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1.
河北沧州小山火山的ESR年代学研究 总被引：3，自引：1，他引：2
河北沧州小山火山是河北平原,包括华北平原少有的出露地表的第四纪火山,也可能是华北平原区最后一个活动的火山。因此,此火山极其重要,可是至今没有确切的年代学数据。本次研究分别从小山火山地表和钻孔中采集了7个样品,进行了电子自旋共振测年。每个样品都分选出了石英颗粒,这表明火山堆积物不是纯的凝灰岩,而是火山活动时,同时带有地表物质的混入。样品ESR测年结果在误差范围内一致,平均值为41.4±8.6ka。小山火山活动可能发生于41ka BP.,测年结果表明小山火山最后一次活动在晚更新世晚期。 相似文献
2.
SANDA BALESCU MICHEL LAMOTHE JEAN-PIERRE LAUTRIDOU 《Boreas: An International Journal of Quaternary Research》1997,26(1):61-72
The infrared stimulated luminescence (IRSL) dating method is applied to alkali feldspar coarse grains from the two distinct Middle Pleistocene interglacial estuarine deposits of Tourville, located along the Seine Valley. The upper deposit (unit D), previously dated at 200 ka by ESR on in situ shells and correlated with a stage 7 high sea-level stand (186–245 ka), yields a measured IRSL age of 176 ± 21 ka. The lower deposit (unit B) assigned to a distinctly older high sea-level event (stage 9: 303–339 ka) yields a measured IRSL age of 273 ± 28 ka. The nearby stage 7 raised beach of Sangatte, in Northwestern France, previously dated by TL on quartz (229 ± 18 ka) yields a measured IRSL age of 186 ± 19 ka. These IRSL age estimates systematically underestimate the expected geological ages. This could be due to the long-term fading or instability of the luminescence signal in alkali feldspars. The correction for long-term fading has been tested on these samples. At Tourville, it yields corrected IRSL ages of 196 ± 23ka and 314 ± 32ka, for the upper and lower units respectively and, at Sangatte, a corrected IRSL age of 206 ± 20 ka. These corrected IRSL age estimates are in better agreement with the expected geological ages. This study demonstrates the potential of the feldspar luminescence dating method to provide chronological information on Middle Pleistocene interglacial estuarine sediments within the North Sea-English Channel Basin. 相似文献
3.
《Quaternary Science Reviews》2003,22(10-13):1339-1343
The Wangsan fault is exposed at Kyeongju, Korea. The andesite is unconformably covered by Quaternary alternating conglomerate and sandstone deposits. The unconformity is cut by the thrust fault which displaces a hanging wall block of about 30 m. Exposed at the surface of this fault is a light gray and brown fault gouge, about 40–120 cm thick. In order to test the consistency of ESR ages from a single fault gouge zone, we collected six gouge samples systematically along and across the Wangsan fault. We found that six samples collected from the same gouge zone show consistent ESR date estimates (average 550 ka). Because fault rock is rare along faults in unconsolidated sediments due to low confining stress near the surface, we consider that this fault gouge has been moved up with the hanging wall block along the fault. The estimated average uplift rate of the hanging wall block is about 0.04 cm/year based on the age of the displaced Quaternary deposits (vertical separation; about 20 m) dated by OSL dating methods. The depth of the fault gouge at the time of reactivation, which was estimated from uplift rate and the ESR ages, is about 220 m. Therefore, we conclude that the results of ESR age estimates represent the time of reactivation of the fault gouge at a depth of 220 m in the past during fault movement, because later movements which occurred during uplift near the surface may not have zeroed ESR signals significantly for ESR dating of fault movements. 相似文献
4.
