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1.
Pompeii, buried by the explosive A.D. 79 eruption of Somma‐Vesuvius, is one of the most studied ancient cities in the Roman world. However, until very recently, the rural settlement in its hinterland had been largely ignored by systematic archaeological research. The ancient landscape around Pompeii consisted of a dense network of Roman farms (villae rusticae). They are believed to have played a vital role in ancient rural life and economy and thus represented the interactive rural–urban relationship in the Sarno River plain. The systematic investigation of published work combined with new fieldwork has yielded a data set of 140 villae rusticae in the Sarno River plain. Geographic information system based spatial statistics as well as predictive modeling were applied to gain a more detailed understanding of the ancient rural settlement structure in relation to the underlying paleoenvironmental and socioeconomic conditions. A high‐resolution pre‐A.D. 79 paleolandscape model of the Sarno River plain was utilized. The aim of this paper is to address theoretical considerations, the methodological implementation, and the archaeological discussion of the analysis of the ancient rural settlements and agriculture around Pompeii.  相似文献   

2.
Pasargadae complex had been the main center of Persian history during the Achaemenian period (560–330 bc), registered as one of the world heritage sites by UNESCO in 2004. This research is an attempt to recognize the natural setting and landscape of Pasargadae during the Achaemenian period, in Iran. The method is based on the application of a multi-layer technique. Collected data by fieldwork, especially in geology, hydrology, and hydrogeology, along with the analysis of aerial data and satellite information provided the baseline information for preparing historic and environmental layers and have made it possible to recognize a natural lakelet in the this area. The results show that the geometry of lakelet together with the ancient river of Pasargadae had been the main elements that formed the character of the site; they were also important in the locations of buildings in the Pasargadae complex.  相似文献   

3.
The evolution of Elephantidae has been intensively studied in the past few years, especially after 2006. The molecular approaches have made great contribution to the assumption that the extinct woolly mammoth has a close relationship with the Asian elephant instead of the African elephant. In this study, partial ancient DNA sequences of cytochrome b (cyt b) gene in mitochondrial genome were successfully retrieved from Late Pleistocene Mammuthus primigenius bones collected from Heilongjiang Province in Northeast China. Both the partial and complete homologous cyt b gene sequences and the whole mitochondrial genome sequences extracted from GenBank were aligned and used as datasets for phylogenetic analyses. All of the phylogenetic trees, based on either the partial or the complete cyt b gene, reject the relationship constructed by the whole mitochondrial genome, showing the occurrence of an effect of sequence length of cyt b gene on mammoth phylogenetic analyses.  相似文献   

4.
With increased demand for the tunnel construction in rock–soil interface composite formations, the influence on surrounding environment especially the excavation face instability during construction and ground settlement in the long term has gained great attention. The researches about environmental disturbance by shield tunneling construction in single ground as the soil or rock conditions have been developed continuously. However, due to the complexity and uncertainty of the interaction between rock–soil interface composite formations and shield machines, works on these special conditions have not been carried out sufficiently. In this paper the theoretical, experimental and numerical researches on the excavation face stability and ground settlement are discussed while the in situ datum are used to support them. First, the typical projects in rock–soil interface composite formations are listed and the difficulties met are summarized. Second, the failure model of excavation face and support pressure from the tunneling shield in rock–soil interface composite formations are discussed. Then, a comprehensive survey of the factors of ground settlement during and after construction and some effective prediction models are made. Finally, the existing problems and directions for future research are introduced.  相似文献   

5.
In some applications, especially for tunnel surveys and ancient tomb investigations, the scale of survey location is so small that it is impossible to lay a large enough transmitter loop for detection. A small-scale and high-power Transient Electromagnetic (TEM) transmitter configuration must be adapted to detect longer distance or greater depth. Redesigning the TEM surveying configuration may facilitate improving signal penetration and precision of TEM soundings. Based on physical simulation, a newly designed special-loop-source TEM survey configuration has been introduced, which employs four square apertures within a single large transmitter loop to excite stronger fields. The primary and secondary fields have been measured using both the new special-loop system and standard normal single loop TEM configuration for different receiver-transmitter separations and for different target depths. The response curves were compared, revealing that the primary field intensity and the secondary field response were improved by the special-loop transmitter system as compared to the standard system. The new special-loop configuration can be used for tunnel TEM prediction and other TEM investigations. A case study was conducted on tunnel forecasting in Hubei Province, China. This terra TEM survey showed that it is an effective and successful method for exploring and predicting challenging geological structures ahead of a tunnel wall during excavation.  相似文献   

6.

