Peterson C.D.,Portland State University |
Stock E.,Triple E Consultants |
Meyer J.,Far Western Anthropological Research Group |
Kaijankoski P.,Far Western Anthropological Research Group |
Price D.M.,University of Wollongong
Journal of Coastal Research | Year: 2015
Peterson, C.D.; Stock, E.; Meyer, J.; Kaijankoski, P., and Price, D.M., 2015. Origins of Quaternary coastal dune sheets in San Francisco and Monterey Bay, central California coast, U.S.A.: Reflecting contrasts in shelf depocenters and coastal neotectonics. The San Francisco and Monterey Bay coastal dune sheets derive from similar origins in the central California coast but differ substantially in size (respectively, ~400 and ~900 km2) and age (respectively, <0.1 and >1.0 Ma). The San Francisco dune sheet is restricted to a short alongshore interval (<20 km) within a relatively straight coastline (150 km in length) that borders a broad shelf (~40 km in width). The Monterey Bay dune sheet is restricted to the Monterey Bay embayment (41 km alongshore length). The embayment includes a very narrow shelf (3-15 km in width), which is dissected by the Monterey Submarine Canyon. Generally low onshore topographic relief (<150 m elevation) likely enhanced inland transgression of Late Pleistocene dune fields in both the San Francisco and Monterey Bay areas. The locations of the dune sheets are directly related to sand accumulations in marine low-stand depocenters that supplied sand to the adjacent dune fields by eolian transport across the emerged inner shelves. The San Francisco shelf depocenter is apparently localized at a midshelf bight (-50 to-100 m elevation) that extends 25 km (east-west) offshore of a paleoriver mouth of a major river system, the Sacramento-San Joaquin River. The Monterey Bay shelf depocenter is bounded alongshore by major headlands and converging paleoshorelines (-30 to-90 m elevation) that effectively trapped littoral sand from small coastal drainages, primarily the Salinas River. High vertical rates of neotectonic deformation in the San Francisco dune sheet (0.4-1.0 mm y-1) limited dune sheet longevity and deposit thickness (5-35 m). Low uplift rates (~0.1 mm y-1) in the central Monterey Bay dune sheet permitted deposit accumulations of up to 250 m thickness. The differences in dune sheet extent, thickness, and age resulted from key differences in localized shelf accommodation space and coastal neotectonic vertical movements. © 2015 Coastel Education and Research, Inc.
Rosendahl D.,James Cook University |
Ulm S.,James Cook University |
Sloss C.,Queensland University of Technology |
Steinberger L.,University of Queensland |
And 4 more authors.
Quaternary International | Year: 2015
Claims for mid-Holocene Aboriginal occupation at the shell matrix site of Wurdukanhan, Mornington Island, Gulf of Carpentaria, Australia, are reassessed through an analysis of the excavated assemblage coupled with new surveys and an extensive dating program. Memmott etal. (2006, pp. 38, 39) reported basal ages of c.5000-5500 years from Wurdukanhan as 'the oldest date yet obtained for any archaeological site on the coast of the southern Gulf of Carpentaria' and used these dates to argue for 'a relatively lengthy occupation since at least the mid-Holocene'. If substantiated, with the exception of western Torres Strait, these claims make Mornington Island the only offshore island used across northern Australia in the mid-Holocene where it is conventionally thought that Aboriginal people only (re)colonised islands after sea-level maximum was achieved after the mid-Holocene. Our analysis of Wurdukanhan demonstrates high shellfish taxa diversity, high rates of natural shell predation and high densities of foraminifera throughout the deposit demonstrating a natural origin for the assemblage. Results are considered in the context of other dated shell matrix sites in the area and a geomorphological model for landscape development of the Sandalwood River catchment. © 2015 Elsevier Ltd and INQUA.
Robins R.,Everick Heritage Consultants |
Hall J.,University of Queensland |
Stock E.,Triple E Consultants
Quaternary International | Year: 2015
Some 30 years of intensive archaeological research in coastal southeast Queensland and northern New South Wales have produced a large database of dated sites recording over at least 20,000 years of Aboriginal occupation. This database, and in particular the spatio-temporal distribution of dated sites, has been employed somewhat uncritically as a representative sample to support various interpretive models of cultural change in the region. However, as little attention has been paid to the substantial sample biases inherent in this important record such interpretive arguments remain rather speculative scenarios. This paper identifies and explicates critical issues relating to the use of such data in constructing models of cultural change in this region via three case studies and closes with an appeal for consideration of these in future research. © 2015 Elsevier Ltd and INQUA.