Morten B. Andersen Claudine H. Stirling Emma-Kate Potter Steve G. Blake Bridget F. Ayling 《Geochimica et cosmochimica acta》2010,74(12):3598-7020
Direct dating of fossil coral reefs using the U-series chronometer provides an important independent test of the Milankovitch orbital forcing theory of climate change. However, well-dated fossil corals pre-dating the last interglacial period (>130 thousand years ago; ka) are scarce due to, (1) a lack of sampling localities, (2) insufficient analytical precision in U-series dating methods, and (3) diagenesis which acts to violate the assumption of closed-system U-series isotopic decay in fossil corals. Here we present 50 new high-precision U-series age determinations for fossil corals from Henderson Island, an emergent coral atoll in the central South Pacific. U-series age determinations associated with the Marine Isotope Stage (MIS) 9 interglacial and MIS 7.5 interstadial periods are reported. The fossil corals show relatively little open-system U-series behaviour in comparison to other localities with fossil coral reefs formed prior to the last glacial cycle, however, open-system U-series behaviour is still evident in most of the dated corals. In particular, percent-level shifts in the [230Th/238U]act composition are observed, leading to conventional U-series ages that are significantly younger or older than the true sample age. This open-system U-series behaviour is not accounted for by any of the open-system U-series models, indicating that new models should be derived. The new U-series ages reported here support and extend earlier findings reported in Stirling et al. (2001), providing evidence of prolific coral reef development on Henderson Island at ∼320 ka, most likely correlated with MIS 9.3, and subsequent reef development at ∼307 ka during MIS 9.1, while relative sea-level was potentially ∼20 m lower than during MIS 9.3. The U-series ages for additional well-preserved fossil corals are suggestive of minor reef development on Henderson Island during MIS 7.5 (245-230 ka) at 240.3 ± 0.8 and 234.7 ± 1.3 ka. All U-series observations are consistent with the Milankovitch theory of climate change, in terms of the timing of onset and termination of the dated interglacial and interstadial periods. The best preserved samples also suggest that the oceanic 234U/238U during MIS 9 and MIS 7.5 was within five permil of the modern open ocean composition. 相似文献
5.
秦岭南麓汉江流域上游地区分布着厚达二、三十米的黄土堆积,与秦岭以北地区黄土相比差异明显。汉江流域黄土中的钙结核分布十分广泛,钙结核内壁附着纯净致密的碳酸盐晶体,而秦岭以北黄土钙结核中却少有碳酸盐晶体析出。铀系不平衡测年是一门发展成熟、测年精度高、测年范围相对较广的第四纪重要测年方法,本文尝试利用铀系测年法对汉江流域上游柳陂黄土剖面钙结核样品内的碳酸盐晶体进行了铀系测年分析。柳陂剖面厚约17 m,可辨认出多层古土壤与黄土地层。自柳陂剖面中下部获取的4件钙结核样品测年结果分别为距今115.57±0.66 ka、130.15±0.65 ka、303.97±14.47 ka和356.40±11.60 ka,随着地层深度增加,^230Th年代增长,且与磁化率揭示的土壤地层序列基本一致。所以初步推断柳陂黄土剖面的地层序列为S1、L2、S2-I、S2-II、L3和S3。研究表明,秦岭南麓钙结核的^230Th年龄可为黄土地层的独立定年提供重要参考。根据碳酸盐钙结核形成机制,认为钙结核中碳酸盐晶体的^230Th年代能够指示相应黄土地层的最小年龄。 相似文献
6.
中国泥河湾盆地以发育我国北方晚新生代湖相地层和数目众多的古人类文化遗址而闻名于世,是研究中国北方第四纪地质与环境、新旧石器和早期人类演化的一个关键地区。东坡遗址是泥河湾遗址之一,形成时代一直没有确定。根据古地磁和区域地质等分析,初步认为东坡遗址形成时代不早于距今780ka。本文利用石英Ti心ESR法对泥河湾东谷坨剖面B/M界限样品进行了测量,年龄为 750±88ka,这表明利用该方法对泥河湾层水相沉积物进行测年是可行的。我们利用同样方法和参数对东坡遗址进行ESR年代学研究,结果表明东坡遗址文化层的形成时代为距今 304±12ka到333±23ka,平均年龄为321±15ka。 相似文献
7.
Jonathan J. Liberda Jeroen W. Thompson W. Jack Rink Federico Bernaldo de Quirs Rohit Jayaraman Kailash Selvaretinam Kerry Chancellor‐Maddison Vito Volterra 《Geoarchaeology》2010,25(4):467-474
Nine faunal teeth from layer 20 of El Castillo cave in Cantabrian Spain were dated using electron spin resonance (ESR). Two teeth were rejected due to inconsistent subsample ages, while the remaining teeth yielded a mean age that is consistent with the stratigraphic expectations: 42.7±3.5. Uncertainty in the external γ dose rate results in a potential systematic uncertainty of±6.4ka that should affect all samples equally. The results provide independent confirmation of previously reported 14C ages for layer 20. © 2010 Wiley Periodicals, Inc. 相似文献
8.
