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1.
Four samples of carbonate sinters from two sites of the Roman Serino aqueduct were studied in order to better constrain the history of the aqueduct and to estimate to what extent natural hazards can be recorded in such deposits. Micromorphological observations, trace element, stable oxygen and carbon isotope analyses were performed on the samples. Together with new quantitative observations on the construction techniques of the aqueduct, our results highlight the imprint left by geological hazards on the Serino aqueduct. Damage, disruption, ground movement and a debris‐flow are evidenced.  相似文献   

2.
Numerous studies have proposed that movement along the 3400‐km2 low‐angle (<3°) Heart Mountain detachment fault of north‐western Wyoming and south‐western Montana was facilitated by the presence of lubricating fluids. A recent stable isotope study suggested that the fluids along the Heart Mountain fault originated from large hydrothermal systems associated with Eocene intrusive centers. Herein, we present results from a combined stable isotope, fluid inclusion, and 40Ar/39Ar geochronology study of the relationship between shallow crustal fluids from Eocene intrusive centers in the New World Mining district and fluids associated with the Heart Mountain fault. Our results suggest that: (i) Eocene intrusive bodies within the New World Mining District focused hydrothermal fluids along specific units and structures from the ore deposit centers along the Heart Mountain fault detachment surface; (ii) hydrothermal waters were focused along the Heart Mountain fault from the breakaway region near Silvergate, Montana toward Heart Mountain in Cody, Wyoming; and (iii) hydrothermal activity along the Heart Mountain fault occurred at the same time as emplacement of the Eocene intrusives, between 50.1 and 48.1 Ma. These data, taken together, suggest that the hydrothermal activity generated by intrusion of Eocene rhyodacites and dacites provided the source of fluids found along the Heart Mountain fault plane.  相似文献   

3.
Hydrothermal polymetallic veins of the Gemeric unit of the Western Carpathians are oriented coherently with the foliation of their low‐grade Variscan basement host. Early siderite precipitated from homogeneous NaCl‐KCl‐CaCl2‐H2O brines with minor CO2, while immiscible gas–brine mixtures are indicative of the superimposed barite, quartz–tourmaline and quartz–sulphide stages. The high‐salinity aqueous fluid (18–35 wt%) found in all mineralization stages corresponds to formation water modified by interaction with crystalline basement rocks at temperatures between 140 and 300°C. High brominity (around 1000 ppm in average) resulted from evaporation and anhydrite precipitation in a Permo‐Triassic marine basin, and from secondary enrichment by dissolution of organic matter in the marine sediments at diagenetic temperatures. Sulphate depletion reflects thermogenic reduction during infiltration of the formation waters into the Variscan crystalline basement. Crystallization temperatures of the siderite fill (140–300°C) and oxygen isotope ratios of the parental fluids (4–10‰) increase towards the centre of the Gemeric cleavage fan, probably as a consequence of decreasing water/rock ratios in rock‐buffered hydrothermal systems operating during the initial stages of vein evolution. In contrast, buoyant gas–water mixtures, variable salinities and strongly fluctuating P–T parameters in the successive mineralization stages reflect transition from a closed to an open hydrothermal system and mixing of fluids from various sources. Depths of burial were 6–14 km (1.7–4.4 kbar, in a predominantly lithostatic fluid regime) during the siderite and barite sub‐stages of the north‐Gemeric veins, and up to 16 km (1.6–4.5 kbar, in a hydrostatic to lithostatic fluid regime) in the quartz–tourmaline stage of the south‐Gemeric veins. The fluid pressure decreased down to approximately 0.6 kbar during crystallization of sulphides. U‐Pb‐Th, 40Ar/39Ar and K/Ar geochronology applied to hydrothermal muscovite–phengite and monazite, as well as cleavage phyllosilicates in the adjacent basement rocks and deformed Permian conglomerates corroborated the opening of hydrothermal veins during Lower Cretaceous thrusting and their rejuvenation during Late Cretaceous sinistral transpressive shearing and extension.  相似文献   

