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1.
The conventional approach to assessing the archaeological record in most parts of the world involves a combination of excavation of stratified deposits and extensive survey of surface deposits. Although widely applied in Australia, in both research‐based and management archaeology, the method does not conform well to the nature of the surface archaeological record here. Over much of semi‐arid and arid Australia, archaeological “sites” are, in fact, accretion phenomena that are not easily interpreted as the outcome of short‐term behavioral events. Using results from twelve years of geoarchaeological research in western New South Wales, we demonstrate that there is considerable variability in landsurface age, and hence the “availability” of archaeological surfaces, over relatively short distances. Therefore, it cannot be assumed that stone artifact deposits, for example, that appear to be similar in character are of similar age. Data are also presented that demonstrate that the presence of artifacts on the surface, their apparent absence in sediments buried beneath the surface, and the apparent recent ubiquity of the archaeological record are all a function of geomorphic processes that, at the same time, expose some artifact deposits at the surface and erode and bury others amid large volumes of sediment. Interpreting the surface artifact record within a spatial and temporal geomorphic framework is crucial to understanding the past human behavior that the artifact deposits represent. © 2009 Wiley Periodicals, Inc.  相似文献   

2.
Accretionary desert pavements on the eastern Libyan Plateau of central Egypt support a rich Middle and Upper Paleolithic artifact assemblage exhibiting intensive blank production and minimal tool production. These assemblages appear to be in primary context with numerous examples of lithic refits showing on‐site lithic production. However, the smallest (length ≤2.5 cm) archaeological fragments are recovered at a much lower rate on this desert pavement surface than expected given comparable data from lithic assemblages in cave and shelter contexts in France. Excavation of archaeological contexts on the Libyan Plateau reveals the loss of small artifact fragments into the subsurface due to aeolian accumulation of silts, whereas geomorphic examination of desert pavement surfaces suggests a potential for relatively isolated bioturbation as a source of lateral and vertical disturbance of desert pavement surfaces over small areas. Archaeologists should be aware of the potential for long‐term assemblage stability as well as small artifact burial in surficial desert pavement contexts.  相似文献   

3.
Excavations at the Wenas Creek Mammoth Site yielded mammoth, bison, and two possible artifacts in a single colluvial stratum, with radiocarbon bone dates ∼17 ka. Eight infrared‐stimulated luminescence (IRSL) samples were collected to establish general ages of site strata, returning multi‐grain estimates consistent with stratigraphic integrity and the radiocarbon dates. Four additional IRSL samples were collected to estimate the depositional age of one artifact found in place. These produced a pooled total of 94 single‐grain estimates from near the artifact, 80% averaging 16.8 ± 0.9 ka, and 20% averaging 5.1 ± 0.5 ka. These results could be interpreted to demonstrate pre‐Clovis age artifact deposition consistent with the bone dates, or a mid to late Holocene intrusion into older deposits, possibly by bioturbation. The single‐grain IRSL dates do not provide proof of pre‐Clovis presence beyond reasonable doubt at this site, but do show that this technique is valuable in assessing the stratigraphic integrity needed for any such claim.  相似文献   

4.
A detailed taphonomic study was undertaken at the Tayara site in order to determine the impact of natural processes such as surface water flow on spatial patterning and site formation. The study focused on Paleoeskimo level II, which contains many lithics and significant faunal remains. Level II integrity was assessed through spatial analysis and by examining the size distribution of lithic artifacts and bone orientation. Experimental knapping aimed at replicating Paleoeskimo lithic technology was used to assess the possible size sorting of lithics. The study indicates that artifact burial by water‐laid sediments did not result in a selective impoverishment in small‐sized lithics. Statistically significant lithic concentrations and associations suggest that spatial distribution was not significantly modified by site formation processes. However, slight post‐depositional changes were presumably induced by water flows in the form of statistically significant horizontal bone reorientations. These occurred when gently flowing water inundated bone accumulations without inducing significant washing or sorting of smaller lithic debris. The spatial integrity evaluation of the level II assemblage reveals a low degree of spatial disturbance and disorganization of the material (i.e., limited entropy), which is likely related to low‐energy hydraulic forces and rapid burial soon after Paleoeskimo occupation. The grouping and deposition of much of the occupation debris is likely the result of Paleoeskimo activities (e.g., knapping and butchering), and the lithics and fauna specimens are probably at or very near their original location. These results show the behavioral significance of the grouping and deposition of debris in Tayara's level II. © 2009 Wiley Periodicals, Inc.  相似文献   

