Thermoluminescence dating of pottery from Sringaverapura—A Ramayana site

The first thermoluminescence (TL) dates of pottery from aRamayana associated site are reported. The TL dates for pre-NBPW Black-Slipped Ware levels are 730 and 765 B.C., while radiocarbon date takes the earliest Black Slipped Ware level (for which no TL dates are available) to 905 B.C. (uncorrected). For the OCW level, three TL dates are available which range from 1035 B.C. to 875 B.C. The early NBPW period believed to be associated with theRamayana episode will thus be post-750 B.C.     

Thermoluminescence dating of sediments

The potential for using the thermoluminescence behaviour of sediments for dating them was first recognized by Soviet scientists G.V. Morozov and V.N. Shelkoplyas, and for over a decade their TL dates, obtained from a variety of sediments, have appeared in the Soviet literature. Since 1977 TL sediment dates have been published by six additional groups using a variety of methods.In this review we describe the principles of TL dating, the various methods used, and contrast TL dating of sediments with the now well-accepted TL dating of pottery. We conclude that while TL dating has the potential to solve many sedimentary problems, more fundamental research needs to be carried out before such dates should be accepted. A set of criteria for acceptable dates is proposed.     

Thermoluminescence dating of sediments from Oulainen and Vimpeli, Ostrobothnia, Finland

Mean ages of 94 ka and 121 ka were obtained at Oulainen for two sand layers situated above and below an organic deposit previously correlated with the Brörup interstadial. At Vimpeli, TL dates obtained for sand layers embedded in an organic deposit suggest an age for this deposit of 107 ka. The uncertainty in this result is considerable, however. Problems encountered in dating these sediments and the reliability of the results are discussed.     

Thermoluminescence dating of the eruption at Mt Schank,South Australia

Mount Schank, a young volcano in southeastern South Australia, has been dated by thermoluminescence. The dated material was quartz from a former beach dune overlain by the lava flow. Disequilibrium in the uranium decay series required a detailed analysis of the isotopic concentrations in the sand. The samples dated yielded an average age of 4930 ± 540 years BP which is consistent with palaeomagnetic measurements. Combined thermoluminescence, palaeomagnetic and radiocarbon evidence leave unresolved the relative chronologies of Mt Schank and nearby Mt Gambier.     

Thermoluminescence dating of the holsteinian marine formation of Herzeele,northern France

Thermoluminescence dating of potassium feldspar coarse grains from the fossiliferous Holsteinian marine formation of Herzeele, at the southern limit of the North Sea Basin, yields a minimum age of 228 £ 30 ka. A tentative correction for the long-term fading of the TL signal in potassium feldspar is proposed, assuming a lifetime (τ) of 711 ka. This correction would yield a preliminary age estimate of 271 £ 36 ka. These results support a minimum Oxygen Isotope Stage 7 age, but do not preclude, at this stage of our research, a possible correlation with late Oxygen Isotope Stage 9. These results are in agreement, within the error of the method, with independent absolute dates (U-Th and ESR) obtained on in situ marine shells, which range from 225 ka to 348 ka. This study provides evidence of the reliability of TL age estimates on potassium feldspar coarse grains from shallow-marine sediments older than the Last Interglacial.     

Late middle pleistocene interglacial deposits at upper strensham,worcestershire, england

Pleistocene deposits containing the disarticulated skeleton of a mammoth, and associated faunal and floral remains, were discovered in July 1990 at Upper Strensham, Worcestershire. The environmental evidence from the fauna and flora together with limited geological evidence, indicates that the deposits accumulated within a low energy fluvial environment with a surrounding marsh and restricted tree cover on, or close to, the floodplain. The patchy occurrence of trees in a species-rich grassland is discussed, and the climatic significance of the fauna and flora is considered. The Strensham site lies within the valley of the River Avon, which is known to contain at least five altitudinally distinct river terraces. The deposits at Strensham lie beneath a terraced surface that cannot be accommodated within the existing framework of terrace development in the valley, and evidence is presented which may suggest that these deposits form a previously unrecognised fluvial unit, the Strensham Member of the Avon Valley Formation. Amino-acid age estimates from shells taken from the fossiliferous sediments of the Strensham Member suggest a correlation with Oxygen Isotope Stage 7. This correlation suggests that the temperate deposits at this site should be correlated with the temperate phase recorded at Marsworth, Buckinghamshire and Stoke Goldington in the valley of the Great Ouse.     

