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1.
《Quaternary Science Reviews》2003,22(10-13):1291-1297
We report the first luminescence ages for the archeological and geological sediments forming the substrate of the Birimi archaeological site in the Northern Region of Ghana. The site's significance rests on the fact that it contains a rich collection of artifact assemblages representative of three distinct cultures, and that, on the basis of artifact typology, the earliest assemblage is diagnostic of the Middle Stone Age (MSA). In situ occurrences of MSA artifacts are found at over 1 m below today's surface. They are overlain by a ceramic-rich complex of a sedentary or semi-sendentary Later Stone Age culture known as the Kintampo. The western half of the site is dominated by the industrial remains of Iron Age smelting activity.Elemental, mineralogical, and sedimentological analysis of the cultural and sub-cultural sedimentary horizons at the site revealed at least three distinct lithostratigraphic units. The quartz sediments are derived from the sandstone of the Gambaga escarpment, mass wasted and accreted fluvially at a rate of 3.2 cm/ka, forming a wide terrace at Birimi. Silts and finer fractions derive from windblown dust, likely from White Volta River and granitic sources to the north. Soil forming processes and wide fluctuations in moisture have progressively reduced the sediments at depth to the resistant quartz and kaolinite, with rich iron oxide coatings, and created two ironstone horizons composed of goethite-cemented quartz nodules.Multiple aliquot green-light stimulated optical ages for 125–150 μm quartz grains yielded ages of 23.6±2.9 and 40.8±11.8 ka for the MSA-bearing sediments, and 58.4±15.3 ka for the base of the terrace. Radiocarbon ages on charcoal from Kintampo-bearing units are 3.36–3.83 ka cal BP, and are supported by thermoluminescence (TL) ages on pottery sherds and burnt house daub fragments of this cultural complex. A 0.4 ka age on sediment from the site's surface confirms that the quartz zeroes well when exposed to natural light. Sediments bearing the Kintampo artifacts, however, yielded ages of 7.8–16.9 ka. These ages were obtained on sediments from large pits, some over 50 cm deep, and they deviate only slightly from the ages expected for naturally aggraded sediments at these depths. We conclude, therefore, that extensive digging of pits by the Kintampo dwellers was followed by rapid refilling, and that the bulk mobilization of the matrix did not permit the sedimentary quartz grains to experience any appreciable zeroing at that time.  相似文献   

2.
The quest for direct lines of evidence for Paleolithic plant consumption during the African Middle Stone Age has led scientists to study residues and use-wear on flaked stone tools. Past work has established lithic function through multiple lines of evidence and the spatial breakdown of use-wear and microscopic traces on tool surfaces. This paper focuses on the quantitative analysis of starch assemblages and the botanical identification of grains from flake and core tools to learn about human ecology of carbohydrate use around the Niassa woodlands, in the Mozambican Rift. The processing of starchy plant parts is deduced from the occurrence of starch assemblages that presumably got attached to stone tool surfaces by actions associated with extractive or culinary activities. Specifically, we investigate starch grains from stone tools recently excavated in northern Mozambique at the site of Mikuyu; which presumably spans the middle to late Pleistocene and represents similar sites found along the Malawi/Niassa corridor that links East, Southern, and Central Africa. Starch was extracted and processed with a diverse tool kit consisting of scrapers, cores, points, flakes, and other kinds of tools. The microbotanical data suggests consumption of seeds, legumes, caryopses, piths, underground storage organs, nuts, and mesocarps from more than a dozen families. Our data suggest a great antiquity for starch use in Africa as well as an expanded diet and intensification.  相似文献   

