首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13篇
  免费   0篇
  2014年   2篇
  2013年   5篇
  2010年   1篇
  1997年   1篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1982年   1篇
排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
A rich stone tool assemblage is described of the Sangoan-type from a potentially semi-primary site, in association with a well-preserved fauna, and in paleo-environmental context. The site appears to be late Middle Pleistocene and contains a high proportion of small to medium-sized mammals (e.g. rodents, monkeys) deposited in low energy conditions. The environment is suggestive of a fringing woodland or riverine forest contained in a subarid climate.  相似文献   
2.
Ferrari, M., El-Hedeny, M., Zakhera, M., El-Sabbagh, A. & Al Farraj, S., May 2018. Middle?Upper Jurassic marine gastropods from central Saudi Arabia. Alcheringa.

A total of 68 gastropod specimens are reported from the Middle?Upper Jurassic sedimentary successions exposed at central Saudi Arabia. The studied material comes from the Tuwaiq Mountain and Hanifa formations at the Khashm al Qaddiyah, Dirab, Jabal al Abakkayn and Maáshabah sections. Thirteen species are identified, described and illustrated. Among them, a new Aporrhais species (A. sauditica sp. nov.) is introduced. In addition, two further possible new Pseudomelania species from the same strata are mentioned. Other members of the assemblage include Kosmomphalus? sp. aff. K. reticulatus Fischer, Bourguetia? sp. aff. B. saemanni (Oppel), Bourguetia? sp., Ampullospira sp., Globularia? sp. cf. G. bajociana Fischer, Purpuroidea sp. aff. P. glabra Morris and Lycett, Purpuroidea sp., Cossmannea sp. aff. C. desvoidyi (d’Orbigny), Cryptoplocus sp. aff. C. depressus (Voltz) and Actaeonina? sp. Stratigraphically, seven species of this gastropod assemblage were only reported from the Middle Jurassic, whereas the other six ones are extending from the Middle to the Upper Jurassic of the studied succession. As compared with their gastropod content, the Khashm al Qaddiyah represents the richest section (33 out of 68 specimens, 48.5%), whereas the Maáshabah section showed an impoverished gastropod assemblage (only three specimens, 4.4%). The species reported here show paleobiogeographical affinities with coeval gastropod assemblages from India, east Africa, Middle East (Israel, the Sinai of Egypt) and western Tethys. The identified species confirm three depositional settings: open shelf lagoon, shoal/fore-shoal and open marine environments. The lower degree of fragmentation, poor sorting and scarcity of abrasion indicate a parautochthonous faunal assemblage.

Mariel Ferrari [] Instituto Patagónico de Geología y Paleontología (IPGP-CCT CONICET-CENPAT), Bvd. Brown 2915, U9120CD, Puerto Madryn?Chubut, Argentina; Magdy El-Hedeny* [] Department of Geology, Faculty of Science, Alexandria University, Alexandria 21568, Egypt; Mohamed Zakhera? [] Department of Geology, Faculty of Science, Aswan University, Aswan 81528, Egypt; Ahmed El-Sabbagh [] Department of Geology, Faculty of Science, Alexandria University, Alexandria 21568, Egypt; Saleh Al Farraj [] College of Science, King Saud University, Riyadh 12371, Saudi Arabia. *Also affiliated with Deanship of Scientific Research, King Saud University, Riyadh 11451, Saudi Arabia. ?Also affiliated with Vice Rectorate for Development and Quality, Najran University, Najran 11001, Saudi Arabia.  相似文献   
3.
Examination of climatic inferences based on palynological, geomorphic, sedimentological, and other proxy data reveals a coherent picture of a generally wet early Holocene and drier conditions, with a time-transgressive clinal change commencing ca, 4500 B.P. The large-scale climatic periods in Africa during the Late Quaternary were interrupted by abrupt oscillations and rapid transitions. The magnitude and direction of climatic changes show distinct regional variation. However, in the monsoon-domain areas, abrupt drought events occurred conspicuously at ca. 12,000–11,500, 8500, 7500, 4500, 4000–3700, and 2000 uncalibrated radiocarbon years B.P. Further investigations are required to gain a more precise chronology of these events, which appear to have been crucial for some of the most salient developments in Africa's prehistory.  相似文献   
4.
Bone chemistry paleodietary studies are emerging as important research areas in archaeology, biological anthropology, and paleontology. With appropriate controls, the inorganic and organic chemical composition of bones and teeth can provide information about past diet and habitat use. Chemical signatures are used to address individual dietary variability in early hominid fossils, paleontological remains, and more recent human and faunal populations.  相似文献   
5.
Phytolith analysis is now sufficiently mature to provide an independent source of data in tropical paleoethnobotany and paleoecology. At the same time, ongoing studies of phytoliths from tropical plants and sediments are discovering new applications. There are, to be sure, problems in interpreting prehistoric plant use and paleoecology which cannot be addressed through phytolith analysis; some of the more important ones are listed. Through a review of recent studies in the New World tropics, this paper presents some contributions to, problems of, and prospects for phytolith analysis to inform the archaeological community about such issues as (1) the origins and dispersals of domesticated plants, (2) the development of tropical forest agriculture, (3) the uses of tropical plants in prehistory, and (4) the distribution and composition of past plant communities.  相似文献   
6.
