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1.
The naturally occurring radioisotope 87Rb makes a small contribution to the total dose-rate. Assuming an average potassium:rubidium ratio of 200:1 the contribution is estimated at 2.9% of the B dose-rate From potassium. The effect will be negligible in quartz inclusion dating because of the strong attenuation of the B- emission from 87Rb. In fine-grain dating the omission of the 87Rb contribution will overestimate the age of a pottery sherd by not more than 2% and this is regarded as of minor importance when the total error in the technique is at least 15%.  相似文献   

2.
The Palmottu hydrosystem is located in a granitic host rock in southern Finland. Along well‐defined pathways in the fractured crystalline rock, strontium isotopes are used to trace the degree of water–rock interaction (WRI) and mixing processes in groundwaters. The 87Sr/86Sr ratios range between 0.716910 and 0.735606 in the surface waters and between 0.719991 and 0.750787 in the groundwaters, but are between 0.720 and 0.735 in most of the samples. Moreover, the results show a lack of correlation between the water chemistries determining the classification into different water‐types (Na–Cl, Na–SO4, etc.) and the results of the strontium (Sr) contents and Sr isotopic ratios. From a WRI standpoint, this implies that the Sr behaviour is independent of the water chemistry; the occurrence of large 87Sr/86Sr variations is site specific and mainly dependent on the lithology. A model to determine the 87Sr/86Sr ratio of water after interaction with granite was developed. This model is based on the assumption that Sr was derived from three minerals: plagioclase, K‐feldspar and biotite. The results of the calculation indicate that around half of the water analysed within the Palmottu hydrosystem can be explained by the weathering of the granites. However, clearly lower 87Sr/86Sr are observed in waters when compared to the calculated 87Sr/86Sr and other sources of Sr, with low 87Sr/86Sr, rather than the calculated granite–water interaction, which may be suspected. When comparing the 87Sr/86Sr and ion ratios (Ca/Na, Mg/Na, Sr/Na, Cl/Na), the scattering of the data can be explained by the presence of four end‐members: a brine component (low 87Sr/86Sr and Ca/Na ratios…), a deep granitic component (high 87Sr/86Sr ratios and low Ca/Na ratios…), a subsurface component (intermediate 87Sr/86Sr ratios associated with high Ca/Na ratios…) and a surface end‐member:snow and river drainage (low 87Sr/86Sr and low Ca/Na ratios…). These extreme end‐members define a series of WRI‐mixing line within a rather complex hydrosystem.  相似文献   

3.
Abstract

In America, Tocqueville writes, men were born equal; they did not have to become so.1 But he is not unaware of the radical democratic character of the American revolution of which Gordon Wood has reminded us.2 Prior to 1776, Tocqueville observes, the democratic principle was “far from dominating the government of society.” It was the Revolution that made it “the law of laws.” “The war was fought and victory obtained in its name” (1:1, ch. 4. 59).  相似文献   

4.
Carbon (13C:12C) and oxygen (18O:16O) stable isotope ratio analysis was performed on well-preserved tooth enamel carbonate from fossil fauna recovered from a single excavation at the early hominid site of Allia Bay, East Turkana, Kenya. These data show greater enrichment in both 12C and in 16O than expected, based on the oxygen isotope composition of the middle Pliocene ocean, and on today’s ecology. The pattern of these data argues against a diagenetic explanation for the enrichment. The carbon stable isotope data of known browsers suggest a more extensive canopy cover during the middle Pliocene than today’s environments. The presence of browsing pig genera, hippo genera, deinotheres, and giraffes with δ13C values more negative than today’s all argue for woodland habitats. The presence of several grazing genera point to the presence of grasslands as well. The oxygen stable isotope ratios indicate that the site was better-watered than today, although the source, seasonal pattern, and actual amount of water cannot be determined from these data. The overall mosaic of environments suggested by these data, in combination with reports of exotic trees recovered in nearby deposits, indicate that woodlands were present in the region 3.9 my, unlike today. Such a setting matches expectations for the selective advantages of nut-eating, bipedal hominids over other hominoids.  相似文献   

5.
6.
We analyzed carbon stable isotope data from bone collagen of animals consuming varied experimental diets, including recently published data from Warinner and Tuross [Warinner, C., Tuross, N., 2009. Alkaline cooking and stable isotope tissue–diet spacing in swine: archaeological implications. Journal of Archaeological Science 36, 1690–1697; this journal]. Comparing regression lines for the relationship between collagen and diet δ13C, we show that protein source, and not physiology, explains the apparent taxonomic difference between swine and rodents reported in that paper. Our results reveal a complex relationship between whole diet and dietary protein in determining collagen δ13C values, such that in many cases, collagen alone may not provide reliable reconstructions of paleodiet. We advocate the simultaneous use of both collagen and apatite δ13C, whenever possible, to assess the diets of prehistoric peoples.  相似文献   