3.
The distribution of a number of trace elements in the Navarino Bay surface sediments is examined and their source and association with the major phases is determined. Cobalt follows Al in its distribution, having its highest vaues towards the center and deeper parts of the bay; Zn and Cu have their highest values at the effluent outfalls of a distillery and an olive oil and olive kernel factory (at the port of Yalova), being decreased away. The highest concentration of Ni is found near the town Pylos, while the highest concentrations of Rb and Y are observed at the mouths of rivers Yalovas and Xerias. Organic matter has its highest content at the port of Pylos, while no significant variations have been observed in the distribution of Sn and Ga. It is demonstrated that there is an anthropogenic input of Zn, Cu, and Corg in the bay. Zn and Cu are discharged by a distillery and an olive oil and olive kernel factory, at Yalova. Organic matter is mainly derived from domestic sewage. Ni enters the bay from its southern coasts and might be derived from weathering of bauxite deposits present in the adjacent limestones. Rb and Y are transported by the rivers Yalovas and Xerias from the northeastern adjacent land area; Ni, Co, and Cu show positive correlation with Al, suggesting their incorporation in clay minerals, while Rb shows positive correlation with Si, suggesting its incorporation in silicate detrital minerals. The following areas in the bay are considered to be heavily polluted: (1) the port and a large zone near Pylos (domestic sewage); (2) the port and a small area near Yalova (domestic sewage and industrial effluents); and (3) the eastern coast of the island Sphaktiria (oil). The domestic sewage pollution in Navarino Bay is of the same level as that in other Greek bays.  相似文献   

4.
Flint implements with rounded ends, excavated at several Late Palaeolithic sites in Denmark and the Netherlands, are described and interpreted as strike-a-lights used in combination with pyrites. Experiments were carried out; the use-wear traces on the experimental pieces are similar to those occurring on the prehistoric specimens. It is concluded that the pyrite technique for fire production most probably predated wood-on-wood techniques, both in Europe and Greenland.  相似文献   

5.
《Sedimentary Geology》1969,3(1):35-57
A preserved maximum thickness of 3,400 m of Devonian breccia, conglomerate, and sandstone of the Buelandet-Vaerlandet Formation crop out in the Buelandet-Vaerlandet district. The sedimentary rocks rest unconformably on Cambro-Silurian greenschist. Fragments of Psilophyton sp. found in the upper part of the stratigraphic sequence suggest an Early Devonian or early Middle Devonian age. The strictly continental sediments were deposited in a structurally formed half-graben by streams draining a complex crystalline source area to the north. This depositional basin was one of six separate Devonian basins located in the area of the former eugeosynclinal portion of the Caledonian geosyncline. The initial tectonism, resulting in the formation of Devonian grabens, was later followed by folding and faulting of the sedimentary basins during the Svalbardian disturbance. The tectono-sedimentologic environment of the Buelandet-Vaerlandet district is thought to have been similar to that of the Triassic Newark basins of the North American Appalachian Mountains.The oldest member of the here-named Buelandet-Vaerlandet Formation, the Melvaer Breccia, consists of angular, chaotically arranged greenschist fragments deposited as mudflows, sheetfloods and talus accumulations on the surfaces of alluvial fans. The intermediate Vaeroy Conglomerate consists of polymict alluvial fanglomerates deposited by braided distributaries of major streams that cut deep canyons into the northerly provenance area. The youngest unit is the Sörlandet Sandstone Member, a green arkosic deposit of larger braided streams, with local gravel bars preserved. Textural, fabric and paleocurrent data indicate a facies gradation southward along the paleoslope from breccia to sandstone. Tectonic uplift of the source area contemporaneous with fan sedimentation is suggested by the thickness and coarseness of fanglomerates. Rapid deposition in upperflow regime conditions, and a temperate or humid climate are indicated.  相似文献   

6.
The domestic and industrial waste water from most of the greater Athens, Greece area is discharged into shallow water at the upper end of the semi-enclosed Saronikos Gulf. The lack of circulation and excess organic matter has led to the formation of a rapidly expanding sludge field. Black anoxic sediments high in organic carbon now cover almost 9 sq km of sea floor and contain high concentrations of heavy metals. Maximum increases above background values range from 22× for mercury, 1500× for arsenic, 1200× for chromium, to 3000× for zinc. The principal sources of metals are 1) a fertilizer factory, 2) the Athens sewer outfall, and 3) the industries in eastern Elefsis Bay.  相似文献   