4.
P. W. Cromie  Khin Zaw 《Geofluids》2003,3(2):133-143
Carlin‐type gold deposits in southern China are present in Palaeozoic to Mesozoic siliciclastic and carbonate rocks. The border region of Yunnan, Guizhou and Guangxi Provinces contains gold deposits on the south‐western margin of the Pre‐Cambrian South China Craton in south‐eastern Yunnan Province. The Fu Ning gold deposits host epigenetic, micron‐sized disseminated gold in: (i) Middle Devonian (D1p) black carbonaceous mudstone at the Kuzhubao gold deposit and (ii) fault breccia zones at the contact between Triassic gabbro (β ) and the Devonian mudstone (D1p) at the Bashishan gold deposit. The deposits are associated with zones of intense deformation with enhanced permeability and porosity that focused hydrothermal fluid flow, especially where low‐angle N‐S striking thrust faults are cut by NW striking strike‐slip and/or NE striking normal faults. Major sulphide ore minerals in the Fu Ning gold deposits are pyrite, arsenopyrite, arsenic‐rich pyrite, stibnite and minor iron‐poor sphalerite. Gangue minerals are quartz, sericite, calcite, ankerite and chlorite. Hypogene ore grades range from 1 to 7 g t?1 Au and up to 18 g t?1 Au at the Kuzhubao gold deposit and are generally less than 3 g t?1 Au at the Bashishan gold deposit. Sub‐microscopic gold mineralization is associated with finely disseminated arsenic‐rich pyrite in the Stage III mineral assemblage. Two types of primary fluid inclusions have been recorded: Type I liquid–vapour inclusions with moderate‐to‐high liquid/vapour ratios, and Type II inclusions containing moderate liquid/vapour ratios with CO2 as determined from laser Raman analysis. Temperature of homogenization (Th) data collected from these primary fluid inclusions in gold‐ore Stage III quartz ranged from 180 to 275°C at the Kuzhubao gold deposit and 210 to 330°C at the Bashishan gold deposit. Salinity results indicate that there were possibly two fluids present during gold deposition, including: (i) an early fluid with 0.8–6.5 wt.% NaCl equivalent, similar to salinity in shear‐zone‐hosted gold deposits with metamorphic derived fluids; and (ii) a late fluid with 11.8–13.4 wt.% NaCl equivalent, indicating possible derivation from connate waters and/or brine sources. CO2 and trace CH4 were only detected by laser Raman spectrometry in gold‐ore‐stage primary fluid inclusions. Results of sulphur isotope studies showed that δ34S values for pyrite and arsenopyrite associated with gold‐ore mineralization during Stage III at the Kuzhubao and Bashishan gold deposits are isotopically similar and moderately heavy with a range from +9 to +15 per mil, and also fall into the range of δ34S values reported for Carlin‐type gold deposits. Sulphur isotopes suggest that the Fu Ning gold deposits were formed from connate waters and/or basinal brines. Fluid geochemistry data from the Fu Ning gold deposits suggest a Carlin‐type genetic model, involving fluid mixing between: (i) deep CO2‐rich metamorphic fluids, (ii) moderately saline, reduced connate waters and/or basinal brines; and (iii) evolved meteoric waters.  相似文献   

5.
Fluid inclusion and stable isotope data from quartz and carbonate minerals in fracture fillings and ‘ironstone’ nodules from the South Wales Coalfield have been used to characterise the fluids generated during basin evolution and associated coalification. Carbonates grew first, probably at relatively shallow depths and low temperatures (<100°C). The carbonates exhibit a trend of increasing C‐isotopic values across the coalfield, ranging from δ13C = ?12‰ VPDB in the SE of the coalfield to 0‰ VPDB in the NW, possibly as a result of increasing methanogenesis in the deeper (NW) parts of the coalfield. Quartz formed at a later stage of basin formation, probably at temperatures between 150 and 200°C. Fluid inclusions in these minerals suggest that burial and coalification of the sediments were associated with mixed aqueous–petroleum fluids. Furthermore, the density of these petroleum fluids decreases towards the NW of the coalfield, where the rank of the associated coal increases to anthracite grade. The study confirms that the composition and temperature of these fluids closely correlate with the variations in coal rank, indicating a possible causal link. The data also give general support to models that propose regional fluid flow in the basin. and are consistent with the erosion of approximately 2 km of section which is not preserved today. A geothermal gradient (at maximum burial) of 45°C km?1 is proposed, and thus no exceptionally anomalous thermal regime is required to explain coal rank variation.  相似文献   

