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The effects of the Mazama tephra-falls : a geoarchaeological approachMatz, Stephan E. 28 May 1987 (has links)
About 7,000 years ago two major tephra-falls blanketed the
Pacific Northwest in volcanic ash. These two tephra-falls, identified
as the Llao and climatic tephra-falls, were a part of the eruptive
events that led up to the collapse of Mount Mazama to form Crater Lake
in the southern Oregon Cascades.
The tephra-falls occurred about 200
years apart at around 7,000 years B.P. and 6,800 years B.P. for the
Llao and climatic eruptions respectively.
The effects of the tephra-falls on the flora, fauna, and people of the period have been
characterized by different researchers as ranging from minimal to
catastrophic.
In an attempt to better understand the affects of these two
events on the flora, fauna, and people, a model is presented to help
organize the various lines of research into a coherent whole and to
suggest profitable areas of research which have not yet been completed.
The model is based on ecological and anthropological theory with a
strong reliance on analogy with modern ecosystems and volcanic hazards
research.
The model makes use of the ecosystem concept as the framework
for the interaction of the abiotic, or nonliving habitat, with the
biotic, or living system. The biotic organisms are adapted to the
characteristics of the abiotic habitat and in many respects the
composition, frequencies, and distributions of biotic organisms are
determined by their tolorance levels to these characteristics. Tephra-falls act as environmental disturbances which change the abiotic
habitat of the ecosystem. Therefore, any changes caused by such
a disturbance in the abiotic characteristics that are not optimal or
are outside of the tolorance limits of the biotic (flora and fauna)
components should cause changes in the composition, distribution, and
frequency of organisms within the ecosystem. The changes brought
about by the tephra-falls may be described by successional and
evolutionary processes through analysis of pollen and faunal remains,
population demography as described by mortality profiles, and research
into the reaction of specific flora and fauna within adaptational
types to the properties of tephra-falls and the tephra as a soil
body.
The state factors used to describe the abiotic component of the
ecosystem are: time, distribution, material properties, climate, and
geomorphology. The state factor of time involves the determination
of the occurrence in time of the event(s), the duration of the event(s),
the season of occurrence of the event(s), and the residence time of
tephra in the ecosystem. This state factor is used to define the
specific point in time and duration of the effects of the tephra-fall(s) for individual ecosystems. The state factor of distribution
describes the aerial extent and thickness of the air-fall deposits.
This state factor determines the extent of the initial disturbance.
The state factor of climate describes the specific components of
rainfall, wind, and temperature which control ecosystem composition
and development, and the changes to the climate which may have occurred
due to volcanic aerosols associated with the eruption. The state
factor of geomorphology describes the location of tephra and nontephra
bodies across the landscape and through time as the tephra is reworked
by wind, water, and gravity from the initial air-fall positions. The
determination of the long term distribution of the tephra is important
in determining post-event influences on ecosystems as described by
the material properties of the tephra.
It is argued that most people were not greatly harmed by the
Mazama tephra-fall events themselves, but instead may have been
greatly affected by a loss of food resources during and after the
events. Changes in food resource availability and exploitation
locations due to the tephra-falls may have resulted in changes in
both settlement and subsistence activities. Changes in settlement and
subsistence activities may be seen in a corresponding change in
differential frequencies of functional tool types across space and
time. The kind and amount of expected changes in settlement and
subsistence systems are linked to distance from the source of the
tephra, the stability and compostion of pre-disturbance ecosystems,
the types and intensity of resource exploitation, and the amount of
variability in subsistence and settlement traits which were available
to the sociocultural system. / Graduation date: 1988
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Environmental changes associated with Native American land use practices a geoarcheological investigation of an Appalachian watershed /Mihindukulasooriya, Lorita N. January 2009 (has links)
Thesis (M.S.)--Ohio University, November, 2009. / Title from PDF t.p. Includes bibliographical references.
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Predicting archaeo-colluvium on the Berkshire DownsDay, Christopher A. January 1999 (has links)
A new and relatively unexplored source of archaeological and environmental information on the Chalkland are the sediments of dry valleys. From relatively recent studies these deposits have been shown to be the product of ancient land use and soil loss and a rich repository of both primary and archaeological material. There have, however, been no attempts to determine the spatial distribution of this class of ancient valley deposit - for the purpose of this project termed archaeo-colluvium. The study focuses on the north-west part of the Berkshire Downs (58km<sup>2</sup>), a landscape of both chalk and superficial drift deposits, which together with relict ancient fields, lynchets and settlement features offered a suitable area in which to develop and test a method for predicting the distribution of these deposits. The project uses a multi-disciplinary approach which combines the traces of ancient arable (Celtic fields), some topographic parameters and assumptions about past soils, erosion regimes, and colluvial preservation in the development a GIS-based predictive model for the distribution of archaeo-colluvium within this study region. Following the production of a map of predicted sites, archaeo-colluvium was checked in the field by an extensive auger and trench survey of the main valleys and tributaries. Dry valley sequences were assembled and dated, both for the purposes of evaluating the accuracy of the model and to draw some archaeological implications from the nature and distribution of these deposits. A synthesis of local soils, colluvium and wider archaeological observations suggested a three-stage chronology for prehistoric and Romano-British land use on the Berkshire Downs, centred around earliest arable use at Seven Barrows with later shifts to surrounding catchments of mixed chalk and clay soils. The results of the field program were encouraging with the predictive model verified at 71% of target sites. A number of field observations were contrary to the original model, notable among these were that thicker sequences were common in landscapes of heavier soils as was evacuation of valley sediments from open chalk landscapes. This feedback allowed some modified principles to be briefly tested on three other Chalkland landscapes.
