摘要:

AbstractEnvironmental archaeology studies on samples from an agricultural context provide information that may be used to answer questions of climatic vs. human impact on Hohokam prehistory. Hohokam irrigation systems were fragile and subject to episodic damage and destruction. Ostracodes are sensitive to hydrochemical changes. Their fossil record in Hohokam canals can provide useful data to understand human/environment relationships in the past. Low‐Mg calcite ostracode carapaces form in thermal and chemical equilibrium with the host water. Magnesium and strontium are commonly incorporated into the shell as trace elements, which can be used to track paleotemperature and paleosalinity variations. Thus, fossil ostracodes reflect the water chemistry in which the valves were precipitated. Valves ofLimnocythere staplini, Candona patzcuaro, andCypridopsis viduawere analyzed using inductively coupled plasma mass spectrometry (ICP‐MS) to determine the Mg/Ca and Sr/Ca ratios. Trace element data were used to reconstruct the canal water chemistry and to propose paleoclimatic and human‐impact hypotheses for environmental change. The ostracode record shows some evidence of a progressive salinization process between A. D. 1025 and 1425 that may be the result of human disturbance; this inference is supported by independent evidence from geographic, palynologic, and dendroclimatologic data. In addition, two major climatic events, large enough not to be masked by human activity, were also recorded by ostracode geochemistry: a flood between A. D. 855 and 910, another flood prior to A. D. 1350, and a drought between A. D. 1365 and 1425. © 1994 John Wiley&Son

ISSN:0883-6353    

DOI:10.1002/gea.3340090102

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractRemnant lake and stream terraces of the Wadi el Hasa (west‐central Jordan) are associated within situprehistoric sites spanning>100,000 years. Eighteen radiocarbon dates from cultural and geological deposits on the terraces facilitate the first comprehensive prehistoric landscape chronology for the southern Levant east of the Jordan Rift. In the eastern Hasa basin, the uppermost of three cut and fill surfaces (>20 m) is linked to massive fossil spring deposits and an early Middle Paleolithic occupation (100,000–70,000 B. P.), suggestive of considerably wetter climates. A later Middle Paleolithic occupation may be synchronous with the emergence of Pleistocene Lake Hasa (ca. 70,000 B. P.). Peak lake levels were attained 40,000 years ago. Dates proliferate after 25,000 B. P. and register recession of Lake Hasa (ca. 20,000 B. P.), an intervening erosional phase, and the initiation of complex humid‐desiccation cycles for the terminal Pleistocene—Holocene (17,000–9,000 B. P.). The contemporary Wadi el Hasa channel began aggrading its floodplain after 8000 B. P. and was incised to its present depths 1000–500 years ago. The prehistoric landscape history of the Hasa drainage is broadly synchronous with sequences in the Rift Valley and Negev desert and offers baseline chronologies for the Late Quaternary of eastern Jordan and the Arabian peninsula. © 1994 John Wil

ISSN:0883-6353    

DOI:10.1002/gea.3340090103

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractSuccint results of recent geomorphological research conducted by a Canadian team from Université Laval (Quebec city) in the Khabur valley of northeastern Syria confirms the hypothesis put forward by one of the authors concerning the function of the tell 'Atij site during the Early Bronze Age period (3000–2500 B. C.). The detailed study of a stratigraphically controlled cross section of 25 m × 6 m, on the abrupt western side of the main tell of the site, combined with observations made in a trench linking the principal tell to the secondary one showed that these two tells, now forming 'Atij, were small islands on the ancient Khabur River. At the time of their occupation, i. e., the first half of the 3rd millenium, the Khabur was wider, deeper and navigable. Another investigation trench, 400 m N. E. of the main tell, disproved the suggested existence of an ancient irrigation canal in the area. © 1994 John Wiley&Sons,

ISSN:0883-6353    

DOI:10.1002/gea.3340090104

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340090105

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340090107

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340090108

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340090109

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY

ISSN:0883-6353    

DOI:10.1002/gea.3340090101

出版商:John Wiley&Sons, Inc.    

年代:1994

数据来源: WILEY