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51.
A set of 104 independently dated archaeomagnetic directions was used to extend the U.S. Southwest reference curve back to 375 cal BC and to calculate isolated mean VGPs centered on 960 cal BC and 2390 cal BC. Prior to this study, most U.S. Southwest reference curves extended to only ca. AD 585. This study employed Sternberg’s moving window technique with variably sized windows, rather than fixed windows, to smooth the dataset into a continuous curve. The size of each averaging window was determined by the density of data captured by the window, such that each window had a minimum data density of 5.0 and a minimum window size of 50 years. This approach differs from previous studies in the U.S. Southwest, which have applied a uniformly sized averaging window to a dataset regardless of the temporal distribution of the data.  相似文献   
52.
A new sedimentary morphogenic analysis was carried out at the Divje babe I Paleolithic site to determine paleotemperatures for Late Pleistocene deposits (around 80,000–40,000 BP) and to discover hiatuses in the sedimentary sequence. The Divje babe I paleotemperature record is based on the relative abundance of congelifracts in a 280 cm thick sedimentary sequence. Congelifracts are clasts whose morphogenesis is directly associated with post-depositional frost wedging. The Divje babe I paleotemperature record compares well with global GRIP (Summit) and other regional paleotemperature records for the Late Pleistocene. Comparisons are supported by ESR dates from the Divje babe I site. Two significantly cool climate phases were identified in the Divje babe I record. The older cool phase was placed between 67,000 BP and 62,000 BP and the second, younger cool phase was placed between 61,000 BP and 58,000 BP (both Middle Würmian) according to correlations with the GRIP record. The main disadvantage with the Divje babe I paleotemperature record is missing data. The sequence of cave sediments is not complete in Divje babe I due to breaks in sedimentation. Two reliable and two assumed hiatuses were identified in the studied sedimentary sequence.  相似文献   
53.
2003年2月,云南省文物考古研究所为配合三峡工程建设,对位于重庆万州区武陵镇的中嘴遗址进行了考古发掘。本次发掘的遗存以隋唐时期为主,出土了陶器、瓷器以及其他遗物,从中透射出渔业活动是当时当地居民生产生活的一个重要方面,同时也可看到当地文化与周边文化的交流。  相似文献   
54.
The Aterian has a huge geographic extension covering all North Africa, although it was not supposed to exist in the mountain ranges of the central Sahara. Its chronological context is not yet definitively determined and it is still difficult to say whether the Aterian tools are technological, typological, functional, or chronological markers. Recent surveys and excavations at Uan Tabu and Uan Afuda, two rock-shelters located in the central Tadrart Acacus, provide the first chronological, environmental and archaeological indications on this Late Pleistocene human occupation in the area. The lack of organic matter led us to perform OSL and TL analyses on sand. L'Atérien a une énorme extension géographique qui couvre tout le Nord de l'Afrique, tandis qu'on ne pensait pas qu'il existait dans les montagnes du Sahara central. Son contexte culturel n'est pas définitivement déterminé et il est encore difficile de dire si les instruments atériens sont des indicateurs téchnologiques, typologiques, fonctionels ou culturels. Reconnaissances et fouilles récentes à Uan Tabu et Uan Afuda, deux abris situés dans l'Acacous central, fournissent les premières indications sur la chronologie, l'environnement et l'archéologie de l'Atérien dans la région. L'absence de la substance organique, nous a porté à faire des déterminations OSL et TL sur les sables.  相似文献   
55.
Two significant events in the late Holocene history of Madagascar were (a) the arrival of people, and (b) the loss of nearly two dozen species of land vertebrates in the socalled “subfossil extinctions”. The consensus is that the faunal losses occurred shortly subsequent to human arrival, but the timing of these events is poorly constrained. The minimum age for initial human presence on the island may now be set at approximately 2000 bp, on the basis of AMS 14C dates for human-modified femora of extinct dwarf hippos from SW Madagascar. Assuming that this date also marks the beginning of deleterious human interactions with the subfossil fauna, and assuming that this fauna became completely extinct by 900 bp, the width of the anthropogenic “extinction window” may have been as long as c. 1000 a. This estimate, nearly twice the length of previous ones, is close to the unadjusted minimum for the duration of the terminal Pleistocene extinction event in the Americas. Whether or not this length of time comports with theoretical expectations of a “blitzkrieg” pattern of losses is uncertain, but greater refinement in dating the end of the subfossil extinctions is unlikely to produce radically shorter estimates of duration.  相似文献   
56.
夏商周断代工程采用系列样品进行14C年代测定,得出了夏商西周的年代框架,与考古遗址相对应,解决了三代考古学的分期.登封王城岗古城约为公元前2070年,即夏的起始年代.偃师商城始建于公元前1600年,郑州商城始建于公元前1580年,前者早于后者,偃师商城遂成为夏商分界的界标.就作为都城而言,郑州商城开始作为王都的时间比起偃师商城开始作为王都的时间要晚得更多.  相似文献   
57.
Anthropomorphic wooden figures found in peat-bogs east of the Urals are described. Their archaeological context, chronology, and stylistics are analyzed. The Uralian specimens are compared with those from Western and Eastern Europe. The possible meaning of these representations is reconstructed on the basis of Ob Ugrian rituals and mythology.  相似文献   
58.
Dendrochronology has proved useful in suggesting the provenance of timbers in northern Europe, particularly for ship‐timbers, which may have originated from a distant source. Historical chronologies are usually derived from timbers of uncertain origin. In trying to provenance a new chronology, therefore, trends in the geographical distribution of statistical matches should be viewed, rather than individual strong matches. While it is usual to test a site‐chronology created from several individual timbers, in a situation such as the Mary Rose, where individual timbers may have been sourced from several regions, the matches of individual timbers may shed light on their origins. © 2010 The Author  相似文献   
59.
The Longwangchan Paleolithic site, situated on the Yellow River terraces in the Hukou area, Shaanxi province, China, was found in 2003–2004, and two areas (Localities 1 and 2) of the site were excavated in 2005–2008. Abundant stone artifacts including microliths, a grinding stone fragment and a shovel, with some animal bones and shells, were recovered from Locality 1. In this study, the cultural deposits from Locality 1 were dated using radiocarbon and optical dating techniques, and the sediment properties of the deposits were analyzed. The results show that the age of the deposits ranges from 29 to 21 ka and most of them were deposited between 25 ka and 29 ka. This indicates that corresponds to late Marine Isotope Stage (MIS) 3 and early MIS 2. During the human occupation period, the climate in this area became colder and drier. Sediments from beds where the grinding slab and the shovel were found were dated to ∼25 ka, which is the oldest among the grinding stones found in China. The microliths and the grinding stone are important evidence for an incipient socio-economic process that eventually led to the regional transition from hunting-foraging to farming.  相似文献   
60.
微腐蚀测年通过观测矿物晶体上的"石亏"来获知岩画的制作年代,是一种无损的"直接断代法"。仙居岩画的测年工作主要在送龙山和小方岩两处地点开展,经过观测,研究人员从岩画刻槽中取得了十一组石亏微腐蚀数据,以及两组来自吴芾墓附属石刻的校准数据。由校准后的年代计算结果可知,小方岩岩画的制作开始于东吴末年,贯穿了两晋及南北朝时期,一直延续至唐初,而送龙山岩画则为唐代作品。  相似文献   
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