An axisymmetric lower bound limit analysis technique in combination with the finite elements has been used to investigate the effect of considering a non-associated flow rule on the stability number (γH/c) for a vertical circular unsupported excavation in a general cohesive–frictional soil medium, where (1) H is the excavation height, (2) γ defines the unit weight of the soil mass, and (3) c indicates the cohesion of the soil mass. The results are derived for different magnitudes of dilative coefficient (η), friction angle (?), and normalized excavation height (H/b), where b = the radius of the excavation. The results clearly indicate the increase in γH/c with an increase in η value. It is expected that the charts provided in this note will be quite helpful for the practicing engineers.

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7.
Although the ancient site of Utica has been studied since the 19th century, the location of its harbors remains unresolved as they were buried under sediments as the Mejerda delta prograded and left Utica 10 km inland. Using relief data and a coring survey with sedimentological analysis, we identify the dynamics of the delta's progradation, which produced a double system of alluvial fans. These show that the ancient bay of Utica silted up faster and earlier than was thought, probably before the end of the Punic period. Combined with the radiocarbon dates from coring, this suggests that the harbor lay on the north‐western side of the Utica promontory, communicating with the sea by a marine corridor west of the northern compartment of the delta. As the infilling of the ancient bay progressed, this corridor narrowed until it disappeared completely in the early 5th/mid‐6th century A.D., when a peat bog developed on the northern side of the promontory, sealing the fate of Utica as a port. This relative environmental stability ended in the 9th–10th century A.D. when about 4 m of sediment, probably of fluvial origin, covered the peat bog, leaving the site more than 4.5 m above the local sea level.  相似文献   

8.
Soils of the Chinese Loess Plateau(CLP)contain substantial amounts of soil inorganic carbon(SIC),as well as recent and ancient soil organic carbon(SOC).With the advent of the Anthropocene,human perturbation,including excavation,has increased soil CO2 emission from the huge loess carbon pool.This study aims to determine the potential of loess CO2 emission induced by excavation.Soil CO2 were continuously monitored for seven years on a newly-excavated profile in the central CLP and the stable C isotope compositions of soil CO2 and SOC were used to identify their sources.The results showed that the soil CO2 concentrations ranged from 830μL·L-1 to 11190μL·L-1 with an annually reducing trend after excavation,indicating that the human excavation can induce CO2 production in loess profile.Theδ13 C of CO2 ranged from–21.27‰to–19.22‰(mean:–20.11‰),with positive deviation from top to bottom.The range of δ13CSOC was–24.0‰to–21.1‰with an average of–23.1‰.Theδ13 C-CO2 in this study has a positive relationship with the reversed CO2 concentration,and it is calculated that 80.22%of the soil CO2 in this profile is from the microbial decomposition of SOC and 19.78%from the degasification during carbonate precipitation.We conclude that the human excavation can significantly enhance the decomposition of the ancient OC in loess during the first two years after perturbation,producing and releasing soil CO2 to atmosphere.  相似文献   

9.
与古遗址相邻的江、河由于后期的工程活动,如水库、大坝的修建和蓄水,水位上升,将对遗址区地下水的运动规律及渗流场产生较大影响。在其影响下,古遗址可能产生各种环境地质灾害并对其发掘安全产生不利影响。论文以国家重点文物——湖南里耶秦代古城遗址安全发掘深度研究为例,在分析水库蓄水诱发的环境地质灾害的基础上,对遗址在不同库水位下的安全发掘深度及发掘方案进行了研究,提出了保障发掘安全的工程措施。研究成果为国家重点文物的保护和进一步发掘提供了科学依据。对类似文物工程的保护和发掘具有借鉴意义。  相似文献   

10.
A recent multidisciplinary study, comprising existing data analysis and geomorphological and geological fieldwork, has helped clarify marine erosion processes of Pyrenean formations along the Basque Coast. An important discovery was made during our study of an alterite of regional extent, which calls into question recent and present evolution of the Basque Coast and the processes leading to coastline retreat. Modelling these factors has made it possible to propose a predictive scenario for future coastal evolution. To cite this article: A. Genna et al., C. R. Geoscience 337 (2005).  相似文献   

