Copyright 1992 by the American Geophysical Union.
Year of Publication: 1992
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 20 Geophysics, Applied; Atlantic Ocean; DIANAUT; DSDP Site 333; DSDP Site 395; DSDP Site 534; Deep Sea Drilling Project; Geophysical surveys; IPOD; Instruments; Interpretation; Leg 109; Leg 37; Leg 45; Leg 76; Leg 78B; Ocean Drilling Program; Ocean floors; Surveys; Temperature logging; Well-logging
Coordinates: N365027 N365027 W0334003 W0334003
N224521 N224521 W0460454 W0460454
N282036 N282036 W0752254 W0752254
N224521 N233102 W0445651 W0460454
N220000 N230000 W0430000 W0470000
N224521 N224521 W0460454 W0460454
Record ID: 1992021888
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