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Erosional origin of linear dunes on Earth and Saturn's moon Titan

Date:
February 24, 2012
Source:
Geological Society of America
Summary:
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 indicates that erosional origin models should not be ruled out.
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Artificially excavated cross sections showing internal structures of linear dunes (Fig. 2 of Zhou et al.).
Credit: Image courtesy of Geological Society of America

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 & 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."


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The above post is reprinted from materials provided by Geological Society of America. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jianxun Zhou, Ying Zhu, Chongqian Yuan. 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. GSA Bulletin, 2012; DOI: 10.1130/B30550.1

Cite This Page:

Geological Society of America. "Erosional origin of linear dunes on Earth and Saturn's moon Titan." ScienceDaily. ScienceDaily, 24 February 2012. <www.sciencedaily.com/releases/2012/02/120224140615.htm>.
Geological Society of America. (2012, February 24). Erosional origin of linear dunes on Earth and Saturn's moon Titan. ScienceDaily. Retrieved August 2, 2015 from www.sciencedaily.com/releases/2012/02/120224140615.htm
Geological Society of America. "Erosional origin of linear dunes on Earth and Saturn's moon Titan." ScienceDaily. www.sciencedaily.com/releases/2012/02/120224140615.htm (accessed August 2, 2015).

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