Thermoluminescence dating of Dimlington Stadial deposits in eastern England

The loess component of a solifluction deposit of the Dimlington Stadial exposed at the inland site of Eppleworth in eastern England gave a thermoluminescence date of 17.5 ± 1.6 × 10³ years. The solifluction deposit is overlain by a slightly weathered till correlated with the Skipsea Till of coastal exposures. which lies between organic horizons with radiocarbon dates of 18,500–18,240 B.P. and 13,045 B.P. Although the till must have been deposited during the Dimlington Stadial (after 18,240 B.P. at Dimlington and after 17,500 B.P. at Epplcworth), it gave apparent TL dates of 42.1 ± 3.6 × 10³ years at Eppleworth and 102 ± 9 × 10³ years at Dimlington, indicating that the components of the till were not exposed to light immediately before deposition.     

Thermoluminescence dating of the Eemian-Early Weichselian sequence at Fjøsanger, western Norway

Thermoluminescence (TL) dating of shallow marine sediments from the well studied interglacial-carly glacial sequence at Fjtfsangcr, western Norway has yielded ages that with few exceptions become progressively older with depth. For Ecmian samples the TL method yielded a mean of 111,000 ± 23,000 years, close to the often postulated age of 125,000 years. For the Early Weichselian the TL dates were younger than suggested by the amino-acid method.     

Reconstruction of the upper pleistocene glaciation of East Pamir

The paper deals with type, age, and climatic conditions of the last vast glaciation in the East Pamir Mountains. The combination of paleobotanic and geomorphological data as well as absolute age dating of the Kara-Kul lake terrace (27,700 ± 700 years old) supports the thesis that maximum glaciation occurred in the Upper Pleistocene, 14–15 thousand years ago. By special calculations it was established that the tectonic factor of glaciation practically did not exist. This confirmed the existing opinion of a number of scientists that by the beginning of the Upper Pleistocene the Pamir Mountains had almost achieved their present altitude. The analysis of paleobotanic literature permitted the assumption that the amount of precipitation was about the same as it is now: 750 mm/year at an altitude of 4950 m (altitude of the present-day firn line). It was established that the Upper Pleistocene glaciation was caused only by general climatic cooling.     

Palynological dating (Arenig) of the sedimentary sequence overlying the Ishkarwaz Granite (upper Yarkhun valley, Chitral, Pakistan)

A sedimentary sequence overlying a granite pluton near Ishkarwaz (upper Yarkhun valley, Chitral, Pakistan; Karakorum Microplate) contains abundant, but poorly preserved, acritarchs probably referable to the late early Arenig-early late Arenig interval. The palynological assemblages of Karakorum show a marked similarity to the cold water Peri-Gondwana assemblages; i.e. to those of Li Jun's Arbusculidium-Coryphidium-Striatotheca 'Mediterranean' Bioprovince. Biogeographical and geological comparisons suggest that, before the accretion of Cimmerian microplates to the Eurasian continent, the Karakorum Microplate was located along the northern margin of Gondwana in a latitude intermediate between the Mediterranean region and South China (Yangtze Platform).     

Thermoluminescence dating and geochemistry of loessic deposits in southeast England

The results of a thermoluminescence (TL) dating and geochemical survey of loessic deposits in southeast England, involving sampling at 26 localities, demonstrate that the loessic deposits appear to be the product of at least three depositional phases of aeolian silt during the Late Pleistocene, namely 10-25 ka BP, 50–125 ka BP and > 170 ka BP. The majority of localities sampled date to the Late Devensian, but isolated pockets of older material were found throughout the area. The majority of the samples analysed were of decalcified material. The results of geochemical analyses of major oxide and trace element concentrations indicate the uniformity of material and suggest a common provenance.     

长白山地区最近一次火山喷发的热释光年龄

长白山天池在近代和历史时期有过多次喷发 ,目前仍具潜在喷发危险。因此 ,确定最后一次喷发的时代具有重要意义。在长白山白云峰至天池的坡上采集了粗面岩样品 ,通过热释光测年法中的前剂量技术测定 ,获得了各样品的 TL年龄 ,由于原先的粗面岩受到了后期火山活动时岩浆的高温烘烤 ,其热释光年龄代表了天池最后一次喷发的时代 ,距今约 5 33± 2 6 6年     

Back-arc basin assemblages in Kohistan,Northern Pakistan

Abstract

The east central part of the Kohistan magmatic arc is made up principally of the Jaglot Group. From bottom to top it consists of I) paragneisses and schists intercalated with amphibolites and calc-silicates (Gilgit Formation), II) Gashu-Confluence Volcanics (GCV) and III) the Thelichi Formation comprising a volcanic base (Majne volcanics) and turbidites, marble, volcanoclastic sediments and lava flows. Metamorphic grade varies up to the sillimanite zone. The GCV are correlated with the Chalt volcanics and the Thelichi Formation with the Yasin Group. Other lithologies include the Chilas Complex, the Kohistan Batholith and part of the Kamila Amphibolite. Metavolcanics show a broad range in chemical composition. Geochemical parameters used to specify the tecto-nomagmatic regime suggest affinities of both island arc and MORB-like back-arc basin basalts. Kohistan can be divided into three tectonic zones, I) the southern (Kamila) zone comprises amphibolitized basalts, and mafic and ultramafic rocks, II) the central Chilas Complex, and III) the northern (Gilgit) zone i.e., the Jaglot Group. Previous tectonic models considered the southern two zones as the crust of a Cretaceous island arc. This investigation concludes that only the southern zone represents a true island arc. The Jaglot Group derives from back-arc basin assemblages and the Chilas Complex is a magmatic diapir emplaced in the back-arc basin.     

