Thermal regime of the Costa Rican convergent margin: 1. Along-strike variations in heat flow from probe measurements and estimated from bottom-simulating reflectors.

Harris, Robert N., Grevemeyer, Ingo , Ranero, Cesar R., Villinger, Heinrich, Barckhausen, Udo, Henke, Thomas, Mueller, Christian and Neben, Soenke (2010) Thermal regime of the Costa Rican convergent margin: 1. Along-strike variations in heat flow from probe measurements and estimated from bottom-simulating reflectors. Open Access Geochemistry, Geophysics, Geosystems, 11 (12). Q12S28. DOI 10.1029/2010GC003272.

[img]
Preview
Text
2010_Harris_Grevemeyer_GGG_2010GC003272.pdf - Published Version

Download (4Mb)

Supplementary data:

Abstract

The thermal structure of convergent margins provides information related to the tectonics, geodynamics, metamorphism, and fluid flow of active plate boundaries. We report 176 heat flow measurements made with a violin bow style probe across the Costa Rican margin at the Middle America Trench. The probe measurements are collocated with seismic reflection lines. These seismic reflection lines show widespread distribution of bottom‐simulating reflectors (BSRs). To extend the spatial coverage of heat flow measurements we estimate heat flow from the depth of BSRs. Comparisons between probe measurements and BSR‐derived estimates of heat flow are generally within 10% and improve with distance landward of the deformation front. Together, these determinations provide new information on the thermal regime of this margin. Consistent with previous studies, the margin associated with the northern Nicoya Peninsula is remarkably cool. We define better the southern boundary of the cool region. The northern extent of the cool region remains poorly determined. A regional trend of decreasing heat flow landward of the deformation front is apparent, consistent with the downward advection of heat by the subducting Cocos Plate. High wave number variability at a scale of 5–10 km is significantly greater than the measurement uncertainty and is greater south of the northern Nicoya Peninsula. These heat flow anomalies vary between approximately 20 and 60 mW m−2 and are most likely due to localized fluid flow through mounds and faults on the margin. Simple one‐dimensional models show that these anomalies are consistent with flow rates of 7–15 mm yr−1. Across the margin toe variability is significant and likely due to fluid flow through deformation structures associated with the frontal sedimentary prism.

Document Type: Article
Keywords: Gas hydrates; Meeresgeologie; Geophysics; Subduction zone, heat flow, fluid flow, Middle America Trench
Research affiliation: OceanRep > SFB 574
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1029/2010GC003272
ISSN: 1525-2027
Projects: Future Ocean, SFB574, REPSOL
Expeditions/Models/Experiments:
Date Deposited: 17 Dec 2010 10:26
Last Modified: 07 Nov 2017 09:28
URI: http://oceanrep.geomar.de/id/eprint/10577

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...