7.
对凌家滩遗址出土的闪石类玉器做了矿物成分、结构等方面的研究工作,表明其主要为透闪石玉,为今后考古研究提供了重要依据.  相似文献   

8.
中国新石器时代绿松石文化   总被引:2,自引:0,他引:2  
绿松石在中国文化、文明和传统起源过程中有着某种神秘而特殊的位置.新中国建国以来,数以千万个(次)考古发掘,出土了大量绿松石随葬器,并被视为国家保护文物.文物是历史的见证,是我国文明史的缩影和载体,是一部活生生的史书.这里仅就自数千件文献中收集到的绿松石遗存200余处进行分析.  相似文献   

9.
池希武 《福建地质》2012,31(4):351-357
根据对永安石林地区地质、水文地质条件的分析,利用不平衡铀系法,对区内不同高程位置的钙华沉积物岩样进行年龄测定,确定了永安石林形成年代在中更新世以来约25万年。并结合永安地区地质构造历史及闽江流域发育演化过程,分析得出永安石林主要是在第四纪以后大湖盆地处于剥蚀环境下,伴随地壳间歇性抬升运动,石炭纪、二叠纪石灰岩上覆岩层逐渐被风化剥蚀后形成的。  相似文献   

10.
The broad range of time over which ribbon bedded cherts were deposited does not extend into the present marine environment, and no ribbon cherts have been recovered from the sea floor by the Deep Sea Drilling Project. The depositional environment of bedded cherts is difficult to determine, but extra-silicic impurities in the rock may offer clues about the provenance of the non-biogenic component. To test the usefulness of relative abundances of the extra silicic components in extracting information on the depositional environment of the chert, I analyzed the major element chemistry of chert samples from a broad range of environments including ophiolite-associated chert from the Franciscan Formation of California, deep-sea chert and porcellanite from the northwest Pacific (DSDP Leg 32), shallow pelagic shelf chert nodules from the Chalk of Britain, continental marginal basin chert from the Monterey Formation of California, and continental marginal basin chert from the Pindos Zone of Greece. The ratios FeO/A12O3, TiO2/A12O3 and A1/A1+Fe+Mn were considered in detail. The interpretative logic is simple but empirically supported by observations of these ratio values at different depositional environments in the Pacific: A1 is concentrated most highly in continental material while Fe and Mn are more concentrated in pelagic sediments. FeO/A12O3 can be used to differentiate between ophiolite associated chert and chert associated only with other sediments. TiO2/A12O3 is not a useful indicator, possibly because of the equalizing effect of widespread eolian transport. The A1/A1+Fe+Mn ratio was measured in detail in one stratigraphic section in central continental Greece. This ratio varied with the type of sediment admixture, decreasing in value after the influx of ophiolite debris-bearing sediments, even when their presence was undetectable in hand sample or under petrographic microscope.To help clarify the paleogeography of the main study area, the Pindos Zone, and to identify sources and dispersal patterns of extra-basinal materials, isopach maps of sedimentary facies of the Pindos were constructed. Superimposed directly upon the series of imbricated thrust slices that comprise the Pindos Zone, the maps are at best compressed pictures of the Pindos Sea Floor. Persistent regional variation of facies thicknesses over time suggests the existence of several smaller depressions surrounded by submarine highs in the Pindos Basin.  相似文献   

11.
<正>1 Introduction The Pearl River Delta(PRD)is located in the north coast area of the South China Sea(SCS).As one of the largest delta in China,only the two latest events among the several tens of eustatic fluctuations occurring in the Quaternary were recorded in almost whole area of the PRD.There has been consensus on the age of the younger transgression sequence,which was dated to the Holocenc and resulted from a postglacial sea level rise,while there  相似文献   

