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Taphonomic Processes (taphonomic + process)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

CYTOPLASMIC MASSES PRESERVED IN EARLY HOLOCENE DIATOMS: A POSSIBLE TAPHONOMIC PROCESS AND ITS PALEO-ECOLOGICAL IMPLICATIONS,

JOURNAL OF PHYCOLOGY, Issue 2 2006
Yoshihiro Tanimura
In Lake Suigetsu, central Japan, greenish/light-brown granules identified as cytoplasmic masses had been preserved in siliceous cell walls of freshwater diatoms in annual layers of lacustrine muds since the early Holocene. The lacustrine muds consisted of alternating dark-colored (rich in diatom valves, clay, and organic matter) and light-colored (mainly diatom valves) laminae. The greenish/light-brown granules were predominately preserved in frustules of the genus Aulacoseira preserved in the dark-colored laminae. The dark-colored laminae were inferred to have formed annually under stratified water caused by surface water warming in summer that caused the formation of an organic-rich anoxic layer on the lake bottom that favored granule preservation. The good preservation of cytoplasmic masses in dark-colored laminae suggested a cause for diatom assemblage periodicity, a phenomenon that was commonly noted in temperate lakes: the cells containing these masses could be potential seed stocks for subsequent spring blooms. Frustules of the most abundant granule-containing species, Aulacoseira nipponica (Skvortzow) Tuji, in the dark-colored laminae of the Early Holocene muds were abundant in the overlying light-colored laminae, suggesting that these species reproduced abundantly in springtime yielding a massive diatom bloom. [source]

Taphonomic Changes to Blunt Force Trauma: A Preliminary Study,

JOURNAL OF FORENSIC SCIENCES, Issue 3 2007
Stephanie E. Calce B.Sc.
Abstract: This study examines the effects of taphonomic processes on blunt force trauma (BFT) through an experimental study involving pig heads. Of particular concern is the possibility that taphonomic changes can create pseudo-trauma and/or conceal evidence of actual trauma. BFT was inflicted on 10 pig skulls using a hammer. The skulls were subsequently exposed to the environment for 12 months. Seven taphonomic changes were evaluated: the freeze,thaw cycle; rodent gnawing; carnivore scavenging; presence/weight of soil; presence/weight of rain and snow; movement/displacement of bones; and discoloration due to sun bleaching and grass staining. Taphonomic effects varied between cancellous, compact, fresh, and degreased bone. Freezing and thawing, exposure to rain and snow, movement of the skulls, and soil erosion altered and, in some cases disguised, pre-existing trauma. Rodent and carnivore activity did not obliterate evidence of BFT. Recommendations for evaluating BFT on remains affected by taphonomic processes are presented. As each taphonomic process outlined by this study has the potential to disguise antemortem injury, the authors propose that one must carefully examine large, circular openings in the skull that may represent the remnant evidence of BFT. [source]

Archaeological site distribution by geomorphic setting in the southern lower Cuyahoga River Valley, northeastern Ohio: Initial observations from a GIS database

GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2004
Andrew Bauer
In this study, we compiled unpublished archival documentation of archaeological site locations from the southern part of the Cuyahoga River Valley in northeastern Ohio, USA, registered at the State of Ohio Historic Preservation Office into a Geographic Information Systems (GIS) database. Using digitized soil shapefiles to generate a geomorphic data layer, we assessed the spatial and temporal distribution of 79 known archaeological sites by landform association. This digital compilation indicates that Woodland period, Late Prehistoric, and Historic sites occur in most geomorphic settings along the river valley. In contrast, Paleoindian and Archaic sites only occur on Wisconsinan cut terraces and in upland interfluve settings, indicating that most of these documented sites are in primary contexts and have not been reworked. We discuss the distribution of archaeological sites in the study region as a function of various factors, including cultural activities, taphonomic processes, landform development, and the nature and extent of the original archaeological surveys. Observed spatial patterns of known sites clearly reflect local geomorphological controls; artifactual contexts from the earlier prehistoric periods are underrepresented in the database. We conclude that additional site surveys, as well as the excavation and documentation of new sites in this part of Ohio, are required to understand local prehistoric economies and to ascertain patterns of culturally mediated land use. © 2004 Wiley Periodicals, Inc. [source]

Eolian processes, ground cover, and the archaeology of coastal dunes: A taphonomic case study from San Miguel Island, California, U.S.A.

GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2002
Torben C. Rick
Geomorphological evidence and historical wind records indicate that eolian processes have heavily influenced San Miguel Island environments for much of the Late Quaternary. The island is almost constantly bombarded by prevailing northwesterly winds, with peak velocities exceeding 75 km/h and wind gusts reaching over 100 km/h. These strong winds played an important role in the location, formation, and preservation of the island's more than 600 archaeological sites. Excavation and surface collection at a stratified Middle and Late Holocene archaeological site on the island's north coast suggest that wind related disturbances result in significant displacement of light fish bones, produce concentrations of shellfish and heavy mammal bones, and cause significant abrasion, etching, and polishing of bones, shells, and artifacts. These data illustrate that wind not only alters surface materials but can significantly disturb subsurface deposits to a depth of at least 20 cm. Working in concert with a variety of taphonomic processes, wind can play a fundamental role in the preservation of archaeological sites and careful scrutiny during excavation and laboratory analysis is required to delineate its effects. © 2002 Wiley Periodicals, Inc. [source]

Microscopic configurations on the bare-bone surfaces of mammalian synovial joints

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 6 2001
A.E.W. MilesArticle first published online: 30 NOV 200
Abstract The smoothness characteristic of synovial joint surfaces of bare bones is shown to be an illusion; low-power microscopy of young adult human bones from interments revealed, on the surfaces of a variety of synovial joints, a system of basically hemispherical elevations, often united as short chains or groups. This system was also found on joints of a variety of species of six mammalian orders. Under the higher magnification of scanning electron microscopy (SEM), many elevations had a pit at their summits. The bare-bone surfaces of synovial joints have a thin covering of mineralized cartilage, including its mineralizing-front, which survives taphonomic processes, as well as the preparative procedures used in the study of articular surfaces. In its formative phase, the front has the chondrocyte,columnar structure of cartilage. It is postulated here that the newly-discovered elevations arise when cartilage formation is ceasing, or becoming dormant, and that each column-unit produces a globular mineralized mass, often with a pit which had accommodated a chondrocyte. These masses may incorporate the fibre systems of the unmineralized cartilage and aid in its attachment to the bony surface. Copyright © 2001 John Wiley & Sons, Ltd. [source]