7.
In bone, the spacing between δ13C in collagen and bioapatite carbonate is greater in herbivores than carnivores, with implications for understanding animal dietary ecology from surviving hard tissues. Two explanations have been proposed: varying diet composition or differences in physiology between herbivores and carnivores. We measured the isotopic effects of carnivorous and herbivorous diets on a single species, to test the effect of diet composition alone. Protein δ13C and δ15N and carbonate δ13C were measured on egg and bone from hens on different diets. Herbivorous hens had a +14.3‰ spacing between egg albumen and shell δ13C, compared to +12.4‰ for omnivorous hens, and +11.5‰ for carnivorous hens. The bioapatite–collagen Δ13C spacing was measured as +6.2‰ for herbivorous hens, and calculated as +4.3‰ for omnivorous hens, and +3.4‰ for carnivorous hens—similar to observed mammalian herbivore and carnivore bioapatite–collagen Δ13C differences. We conclude that a shift in diet composition from herbivory to carnivory in a single species does alter the bioapatite–collagen carbon isotopic spacing. Our data strongly suggest that this results from differences in the Δ13Cbioapatite–diet spacing, and not that of Δ13Ccollagen–diet.  相似文献   

8.
While the use of radiogenic strontium isotope values to examine paleomobility is increasingly common in the Andes, and beyond, many questions about baseline variability remain. To better understand baseline radiogenic strontium isotope compositions in the Andes, we present new 87Sr/86Sr values from Peruvian soil samples. Modern soil samples were collected from agricultural fields from the following areas in central and southern Peru: Arequipa, Atico, Camaná, Chala, Cusco, Ica, Ilo, Lima, Mejía, Moquegua, Nazca, Ocoña, Palpa, Pisco, Puno, Tacna, and Yauca. Samples were partially dissolved to better approximate the bioavailable strontium. Radiogenic strontium isotope values from the partially dissolved soil samples range from 87Sr/86Sr?=?0.70202 to 0.71894 and, for all soil samples, have a mean of 87Sr/86Sr?=?0.70773?±?0.00166 (1σ, n?=?114). In general, the 87Sr/86Sr values measured for soil samples collected from modern agricultural fields reflect the expected 87Sr/86Sr values based on bedrock geology. Comparing our new soil data with published radiogenic strontium isotope data for bedrock, soil, water, and faunal samples provides constraints on the regions in the Andes that can, and cannot, be distinguished through radiogenic strontium isotope analysis.  相似文献   

9.
Ten years after Raymond Mauny's overview of Ivory Coast archaeology, Robert Chenorkian summarizes and illustrates recent developments in Ivoirian prehistory: palaeolithic industries discovered in stratigraphy, epipalaeolithic artefacts with14C dating, neolithic industries, and new data on shell middens. A table of radiocarbon dates resulting from the last ten years of research is included.  相似文献   

10.
Groundwater seeps are known to occur in Eckernförde Bay, Baltic Sea. Their discharge rate and dispersion were investigated with a new schlieren technique application, which is able to visualize heterogeneous water parcels with density anomalies down to Δσt = 0.049 on the scale of millimeters. With the use of an inverted funnel, discharged fluids can be captured and the outflow velocity can be determined. Overall, 46 stations could be categorized by three different cases: active vent sites, seep‐influenced sites, and non‐seep sites. New seep locations were discovered, even at shallow near‐shore sites, lacking prominent sediment depression, which indicate submarine springs. The detection of numerous seeps was possible and the groundwater‐influenced area was defined to be approximately 6.3 km2. Flow rates of between 0.05 and 0.71 l m?2 min?1 were measured. A single focused fluid plume, which was not disturbed by the funnel was recorded and revealed a flux of 59.6 ± 20 ml cm?2 min?1 and it was calculated that this single focused plume would be strong enough to produce a flow rate through the funnel of 1.32 ± 0.44 l m?2 min?1. The effect of different seep‐meter funnel sizes is discussed.  相似文献   

