Title:

Combining ground penetrating radar surveys and optical dating to determine dune migration in Namibia

Publication Year:
2005
Abstract:

Ground penetrating radar (GPR) profiles across a complex linear dune in the Namib Sand Sea have been used to image sets of cross-stratification and their bounding surfaces. A combination of radar facies analysis and radar stratigraphy has been used to interpret the radar profiles and define a relative chronology. Thick sets of cross-stratification indicate when the dune was most active, whereas thin sets of crossstratification are interpreted to indicate the increased prevalence of wind reversals and lower rates of dune migration, with bounding surfaces formed during periods of stabilization, non-deposition or erosion. A drilling and dating campaign was designed on the basis of the dune stratigraphy as defined by the GPR survey. Sampling was targeted at large sets of cross-stratification formed when the dunes were most active, and avoiding bounding surfaces formed when the dune was stable or even eroded. The results from optical dating give ages between 0.34 +- 0.02 ka and 1.57 +- 0.07 ka, indicating a time-averaged dune migration rate of 0.12 m a1 over the past 1600 years. Keywords: Holocene, Namib desert, GPR, OSL, stratigraphy, aeolian dune migration.

Publication Title:

Journal of the Geological Society

Volume:
162
Pages:
315โ€“321
Item Type:
Journal Article
Language:
en