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Titolo:
FRACTURE-INDUCED HYDROTHERMAL CONVECTION IN THE OCEANIC-CRUST AND THEINTERPRETATION OF HEAT-FLOW DATA
Autore:
YANG JW; EDWARDS RN; MOLSON JW; SUDICKY EA;
Indirizzi:
UNIV TORONTO,DEPT PHYS,60 ST GEORGE ST TORONTO ON M5S 1A7 CANADA UNIV WATERLOO,WATERLOO CTR GROUNDWATER RES WATERLOO ON N2L 3G1 CANADA
Titolo Testata:
Geophysical research letters
fascicolo: 9, volume: 23, anno: 1996,
pagine: 929 - 932
SICI:
0094-8276(1996)23:9<929:FHCITO>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
TRANSPORT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
10
Recensione:
Indirizzi per estratti:
Citazione:
J.W. Yang et al., "FRACTURE-INDUCED HYDROTHERMAL CONVECTION IN THE OCEANIC-CRUST AND THEINTERPRETATION OF HEAT-FLOW DATA", Geophysical research letters, 23(9), 1996, pp. 929-932

Abstract

Small-scale seafloor heat-flow variations with a characteristic wavelength of about 1200 m have been observed on a profile over a sediment-sealed ridge flank. Two theories have been advanced to explain them - low aspect ratio hydrothermal convection in a highly permeable basement layer 600 m thick, or high aspect ratio convection in an anisotropicpermeable layer 200 m thick, induced by 20 m topographic variations with a 1000 m half wavelength. Neither theory is totally satisfactory. The first requires a very thick highly permeable zone while the absence of any resolvable basement relief on a complementary seismic survey limits the credibility of the second. We hypothesize that sub-criticalhydrothermal convection in normal upper oceanic crust, driven by discrete fractures, can cause the observed heat flow anomalies. We test the hypothesis by using a finite-element code to solve the coupled time-dependent heat transport and fluid flow differential equations. Discrete fractures are incorporated explicitly. We show that the inclusion of fractures in layers 2A and 2B promotes convection. Fluid flow through fractures causes horizontal thermal gradients, and initiates and maintains sub-critical convection within the upper basalts. The predictedheat flow variations are comparable with the observed data.

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Documento generato il 03/12/20 alle ore 05:48:06