5.
Stratigraphic, topographic, and ground‐penetrating radar data obtained from a ca. 1800‐year‐old embankment and adjacent ditch at the Hopewell Mound Group (Chillicothe, Ohio) are used to validate the archaeological application of a simple finite‐differences diffusion model employed frequently to assess geomorphic change in natural landscapes. Although diffusion models have been used to describe the topographic degradation of landforms in a variety of geomorphic terrains, the approach has not been applied to ancient earthworks in an archaeological context. The results of this study indicate that a variety of initial earthwork forms can result in the sinusoidal profile apparent on the current landscape. Using the model results to interpret the field data, we suggest that the initial embankment form was steeper and the adjacent ditch was deeper. As a result of natural degradation processes, the earthwork widened and flattened over time. These results have broad implications for any study aimed at: (1) assessing the function of original earthwork forms, (2) determining the formation processes of complicated stratigraphies or artifact assemblages, (3) estimating the time and labor investment required for construction, or (4) identifying the socio‐political structures necessary to build earthworks. © 2005 Wiley Periodicals, Inc.  相似文献   

6.
Archaeological surface surveys have located open‐air sites on cropland in the Sierra de Atapuerca (Burgos, Spain). To what degree agricultural disturbances have impacted archaeological site integrity is poorly defined and may greatly affect interpretations of prehistoric land use. This paper presents the results of three experiments concerned with the effects of tillage on artifact distribution, focusing specifically on lateral and vertical artifact displacement. We demonstrate highly variable horizontal displacement of artifacts by plowing and overall downward movement of lithic materials within the soil. This results in an expansion of site boundaries and reduction of surface artifact density, yielding a biased and unrepresentative picture of past human activity. More experimental studies are needed to better define agricultural disturbances to surface archaeological assemblages. © 2008 Wiley Periodicals, Inc.  相似文献   

7.
Susan E. Hogg 《Earth》1982,18(1):59-76
Following McGee's (1897) use of the term sheetflood, there developed a variety of conflicting opinions and numerous terminologies relating to this process, many of which are ill-considered and poorly defined. A classification system is devised on both a hydrologic and geomorphic basis which dispenses with many superfluous terms that have been used with respect to sheetfloods. Magnitude of a storm is expressed in terms of the amount of surface runoff generated from a given storm due to the surface conditions.A sheetflood is defined as a sheet of unconfined flood water moving down a slope. The frequency of a sheetflood is relatively low while its magnitude is relatively great. Sheetflow is defined as relatively high-frequency, low-magnitude overland flow occurring in a continuous sheet and is restricted to laminar flow conditions. Sheetwash, a term of geomorphic origin, is considered to be redundant and is superseded by the more meaningful term rainwash defined as the washing action of rain on slopes.  相似文献   

