Abstract
The preservation of terrestrial dune field in a tropical region is rare and relies significantly on the degree of weathering process, humidity and anthropogenic condition. In this paper, we report the remnants of sand dunes that is uncovered from Thungkula Ronghai (TKR) dune field in the southern part of the Khorat Plateau, northeastern Thailand. We reveal, for the first time, the results of systematic geomorphological, sedimentological and chronological analyzes of barchanoid ridges and parabolic dunes found on terraces of the Mun and the Chi Rivers. Interpretation in a series of 1952 aerial photographs, satellite images coupled with Ground Penetrating Radar (GPR) survey, and optically stimulated luminescence (OSL) dating were applied. As a result, we found remnants of mega-barchanoid ridges and isolated parabolic dunes varying in height from 1-2 m with maximum length of 4 km, locally distributed in between terraces of the Mun and Chi Rivers, the middle to eastern part of TKR. Dune shapes include lobate, en-echelon and elongate partially overlying on crevasse sand splay, meandered scar, paleo-channel, mid-channel bar of the fluvial depositional sequences. Orientation of all dunes is in NW-SE direction reflecting the formation was due to the prevailing NW monsoon wind. Transition from barchanoid ridge to parabolic dune was observed. Preliminary OSL dating reveals the deposition of sand dunes occurred between 45 to 28 ka. This age range can be inferred to a warmer and drier period occurred in Marine Isotope Stage 3 (MIS3) before the Last Glacial Maximum.
Highlights
Sand dune is one of spectacular landforms on earth that is widely distributed around the world’s deserts and coastlines
Remnants of sand dunes preserved in Thungkula Ronghai (TKR) dune field were interpreted based on Pye (1993) into simple, compound and complex types (Table 1)
It is suggested that the physiography of the Khorat Plateau favors for the preservation of climate record both warm and cold periods throughout the Quaternary
Summary
Sand dune is one of spectacular landforms on earth that is widely distributed around the world’s deserts and coastlines. Aeolian desert and coastal sand dune types were classified as shadow dune, barchan, parabolic, barchanoid ridge, linear, transverse and star dunes (Pye, 1993). McKee (1979) classified sand dunes based on a combination of shape, number and orientation of slip-faces close to the prevailing wind or sand drift direction, and degree of form mobility. The depositional lobe can be defined as a mound of active to partially vegetated sand on the downwind extent of the dune (Thompson, 1983). It is oriented transverse to the predominant wind direction and migrates forward It has gently dipping windward slopes and steeply dipping leeward slopes. Barchans, occur in areas of limited sand supply; they coalesce laterally to form crescentic (barchanoid) ridges as sand supply increases. Where vegetation controls accumulation dynamics, the system is known as a stabilizing aeolian system (Lancaster, 2014)
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