Title: Early crustal evolution of mars

Author(s): Nimmo F, Tanaka K

Source: ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES 33: 133-161 2005

Document Type: Review

Language: English

Abstract: The bulk of the similar to 50-km-thick Martian crust formed at similar to 4.5 Gyr B.P., perhaps from a magma ocean. This crust is probably a basaltic andesite or andesite and is enriched in incompatible and heat-producing elements. Later additions of denser basalt to the crust were volumetrically minor, but resurfaced significant portions of the Northern hemisphere. A significant fraction of the total thickness of the crust was magnetized prior to 4 Gyr B.P., with the magnetization later selectively removed by large impacts. Early large impacts also modified the hemispheric contrast in crustal thickness (the dichotomy), which was possibly caused by long-wavelength mantle convection. Subsequent Noachian modification of the crust included further impacts, significant fluvial erosion, and volcanism associated with the formation of the Tharsis rise. Remaining outstanding questions include the origin of the dichotomy and the nature of the magnetic anomalies.

Author Keywords: gravity; topography; magnetism; geology; comparative planetology

KeyWords Plus: MARTIAN HEMISPHERIC DICHOTOMY; EARLY PLATE-TECTONICS; X-RAY SPECTROMETER; ART. NO. 5054; MAGNETIC-FIELD; THERMAL EVOLUTION; MANTLE CONVECTION; SNC METEORITES; LANDING SITE; GUSEV CRATER

Addresses: Nimmo F (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA
Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA
US Geol Survey, Flagstaff, AZ 86001 USA

E-mail Addresses: nimmo@ess.ucla.edu, ktanaka@usgs.gov

Publisher: ANNUAL REVIEWS, 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA

Subject Category: GEOSCIENCES, MULTIDISCIPLINARY; ASTRONOMY & ASTROPHYSICS

IDS Number: 936FK