The Itasca Bison site near the prairie-forest border in central Minnesota is important to understanding the cultural and ecological role of bison in the upper Midwest during the middle Holocene. Recent reanalyses of this assemblage support the original interpretation of a taphonomically complex, fluvially modified site. Despite this taphonmic complexity, the role of humans in the butchering and possible accumulation of some of the bison fauna is also supported, although not as the only mechanism of accumulation. The bison assemblage is slightly biased toward males, and seasonality estimates are spread throughout the year. New direct accelerator mass spectrometry dates indicate a minimum of two highly mixed depositional events: one at 7970–7790 cal B.P. and an earlier event between 8520 and 8180 cal B.P.  相似文献   
7.
Numerous anthropogenic stressors have impacted the region surrounding Sudbury, Ontario, leading to pronounced vegetation and landscape change. Few long‐term records exist to understand the nature or timing of this change. We use pollen analysis from radiometrically dated sediments of Clearwater Lake to compare pre‐ and post‐settlement vegetation. Beginning ~1850 CE, the record shows major shifts in forest composition, coincident with settlement and the beginnings of lumbering. These changes are unprecedented for the past ~5000 years, and consist of increases in diversity and abundance of deciduous tree taxa and herbaceous disturbance indicators. While evidence of mining appears as early as 1900 CE, little effect is seen in the pollen record until ~1930 CE, when sedimentation rates increased and acidification of the lake also began. At this time, further increases in palynological disturbance indicators and minimum sediment organic matter levels indicate the period of maximum vegetation loss. As a result of reduced emissions since the 1970s, water quality began to improve in Clearwater Lake and there are some decreases in the abundances of shade‐intolerant disturbance indicators in the pollen record. However, the fact that the pollen assemblages do not resemble those prior to 1850 suggests lasting vegetation changes.  相似文献   
8.
This research reports the herpetological (reptile and amphibian) remains from Khonkho Wankane, an urban and ceremonial centre in the southern Lake Titicaca region of the Bolivian Altiplano, which fluoresced during the Late Formative period. The total n = 1710, including a minimum of six taxa and representing a significant portion of the relatively depauperate modern herpetofauna recorded for the Lake Titicaca area. A lizard of the genus Liolaemus (Tropiduridae) was identified. Amphibians are represented by Andean toad Rhinella spinulosa (Bufonidae) and by at least four taxa of frogs: [cf. Gastrotheca marsupiata (Hylidae) and Pleurodema marmorata or P. cinerea and Telmatobius spp. (Leptodactylidae)]. The latter genus does not include members of the giant variants (T. culeus) that dwell in Lake Titicaca. The question of how these remains were incorporated into the site deposits is examined taphonomically. No indicators of human or small carnivore predation were detected. Significant spatial clustering of amphibian remains was detected, with two clusters contributing n = 1562 or 92.4% of the amphibian total (n = 1690). These concentrations also are characterised by a depressed ratio of cranial versus postcranial elements, which cannot be explained by recovery methods. These concentrations of herpetofaunal remains likely represent in‐burrow deaths of species sheltering for thermoregulatory benefits away from this harsh Altiplano environment, with the lowered recovery of cranial elements hypothesised to have resulted from a lack of ossification. The bulk of herpetofaunal remains recovered therefore likely were recent intrusions into the site deposits and do not represent the residue of human exploitation during the occupation of Khonkho Wankane. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
9.
Based on the stratigraphy of Paleolithic sites on the northern Angara, the Upper Pleistocene and Holocene history of the region is reconstructed. Findings of recent salvage excavations in the Boguchany flooding zone as well as the evidence of Quaternary geology, geomorphology, neotectonics, and archaeology jointly disprove the “young Angara” model proposed by G.I. Medvedev and other “geoarchaeologists.” The principal event postulated by that model – the alleged disastrous outburst of the Angara along the Baikal channel 12–7 ka BP is supported neither by the relief nor by the Upper Pleistocene and Holocene sedimentation record nor by the stratigraphy of the Paleolithic sites on the northern Angara.  相似文献   
10.
Paleoenvironmental science has experienced a recent surge in interest and activity as concerns grow over global environmental change. Key research questions in the biotic realm of paleoenvironmental science focus on explaining climatic change at time scales of decades to centuries and understanding ecosystem responses to these changes. Biotic responses are increasingly being studied at smaller spatial scales to identify local factors that determine the sensitivity of a particular system to climatic change. These findings can then be applied to solving a variety of problems, such as setting conservation targets or testing mechanisms for observed climatic and biogeographic phenomena. Research approaches commonly used today include hypothesis testing, which has now become more sophisticated as paleoecologists and paleoclimatologists integrate with modellers. Other frameworks involve the quantitative integration of multiple proxy indicators and the use of extensive publicly available data networks to produce new datasets for paleoclimatic reconstructions and other applications.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号