6.
The first years of World War II were marked by a series of battles in and over the fields of California. Workers struggled with growers, growers struggled with the state, and federal and California bureaucrats struggled to gain control over the anarchic labor conditions that marked California agriculture. The introduction of a guest worker program – the bracero program – that brought farmworkers from Mexico to the harvests of California and other states, brought these battles to a head as growers ought to secure their traditional access to ‘cheap labor’ and their presumed right to control the farm labor process in the state. This paper examines these battles to show how growers fought – and managed – to preserve a landscape of great power and profit. The paper argues that the agricultural landscape extant at the beginning of the war shaped the nature of these multifaceted struggles, even as it was an object of those struggles.  相似文献   

7.
The relationship between major and minor elements, trace element composition, and age of obsidian sources within a volcanic field, is of considerable interest for obsidian source and artifact research in the New and Old World. The present study investigates this relationship in the Medicine Lake Highland of western North America. Geological evidence had indicated a very young age for all obsidian sources in the Highland, yet archaeological evidence suggested that obsidian was utilized for several thousand years. X-ray fluorescence analysis distinguished the latest flow (Glass Mountain) from the Cougar Butte, Grasshopper Flat, and Lost Iron Wells sources. Data obtained from two nearby archaeological sites showed that obsidian from the latter two sources was used by c. 7500 bc, while Glass Mountain material was not used (or available) until after 1360± 240 bp. These findings indicate that inferences of an extremely recent age for all obsidian sources in the volcanic field were unwarranted. Further analysis of major and minor elements indicated different hydration rates for these sources. The results argue that significant geochemical variability, as well as age differences, can exist between obsidian sources within the same volcanic field.  相似文献   

8.
J. Cao  W. Hu  X. Wang  D. Zhu  Y. Tang  B. Xiang  M. Wu 《Geofluids》2015,15(3):410-420
In this paper, we attempt to differentiate hydrocarbon‐bearing reservoir horizons of the Junggar Basin of NW China based on the characteristics of diagenesis and associated elemental geochemistry. Reservoirs at this site have varying levels of oil saturation that correlate with the degree of dissolution in minerals (e.g., calcite and feldspar). Four different horizons with varying diagenetic mineral assemblages were observed, including (i) kaolinite‐rich, oil‐dominated horizons, (ii) kaolinite–pyrite–hematite‐rich, oil–water‐dominated horizons, (iii) siderite–chlorite‐rich, water‐dominated horizons, and (iv) chlorite‐rich horizons with negligible hydrocarbon production. The mean MnO content of the representative diagenetic mineral (e.g., calcite) in each of the above horizons is >2.5, 2.0–2.5, 1.5–2.0, and <1.0 wt%, respectively. We propose that the above methodology can be used for the identification of reservoir hydrocarbon‐bearing horizons. We argue that the indicators presented here can be applied in oil exploration across the Junggar Basin.  相似文献   

9.
An integrated fluid inclusion and stable isotope study was carried out on hydrothermal veins (Sb‐bearing quartz veins, metal‐bearing fluorite–barite–quartz veins) from the Schwarzwald district, Germany. A total number of 106 Variscan (quartz veins related to Variscan orogenic processes) and post‐Variscan deposits were studied by microthermometry, Raman spectroscopy, and stable isotope analysis. The fluid inclusions in Variscan quartz veins are of the H2O–NaCl–(KCl) type, have low salinities (0–10 wt.% eqv. NaCl) and high Th values (150–350°C). Oxygen isotope data for quartz range from +2.8‰ to +12.2‰ and calculated δ18OH2O values of the fluid are between ?12.5‰ and +4.4‰. The δD values of water extracted from fluid inclusions vary between ?49‰ and +4‰. The geological framework, fluid inclusion and stable isotope characteristics of the Variscan veins suggest an origin from regional metamorphic devolatilization processes. By contrast, the fluid inclusions in post‐Variscan fluorite, calcite, barite, quartz, and sphalerite belong to the H2O–NaCl–CaCl2 type, have high salinities (22–25 wt.% eqv. NaCl) and lower Th values of 90–200°C. A low‐salinity fluid (0–15 wt.% eqv. NaCl) was observed in late‐stage fluorite, calcite, and quartz, which was trapped at similar temperatures. The δ18O values of quartz range between +11.1‰ and +20.9‰, which translates into calculated δ18OH2O values between ?11.0‰ and +4.4‰. This range is consistent with δ18OH2O values of fluid inclusion water extracted from fluorite (?11.6‰ to +1.1‰). The δD values of directly measured fluid inclusion water range between ?29‰ and ?1‰, ?26‰ and ?15‰, and ?63‰ and +9‰ for fluorite, quartz, and calcite, respectively. Calculations using the fluid inclusion and isotope data point to formation of the fluorite–barite–quartz veins under near‐hydrostatic conditions. The δ18OH2O and δD data, particularly the observed wide range in δD, indicate that the mineralization formed through large‐scale mixing of a basement‐derived saline NaCl–CaCl2 brine with meteoric water. Our comprehensive study provides evidence for two fundamentally different fluid systems in the crystalline basement. The Variscan fluid regime is dominated by fluids generated through metamorphic devolatilization and fluid expulsion driven by compressional nappe tectonics. The onset of post‐Variscan extensional tectonics resulted in replacement of the orogenic fluid regime by fluids which have distinct compositional characteristics and are related to a change in the principal fluid sources and the general fluid flow patterns. This younger system shows remarkably persistent geochemical and isotopic features over a prolonged period of more than 100 Ma.  相似文献   