Thermoluminescence dating of coarse-grain quartz from the Malan loess at Zhaitang section, China

Thermoluminescence (TL) ages were obtained for five loess samples taken from the Zhaitang section near Beijing, China, using the coarse-grain quartz technique. The paleodose values have been determined by the method of total sample bleaching and regeneration of the TL growth curve. The method appears to be suitable for the age determination of loess samples up to about 150,000 yr where the annual dose-rate values are of the order 3–4 mGy/yr. This limit is a function of the total accumulated dose. The ages are in good agreement with those obtained by a fine-grain TL technique and are consistent with geological and geomagnetostratigraphic evidence.     

Knickpoints along the upper Indus River,Pakistan: an exploratory survey of geomorphic processes

This article summarizes an exploratory study carried out to investigate the significance of various geomorphic features on the formation of observed knickpoints along the upper Indus River in northern Pakistan. These features include bedrock lithology, active faults, sediment flux from tributary channels, and landslide dams which have blocked the main channel. The knickpoints and their related geomorphic parameters (channel profile, concavity, drainage area and normalized steepness index, etc.) were extracted from Advanced Spaceborne Thermal Emission and Reflection (ASTER) Global Digital Elevation Models (GDEMs) with 30 m resolution using ArcGIS, River Tools, and Matlab software. A total of 251 major and minor knickpoints were extracted from the longitudinal profile along a ~ 750 km reach upstream of Tarbela Reservoir. The identified knickpoints and their respective normalized steepness index (k_sn values) were compared with bedrock lithology, mapped faults, regional landslide/rockslide inventory, and the locations of historic landslide dams. The analyses revealed that the knickpoints do not correlate with the bedrock lithology except where major unit boundaries coexist with mapped faults, especially in reaches criss-crossed by active thrust faults in the Nanga Parbat Haramosh (NPHM) region. Neither did the river’s major confluences exhibit any notable knickpoints, but the correlations between knickpoints, mapped landslides, and historic rockslide avalanche dams accounted for approximately 75% of the observed knickpoints, a surprising finding. These observations suggest that more detailed studies aided by high resolution data should be undertaken to further explore the characteristics of knickpoints triggered by tectonic uplift, local fault offset, bedrock erodibility, and landslide/rockslide dams.     

Uranium/thorium dating of ferricretes from mid- to late pleistocene glacial sediments,western Tasmania,Australia

The uranium/thorium (U/Th) dating method was applied to pedogenic/diagenic ferricretes developed within glacial drifts from the northern West Coast Ranges of Tasmania. The dates derived from the method are, by definition, minima for the sediments, with the ferricretes being secondary mineral deposits which appear in the form of bands, horizons or nodules comprised of indurated masses of iron oxy(hydr)oxides developed post-depositionally within the host sediment or soil. The absence of such deposits in well-identified drift sediments of the last glaciation suggests the development of ferricrete horizons in glacial drifts occurred during earlier interstadials and interglacials. This has been confirmed by the uranium/thorium dating of ferricrete bands within glacigenic sediments obtained from three drill cores from the Boco Valley. The ages derived were found to be consistent with estimates for the timing of glaciation derived from palaeomagnetic analyses, radiocarbon dating and relative dating techniques. The results show that the uranium/thorium method can be used to successfully date ferricretes obtained from within glacial sediments of ages <350000 yr and provides valuable information regarding the minimum age of the host sediment. © 1997 John Wiley & Sons, Ltd.     

Fossil insect evidence for late pleistocene paleoenvironments of the lamb spring site,Colorado

The study of Quarternary insect fossils has shown their value as paleoenvironmental indicators, especially during times of rapid climatic change, and this method is now being introduced into North America archeological studies. Abundant insect fossils have been recovered from 13,000 year old detrital organic materials from silty clays at the Lamb Spring site, south of Denver, Colorado. The spring deposits also contain bones of extinct camel and mammoth, thought to have been modified by human hunters. The late Pleistocene insect fauna from Lamb Spring comprises 71 identified taxa from 6 orders and 14 families, principally beetles, providing substantial paleoenvironmental data. The beetle fauna is a mixture of grassland and mountain elements, and they appear to represent an environment similar to that found today in high mountain valleys, such as South Park, Colorado. Based on this fauna, mean summer temperatures at 13,140 B.P. were probably 10°C cooler than present.