Reconstructing paleoenvironments and palaeoclimates in drylands: what can landform analysis contribute?

Abstract

Quaternary period palaeoenvironmental and palaeoclimatic reconstructions are based on a wide and diverse array of proxy data sets, some of which are geomorphological in nature. In drylands, where organic proxies may be limited, the use of landforms is particularly important, but challenging. The capacity to establish the age of depositional forms, particularly through the use of luminescence dating, has advanced the use of landforms in dryland palaeo‐research, though interpretation of these ‘geoproxy’ records can be complex, especially at the nexus of palaeoclimate and palaeoenvironmental interpretations of past conditions. In this paper the use of aeolian and lacustrine forms in Quaternary research is considered, focusing on the relationships between dynamics, form and climate, and on the essential linkage between process research and palaeoenvironmental research. It is concluded that landform analysis is a critical part of dryland palaeoenvironmental/climate reconstruction, contributing a different set of data compared to other data sources, in terms of the elements of past conditions that are revealed. Five principles are identified to improve the use of geoproxy records in Quaternary research: (1) greater use of geomorphic process studies by Quaternary scientists, to better inform palaeolandform interpretation; (2) further development of the use of chronometric data, especially in terms of interpreting large data; (3) interpret landform records in location‐specific contexts, not in general terms; (4) capitalise of the complexity of spatially‐extensive landform records, which may offer better representations of real Quaternary environmental complexity than ‘at a point’ proxies; (5) establish ways of integrating spatially‐extensive geoproxy records with other palaeoenvironmental records. These challenges are major, but not insurmountable, and should represent goals for geomorphologists, chronologists and quaternary scientists alike. Copyright © 2011 John Wiley & Sons, Ltd.

Climate-driven changes to dune activity during the Last Glacial Maximum and deglaciation in the Mu Us dune field, north-central China

“…The relationship between OSL age clusters in dune field chronologies and past environmental or climatic change may not be straightforward (Thomas and Burrough, 2012;Telfer and Hesse, 2013;Thomas, 2013;Lancaster et al, 2013), because multiple environmental factors influence how and where the datable sand is preserved, and hence dune field chronologies (Leighton et al, 2014b(Leighton et al, , 2014aXu et al, 2015).…”

The Evolution and Ages of Makgadikgadi Palaeo-Lakes: Consilient Evidence From Kalahari Drainage Evolution South-Central Africa

“…The Regional Model requires major downward revision of palaeo-lake ages, previously constrained by radiocarbon dates of calcretes, and Thermoluminescence (TL) and Optically Stimulated LuiTiinescence dating of quartz grains (collated by Thomas (2012) and here collectively termed Luminescence Dating or LD). Exploring the interplay between these controls of hydrological dynamics, our tnodel reveals how tectonic changes to river topology exercised first order control over palaeo-lake evolution (with ancillary controls of local climate over the largest lake stands).…”

50,000 years of vegetation and climate change in the southern Namib Desert, Pella, South Africa

“…The arid environment has precluded the preservation of organic material, and most palaeoenvironmental records have been obtained from a diversity of geomorphic features such as dune sediments (Bateman et al, 2003;Blümel et al, 1998;Bristow et al, 2007;Chase and Thomas, 2006;Chase and Thomas, 2007;Eitel et al, 2002;Stokes et al, 1997;Stone and Thomas, 2008;Telfer, 2007;Thomas et al, 1998;Thomas et al, 1997), fluvial deposits (Blumel et al, 2000;Bourke et al, 2003;Eitel et al, 2002;Eitel and Zöller, 1996;Heine, 2004;Heine and Heine, 2002;Heine and Völkel, 2009;Lancaster, 2002;Srivastava et al, 2006;Stone et al, 2010;Vogel, 1982) and fragmentary lacustrine records (Cooke and Heine, 1979;Deacon and Lancaster, 1988;Heine, 1978Heine, , 1982Lancaster, 1979Lancaster, , 1984Lancaster, 1986;Lancaster and Teller, 1988;Teller and Lancaster, 1985;Teller and Lancaster, 1986;Teller et al, 1990;Ward, 1984). Many of these, while being potentially valuable indicators of landscape dynamics (Thomas, 2013), are of debatable palaeoclimatic significance (Chase, 2009;Chase and Brewer, 2009;Lancaster, 2002;…”