10.
与古代埃及和西亚诸国只留下编年体的历史记载不同,古代以色列民族具有自己鲜明的历史意识;与古代希腊充满人本精神的历史记载也不同,以色列民族历史观的实质是一神论的神权历史观.他们将对耶和华神的信仰融入对民族历史发展的思考和解释之中,其历史书卷的编写几乎持续了一千年之久,在这一过程中,以色列历史成为"历史就是耶和华神对以色列民族的救赎史"的生动体现.  相似文献   

11.
Recent years have seen increased interest in skeletal populations from the Imperial Roman Age in Italy, but much less is known about diet and standards of living in the subsequent medieval period. To fill this gap, we conducted a morphological analysis of human remains from Albano, an Italian town near Rome, as well as a stable isotope analysis of bone collagen to reconstruct diet. The sample was recovered from a Medieval cemetery (1040–1220 cal. yr. BP) located in the gardens of the historical Palazzo Doria Pamphili in Albano. A minimum number of 40 individuals (31 adults and 9 sub‐adults) were examined using standard methods. Though the general health status of the population was good, signs of cribra orbitalia and diffuse enthesopathies were noted during the morphological examination. Stable carbon and nitrogen isotope analyses of the bone collagen from 24 adult humans and three faunal bones indicate that the diet of the population may be described as predominantly terrestrial and C3‐plant based although the data for some of the individuals suggest a modest consumption of C4‐(millet) based or aquatic proteins. No evidence of significant dietary differences between the sexes was found. The comparison of the isotope data from Albano with those from populations recovered in the same region is consistent with a shift from a terrestrial, possibly plant foods‐dominated subsistence in the Early Middle Ages to a diet with a higher contribution from animal proteins, both terrestrial and aquatic, in the Later Middle Ages. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

12.
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   

13.
卢松  张捷 《旅游科学》2009,23(3):41-47
在市场需求与政府战略双重导向的推动下,古村落正日益发展成为国内重要的旅游地类型。本文以世界文化遗产皖南古村落为案例,通过对调查所得数据采用均值分析、相关分析和矩阵分析等方法,分析了古村落居民的社区生活满意度及其影响因素,提出了未来古村落旅游社区建设的重点和方向。分析结果表明:(1)住房条件、经济收入水平、学校教育、村民参与事务管理状况、社会福利和社会保障等是古村落社区建设与发展中急需改进的因素,也是未来工作中的重点建设方向;(2)村容村貌、道路交通、村内环境卫生、自然环境、基础设施、消防设施、医疗服务等是需要重点维护和完善的因素;(3)物价水平、休闲娱乐设施、就业机会、当地政府工作、公共休闲空间、文体设施等是可以逐步解决的因素;(4)与其他村民的关系处理、购物方便程度、社会治安等是需要不断维护的方面。  相似文献   

