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Titolo:
A PLUME TECTONICS MODEL FOR THE THARSIS PROVINCE, MARS
Autore:
MEGE D; MASSON P;
Indirizzi:
UNIV PARIS 11,URA CNRS D1369,LAB GEOL DYNAM TERRE & PLANETES,BATIMENT509 F-91405 ORSAY FRANCE
Titolo Testata:
Planetary and space science
fascicolo: 12, volume: 44, anno: 1996,
pagine: 1499 - 1546
SICI:
0032-0633(1996)44:12<1499:APTMFT>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
KRAFLA FISSURE SWARM; VOLCANIC RIFT ZONES; VALLES-MARINERIS; DYKE SWARM; SURFACE DEFORMATION; WRINKLE RIDGES; FLOOD BASALTS; MANTLE PLUME; HYDROVOLCANIC EXPLOSIONS; TERRESTRIAL PLANETS;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
239
Recensione:
Indirizzi per estratti:
Citazione:
D. Mege e P. Masson, "A PLUME TECTONICS MODEL FOR THE THARSIS PROVINCE, MARS", Planetary and space science, 44(12), 1996, pp. 1499-1546

Abstract

Morphological and structural data from the whole Tharsis province suggest that a number of shallow grabens radially oriented about the Tharsis bulge on Mars are underlain by dykes, which define giant radiatingswarms similar to, e.g. the Mackenzie dyke swarm of the Canadian shield. Mechanisms for graben formation are proposed, and the depth, width, and height of the associated dykes are estimated. Structural mappingleads to define successive stages of dyke emplacement, and provide stress-trajectory maps that indicate a steady source of the regional stress during the whole history of the Tharsis province. A new tectonic model of Tharsis is presented, based on an analogy with dyke swarms on the Earth that form inside hot spots. This model successfully matches the following features: (1) the geometry of the South Tharsis Ridge Belt, which may have been a consequence of the compressional stress field at the boundary between the uplifted and non-uplifted areas in the upper part of the lithosphere at the onset of hot spot activity; (2) extensive lava flooding, interpreted as a consequence of the high thermal anomaly at the onset of plume (hot spot) activity; (3) wrinkle ridgegeometry in the Tharsis hemisphere, the formation of which is interpreted as a consequence of buoyant subsidence of the brittle crust in response to the lava load; (4) Valles Marineris limited stretching by preliminary passive rifting, and uplift, viewed as a necessary consequence of adiabatic mantle decompression induced by stretching. The geometrical analysis of dyke swarms suggests the existence of a large, Tharsis-independent extensional state of stress during all the period of tectonic activity, in which the minimum compressive stress is roughly N-S oriented. Although magmatism must have loaded the lithosphere significantly after the plume activity ceased and be responsible for additional surface deformations, there is no requirement for further loading stress to explain surficial features. Comparison with succession of magmatic and tectonic events related to hotspots on the Earth suggests that the total time required to produce all the surface deformation observed in the Tharsis province over the last 3.8 Ga does probably not exceed 10 or 15 Ma. Copyright (C) 1996 Elsevier Science Ltd.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 16:26:53