采用国际上最先进的高精度热电离质谱测年技术,测定了南京汤山葫芦洞钙板和石笋的年龄。并根据洞穴碳酸盐相与洞穴文化堆积层的地层关系,确定南京直立人化石时代在距今50万年左右。 相似文献
9.
W. Jack Rink H.P. Schwarcz H.K. Lee J. Rees‐Jones R. Rabinovich E. Hovers 《Geoarchaeology》2001,16(6):701-717
Electron spin resonance (ESR) dating and thermal ionization mass spectrometric 230Th/234U dating was conducted on six teeth from the prehistoric site of Amud Cave. By combining the ESR and 230Th/234U analyses, we obtained burial ages for teeth in various layers of the site. Layer B1/6–7, from which the Amud I Neanderthal skeleton was recovered, is dated to 53 ± 8 ka. Layer B2/8, which yielded other important human remains including the Amud 7 skeleton, gives a mean burial age of 61 ± 9 ka. One tooth from the lowest layer (B4) yielded a date of 70 ± 11 ka, but another tooth from this layer gave an 113 ± 18 ka. Despite this discrepancy, these ages agree with previously published TL ages on heated flints for the corresponding layers. This agreement between ESR on tooth enamel and TL on burned flint is also seen at all other sites studied with both methods in Israel. © 2001 John Wiley & Sons, Inc. 相似文献
10.
Tatsuro Fukuchi 《Quaternary Science Reviews》1988,7(3-4)
No direct method for dating the fault movement has been hitherto established, except ESR dating whose applicability is disputed however. The most serious question in ESR dating is whether accumulated ESR signals are completely reset at the time of fault movement. When the defect centres are partially preserved at the time of previous faulting, the date obtained is uncertain. We have shown (Fukuchi et al., 1985, 1986), however, that we can judge correctly whether ESR signals were completely reset or not when the ESR signal counting is done for multiple ESR centres of different stabilities for resetting. From the data for completely reset centres, actual date of fault movement can be calculated.This multiple centre method was tested with samples whose ESR signal intensities are judged to be about zero at the time of fault movement. The result, which confirms the applicability for the fault movement dated back to 100 ka BP, is presented in this paper. 相似文献
11.
天津大直沽晚第四纪沉积物红外释光测年及环境变迁年代学 总被引：7，自引：0，他引：7
对天津大直沽ZH2钻孔晚第四纪沉积物岩芯12个样品的红外释光(IRSL)测年及沉积物记录的环境变化研究结果表明:1)细颗粒(4～11μm)多测片的红外释光(IRSL)技术对水悬浮沉积物的年龄测定有着巨大的潜力,渤海湾西岸全新世环境变化的IRSL年代可与14C年代相对比;2)大直沽ZH2孔所在地未见晚更新世海侵,并在距今约30 ka至约10 ka期间处于沉积间断状态,距今9.5 ka开始发生海侵,距今5.1 ka发生海退,距今4.4 ka海水已退出ZH2孔所在地,距今2 ka左右已有人类活动. 相似文献
12.
ANATOLY MOLODKOV VLADIMIR YEVZEROV 《Boreas: An International Journal of Quaternary Research》2004,33(2):123-131
The occurrence of sandy clay deposited in a warm marine environment just below the till of the last glaciation has created controversy about its age and stratigraphic position in the sedimentary basin of the Kola Peninsula. Data on marine microfauna, diatoms, malacofauna and pollen composition indicate that during the period when the sandy clay was deposited the climate was similar or even warmer than at present. According to 14 C dates, sedimentation of the sandy clay occurred around 40 ka BP. Based on these data, some researchers have attributed these marine deposits to the third Late Pleistocene Belomorian (sensu Lavrova 1960) interglacial transgression. At the same time there are geological indications suggesting re-deposition of these subtill sediments. To solve this problem we have reinvestigated the subtill interglacial marine deposits from the Varzuga section (∼66.4° N and 36.6° E). Four different marine shell species and enclosing sandy clay sediments taken from the subtill marine unit of the section were dated by the electron spin resonance (ESR) and optically-stimulated luminescence (OSL) methods at about 103 and 104 ka, respectively. The results indicate that the subtill marine deposits belong to the first Late Pleistocene Boreal transgression that, according to our previous studies of the marginal areas of the Eurasian North, has occurred in the time interval from approximately 145 to 70 ka BP. 相似文献
13.
14.
15.