8.
Understanding site formation processes is crucial for interpreting archaeological context patterns and hominin behaviour as these affect the preserved condition of a site and the integrity of archaeological remains. The fluvio‐lacustrine sequences in the Nihewan Basin of North China are rich sources of early Pleistocene archaeological sites, which offer an important opportunity to investigate human evolution and adapted behaviours in East Asia. Although many Palaeolithic sites have been reported from the Nihewan Basin, North China, few of them focus on site formation processes before interpreting the hominin behaviour patterns. Here, we present a site formation study of four archaeological layers (Layers 6D, 6C, 6B and 6A) in Trench 1 from the Donggutuo (namely DGT‐T1) site in the Nihewan Basin with an age of 1.1 Ma. Through the study of sedimentary contexts, spatial distributions of artefacts and fossils, intra‐assemblage category ratios, debitage size distributions, lithic abrasion, artifact orientation and planar dip, our results show that all the layers had been disturbed by low‐energy sheet wash across the lake shore setting, but to differing extents. The post‐depositional disturbance caused by water decreased from the lower to the upper layers, from Layer 6D to Layer 6A. This indicates that the archaeological remains in DGT‐T1 have not been subject to significant natural modifications and are thus suitable for studying early hominin behaviour in North China. Copyright © 2019 John Wiley & Sons, Ltd.  相似文献   

9.
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10.
Artifacts are commonly buried by approximately 50 cm of sediment at prehistoric archeological sites (early Archaic through Mississippian) on uplands of the Sandhills of the upper Coastal Plain of the southeastern United States. Bioturbation, eolian sedimentation, and colluviation are the primary processes that can explain artifact burial because of the upland position of the sites in an erosional landscape setting. Colluvial sedimentation is discounted at most of the sites because they occur on interstream divides and upper hillslope positions. Thus, the focus is on eolian sedimentation versus bioturbation as burial agents. Six sites in the midst of the Sandhills region along the corridor of South Carolina Highway 151 in Chesterfield County provide the data. The Sandhills consist primarily of Cretaceous and Tertiary marine, fluvial, and eolian sediments that are highly dissected and overlie crystalline rocks in the deep subsurface. Two of the sites are on high fluvial terrace remnants that predate 12 ka and serve as controls where bioturbation is the only reasonable burial process. Hillslope positions of the sites are on erosional elements of the landscape (crests, shoulder slopes, and upper backslopes) where sediment transfer operates (colluvial and overland flow), but where deposition is minimal. The sites occur on very sandy soils having a texture of loamy sand to sand. In some instances, a fine textured cover sand, which is about 1.5 m thick, overlies a clayey subsoil or Bt horizon. This cover sand has been interpreted by some as an eolian sand sheet that buries a second parent material and paleosol, but standard particle size and heavy mineral data indicate that it is simply a thick E horizon over a Bt horizon. Standard particle size fractionation at whole phi intervals, and particle size analysis of the heavy mineral fraction, indicate that eolian sedimentation is unlikely at five of the six sites. Heavy minerals were analyzed with respect to the sedimentological principle of hydraulic equivalence, which provides clear separation of eolian versus water-laid sediment. Results of particle size analysis suggest that the cover sands are water-laid (probably fluvial) at five of the six sites, which favors the bioturbation process of artifact burial. Heavy mineral analysis corroborates the standard particle size data, indicating that only one site, 38CT16, possibly is composed of eolian sediment. Soil profile development suggests that the age of the sediment at site 38CT16 probably is older than 12 ka and was in place prior to human occupation. Therefore, possible eolian sedimentation at that site is not relevant to artifact burial, which also suggests bioturbation is the primary process of artifact burial. Additional evidence favoring bioturbation as a vigorous artifact burial process in the Sandhills comes from the two sites on high elevation sandy fluvial terraces (38CT34, 38CT17) where artifacts are also buried. At these terraced sites bioturbation is the only possible burial process. Overall results suggest that bioturbation best explains the occurrence of buried artifacts and that eolian sedimentation processes are not readily apparent, and are not required, in explaining artifact burial. © 1998 John Wiley & Sons, Inc.  相似文献   