14.
We present the results of analysing stable carbon and nitrogen isotopes in camelid remains found at the Late Archaic site TU‐52 (ca. 5000–3800 bp ), the Tarajne Phase site TU‐94 and the Early Formative sites TU‐54, TU‐85 and TU‐122 (ca. 3100–2400 bp ). All of the sites are located in the Puna de Atacama (Northern Chile) along the 14 km Tulan transect, between the head of Tulan ravine (ca. 3000 m.a.s.l.) and the border of the Salar de Atacama (2317 m.a.s.l.). Our aim is to understand how the space was used by hunter‐gatherers and early herders from the beginning of camelid domestication to the consolidation of herding practices. Isotopic analyses were complemented with osteometric data in order to correlate changes in animal size and isotopic values with the initiation of animal husbandry. Isotopic and osteometric results show less variability of δ13C and δ15N values during the Late Archaic and Tarajne Phase, whereas variability is higher during the Early Formative. We postulate that during the latter period, there was more widespread use of hunting and herding spaces along the Tulan ravine, including areas above 3000 m.a.s.l. as result of more consolidated herding practices, while the highlands were used as a complementary space to hold livestock near ritual sites and residential settlements. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

15.
The concentrations of H2, O2, CO2, and concentrations and isotopic composition of the noble gases (including 222Rn), N2, CH4, and higher hydrocarbons dissolved in 4000 m deep‐seated fluids from a 12‐month fluid production test in the KTB pilot hole were analyzed. This determination of the gas geochemistry during the test in combination with the knowledge of the hydraulic data provides relevant information about the fluid hydraulics of the deep system. All gas concentrations and isotopic signatures, except for 222Rn, showed constancy during the course of the test. This, in combination with large fluid flow rates at a moderate water table drawdown, imply an almost infinite fluid reservoir in 4000 m depth. From the change in 222Rn‐activity as a function of pump rate, the contribution of smaller and wider pores to the overall fluid flow in an aquifer can be deduced. This 222Rn‐activity monitoring proved therefore to be a valuable instrument for the qualitative observation of the scavenging of pore and fracture surfaces, a hydraulic feature invisible to standard hydraulic testing tools. The observance of this scavenging effect is due to (i) the continuous on‐line geochemical monitoring, (ii) the durability of the test, (iii) a change in pump rate during the course of the test, and (iv) due to the short half‐life of 222Rn. The fluids have a 5.9% mantle He component, and a δ21Ne excess of 14%, and a noble gas model age of about (5.5–6.2) ± 2.0 Myr. The mean N2/Ar‐ratio of 516 and δ15N‐data of about +1.5‰ indicates sedimentary or metamorphic origin of N2. The hydrocarbons, amounting to 33 vol.% in the gas phase, are derived from thermal decomposition of marine organic matter of low maturity. But a key question, the identification of the potential source region of the fluids and the migration pathway, is still unidentified.  相似文献   

16.
Mesolithic human remains are rare in the archaeological record of the French Mediterranean. Only the island of Corsica has so far produced relatively well‐preserved burials, and recent archaeological excavations have brought to light new Mesolithic human remains. The site of Campu Stefanu , located in Sollacaro in the southeast of the island, contained a collective burial of seven to eight individuals in a previously unobserved funerary context. A re‐evaluation of collections in regional museums yielded the remains from another Mesolithic individual from the site of Torre d 'Aquila , excavated at Pietracorbara, in the northern part of the island, at the beginning of the 1990s. These two discoveries presented the rare opportunity to obtain new radiocarbon dates and paleodietary insights from this crucial time period using stable isotope analysis (δ13C, δ15N) on collagen. From Campu Stefanu, one individual had sufficient collagen preserved for radiocarbon dating, revealing that it is the oldest Mesolithic human known on the island, dated to 10216–9920 cal. BP. At Torre d'Aquila, radiocarbon dates indicate that the individual belonged to a younger Mesolithic phase than Campu Stefanu, dated to 9903–9596 cal. BP. δ13C and δ15N isotope ratios are similar between the Campu Stefanu and Torre d'Aquila individuals and indicate a diet dominated by the consumption of terrestrial animal protein and a lack of marine resources. These findings are in contrast with the previous results from two other Mesolithic individuals from Corsica from the sites of Araguina Sennola and Monte Leone , for which about 25–30% of the consumed proteins came from a marine diet. The dietary variability recorded in Corsica is consistent with results obtained from Mesolithic human remains of Sicily and the Iberian Peninsula. We can hypothesise, that despite the nomadic lifestyle, the distance to the sea played a major role in Mesolithic food choices in Corsica. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