11.
Antrim porcellanite (thermally metamorphosed Tertiary laterite) was the most common raw material used in the production of stone implements during the Neolithic in Ireland and was worked at two localities in North Antrim: Tievebulliagh, near Cushendall and Brockley on Rathlin Island.Attempts have been made to provenance material from these two known sources, the most successful to date being the use of geochemical data (Sr and Yppm). Here we present a new geochemical discriminant—Sr isotopic data—which reveal that Tievebulliagh and Brockley porcellanites are distinctive. Present-day87Sr/86Sr ratios form two discrete groupings ranging from 0·705894±25–0·706443±24 at Tievebulliagh and 0·704088±27–0·704587±25 at Brockley. A coherent relationship between87Sr/86Sr and Sr (ppm) reiterates the use of Sr content as a discriminant and illustrates the geochemical variability of Sr between these two sources.Although this is a destructive technique,87Sr/86Sr represents the best discriminant to date for Antrim porcellanites and will enable definitive provenancing of porcellanite artifacts from Ireland with important archaeological implications.  相似文献   

12.
There is a strong relation between people's structured identities and their chemical biographies: these can reflect the way individuals choose to reside and/or move. The strontium isotope ratio (87Sr/86Sr) of skeletal remains is considered a useful proxy to assess residential mobility and social practices in past populations; however, so far, it has only occasionally been applied to prehistoric contexts in the Mediterranean. In this paper, we present 87Sr/86Sr data of human and animal samples from several Neolithic sites in the Apulian Tavoliere (southeastern Italy), namely, Grotta Scaloria, Passo di Corvo, Masseria Candelaro and La Torretta/Poggio Imperiale. Data obtained from dental enamel reflect the local origin of the individuals and allowed us to differentiate function and meaning of the sites examined. In particular, within a generally homogeneous background of Sr signatures, the range of 87Sr/86Sr at Scaloria Cave is greater than at the other sites, with variation likely to be related to funerary practices. We interpret this as the evidence of the ritual use of the cave, which implied the gathering of people of different origin. The relative variation of the Sr signature among individuals, either intersite or intrasite can be tentatively associated with mobility during life as well as with social practices, such as access to foods from geologically different environments. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

13.
The boron stable isotope ratio δ11B of 12 water samples representative of three chemical facies (fresh Na‐bicarbonate, brackish Na‐chloride, saline, and brine Ca‐chloride) has been analyzed. Interpretation of the δ11B data, along with the chemical compositions, reveals that Na‐carbonate waters from the Northern Apennine are of meteoric origin, with boron contributions from clay desorption and mixing with seawater‐derived fluids of Na‐chloride or Ca‐chloride compositions. The comparison of our new results with the literature data on other sedimentary basins of Mediterranean, and worldwide, confirms the contribution of Na‐bicarbonate waters to the genesis of mud volcano fluids. The Na‐chloride sample of Salvarola (SAL), which may represent the end‐member of the mud volcanoes, and the Ca‐chloride brine water from Salsomaggiore (SM) indicate boron release from clays compatible with the diagenetic process. The empirical equation: relating boron concentration and the stable isotope composition of the fluids observed in this study and the literature is proposed to trace the effect of diagenesis in sedimentary basins. A geothermometer associated to the diagenetic equation is also proposed: The application of this equation to obtain reservoir temperatures from δ11B compositions of waters should be carefully evaluated against the results obtained from other chemical and isotopic geothermometers from other basins around the world.  相似文献   

14.
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 0311-5518

A 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 [], 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 [], Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK. Ty Hibberd [], Australian Antarctic Division, Channel Highway, Kingston, Tasmania 7050, Australia.  相似文献   

15.
Measurements of the E-region electron density were made with the Saint-Santin incoherent scatter radar during consecutive days in June 1978, March 1979 and December 1980. On the basis of a statistical study, the observations show the presence of a diurnal asymmetry of the electron density, with morning values usually exceeding the afternoon densities by 3–20%. Two possible causes of the dissymmetry are examined: the asymmetry in the diurnal variation of the neutral composition and the effect of nitric oxide. The presence of NO partly converts O2+ into NO+ ions and increases the effective recombination rate of the electrons in the afternoon. Numerical simulations assessing the relative importance of the two factors are, in general, in good agreement with the measurements.  相似文献   

16.
Peyote, a psychoactive cactus native to the Chihuahuan Desert, has been preserved from excavations at only two archaeological sites: Shumla Caves in the Lower Pecos region of southwest Texas and shelter CM-79 near Cuatro Ciénegas in Coahuila, Mexico. We determined three indistinguishable radiocarbon ages of 5160 ± 45, 5200 ± 35, and 5210 ± 35 14C years BP, yielding a mean age of 5195 ± 20 14C years BP for the three specimens from Shumla Caves. For one of the Cuatro Ciénegas specimens we obtained the first direct radiocarbon date of 835 ± 35 14C years BP. This study demonstrates the use of peyote by inhabitants of the Lower Pecos region of the Chihuahuan Desert about 6000 calendar years ago, and confirms its use by inhabitants of the Cuatro Ciénegas region of the Chihuahuan Desert in Late Prehistoric times. The Shumla Caves' specimens are composed of an aggregate of ground peyote mixed with other plant material, i.e., they appear to be manufactured peyote effigies, and are definitely not intact peyote buttons.  相似文献   

