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71.
Patrick G. Quilty Nicola Clark Ty Hibberd 《Alcheringa: An Australasian Journal of Paleontology》2013,37(2):200-206
Quilty, P.G., Clark, N. & Hibberd, T., 21.01.2015. Crenostrea sp. cf. C. cannoni (Marwick, 1928) (Bivalvia: Ostreacea) and associated fauna from east of Heard Island, Kerguelen Plateau: age and palaeoenvironmental value. Alcheringa 39, xxx–xxx. ISSN 0311-5518A well-preserved single left valve of a large oyster embedded in coarse volcaniclastic sediment and identified as Crenostrea sp. cf. C. cannoni (Marwick, 1928) was dredged from east of Heard Island, central southern Indian Ocean. It is accompanied by a fragment of the pectinid bivalve Austrochlamys sp. indet. and foraminifera. Austrochlamys sp. indet. and other bivalve fragments were analysed for 87Sr/86Sr, δ18O and δ13C, the results yielding an age of 17.5 Ma (later early Miocene) and a water temperature of ca 10°C. Foraminifera and sediment characteristics indicate that accumulation occurred in mid-continental shelf depths, at a location where nutrient supply was good.Patrick G. Quilty [p. quilty@utas. edu. au], School of Earth Sciences (Private Bag 79) and Institute for Marine and Antarctic Studies (IMAS: Private Bag 129), University of Tasmania, Hobart, Tasmania 7001, Australia. Nicola Clark [nc118@leicester. ac. uk], Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK. Ty Hibberd [ty. hibberd@aad. gov. au], Australian Antarctic Division, Channel Highway, Kingston, Tasmania 7050, Australia. 相似文献
72.
分析了三种测量方法──多次激活、加剂量法和钉子技术的优缺点,并对细粒石英前剂量方法进行了专门研究。结果表明,细粒五英前剂量方法测量简便,减少了来自多次激活、试验剂量和归一引起的误差,最小可测年龄能达到几十年。 相似文献
73.
M. Mashkour H. Monchot E. Trinkaus J.‐L. Reyss F. Biglari S. Bailon S. Heydari K. Abdi 《International Journal of Osteoarchaeology》2009,19(6):678-694
Wezmeh Cave is located on the northeastern edge of the Islamabad plain, a high intermontane valley in the western‐central Zagros. In 1999 a disturbed but large faunal assemblage was recovered from this site. The abundant and extremely diverse faunal spectra present at Wezmeh Cave has highlighted the importance of this assemblage. Carnivore remains constitute the bulk of the assemblage; red fox (Vulpes vulpes) has the highest number of identified specimens followed by spotted hyena (Crocuta crocuta), brown bear (Ursus arctos), wolf (Canis lupus), felids (lion, leopard, lynx/caracal and wildcat), mustelids (badger, polecat, marten) and viverrids (mongoose). Artiodactyls (bovid, cervid, suid), equids, rhinoceros (Dicerorhinus sp.) and small animals (Cape hare, porcupine, tortoise, snake, birds) are also present. According to U‐series dating, the site was occupied from around 70 ka BP through to sub‐recent periods by carnivores. Amongst this rich assemblage, a human fossil tooth was also found and dated by non‐invasive spectrometry gamma dating to 20–25 ka BP. A preliminary zooarchaeological and taphonomic study shows that Wezmeh Cave was used by multiple carnivore species, a unique phenomenon in the Zagros Mountains in particular and southwest Asia in general. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
74.
Uranium-series (U-series) dating of speleothems is frequently used for palaeoclimate studies but its archaeological and palaeontological applications are limited to stratigraphically significant speleothem formations, such as flowstones, to provide maximum and minimum temporal points. This study targeted soda straw stalactites for U-series dating. In contrast to other speleothem formations, soda straw stalactites are fragile, have typically short life spans (usually only years but rarely up to a few hundred years) and are frequently incorporated into cave deposits. Results of thermal ionisation mass spectrometry (TIMS) U-series dating of soda straw stalactites from palaeontological excavations at Blanche Cave, South Australia, show that small, dense, clean straws tend to yield ages closest to the time of stratigraphic deposition. A correlation between soda straw U-series ages and radiocarbon ages of charcoal from the site is shown. Multiple soda straw age determinations for a single stratigraphic unit are required in order to verify age concordance. In conjunction with other dating methods, U-series dating of soda straw stalactites may help to significantly constrain the age of stratigraphic units and associated archaeological and palaeontological deposits in order to provide more robust chronologies. Here we advocate the collection of soda straw stalactites at future excavations of limestone cave sites. 相似文献
75.
Hendrik J. Bruins J. Alexander MacGillivray Costas E. Synolakis Chaim Benjamini Jörg Keller Hanan J. Kisch Andreas Klügel Johannes van der Plicht 《Journal of archaeological science》2008
The explosive eruption at Santorini in the Aegean Sea during the second millennium BCE was the largest Holocene volcanic upheaval in the Eastern Mediterranean region. The eruption was disastrous for the Minoan settlements at Santorini, but the effect on human society in the neighbouring islands and regions is still clouded in uncertainty. Tsunami generation was suggested, but comparatively little evidence was found. The lack of firm tsunami traces is particularly puzzling in Crete with its coastal settlements of the Late Minoan IA period, during which the Santorini eruption occurred. Here, we report the discovery of extensive geoarchaeological tsunami deposits at Palaikastro in north-eastern Crete. These deposits are characterized by a mixture of geological materials, including volcanic Santorini ash, and archaeological settlement debris. Various tsunami signatures were identified: (1) erosional contact with the underlying strata, (2) volcanic ash intraclasts in the lower part of the deposit, (3) reworked building stone material in the lower part of the deposit, (4) individual marine shells, (5) marine micro-fauna, (6) imbrication of rounded beach pebbles, settlement debris, ceramic sherds and even bones, (7) multi-modal chaotic composition. Late Minoan human settlement activities at Palaikastro provided architectural and stratigraphic frameworks in space and time that recorded and preserved tsunami evidence as geoarchaeological deposits. Such stratigraphic resolution and preservation may not occur in the natural landscape. Volcanic ash transported by wind from Santorini south-east to Crete preceded the tsunami. Geological, archaeological and radiocarbon dating criteria all converge, indicating that the tsunami deposits are coeval with the Minoan Santorini eruption. Field evidence suggests that tsunami waves at Palaikastro were at least 9 m high. Inverse tsunami modeling was attempted, based on these newly discovered tsunamigenic deposits. The initial wave in the generation region at Santorini that best fits the stratigraphic data is a wave with +35 to −15 m initial amplitude and a crest length of about 15 km. 相似文献
76.
