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991.
The burial and pore fluid pressure history of fluorite ore deposits is reconstructed: (i) at Hammam Zriba–Djebel Guebli along the eastern margin of the Tunisian Atlas; and (ii) at Koh‐i‐Maran within the northern part of the Kirthar Range in Pakistan. Both the deposits are hosted by Late Jurassic carbonate reservoirs, unconformably overlain by Late Cretaceous seals. Microthermometric analyses on aqueous and petroleum fluid inclusions with pressure–volume–temperature–composition (PVTX) modeling of hydrocarbon fluid isochores are integrated with kinematics and thermal 2D basin modeling in order to determine the age of mineralization. The results suggest a Cenozoic age for the fluorite mineralization and a dual fluid migration model for both ore deposits. The PVTX modeling indicates that the initial stage of fluorite cementation at Hammam Zriba occurred under fluid pressures of 115 ± 5 bars and at a temperature close to 130°C. At Koh‐i‐Maran, the F3 geodic fluorite mineralization developed under hydrostatic pressures of 200 ± 10 bars, and at temperatures of 125–130°C. The late increase in temperature recorded in the F3 fluorites can be accounted for by rapid rise of hotter fluids (up to 190°C) along open fractures, resulting from hydraulic fracturing of overpressured sedimentary layers. 相似文献
992.
C. TRIBOLO N. MERCIER M. SELO H. VALLADAS J.‐L. JORON J.‐L. REYSS C. HENSHILWOOD J. SEALY R. YATES 《Archaeometry》2006,48(2):341-357
This paper presents the first TL dates for burnt quartzites and silcretes from the Still Bay layers of Blombos Cave (South Africa). These layers contained engraved ochres and marine shell beads that could be an early manifestation of symbolic and thus ‘modern’ behaviour by the Middle Stone Age humans. The procedure devised to calculate the ages is presented in detail, particularly with regard to internal microdosimetry, because the problems faced in estimating the dose rates require an approach different from the one usually used on flints and sediments. A mean age of 74 ± 5 ka was obtained for five burnt lithics unearthed in the BBC M1 member of the Still Bay layers. This result is in good agreement with both ESR dates on teeth and OSL dates on sediment, and demonstrates the great antiquity of the archaeological remains discovered at Blombos Cave. 相似文献
993.
N. Edward Coulson 《Journal of regional science》2006,46(1):147-168
Abstract. Panel regressions indicate that state electricity deregulation in the US is associated with higher housing prices, increased activity in the housing market, and lower wages, all of which are consistent with a model of compensating differentials wherein deregulation (which is shown to indeed lower electricity prices) increased the utility of state residents. On the other hand, there is no link between deregulation and job creation. 相似文献
994.
A. N. Beasley 《Oceania; a journal devoted to the study of the native peoples of Australia, New Guinea, and the Islands of the Pacific》2006,76(2):186-202
This paper explores the oral narratives of five South Fore men who assisted with the scientific investigation of kuru. Drawing on the framework of the dramaturgic form of epidemics, the narratives start with childhood memories of the social crisis at the height of the kuru epidemic. With the arrival of the European scientists they build to a climax of optimism over the prospect of a cure for kuru and enhanced personal futures before descending into disillusionment over the scientists' departure and a return to traditional village life. 相似文献
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This paper details the differential diagnosis of an unusual tooth morphology observed in two adult males from the identified osteological collections held at the Museum of Anthropology of the University of Coimbra, Portugal. The differential diagnosis is based on the morphological and radiographic analysis of the teeth of these individuals, and gives rise to several possible pathological conditions, namely: regurgitation erosion, mottled enamel due to fluorosis, dentinogenesis imperfecta, amelogenesis imperfecta, and osteogenesis imperfecta. Of these, amelogenesis imperfecta remains the most probable cause for one individual, and although dentinogenesis imperfecta was considered for the other based on the morphological features, the final diagnosis was changed to the former based on accurate radiological evidence. Since there are only a few reported cases of these conditions in the osteoarchaeological literature, we find it to be interesting and important to report these two cases. The scarcity of reports in the palaeopathological literature, compared with the prevalence of these tooth structure anomalies in living populations, lead us to consider amelogenesis imperfecta and dentinogenesis imperfecta to be probably misdiagnosed, and hence under‐reported. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献