11.
Shallowly buried archaeological sites are particularly susceptible to surface and subsurface disturbance processes. Yet, because cultural deposition often operates on short time scales relative to geologic deposition, vertical artifact distributions can be used to clarify questions of site formation. In particular, patterns in artifact distributions that cannot be explained by occupation histories must be explained by natural processes that have affected sites. Buried only 10–50 cm beneath the ground surface for 10,450 14C yr, the Folsom component at Barger Gulch Locality B (Middle Park, Colorado) exhibits many signs of post‐depositional disturbance. Through examination of variation in the vertical distribution of the artifact assemblage, we are able to establish that only a Folsom component is present. Using vertical artifact distributions, stratigraphy, and radiocarbon dating, we are able to reconstruct the series of events that have impacted the site. The Folsom occupation (˜10,450 14C yr B.P.) was likely initially buried in a late‐Pleistocene eolian silt loam. Erosion brought the artifacts to rest on a deflation surface at some time prior to 9400 14C yr B.P. A mollic epipedon formed in sediments that accumulated between 9400 and 7000 14C yr B.P. Some time after 5200 14C yr B.P., this soil was partially truncated, and artifacts that had previously dispersed upward created a secondary lag at its upper contact. This surface was buried again and artifact dispersal continued. © 2005 Wiley Periodicals, Inc.  相似文献   

12.
Twenty thin sections were studied from Cactus Hill, a ca. 20 ka stratified sand dune site in Virginia, USA, with a Clovis and hypothesized pre‐Clovis component. The high‐resolution soil micromorphology investigation focused on testing the integrity of Clovis and pre‐Clovis stratigraphy from one location where there is a high density of artifacts. Site formation processes were dominated by eolian (dune) sand formation. There was also ephemeral topsoil development and associated occupation, along with their penecontemporaneous disturbance and dispersal by scavenging animals (assumed) and localized down‐working by small invertebrate mesofauna (as evidenced by aggregates of fine phytolith‐rich humic soil and fine soil‐coated charcoal fragments). Partial erosion of these occupation soils (deflation?) was followed by successive sand burial. Post‐depositional processes affecting these sand‐buried occupations involved only small‐scale bioturbation and overprinting of clay lamellae, suggesting site stratigraphy has been stable for a long time. Soil micromorphological analysis has defined a difference between occupational units (pre‐Clovis and Clovis) and sterile units found between these units as well as above and below. In summary, according to this analysis, the site appears intact with only minor disturbances affecting the long‐term integrity of the stratigraphy. © 2008 Wiley Periodicals, Inc.  相似文献   

13.
本文在概述车大人沟河流域泥石流形成的地形地貌、物源和水源等条件的基础上，采用多元线性回归分析方法，选取了物源储量、支沟完整性系数、支沟边坡坡度、支沟沟床比降、冲沟密度、侵蚀模数、不良地质现象和植被覆盖率等八个指标作为自变量，建立与泥石流活跃度间相关关系的数学表达式，计算出车大人沟河40条泥石流支沟活跃度值，从而进行分区评价。将该区泥石流活跃度划分为高、中、低易发区和不发育区，其结果与实地灾情相符，可为车大人沟河流域泥石流防治规划提供科学依据。  相似文献   

14.
An Early Stone Age Acheulean lithic assemblage collected along a 1.5‐km transect at the Garden Route Casino near Pinnacle Point, Mossel Bay, South Africa, was examined in order to assess the relative degree to which assemblage variability is impacted by post‐occupational processes and/or terrain. It was found that post‐occupational variables do vary across the study area, and they affect the positions of artifacts to different degrees. Terrain structure was determined to have minimal effect on artifact movement. Three analysis sections were identified as having artifacts that were likely close to their original positions and compositions. Future interpretations of differential land use can now be tempered with considerations of the post‐occupational processes that formed the recovered assemblage. © 2009 Wiley Periodicals, Inc.  相似文献   