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The bench deposits at Berger Bluff Early Holocene-Late Pleistocene depositional and climatic history /Brown, Kenneth M. January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
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Paleoenvironmental reconstruction of an active margin coast from the Pleistocene to the present : examples from southwestern Oregon /Punke, Michele Leigh. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references. Also available online.
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Identifying and interpreting geoarchaeological sites with high prospecting potential using aerial LIDAR, GIS and sedimentological analysisLausanne, Alexandra 03 May 2018 (has links)
The dynamic environmental history and relative sea level (RSL) changes experienced on the Pacific Northwest Coast of North America during the early post-glacial period and the early Holocene resulted in significant visibility challenges for prospection of early coastal archaeological sites. Archaeological visibility is the degree to which cultural material survives post-depositional processes and is detectable on the landscape today. It is influenced by environmental factors such as localized differences in relative sea level change, the rainforest canopy and dynamic post-glacial activity. This study offers an integrated methodological approach for locating palaeo-coastal sites by combining: i) geomorphic interpretation of landscape attributes captured by LIDAR (Light Detection and Ranging) mapping, ii) GIS-based archaeological site potential mapping, and iii) local RSL history. The RSL history for the study site (Quadra Island, British Columbia, Canada) shows notable regression over the past 14 500 years from a highstand of at least 195 m resulting from post-glacial isostatic rebound. Late Pleistocene and early Holocene palaeo-shorelines are found inland from, and elevated above, modern sea level and represent key areas for archaeological prospecting. Bare-earth Digital Terrain Models (DTMs) derived from the LIDAR dataset were interpreted to identify palaeo-shorelines at 10 m and 30 m above modern mean sea level. A GIS-derived map was created to identify regions of high archaeological potential using a decision tree method with variables including distance to palaeo-shoreline, low slope and a coastal complexity parameter. Select geoarchaeological sites were examined in terms of sedimentology, stratigraphy, microfossil content and geochronology as site-specific examples of sea level regression stillstands. Field validation results suggest that this integrated methodology provides a promising approach for archaeological prospection that could be applied to other post-glacial coastal settings. / Graduate
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Targeting early man sites in the western United States: An assessment of the Manix type section, central Mojave Desert, CaliforniaBudinger, Fred Emil 01 January 1992 (has links)
Geoarchaeology -- Pre-Clovis archaeology -- Site search strategies.
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Quaternary marine terraces on Cyprus : constraints on uplift and pedogenesis, and the geoarchaeology of PalaipafosZomeni, Zomenia 12 June 2012 (has links)
Numerous flights of Quaternary marine terraces are present around the island of Cyprus, in the Eastern Mediterranean. These terraces are a result of the global eustatic sea-level curve and local tectonism. Marine Isotope Stage (MIS) 5 through MIS 13 terraces are identified, mapped and dated. Palaeoshoreline elevation, an excellent indicator for a past sea–level, and new numerical geochronology are used to calculate an Upper Pleistocene uplift rate for various coastal sectors. Southwestern Cyprus presents the highest uplift rates of 0.35-0.65 mm/year with other sections suggesting uplift of 0.07-0.15 mm/year. This Upper Pleistocene tectonic signal is attributed to an active offshore subduction/collision system to the southwest of Cyprus, evidenced from the seismic activity offshore and the surface expression of a blind thrust fault in the Pafos region.
Soil chronosequences and geology in southwestern Cyprus are studied in order to understand the Quaternary development on this uplifting landscape. Soil profile properties are used to calculate a profile development index (PDI), a method often applied to geomorphic surfaces as a relative dating method. Well-developed red and clayey soils occur in the coastal sector, on broad and low-angle surfaces, specifically on marine terraces and alluvial fans. Higher elevations of steep slopes consisting of carbonate and ophiolite lithologies host poorly developed soils. Results show variable PDI's on uplifted terraces, obscured by transported materials, active alluvial fan buildup and hillslope erosion. Calcium carbonate build-up in soil profiles in the form of nodular and laminar accumulations are used as another relative dating method. Geochronology of marine terraces is used as an age range approximation for carbonate stages.