应用同位素稀释法热电离质谱(TIMS)技术测定珊瑚礁的高精度铀系年龄。通过对BarbadosⅢ、Ⅳ阶地等样品分析,RendezvousHil和Curacao+6m的TIMS年龄分别为129.2±1.2kaB.P.和125.4±1.1kaB.P.,对应深海沉积物氧同位素第5期5e段的高海面;Kendal山阶地为208.1±1.9kaB.P.,可能代表7c间冰期高海平面的时代。该结果与Edwards等测定同一阶地的年龄一致,与α谱法数据在误差范围内吻合。另外,探讨了初始铀同位素比值的变化,并对TIMS年龄的可靠性做了评价。 相似文献
16.
《Quaternary Science Reviews》2003,22(10-13):1345-1351
In the last 20 years, the electron spin resonance (ESR) dating method has allowed the establishment of a chronological time frame over most of the history of human evolution. Despite many difficulties found for ESR dating of bones and carbonates, tooth enamel dated by ESR has been proven as a reliable method in its application to fossil teeth and quartz. Both of the latter materials have allowed dating of Early and Middle Pleistocene sites which are not datable using other methods such as the Argon–Argon method. In particular, recent discoveries of human remains in western Europe have been proposed to be sites of the earliest arrival of humans there, and have been dated to the Early Pleistocene by ESR using quartz and tooth enamel.Combined ESR and U-series dating of fossil herbivore teeth are the only means of dating layers from which such ancient remains have been recovered in western Europe. Good examples are the sites of Atapuerca Gran Dolina, Spain and Visogliano, Italy which have been dated using tooth enamel.When no bones and teeth can be found in prehistoric sites, ESR dating on quartz extracted from sediments has been used to date sites whose ages range over the entire Quaternary period. We present here two examples that occur in fluvial terraces of the river Creuse, France and at Monte Poggiolo site, Italy, where several artefacts of an archaic pebble industry have been recovered. 相似文献
17.
Thomas Higham Fiona Brock Marco Peresani Alberto Broglio Rachel Wood Katerina Douka 《Quaternary Science Reviews》2009,28(13-14):1257-1267
Radiocarbon dating of material from Late Pleistocene archaeological sites is challenging. Small amounts of modern 14C-labelled contamination will significantly affect the reliability of dates from the period, producing erroneous results. Recent developments in sample pre-treatment chemistry have shown that problems in reliable age determination during this period are surmountable. In this paper we provide an example of one such case, from the Middle to Upper Palaeolithic transitional site of the Grotta di Fumane, in northern Italy. We AMS dated two fractions of the same charcoal samples derived from a series of superimposed Mousterian, Aurignacian and Gravettian levels excavated at the site. One fraction was treated using the routine acid–base–acid (ABA) method, the other with the more rigorous acid–base-oxidation/stepped combustion (ABOx–SC) method. The latter method produced consistently older, and almost certainly more reliable, results. The eruption of the known-age Campanian Ignimbrite from the Phlegrean Fields near present-day Naples at 39.3 ka yr BP seals Ulluzzian and Proto Aurignacian levels in the south of Italy. Equivalent cultural levels are present at Fumane and the results obtained with the ABOx–SC methods are consistent with the ages inferred for sites in the south of Italy based on the presence of the Campanian Ignimbrite. New results from a sample found beneath the Campanian Ignimbrite at the Russian site of Kostenki, obtained using both the ABA and ABOx–SC, methods are also presented. They support the conclusion reached at Fumane by demonstrating that, in many cases, the ABOX–SC treatment effectively removes contamination where the ABA treatment does not. The results of the work offer a sobering examination of the problems inherent in the current radiocarbon database relating to the period, and highlight the dangers of an uncritical use of the corpus of 14C results obtained over the last few decades. Based on our results, we predict that more than 70% of the 53 previously available determinations from Fumane are erroneously young. A way forward is suggested, using these improved chemical preparation methods, applying analytical methods to characterise the material dated, and testing existing site chronologies to establish which previous determinations are liable to be inaccurate. 相似文献
18.