Infrared spectroscopy provides information not only on the type of calcium carbonate polymorph, but also on the extent of atomic order. In calcite, three major infrared absorption peaks are identified: ν3, ν2, and ν4. It was shown that the ratio between ν2 and ν4 bands reflects the order of the calcite crystal structure. In this paper we analyse this ratio in geologically formed calcites, archaeological plasters, modern plasters and experimentally prepared plasters. For the geological calcite, the values of the ν2/ν4 ratio are around 3, whereas for the experimentally prepared plasters, the values are around 6.5. The ν2/ν4 ratio for archaeological plasters varies from 3 to 6. This shows that a high ratio is indicative of disorder in the crystal, and implies that the calcite was formed from calcium oxide at high temperatures. It also implies that this disorder can be preserved for at least 14,000 years. The ν2/ν4 ratio of calcite from archaeological sites can thus be used to differentiate between anthropogenic calcite, such as in plaster, mortar and wood ash, from geogenic calcite, such as in limestone. The ratio may also be used to identify plaster or ash that still retains its original crystals and therefore carbon-14 content. 相似文献
77.
Jesper Olsen Jan Heinemeier Pia Bennike Cille Krause Karen Margrethe Hornstrup Henrik Thrane 《Journal of archaeological science》2008
The success of radiocarbon dating of burned or cremated bones depends on the exposed temperature during burning and the degree of re-crystallisation of the inorganic bone matrix. We present a method for characterisation of likely cremated bones by employing visual inspection, infrared spectrometry and carbon stable isotope analysis on the bio-apatite fraction. The method of radiocarbon dating of cremated bones was tested by dating paired samples of bone and associated context materials such as pitch, charcoal and a dendrochronologically dated oak coffin. The dating of these paired test samples were largely performed as blind tests and showed excellent agreement between pitch and bone. The weighted mean age difference of all test samples is observed to −9 ± 60 14C yr. To test the indicators and the effects of the degree of burning, a Late-Neolithic human individual has been studied, as this individual exhibits the full spectrum from low temperature burning (charred) to high temperature (“cremated”) from one end of a single bone to the other. This is reflected as a marked step in numerous parameters as well as in a significant difference in 14C age between the charred and the cremated bone samples. 相似文献
78.
79.
The application of radiocarbon dating to archaeological samples generally requires calibration of 14C dates to calendar ages and interpretation of dating errors. In this paper, four recent methods of age calibration are assessed, particularly with regard to their quality of error treatment. Recent experimental research has suggested that commonly quoted errors on “raw” 14C dates may require enlargement to more realistic levels, which, when incorporated in the calibration schemes, produce a considerable increase in the size of the typical calibrated interval. A general decrease in the sensitivity of 14C dating using single, “normal precision” dates is implied. Thus typical calibrated age intervals range from 300 to 1300 years (approximate 95% confidence level), with little improvement resulting if “high precision” calibration systems are used to correct “normal precision” dates. Of the four methods considered here, that proposed by Neftel is found to provide the most objective, flexible, comprehensive and “easy to use” scheme. This method is particularly recommended for its treatment of errors both on the dates to be calibrated and on the calibration curve itself. 相似文献
80.
Bonnie Blackwell Henry P. Schwarcz Andr Debnath 《Journal of archaeological science》1983,10(6):493-513
Two adjacent chambers of the cave of La Chaise, Grotte de Bourgeois-Delaunay (B-D) and Grotte Suard, have been studied. Both were partly filled with detrital sediments containing lower and middle Palaeolithic artifacts and skeletal remains of pre-Neanderthalian hominids. Layers of stalagmitic calcite occur interstratified in the sediments of both chambers. Dates obtained by 230Th/234U ratios have provided a time scale for hominid and cultural evolution as represented in this cave.In B-D the lower travertine rests on a breccia containing cranial remains of juvenile Neanderthals. The base of the travertine dates to 151 ± 15 Ky (Ky = 1000 years BP); the top of the travertine yields a date of 112±5 Ky. The travertine contains pollen of an interglacial flora. Overlying detrital sediments 1·2 m in thickness contain artifacts transitional from Acheulian to Mousterian industries. They are capped by a travertine (Layer 7) whose base is dated at 100±6 Ky, and which is capped by stalagmites ranging in age down to 58±7 Ky. Overlying the travertine is sediment containing first Mousterian, and then Aurignacian artifacts.Near the base of the sediments filling Grotte Suard is a stalagmite layer dated to 249±30 Ky. It contains interglacial pollen and presumably dates to the beginning of the isotope stage 7 interglacial. Neanderthaloid hominid teeth and cranial fragments are found scattered through the overlying sediments, up to a capping stalagmitic layer whose base is dated at 101±7 Ky. The best described hominids from Suard are from a section that was probably overlying the capping stalagmite. The capping stalagmite is temporally correlated with layer 7 of B-D. 相似文献