12.
一、现行养老保险制度的基本政策 1995年3月,根据党的十四届三中全会作出的《关于建立社会主义市场经济体制若干问题的决定》精神,国务院出台了《关于深化企业职工基本养老保险制度的通知》,即国发[1995]6号文件。由于6号文件提出了  相似文献   

13.
Excavations in 1980–1981 at sites (32MZ319 and 32MZ380) along Cinnamon Creek Ridge in the Little Missouri River Badlands of McKenzie County, North Dakota, unexpectedly revealed at each locality the presence of one or more deeply buried paleosols with associated cultural materials. At both sites, 32MZ319 and 32MZ380, multiple paleosols are present, each of which is terminated by an episode of aeolian deposition. Fifteen radiocarbon dates on these paleosols establish an incipient chronology for paleosol development in the study area and permit correlation with other High Plains archaeological complexes. Geological and archaeological data for the two multiple paleosol sites are summarized.  相似文献   

14.
Detailed chemical and mineralogical data are presented for 37 samples of surface sediments collected from the Kalloni gulf, (eastern half), Lesvos island, northern Greece. The sediments are largely carbonate-rich muds, though near the eastern and northern coast of the gulf higher proportions of biogenic and lithogenic sands and gravels occur. The main minerals are quartz, feldspar (andesine), clay minerals (montmorillonite, illite, Kaolinite) and the carbonate minerals (calcite, Mg-calcite, aragonite). The mathematical method of factor analysis was applied in order to explain the mineralogical and geochemical variations. These variations can be interpreted in terms of variations in provenance and depositional environment. Six factors were produced accounting for 83.6 % of the total data variance: (a) a Si-Al-Na-K-Ti-Rb-Ba-Y-Zr factor controlled by clays and detrital minerals such as feldspars and zircon opposed by a CaCO2-Cu-Sc-Sr-La association (carbonate, minerals), (b) an organic carbon factor (C-Fe-Ce-Zn-Rb-Ni-Y-Nb), (c) a Fe-Mg-Cr-Ni factor representing control by peridotite, (d) a Ce-Nd-Fe-Ni-Zn-La factor controlled by silicate minerals, (e) a Al-Fe-Ti-P-V factor controlled by chlorite amphiboles or pyroxenes of volcanic or basaltic intrusions, (f) a Mn-Fe-Zn-factor controlled by iron-manganese oxides. Similarities in trace element composition among Kalloni gulf bottom sediments, and source lithologies indicate that the trace elements are derived from the adjacent landmasses. The AI/Ti ratio of the sediments is consistent with the terrigenous nature of sendimentation in the Kalloni gulf.  相似文献   

15.
晚第三纪以前形成的古土壤可以揭示地质时期的古环境。辨识古土壤的主要标志包括野外形态特征、微形态特征、地球化学特征等。当前古土壤分类一般基于现代土壤的系统分类体系,即采用诊断层和诊断特征,辅之以古土壤总体的化学性质等指标划分古土壤类型。形成于晚第三纪以前的古土壤可以重建全球范围的古气候变化历史,同时揭示前寒武纪时期古大气O2分压以及后寒武纪时期古大气CO2浓度水平的演化过程;古土壤具有空间和时间等多重信息,能反映流域或区域的古景观、古地貌、古水文特征。但目前缺乏一个广为接受的古土壤分类系统,成岩作用对古土壤特征的影响以及古土壤记录的古环境信息机制与解译等方面也还需要深入探讨。今后必须加强成岩作用对古土壤特性的影响以及现代土壤与其环境的对应关系的研究。  相似文献   

16.
Dakhleh Oasis, the largest of the Egyptian Western Desert, presents an opportunity for diachronic study of lithic raw material preferences during the Middle Stone Age (MSA) of the Eastern Sahara. Archaeological aggregates and raw material sources are exposed and easily mapped. Diverse and abundant lithic raw materials derive from sandstone, shale, and limestone sources and are also found in secondary geological contexts. Three main raw materials were used, and there was strong preference for one of these: Tarawan chert. Easily available only in the north‐central oasis, this material was transported substantial distances even when other materials that were known and used by MSA peoples could be found closer at hand. There is little evidence for use of raw materials exogenous to Dakhleh Oasis. This pattern of usage does not appear to change from the older MSA units to the Aterian Dakhleh Unit. © 2002 Wiley Periodicals, Inc.  相似文献   