Geomorphologic mapping focuses on the southeastern part of the Pafos thrust fault, the only point on the landscape where this otherwise blind fault is exposed on the surface. This is the location of Palaipafos, an important Ancient polity, today the site of the village of Kouklia. Geoarchaeological study suggests little landscape change over the last 4000 years in the vicinity of the urban core of Palaipafos, this being attributed to bedrock and landscape resistance of its location, a plateau at 80 m amsl. Copper deposits in the Palaipafos hinterland had provided a valuable resource at one time. Soil and water resources continue to sustain agriculture.Tectonic uplift in this part of the Pafos thrust fault is estimated to be 2.1mm/year, considered, together with Late Holocene sea-level change responsible for the shifting locations and eventual abandonment of the Palaipafos harbor in the coastal lowlands. / Graduation date: 2013
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Beyond the divide: a new geoarchaeology of Aboriginal stone artefact scatters in Western NSW, Australia / New geoarchaeology of Aboriginal stone artefact scatters in Western NSW, AustraliaFanning, Patricia C January 2002 (has links)
Thesis (PhD)--Macquarie University, Division of Environmental & Life Sciences, Graduate School of the Environment, 2002. / Includes bibliographical references: p. 228-232. / Geomorphology, archaeology and geoarchaeology: introduction and background -- Surface stone artefact scatters: why can we see them? -- Geomorphic controls on spatial patterning of the surface stone artefact record -- A temporal framework for interpreting surface artefact scatters in Western NSW -- Synthesis: stone artefact scatters in a dynamic landscape. / Surface scatters of stone artefacts are the most ubiquitous feature of the Australian Aboriginal archaeological record, yet the most underutilized by archaeologists in developing models of Aboriginal prehistory. Among the many reasons for this are the lack of understanding of geomorphic processes that have exposed them, and the lack of a suitable chronological framework for investigating Aboriginal 'use of place'. This thesis addresses both of these issues. -- In arid western NSW, erosion and deposition accelerated as a result of the introduction of sheep grazing in the mid 1800s has resulted in exposure of artefact scatters in some areas, burial in others, and complete removal in those parts of the landscape subject to concentrated flood flows. The result is a patchwork of artefact scatters exhibiting various degrees of preservation, exposure and visibility. My research at Stud Creek, in Sturt National Park in far western NSW, develops artefact and landscape survey protocols to accommodate this dynamic geomorphic setting. A sampling strategy stratified on the basis of landscape morphodynamics is presented that allows archaeologists to target areas of maximum artefact exposure and minimum post-discard disturbance. Differential artefact visibility at the time of the survey is accommodated by incorporating measures of surface cover which quantify the effects of various ephemeral environmental processes, such as deposition of sediments, vegetation growth, and bioturbation, on artefact count. -- While surface stone artefact scatters lack the stratigraphy usually considered necessary for establishing the timing of Aboriginal occupation, a combination of radiocarbon determinations on associated heat-retainer ovens, and stratigraphic analysis and dating of the valley fills which underlie the scatters, allows a two-stage chronology for huntergatherer activity to be developed. In the Stud Creek study area, dating of the valley fill by OSL established a maximum age of 2,040±100 y for surface artefact scatters. The heatretainer ovens ranged in age from 1630±30 y BP to 220±55 y BP. Bayesian statistical analysis of the sample of 28 radiocarbon determinations supported the notion, already established from analysis of the artefacts, that the Stud Creek valley was occupied intermittently for short durations over a relatively long period of time, rather than intensively occupied at any one time. Furthermore, a gap in oven building between about 800 and 1100 years ago was evident. Environmental explanations for this gap are explored, but the paiaeoenvironmental record for this part of the Australian arid zone is too sparse and too coarse to provide explanations of human behaviour on time scales of just a few hundred years. -- Having established a model for Stud Creek of episodic landscape change throughout the late Pleistocene and Holocene, right up to European contact, its veracity was evaluated in a pilot study at another location within the region. The length of the archaeological record preserved in three geomorphically distinct locations at Fowlers Gap, 250 km south of Stud Creek, is a function of geomorphic dynamics, with a record of a few hundred years from sites located on channel margins and low terraces, and the longest record thus far of around 5,000 years from high terrace surfaces more remote from active channel incision. But even here, the record is not continuous, and like Stud Creek, the gaps are interpreted to indicate that Aboriginal people moved into and out of these places intermittently throughout the mid to late Holocene. -- I conclude that episodic nonequilibrium characterizes the geomorphic history of these arid landscapes, with impacts on the preservation of the archaeological record. Dating of both archaeological and landform features shows that the landscape, and the archaeological record it preserves, are both spatially and temporally disjointed. Models of Aboriginal hunter-gatherer behaviour and settlement patterns must take account of these discontinuities in an archaeological record that is controlled by geomorphic activity. -- I propose a new geoarchaeological framework for landscape-based studies of surface artefact scatters that incorporates geomorphic analysis and dating of landscapes, as well as tool typology, into the interpretation of spatial and temporal patterns of Aboriginal huntergatherer 'use of place'. / Mode of access: World Wide Web. / vii, 232 p. ill., maps
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The bench deposits at Berger Bluff : Early Holocene-Late Pleistocene depositional and climatic historyBrown, Kenneth M. 12 August 2011 (has links)
Not available / text
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