15.
This paper compares archaeological evidence of Aboriginal occupation inside rock shelters and outside in adjacent sand sheets, focusing on two locations in the Keep‐River region, northwestern Australia. Luminescence and radiocarbon dating reveal that occupation sequences inside rock shelters are generally younger ( < 10,000 yr B.P.) than outside ( < 18,000 yr B.P.). Differences in occupation chronology and artifact assemblages inside and outside rock shelters result from depositional and postdepositional processes and shifts in site function. An increase in regional sedimentation rate from 10 cm/ka − 1 in the Pleistocene to 20 cm/ka − 1 in the Holocene may account for late buildup of sediments within rock shelters, increased artifact accumulation, and reduced postdepositional disturbance in some settings. More intense use of rock shelters in the Late Holocene is indicated from a change in hunting technology and greater production of rock art. The results indicate that some cultural interpretations might be flawed unless archaeological evidence from rock‐shelter and open‐site excavations is integrated. © 2006 Wiley Periodicals, Inc.  相似文献   

16.
The processes of surface clast dispersal are discussed and it is shown that on flat land the spatial integrity of larger gravel clasts (which include most diagnostic artefacts) is likely to be preserved over long periods. A structured approach is described for predicting land surfaces where Lower Palaeolithic artefact scatters may have survived through the British Quaternary. The topographic map of Britain is subjected to three tests to eliminate areas unlikely to preserve these surfaces. After progressively subtracting glaciated areas, areas covered by superficial deposits, and river basins/areas with slopes steeper than about 2°, the surfaces remaining have the potential for long-term stability. Eight criteria are described to help verify true palaeosurfaces. They comprise mostly high level plateau lands. On to this map are plotted fifteen sample localities known to have yielded Lower Palaeolithic artefacts from surface contexts. Ten lie within the predictive model, the remainder belong to surface fluvial deposits or other superficial deposits. Four sites have been mapped in enough detail to show the distribution of individual artefacts; in three, traces of clustering occurs, suggesting the original scatter patterns have not entirely dispersed in time. The two sites of Warren Hill and the Northern Drift where the author has worked are examined in more detail. Comparison is made with a ‘pristine’ Early/Middle Stone Age surface site from arid terrain in Namibia. It is argued that in certain circumstances even in the volatile British climate surface scatters may not have moved far from their original location. The predictive map can only be a general guide: each site is different, but clay-with-flints has ubiquitous potential. Surface studies include both flint and quartzite artefacts, with their contrasting typologies. It is concluded that surface studies are likely to lead to a more complete understanding of early human occupation patterns.  相似文献   

17.
The geologic setting of an urban environment affects the development of that particular urban culture. Human activities can involve devegetation, soil loosening, soil‐water and ground‐water changes, soil erosion, and changes in surface‐water hydrology. This article focuses on how the geologic resources and history of the Punjab region have greatly influenced the cultural development of the Bronze Age city of Harappa, located in northeast Pakistan. Archaeological deposits at this site date between at least 3300 B.C. and 1700 B.C. A geologic and geomorphic framework is provided which presents the relationships of the ancient Harappans with their local and regional environment, with these geologic processes affecting both the initial settlement and development of this ancient urban center. Buried soil elevation data, mapped soil distributions, and geomorphic models are used to construct an approximation of the preoccupation paleotopography beneath this site. © 2000 John Wiley & Sons, Inc.  相似文献   