17.
We report here on the measurements of carbon and nitrogen stable isotopes of bone collagen from the Middle Byzantine site of Kastella, in the city of Heraklion, on the island of Crete, Greece. The data derived from the analysis suggest a diet based primarily on terrestrial, C3 protein, probably from animal sources, with the inclusion of some marine protein. The adult diet at this site is relatively uniform, with no detectable differences between average isotopic values for males and females. We also found that bone collagen δ15N values for a small number of juveniles decreased to adult levels after the age of two years, indicating that weaning occurred at or before this age. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

18.
We explore subsistence practices and dietary change on islands in the central Lau Group of Fiji with zooarchaeological methods and stable isotopic analysis of human and animal skeletal material interpreted through an ethnoarchaeological lens. Our dataset combines detailed identifications of fauna, especially fishes, with stable isotopic (δ13C, δ15N) values of human and animal bone collagen and apatite carbonate spanning approximately three thousand years of human occupation on three study islands. Additionally, over fifty inshore and offshore contemporary fishing expeditions were observed on all study islands over a six-year period. We integrate these separate lines of evidence to form robust interpretations of Lauan subsistence patterns over a broad temporal scale. We add to the existing literature on stable isotopic analysis of archaeological bone from Remote Oceania and compare all of these groups through time. Our results indicate that Lauans differentially relied on nearshore reef resources rather than pelagic fishes, and terrestrial endemic species may have served as a portion of the diet during the early prehistoric period. Root crops (e.g., taro, yam) provided the majority of calories to the diet; however, sea grapes likely contributed to the early diet. Our isotopic results differ from previous studies of Fijian diet and that of Remote Oceania at a time of probable marine ecosystem shifts (AD 1300) illustrating diet breadth and variability in subsistence strategies potentially due to climatically influenced resource depletion.  相似文献   

19.
Foraging ranges, migrations, and travel among Middle Holocene hunter–gatherers in the Baikal region of Siberia are examined based on carbon and nitrogen stable isotope signatures obtained from 350 human and 203 faunal bone samples. The human materials represent Early Neolithic (8000–6800 cal BP), Late Neolithic (6000–5000 cal BP), and Early Bronze Age periods (∼5000–4000 cal BP) and come from the following four smaller areas of the broader region: the Angara and upper Lena valleys, Little Sea of Baikal’s northwest coast, and southwest Baikal. Forager diets from each area occupy their own distinct position within the stable isotope spectrum. This suggests that foraging ranges were not as large as expected given the distances involved and the lack of geographic obstacles between the micro-regions. All examined individuals followed a similar subsistence strategy: harvesting game and local fishes, and on Lake Baikal also the seal, and to a more limited extent, plant foods. Although well established in their home areas, exchange networks with the other micro-regions appear asymmetrical both in time and direction: more travel and contacts between some micro-regions and less between others. The Angara valley seems to be the only area with the possibility of a temporal change in the foraging strategy from more fishing during the Early Neolithic to more ungulate hunting during the Late Neolithic–Early Bronze Age. However, the shift in stable isotope values suggesting this change can be viewed also as evidence of climate change affecting primary productivity of the Baikal–Angara freshwater system.  相似文献   

20.
This paper presents the results of palaeodietary reconstruction based on stable carbon and nitrogen isotope analysis on bone collagen of five medieval rural populations from the Basque Country (northern Spain) spanning from 5th to 15th centuries ad . One hundred forty‐seven human and 47 domestic faunal samples were successfully analysed with the objective of defining agrarian productive strategies and food consumption patterns. The results grouped the five sites in two clusters: on one side Zaballa and Treviño, whose inhabitants followed diets exclusively based on C3 plants with significant intake of animal protein, and on the other, the populations from Aistra and Zornoztegi, who combined C3 and C4 plants and consumed lower amounts of animal protein. The isotopic values from Dulantzi were intermediate to these two groups. No differences were detected when individual status markers, such as grave goods, were available. Conversely, some restrictions on the access to certain food resources based on sex were uncovered. A relevant change in δ13C values was identified around 10th century, a consequence of a shift in the consumption patterns of C3 and C4 plants. Finally, these Basque sites were compared with those of the medieval Iberian case studies available in the literature. This comparison made evident the distinctive nature of the diet of the Basque medieval rural contexts. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

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