Fossils from Quaternary fluvial archives: Sources of biostratigraphical, biogeographical and palaeoclimatic evidence

Fluvial sedimentary archives have the potential to preserve a wide variety of palaeontological evidence, ranging from robust bones and teeth found in coarse gravel aggradations to delicate insect remains and plant macrofossils from fine-grained deposits. Over the last decade, advances in Quaternary biostratigraphy based on vertebrate and invertebrate fossils (primarily mammals and molluscs) have been made in many parts of the world, resulting in improved relative chronologies for fluviatile sequences. Complementary fossil groups, such as insects, ostracods and plant macrofossils, are also increasingly used in multi-proxy palaeoclimatic and palaeoenvironmental reconstructions, allowing direct comparison of the climates and environments that prevailed at different times across widely separated regions. This paper reviews these topics on a regional basis, with an emphasis on the latest published information, and represents an update to the 2007 review compiled by the FLAG-inspired IGCP 449 biostratigraphy subgroup. Disparities in the level of detail available for different regions can largely be attributed to varying potential for preservation of fossil material, which is especially poor in areas of non-calcareous bedrock, but to some extent also reflect research priorities in different parts of the world. Recognition of the value of biostratigraphical and palaeoclimatic frameworks, which have been refined over many decades in the 'core regions' for such research (particularly for the late Middle and Late Pleistocene of NW Europe), has focussed attention on the need to accumulate similar palaeontological datasets in areas lacking such long research histories. Although the emerging datasets from these understudied regions currently allow only tentative conclusions to be drawn, they represent an important stage in the development of independent biostratigraphical and palaeoenvironmental schemes, which can then be compared and contrasted.