For years, many scientists had thought that plate tectonics existed nowhere in our solar system but on Earth. Now, a UCLA scientist has discovered that the geological phenomenon, which involves the movement of huge crustal plates beneath a planet’s surface, also exists on Mars.
“Mars is at a primitive stage of plate tectonics. It gives us a glimpse of how the early Earth may have looked and may help us understand how plate tectonics began on Earth,” said An Yin, a UCLA professor of Earth and space sciences and the sole author of the new research.
Professor Ed Young of the Department of Earth & Space Sciences at UCLA was recently named a Fellow of the Meteoritical Society, an international organization dedicated to research and education on meteorites and other extraterrestrial materials.
To read more about this honor and the Meteoritical Society, click here.
To read more about Professor Young’s research, click here.
Global topographic map of Mars and location of Valles Marineris.
By Ivy S. Carpenter
A giant gash scars the surface of Mars. Known as Valles Marineris, it is one of the largest and most recognizable topographic features in our solar system. Boasting a whopping 4000-km length and a depth ranging from 10 – 15 km, it easily dwarfs Earth’s Grand Canyon (which is a piddling 2 km deep). But despite the distinction of being the longest trough system in the solar system, its origin and formation remain enigmatic.
In a new study selected as Editor’s Choice in the 2012 June 29th issue of Science and to be published in Lithosphere, UCLA’s Professor An Yin suggests that the current structure of the solar system’s ‘grandest canyon’ is a result of left-lateral transtensional faulting, similar to that found in Earth’s Dead Sea fault system.
A three-dimensional structural model for southern Valles Marineris. Notice that the fault zone consists of multiple faults, and the trough bounded on one side by a normal fault and the other side by a strike slip fault. Circles with dots indicate motion toward the viewer, circles with an X indicate motion away from the viewer.
In his model, transtensional deformation (a result of mixed lateral and extensional movement) occurs as a zone of both strike-slip (horizontal ground motion) and normal (vertical motion) faults. The normal faults allow for the subsidence and subsequent infill of a deep trough area, while strike-slip faults offset these sediments and underlying rock.
In a geological mapping tour-de-force, Yin used high-resolution data from NASA’s Mars Reconnaissance Orbiter and Mars Odyssey spacecraft to define the shapes, orientations, and cross-cutting relationships of surface structures such as landslides, erosion, impact features, strata, marker beds and folds in the southern end of the trough.
The results of the mapping effort show impressive trough-parallel left-slip offsets of 150-160 km throughout the Ius-Melas-Coprates fault zone. Offsets are seen clearly where numerous landslide deposits have been displaced sideways by ground motions (see image below). At a larger-scale, Yin identified a continuous, long (>2000 km) and narrow (<50 km) strike-slip zone with >100 km in total slip that appears strikingly similar to the undisputed plate boundary of the Earth’s Dead Sea fault zone. Some local trough-bounding faults may still be active, as they are seen to cut recent surface deposits and landslides.
(A) Image showing two landslides whose channels and fans have been offset by left-lateral strike slip motion. (B) Restored landslide postions after matching up the edges of the channels with their fans.
An alternate interpretation made recently by Jeffrey Andrews-Hannah of the Colorado School of Mines proposes that Marineris is a subsidence feature that formed as a result of the uplift of the nearby Tharsis bulge (see Andrews-Hanna, J.C. 2012., JGR, 117, E06002 at www.agu.org/pubs). However, Andrews-Hannah’s model does not easily account for the physical evidence of horizontal as well as vertical motion in the trough. The scientific debate has already been highlighted by several sources even before Yin’s paper has been published.
Yin’s study raises the fascinating question of why a planet that has supposedly not had plate tectonics for the past 4 billion years should show a feature that looks convincingly like a plate boundary. Vast areas of Valles Marineris, not to mention the other 143,998,500 square kilometers of Mars’ surface, remain imperfectly explored. Accordingly, there remains huge potential for what geological observations may tell us about the structure of this and other planets in the future.
Explore Your Universe 2012 will take place on Saturday, November 10, 2012 from 12:00 pm to 8:00 pm at UCLA’s campus. This event is FREE of charge to the public and family-friendly! We will feature many activities and demonstrations open to the general public (including students), and we plan to have more than last year! Activities for all ages include workshops, faculty and graduate student talks, planetarium shows, solar telescope viewing, comet making, weather tours, dinosaur fossils, physics demos and much more!
This event includes participation from the Department of Physics and Astronomy, Earth and Space Sciences, Atmospheric Sciences, the CNSI High School NanoScience Program, and the Center for Environmental Implications of Nanotechnology. It is sponsored by the Department of Physics and Astronomy, UCLA Center for Student Programming, and each of the departments listed above. This event was developed by graduate students, faculty, and staff in each of the these departments.
For more information on this year’s event including a full schedule, click here. For more general information on EYU click here. Click on the flyer for a printable PDF version.
Group photo from Day 1 of the IPLEX Ices & Organics in the Inner Solar System Conference
The first IPLEX-hosted conference, titled Ices and Organics in the Inner Solar System, was held in the historic Royce Hall on the UCLA campus on June 12-13, 2012.The conference was a great success, with more than fifty attendees and twenty half-hour featured presentations that covered a diverse array of topics concerning organics found in the inner solar system. Highlights included several talks on recent work involving water-ice distribution and stability on the Moon, Mars and Mercury and recent results from the Mars Phoenix lander indicating the presence of unexpected salts on the surface of Mars.Additionally, asteroidal and cometary ice and volatile transport were discussed in detail.For a complete list of abstracts, click here.
