Correlation of fluvial sequences in the Mediterranean basin over the last 200ka and their relationship to climate change

Abstract

This paper presents a new correlation of Late and Middle Pleistocene fluvial sedimentary sequences in Greek, Libyan and Spanish river basins and evaluates river response to climate change over the Last Interglacial-Glacial Cycle. Over the past 200,000 years there have been at least 13 major alluviation episodes in the Mediterranean, although the amplitude, frequency and possibly, duration of these events varied significantly across the region. Parts of Oxygen Isotope Stage (OIS) 5 appears to have been periods of pronounced landscape change in many Mediterranean catchments with major river aggradation occurring at B109-111 ka (during OIS 5d) and most notably at B88 ka (OIS 5b/5a boundary). Other parts of OIS 5 appear to have been periods of relative fluvial inactivity. OIS 2 and 3 were both characterised by an apparent increase in the number of alluviation events, and this record of river behaviour parallels many other palaeoenvironmental records in the region which also show more frequent climate fluctuations between B12 and 65 ka. There is evidence for a high degree of synchrony in major river aggradation events across the Mediterranean in catchments with very different sizes, tectonic regimes and histories. Climate-related changes in catchment hydrology and vegetation cover over the last 200 ka would appear to be the primary control of large-scale (catchment wide) sedimentation over time periods of between 10 3 and 10 4 years. r

Preliminary slip rate estimates for the Düzce segment of the North Anatolian Fault Zone from offset geomorphic markers

“…This was well documented for the late Quaternary in the Mediterranean region (e.g. Macklin et al, 2002), during which major alluviation episodes were correlated to cooling trends that lasted generally 10-15 ka and culminated with a massive discharge and deposition of debris. These cooling trends were followed by abrupt warming.…”

Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

“…River terraces are known to be preserved in a wide range of settings and basin sizes (Macklin et al, 2002;Bridgland and Westaway, 2008) and have been described here across five catchments in the Wet Tropics region of northeast Australia. This study identified, and classified, dominant terraces across the region, with initial emphasis on available topographic and soils data.…”

“…Terraces have formed in all global regions and are commonly studied to understand how rivers have responded to the combined effects of changes in external controls including climate, tectonics, and sea level (Merritts et al, 1994;Macklin et al, 2002;Bridgland and Westaway, 2008) and in internal controls, such as catchment morphology (Coulthard et al, 2005) and reach-specific conditions (Houben, 2003).…”

Climatically controlled river terrace staircases: A worldwide Quaternary phenomenon

“…In both respects this influence might be expected to decline with decreasing latitude, with lessening of the severity of the cold parts of climate cycles. However, there are indications that temperature is a controlling factor in areas well beyond the reach of the Quaternary glaciations; it has, for example, been invoked as significant in the Mediterranean region (Macklin et al, 2002;Martrat et al, 2004). The relation between the interglacial marine terraces of NW Syria and the fluvial terraces of the Kebir has already been noted (above) as evidence that the latter formed during cold stages, which implies that temperature can be the dominant influence as far south as the Mediterranean regions.…”

“…With the recognition of nine 100 ky cycles since the 'Mid-Pleistocene Revolution', the potential for matching river terraces to climatic forcing is considerable. Detailed studies of fluvial activity during the last climatic cycle have revealed the importance of climate as a forcing factor (e.g, Macklin et al, 2002;Howard et al, 2004), despite such records being variably compromised by anthropogenic influences. It is therefore clear that cyclic changes in climate would be capable of driving terrace formation, given background uplift.…”