18.
Digital echo sounding, SeaBeam swath bathymetry data and sediment cores were collected on the continental slope (1500–3700 m water depth) off southeastern Tasmania in order to study sedimentary processes in the vicinity of an ocean disposal site. The new bathymetry data show that the shallower limits of the disposal site are positioned on the seaward edge of a gently dipping (3°) mid‐slope shoulder, between 1200 and 2100 m water depth. The slope below the disposal site is relatively steep (6.5°) and is cut by submarine canyons which lead into the adjacent East Tasman Saddle. The SeaBeam bathymetry data show a small submarine canyon traversing the slope in 2400 m water depth directly downslope from the disposal site, with local slopes of up to 22°. The canyon feeds into a perched basin at 2450 m, which could be acting as a local sediment trap. Short (<90 cm) gravity cores indicate that indurated erosional surfaces characterise the slope environment. The cores contain Upper Cretaceous (upper Campanian) sandstones and siltstones, which in places crop out on the sea floor where they are locally draped by a thin (0–30 cm), modern layer of hemipelagic calcareous ooze. Five cores collected from the vicinity of the disposal site had lead and zinc concentrations in the surface 1 cm of 10.3 ± 5.0 and 39.5 ± 19.6 mg/kg, respectively, significantly greater than the background values (2.9 ± 1.4 for lead and 21.2 ± 5.4 for zinc) which characterise the underlying unit that is composed of the same hemipelagic calcareous ooze. Lead and zinc are constituents of the dumped material, jarosite, which, after mixing with slope sediments, can be used as sediment tracers. One core contains a fining‐upwards bed which is also elevated in lead and zinc. This is interpreted as evidence for dispersal of the jarosite from the disposal site downslope to depths >3000 m via turbidity flows sometime during the past 24 years. Current meter data collected from 30 m above the sea floor over one year at the disposal site show that bottom currents attain speeds of up to 0.46 m/s. The current events are attributed to eddies shed by the East Australia Current. The measured bottom currents are capable of transporting fine‐grained hemipelagic muds and could provide a trigger mechanism for turbidity flows.  相似文献   

19.
模拟降雨条件下坡面细沟形态演变与量化方法   总被引：7，自引：0，他引：7       下载免费PDF全文
为探明坡面土壤侵蚀过程中细沟的演变规律,研究细沟形态特征量化方法是非常重要的。利用室内土槽模拟降雨试验,对比了45 mm/h、87 mm/h和127 mm/h雨强下容重分别为1.30 g/cm3和1.05 g/cm3两种黄土在20°陡坡坡面细沟发育形态的差异,并分别采用分形维数、拓扑参数对细沟沟网的形态特征进行量化描述,引入地貌信息熵理论进行坡面地貌信息熵计算,然后对各量化参数的敏感性进行了分析。结果表明,分形维数作为整体性的量化参数,对描述发育成熟的细沟形态差异不够灵敏;坡面地貌信息熵能够反映侵蚀过程中侵蚀程度的变化,对细沟发育程度的描述较为灵敏;细沟沟网的拓扑特征参数较好地体现了沟网内部结构的差异,可用于描述沟网内部结构特征的较灵敏参数。  相似文献   

20.
Erosion and sediment redistribution are important processes in landscape changes in the short and long term. In this study, the RMMF model of soil erosion and the SEDD model of sediment delivery were used to estimate annual soil loss and sediment yield in an ungauged catchment of the Spanish Pre-Pyrenees and results were interpreted in the context of the geomorphic features. The Estaña Catchment is divided into 15 endorheic sub-catchments and there are 17 dolines. Gullies and slopes were the main erosive geomorphic elements, whereas the colluvial, alluvial, valley floor, and doline deposits were depositional elements. Spatially distributed maps of gross soil erosion, sediment delivery ratio (SDR), and sediment yield (SY) were generated in a GIS. Severe erosion rates (>100 Mg ha?1 year?1) were found in gullies, whereas mean and maximum erosion rates were very high on slopes developed on Keüper Facies and high in soils on Muschelkalk Facies. Where crops are grown, the depositional-type geoforms were predicted by the models to have an erosive dynamic. Those results were consistent with the rates of erosion quantified by 137Cs which reflects the significant role of human activities in triggering soil erosion. Catchment area was positively correlated with erosion rate, but negatively correlated with SDR and SY. The latter were negatively correlated with the proportion of the surface catchment covered with forests and scrublands. The topography of the area influenced the high SDR and SY in the dolines and valley floors near the sinks. Intra-basin stored sediment was 59.2% of the total annual eroded soil in the catchment. The combination of the RMMF and SEDD models was an appropriate means of assessing the effects of land uses on soil erosion and obtaining a better understanding of the processes that underlie the geomorphic changes occurring in mountainous environments of the Mediterranean region.  相似文献   

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