GIFFORD H. MILLER HANS PETTER SEJRUP JAN MANGERUD BJØRN G. ANDERSEN 《Boreas: An International Journal of Quaternary Research》1983,12(2):107-124
Isoleucine epimerization (alle/Ue) ratios in the pelecypod Mya truncata and benthic foraminifer Cibicides lobalulus from emerged marine units in western Norway allow construction of a regional relative chronostratigraphy for the Ecmian and Weichselian. Two in situ interglacial sections are considered correlative by the similar biostratigraphy and alle/Ile ratios in C. lobalulus. Overlying sediments at the two sites are of both marine and glacial origin. Neither site contains a complete Weichselian record, but allelic ratios, lithostratigraphy and fauna! changes suggest at least four stadial and three interstadial events occurred along the western Norwegian coast during Early and Middle Weichselian time. Kinetic data defining the relationship between the isoleucine epimerization rate constant and temperature for the species studied allow the estimation of paleotemperatures for samples of known age. Accepting published age estimates for the Eemian interglacial beds, the average Weichselian temperature in western Norway is calculated to have been ca. 4°C below the average Holocene temperature, whereas the last interglacial was 1 to 2°C warmer that the Holocene. The limited temperature depression over this region during the Weichselian implies that coastal western Norway was ice-covered only about 30% of this period, and that Atlantic water, although not necessarily in a warm surface current as today, entered the Norwegian Sea during much of marine isotope stage 5 and intermittently during stage 3. Interpolated amino acid ages date interstadial events at ca. 94 ka, 78 ka and 52 ka, B.P., whereas glacial events are dated ca. 103 ka and bracketed by limiting dates between 78 and 89 ka, between 52 and 63 ka and less than 36 ka B.P. 相似文献
19.
《Quaternary Science Reviews》2003,22(10-13):1367-1372
An additional method of coupled ESR/U-series dating is developed for teeth showing post-depositional U-loss. The fundamental parameter for the dose rate calculation is the present-day 230Th-activity because of the geochemical immobility of thorium. Uranium and thorium concentrations are measured by thermal ionization mass spectrometry (TIMS). Due to the unknown uranium history an average saturation uptake of uranium is assumed leading to an average development of U-series activities. Therewith an internal dose rate and the age T can be calculated on condition that the modelled 230Th-activity at time T corresponds with the measured value. Using this new method, teeth, found in archaeological sites in France (Gramat, Bramefond), could be dated even though they show U-loss after U-uptake. Two teeth from Gramat could be dated to 128.3±8.6 and 130.5±10 ka. Two teeth from Bramefond have ages of 104.4±8.4 and 115.1±10.2 ka. Both sites can be ascribed to oxygen isotope stage 5. 相似文献
20.
Darrell S. Kaufman Britta J. L. Jensen Alberto V. Reyes Caleb J. Schiff Duane G. Froese Nicholas J. G. Pearce 《第四纪科学杂志》2012,27(4):344-359
Radiocarbon‐dated sediment cores from six lakes in the Ahklun Mountains, south‐western Alaska, were used to interpolate the ages of late Quaternary tephra beds ranging in age from 25.4 to 0.4 ka. The lakes are located downwind of the Aleutian Arc and Alaska Peninsula volcanoes in the northern Bristol Bay area between 159° and 161°W at around 60°N. Sedimentation‐rate age models for each lake were based on a published spline‐fit procedure that uses Monte Carlo simulation to determine age model uncertainty. In all, 62 14C ages were used to construct the six age models, including 23 ages presented here for the first time. The age model from Lone Spruce Pond is based on 18 ages, and is currently the best‐resolved Holocene age model available from the region, with an average 2σ age uncertainty of about ± 109 years over the past 14.5 ka. The sedimentary sequence from Lone Spruce Pond contains seven tephra beds, more than previously found in any other lake in the area. Of the 26 radiocarbon‐dated tephra beds at the six lakes and from a soil pit, seven are correlated between two or more sites based on their ages. The major‐element geochemistry of glass shards from most of these tephra beds supports the age‐based correlations. The remaining tephra beds appear to be present at only one site based on their unique geochemistry or age. The 5.8 ka tephra is similar to the widespread Aniakchak tephra [3.7 ± 0.2 (1σ) ka], but can be distinguished conclusively based on its trace‐element geochemistry. The 3.1 and 0.4 ka tephras have glass major‐ and trace‐element geochemical compositions indistinguishable from prominent Aniakchak tephra, and might represent redeposited beds. Only two tephra beds are found in all lakes: the Aniakchak tephra (3.7 ± 0.2 ka) and Tephra B (6.1 ± 0.3 ka). The tephra beds can be used as chronostratigraphic markers for other sedimentary sequences in the region, including cores from Cascade and Sunday lakes, which were previously undated and were analyzed in this study to correlate with the new regional tephrostratigraphy. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献