17.
The morphology of paleosols and radiocarbon-dated charcoal from buried surface horizons of soils provide evidence to suggest that between periods of northward forest encroachment tundra climate has dominated areas at least 50 km south of the present forest/tundra border in southwest Keewatin. The present forest/tundra border climate is nearly as severe as any climate that has prevailed in the area since deglaciation.  相似文献   

18.
Excavations in the Helike Delta on the Gulf of Corinth have brought to light architectural remains from the Early Bronze Age (EBA), Geometric, Classical, Hellenistic, Roman, and Byzantine periods. Borehole results suggest that a lagoon intermittently occupied much of the delta during the Holocene. We discovered a well‐preserved EBA settlement about 1km inland from the present shore, buried under 3 to 5m of fine sediments containing marine, brackish, and freshwater microfossils. A Classical site 130m away, buried under 3m of similar sediments, may have been destroyed by the earthquake and tsunami of 373 B.C., which submerged the city of Helike. Possible tsunami evidence is noted. Although the EBA and Classical sites were both long submerged and buried by lagoonal sediments, tectonic uplift has raised both horizons above sea level. A shallow black clay layer suggests that a marsh covered the Classical and EBA sites in Byzantine times. © 2011 Wiley Periodicals, Inc.  相似文献   

19.
The mineralogy of a fault-related uranium occurrence, in clastic rocks overlying granite, is described from borehole material. Coffinite is the only important uranium mineral. Other notable minerals are sulphides, fluorite, calcite and hydrocarbon. Coffinite is epigenetic and paragenetically late, rimming sulphides and hycrocarbon. It occurs partly in spatial association with a TiO2 mineral (probably anatase). This U-Ti association is attributed to adsorption of U by altered Ti-minerals prior to growth of the U mineral. Thus is has similarities with many diagenetic occurrences, though their mineralogy is usually different (the U-Ti association being represented by uranotitanates). The latter are attributed to local supersaturation of TiO2, which did not occur at Ousdale because Ti was relatively mobile in the fluids. Coffinite + TiO2 + quartz is interpreted as a stable low-temperature assemblage. The mineralogy thus indicates a hydrothermal uranium mineralization of an unusual type (without prominent uraninte), formed from relatively low-temperature fluids containing complexing agents which mobilized Ti.  相似文献   

20.
The Messolonghi lagoon complex in Western Greece receives agricultural and domestic effluents both from point and diffused sources. Surface sediments were analyzed for grain size, organic carbon, total nitrogen, total sulfur, major and minor elements, aiming at the identification of geochemical relationships between all variables. Enrichment factors and the modified degree of contamination methods were applied to assess potential heavy metal enrichment related to human activities. Sediment texture was highly variable, with muddy sediments prevailing. In the central sector of the Messolonghi lagoon, organic carbon contents were high. Principal factor analysis revealed the following main groups of variables with common geochemical behavior: (1) terrigenous aluminosilicates (2) organic matter, (3) biogenic carbonates, (4) mineral quartz-aluminosilicates, and (5) Mn-oxides. Enrichment factors estimated for V, Cr, Mn, Co, Ni, Cu, Zn, and Pb using local pre-industrial sediment showed that all metals exhibit almost natural background levels, except for Pb, which was found to be slightly elevated (legacy of leaded fuel). Estimation of contamination factors concluded in similar results, whereas the overall modified degree of contamination was at the lowest level, therefore suggesting that this transitional water body has not been affected by anthropogenic activities. The data set may be considered as a baseline for future monitoring projects according to EU policy.  相似文献   

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