by Staff Writers
Boulder, CO (SPX) Feb 28, 2012
Linear dunes, widespread on Earth and Saturn's moon, Titan, are generally considered to have been formed by deposits of windblown sand. It has been speculated for some time that some linear dunes may have formed by "wind-rift" erosion, but this model has commonly been rejected due to lack of sufficient evidence.
Now, new research supported by China's NSF and published this week in GSA BULLETIN indicates that erosional origin models should not be ruled out.
The linear dunes in China's Qaidam Basin have been proposed to have formed as self-extending lee dunes under a unidirectional wind regime owing to a high level of total silt, clay, and salt content or cohesiveness of sediments, and they have undergone southward lateral migration at rates of up to 3 m/yr.
New GSA BULLETIN research examines the sediments, internal structures, and optically stimulated luminescence ages of the linear dunes in the central Qaidam Basin approximately 80 km north of the city Golmud.
The study's findings suggest that the linear dunes are most likely of erosional origin similar to yardangs with orientations controlled by strikes of joints.
According to the study's lead author, Jianxun Zhou of the China University of Petroleum's State Key Laboratory of Petroleum Resource and Prospecting, "If the control of tectonic structures on the orientation of wind-eroded ridges is taken into account, morphodynamic interpretations for the wind-rift model may become much simpler.
No one has considered the possibility of erosional origin for the linear dunes on Titan.
Nearly all researchers consider the linear dunes on Titan to be of depositional origin, but their morphodynamic interpretations are complicated and their relationships to wind directions are in dispute.
If an erosional origin is considered, the morphodynamic interpretations of the linear dunes on Titan can also be greatly simplified."
Dr. Zhou would like to acknowledge Dr. Jani Radebaugh for her careful and constructive reviews of the study.
Origin and lateral migration of linear dunes in the Qaidam Basin of NW China revealed by dune sediments, internal structures and optically stimulated luminescence ages, with implications for linear dunes on Titan - Jianxun Zhou et al., State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China; doi: 10.1130/B30550.1.
Geological Society of America
Explore The Ring World of Saturn and her moons
Jupiter and its Moons
The million outer planets of a star called Sol
News Flash at Mercury
Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.
Rhea Before Titan
Pasadena CA (JPL) Feb 27, 2012
Craters appear well defined on icy Rhea in front of the hazy orb of the much larger moon Titan in this Cassini spacecraft view of these two Saturn moons. Lit terrain seen here is on the leading hemispheres of Rhea and Titan. North on the moons is up and rotated 13 degrees to the left. The limb, or edge of the visible disk, of Rhea is slightly overexposed in this view. The image ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|