摘要:

AbstractInterpretation of Shuttle Imaging Radar (SIR) images acquired during the November 1981 flight of Columbia led to the idea that a paleodrainage system of regional and perhaps transcontinental proportions crossed southern Egypt and northern Sudan prior to the onset of Quaternary aridity. Three seasons of field investigations in two locales (Wadi Arid and Wadi Safsaf, some 70‐80 km apart) near the Sudan border of southern Egypt confirmed initial interpretations of the radar images and produced geologic evidence of fluvial deposition in broad “radar river” valleys (designated RR‐1) whose presence is now obscured by eolian sand sheets. Development of an integrated, regional river system probably occurred in the late Paleogene or early Neogene. the river courses eventually were disrupted by tectonism, volcanism, and stream piracy. Their broad valleys were almost fully aggraded long before the middle Pleistocene appearance of man in the area. Some of the large paleovalleys on the radar images contain narrow (0.05‐2.0 km wide), braided inset channels (designated RR‐2). the RR‐2 channels, we believe, represent the last episodes of running water in the valleys during the Quaternary pluvials.In Wadi Arid (the type area for the RR‐1 valleys) 36 backhoe trenches and manual excavations yielded Acheulian handaxes, flakes, and cores from nearshore alluvial sediments and surface and shallow subsurface locales. These assemblages are typologically Middle to Late Acheulian and date from ca. 0.15th 0.5 million years ago. the unabraded, unrolled, buried artifacts and their geological contexts indicate that human groups were widely present in a subhumid riparian environment along the edges of the ancient valleys, while these localities were undergoing episodic, local aggradation. Scarce Middle Paleolithic and abundant Neolithic assemblages are widespread along the edges of Wadi Arid and bordering interfluves.In Wadi Safsaf, another broad RR‐1 valley, geologic evidence from 20 backhoe excavations demonstrates that an RR‐2 channel complex is inset into the alluvial fill in the central part of the valley. No artifacts were found in the alluvium excavated there, but Late Acheulian, Middle Paleolithic, and Neolithic surface assemblages are present nearby. Stratigraphic relations indicate the RR‐2 channels are late Pleistocene in age; they were already fully aggraded and their surfaces deflated before an eolian sand sheet of Holocene age was deposited on them. Bir Safsaf, on the northern edge of Wadi Safsaf, was a magnet for Late Acheulian populations, and the paleovalley just south of the bir is bordered with extensive alignments of artifacts, mainly handaxes. Some of these handaxes were foundin situ, embedded in alluvial sediments, while others appear to have been exposed on the surface by deflation of the valley fill.The accumulated data support a provisional archaeo‐geochronological framework for the last half‐million years in the Wadi Arid‐Wadi Safsaf area. This framework provides a new geomorphic explanation for the widespread distribution of buried and exposed Middle Acheulian and Late Acheulian assemblages. the interpretation emphasizes the importance of exploring the non‐oasis zones for their archaeological and geochronological potential. Although our research has literally only scratched the surface, it demonstrates the potential of radar imaging for defining ancient drainage patterns in arid regions and their associated

ISSN:0883-6353    

DOI:10.1002/gea.3340030102

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractMicromammalian remains from archaeological sites in southern Africa provide paleoenvironmental evidence at a number of levels of precision. At the lowest level, broad vegetation categories can be identified. At the second level, proportional representation of vegetation categories and general climatic conditions are indicated. the possible overlying effects of agriculture and sea‐level changes can also be identified. At the third level, there is clear but as yet largely unrealized potential for quantifying climatic variation and specifying environmental factors. In order to improve potential for interpretation, greater rigor is necessary in sample collection and in the establishment of the widest possible comparative data base, with the latter being in particular need of attention. Detailed paleoenvironmental information can also provide an independent data base for assessment of ecological approaches to archaeolog

ISSN:0883-6353    

DOI:10.1002/gea.3340030103

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractArchaeological evidence from the marine terrace and fen at the site indicates brief episodic occupation for over 5000 years. Five cultural episodes have been identified, although the site is renowned for its Norse settlement.A fen on the site has provided both artifacts and fossil pollen. Although the pollen spectra are dominated by disturbance taxa, they indicate little or no human impact. Both the archaeological data and the pollen spectra are consistent with brief episodes of occupancy. Relationships between regional environmental changes and the human response are indistinct, although a cool interval after 2500 B.P. coincides with a 1000 year hiatus in occupation.For the Norse period, the pollen record is compatible with the view that L'Anse aux Meadows was a small, short‐lived way statio

ISSN:0883-6353    

DOI:10.1002/gea.3340030104

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe lower Mississippi River has aggraded throughout the Holocene, resulting in stratification of cultural materials. Determination of this landscape evolution adds a temporal dimension to a model of human settlement. Sites most likely to be settled are high, well‐drained surfaces near a stream. In the middle Holocene, conditions began to be suitable for settlement near Big Lake, Arkansas. A stream developed on the flood plain adjacent to a braided stream terrace. Flooding of the terrace formed a natural levee composed of well‐drained, fertile, loam that was better suited for agriculture, if it existed at this time, and a living substrate than terrace sand to the west and backswamp clay to the east. Water and aquatic food sources were nearby. Open swamp conditions, present during middle Holocene, diminished by Late Holocene as bottomland arboreal habitats were becoming reestablished. This ideal environment has been intensely exploited for the past 3000 years, despite the temporary inconvenience of flood

ISSN:0883-6353    

DOI:10.1002/gea.3340030105

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340030106

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340030108

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340030109

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340030110

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340030111

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340030112

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY