Paleochannels and Patches: A Geoarchaeological Assessment of Silcrete Sources in the Cumberland Plain, Eastern Australia
12
Citation
37
Reference
10
Related Paper
Citation Trend
Abstract:
Although Aboriginal occupation dates to the Pleistocene, silcrete artifacts only begin to dominate archaeological sites found in the Cumberland Plain of western Sydney, eastern Australia, during the mid‐late Holocene. These assemblages routinely include large numbers of backed artifacts. A geoarchaeological survey of five potential silcrete source areas found that silcrete is irregularly distributed along ridgelines within gravel patches that represent paleochannel remnants. Thus, particular parts of the landscape, dictated by the geological history, were more likely to be targeted for stone procurement. The quality of silcrete differs between and within the sources due to variations in grain‐size, degree of silicification, and presence of inclusions/fractures, as well as the destructive influence of bush fires on exposed cobbles, resulting in an overall low abundance of high‐quality silcrete across the Cumberland Plain. Furthermore, a rind or chalky weathering cortex on many cobbles means that testing was required to assess the internal raw material quality. The difficulty in locating suitable raw material for artifact manufacture meant that when good silcrete sources were found, they were heavily targeted. This contextual information provides an essential backdrop in which to understand the archaeology of the Cumberland Plain and broader patterns of landscape use.Keywords:
Butte
Coastal plain
Geoarchaeology
Artifact (error)
Palaeochannel
The study area is located in the north-eastern part of the Pannonian Basin, on the romanian teritory, with a surface of over 3,600 square kilometers. With elevations of 20-30 m above the Timis and Cris plains, is the highest low-western romanian plains (100 – 160 m absolute altitudes), the surface extending on both sides of Somes River. This study aims to report new information on Late Quaternary evolution of fluvial discharge on the surface of Somes alluvial fan. Numerous relict fluvial morphologies were recognized on the surface ofSomesRiveralluvial Plain, by analyzing mainly the fluvial morphologies visible on the second austro-hungarian military maps (reference moment: ca. 1860), and on recent ortophotoplans (reference moment: 2005). The identified palaeochannel types (braided, meandering) and morphometry (large scale meanders vs. small scale meanders), the concentration of these relict features on distinct palaeodrainage directions, the relation of them with the recent fluvial drainage of the area (intersected, partly/ totally used by present day misfit channels), suggest a complex Late Quaternary history of the lower course ofSomesRiver.
Alluvial fan
Palaeochannel
Alluvial plain
Cite
Citations (0)
This study focuses on the single- and multi-storey fluvial palaeochannel lithosomes encased in mud- rich floodplain deposits in the alluvial succession of the late Neogene Wielkopolska Member of the Poznan For- mation, central Poland, well-exposed in the lignite mining pits of the region. The fluvial lithosomes include both sand-filled and mud-filled channel varieties. The channel-fill facies are not diagnostic for any particular type of fluvial system, as the fine- to very fine-grained sandy deposits are massive to trough cross-stratified and also the muddy deposits are massive to weakly flat-laminated. The scarcity of lateral accretion bedding precludes the possibility of meandering rivers, whereas the low width/thickness ratios of the palaeochannels preclude braided rivers. The width/thickness ratio is in the range of 4.5–14 (averaging 7.5) for sand-filled channels and in the range of 6–10 (averaging 9) for mud-filled ones, which indicates narrow ribbons in general classification of fluvial channel belts. The origin of the alluvial succession is attributed to a W-/NW-directed anastomosing river system characterized by laterally inactive cut-and-fill channels with cohesive and vegetated banks. The sand-filled chan- nels conveyed water and sediment discharges on a perennial basis, whereas the mud-filled conduits are thought to have been the cut-and-abandoned branches of the system, filled by overbank flooding from adjacent active channels. Minor lateral migration of channels occurred probably during periods of minimum subsidence rate, when the fluvial system was forced to develop lateral accommodation for its discharges.
Overbank
Palaeochannel
Neogene
Crevasse
Alluvial fan
Cite
Citations (13)
Palaeochannel
Cite
Citations (28)
Palaeochannel
Sinuosity
Crevasse
Cite
Citations (30)