17.
The Sincu Bara site in Senegal is one of the most famous archeological sites in Western Africa. Here we present the results of a multi-proxy study that combined microscopic analyses, carbon content, stable carbon isotope (δ13C) and radiocarbon (14C) measurements. This investigation exhibits a chronological framework in two phases: from 400 yr AD to 650 yr AD and 650 yr AD to 900 yr AD. Furthermore, it shows that besides basic potteries, some potsherds are notable for a temper exclusively made with human-harvested C4 plants. Finally, the 14C analysis performed on the organic slip strongly indicates the use of bitumen or bitumen-derived products for red slip preparation. This suggests the establishment of trade relationships with Nigerian and/or Trans-Saharan populations as early as 400 yr AD.  相似文献   

18.
L. Wang  Y. Cheng  W. Li 《Geofluids》2014,14(4):379-390
This study assesses the displacement of coalbed methane by CO2 migration along a fault into the coal seam in the Yaojie coalfield. Coal and gas samples were collected continuously at various distances in NO.2 coal seam from F19 fault. Vitrinite reflectance, maceral, and pore distributions and proximate analysis of fourteen coal samples were performed. Gas components, concentrations, carbon isotopes of 28 gas samples were determined. We examined the coal–gas trace characteristics of coalbed methane displaced away from the fault by CO2 injection after geological ages. From east to west, away from the F19 fault, the CO2 concentration decreased, whereas the CH4 concentration increased gradually. The δ13C values for CO2 varied between ?9.94‰ and 1.12‰, suggesting a metamorphic origin. A wider range of values (from ?9.94‰ to 20‰) was associated with the mixing of microbial carbon dioxide, isotopic fractionation during CO2 migration through the microporous structures of coals, and/or carbon isotope fractionation during gas–water exchange and dissolution of CO2. Away from the F19 fault, the volumes of micropores, mesopores and macropores decrease gradually. The Dubinin–Radushkevich (DR) micropore volume decreased from 0.0059 to 0.0037 cmg‐1, and the mesopore and macropore volumes decreased from 0.066 to 0.026 cmg‐1. The CO2 injection can mobilize aromatic hydrocarbons and mineral matter from coal matrix, resulting in the decrease in the absorption peak intensity for coal samples after supercritical CO2 treatment, which indicates that chemical reactions occur between coal and CO2, not only physical adsorption.  相似文献   

19.
This paper presents direct evidence of subsistence practices and pottery use at a Late Neolithic site at al-Basatîn, northern Jordan. Measurable concentrations of C16:0 and C18:0 were recovered from 8 of 10 archaeological pottery fragments through use of a microwave-assisted silica gel and aminopropyl solvent protocol developed for the isolation and concentration of free fatty acids in marine sediments. Subsequent isotopic analysis of the surviving C16:0 and C18:0 saturated fatty acids revealed ∂13C ratios consistent with those of adipose fats of ruminant and non-ruminant animals pastured on lands adjacent to the Jordan Valley. The high recovery of diagnostic compounds from the al-Basatîn material is discussed in context of a wider examination of the initial development and use of pottery in the Fertile Crescent, and the emerging debate concerning the efficacy of stable carbon isotope values in characterizing organic residues embedded in pottery fragments recovered from the earliest ceramic horizons in the Middle East and Europe.  相似文献   

20.
The purpose of this paper is to present a critical examination of al-Junayd's notion of unification (tawhid).1 Al-Junayd is without doubt one of the most prominent Sufi leaders of the tenth century A.D. who left their mark on the Sufi traditions. He is remembered especially for his strong advocacy of strict adherence by Sufis to the Quar'an and the Sunnah of the Prophet. His Sufi views called for thorough introspection, purification of one's heart and soul, and conformity to the highest morals. To acquire a more accurate and comprehensive understanding of tawhid, however, some other related Junaydian notions need to be presented where appropriate. The following issues will be discussed in this order: human beings' relationship to God, fana'2 (perishing), unification and its stages, sahw3 (sobriety), and, finally, whether the state of unification is reached by an act of free will and whether this state is purely subjective, i.e., not subject to public demonstration.  相似文献   

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