11.
12.
In all kinds of tunnel excavations, especially those excavated in cities, it is important to control surface settlements and prevent damage to the surface and subsurface structures. For this purpose, in weak rocks and soils, the umbrella arch method (UAM) has been used in addition to the new Austrian tunneling method (NATM). NATM and UAM are the best-known classical methods used in tunnel excavation. In classical tunneling, NATM is usually preferred in normal rocks. However, in some cases, NATM may be insufficient. UAM is a very effective alternative especially in soils and weak rocks. In soil and weak rocks, UAM is especially necessary to prevent excessive deformations. Selection of UAM or NATM is based on the following factors: cost comparison of NATM and UAM, allowable deformations, quality of rock or soil, application time of NATM and UAM, availability of skilled workers, and qualification level of the workers. Therefore, selecting the excavation method in these kinds of grounds is vital in terms of achieving the project goals in time, managing the project costs effectively, and controlling the probable deformations on nearby structures. A critical issue in successful tunneling application is the ability to evaluate and predict the deformations, costs, and project time. In this paper, application times, costs, and deformation effects are compared between NATM and UAM in sensitive regions at the Uskudar-Umraniye-Cekmekoy metro project (UUCMP). Also, efficiency of the deformation control of UAM is demonstrated by using the 2D numerical analysis method. UUCMP is part of the Istanbul metro network. The tunnels have a cross section of 75.60 m2 for NATM and 83.42 m2 for UAM. Geology in this section is composed of weak sandstone. Diabase and andesite dykes are also rarely observed. This study shows that the construction cost of UAM are 1.7 times more expensive than NATM. Although application time of UAM is 2.5 times longer than NATM, it is 2.5 times more efficient in controlling the deformations. This efficiency in controlling the deformations is confirmed via two-dimensional numerical analyses.  相似文献   

13.
《Sedimentology》2018,65(2):400-430
Integrated sedimentological and ichnological case studies of ancient meandering river systems have, for the most part, focused on the deposits of the fluvial–tidal transition zone; much less emphasis has been placed on the purely fluvial realm above the landward limit of tidal effects. This problem needs to be addressed so that in future the defining sedimentological and ichnological criteria assigned to ancient fluvial reaches are sufficiently well‐established to enable their separation from the down‐dip fluvial–tidal transition zone. Accordingly, a case study has been carried out on a well‐exposed meander belt deposit from the Late Jurassic Lourinhã Formation of the Lusitanian Basin, western Portugal (Praia Do Valmitão, Ribamar). Analysis indicates that the meander belt here comprised mixed‐load fluvial channels traversing a vegetated floodplain subject to a seasonal winter wet/summer dry palaeoclimate. This setting facilitated the development of both calcic palaeosols and shallow lakes on the adjacent floodplain. Critically, there is no evidence of the effects of tidal modulation on bedding structures, thereby establishing purely fluvial conditions. Heterolithic point‐bar deposits generated in this setting are bioturbated extensively by a trace fossil assemblage dominated by the meniscate trace Taenidium barretti , with Skolithos linearis , Planolites beverleyensis and Cylindricum isp. also recognized. A number of factors suggest that the Taenidium barretti producer in this case was a subaquatic organism living in an active fluvial channel setting (i.e. not colonizing subaerially exposed channel‐margin/floodplain deposits). Accordingly, there are some implications for current ichnofabric/ichnofacies models in the continental realm. Firstly, Taenidium ‐dominated ichnofabrics need not necessarily be confined to colonization beneath subaerially exposed surfaces; they might also be produced within submerged substrates. Secondly, there is scope to extend the range of the Scoyenia ichnofacies to include active fluvial channels and not simply those channels that were inactive or abandoned.  相似文献   

14.
The soils and subsistence of ancient Maya Chunchucmil in northwestern Yucatán are the focus of this paper. Today and historically, the population and crop yields here have been very low. Archaeological field work, however, has shown the Late Classic site to be highly populated with densely packed walled mound and field groups. It is enigmatic that this high ancient Maya population existed in a region of meager crop and soil potential. This enigma is addressed by investigating contemporary Maya agriculture, geoarchaeological evidence, and soil potential for intensive agriculture. The local Maya soil classification of kancab and boxluum synthesizes the Alfisols, Inceptisols, and Mollisols described here. The major soil limitations are shallowness, broad areas with no soil, insufficient water holding capacity, and variable deficiencies in phosphorous, potassium, and zinc. Evidence for intensive agriculture and alternative crops can be seen in widespread field walls compartmentalizing the landscape, sascaberas, and preliminary phosphate fractionation signatures. © 1998 John Wiley & Sons, Inc.  相似文献   

15.
The ancient city of Kibyra, which has been damaged by ancient earthquakes, is located on the middle part of Burdur‐Fethiye Fault Zone (SW Turkey). The existence of an active NNE‐SSW‐trending left‐lateral fault cutting the stadium of Kibyra has been previously discussed in many publications (Akyüz and Altunel, 1997 , 2001 ; Karabacak, 2011 ). Karabacak et al. ( 2013 ) also adhere to this view and restate it in the recent article published in Geoarchaeology. However, there is no evidence directly indicating a fault cutting the stadium and the earthquake damage to the stadium was most likely caused by ground shaking. In conclusion, the arguments, observations and interpretations presented by Karabacak et al. ( 2013 ) are misleading in key respects and must be reviewed.  相似文献   

16.
In recent years, soil nailing has been widely used to stabilize excavated steep slopes. Its design is often controlled by the allowable deformation level especially when buildings and/or other underground facilities exit near the excavation. In this paper a three-dimensional (3-D) finite element model (FEM) has been developed for the deformation analysis of nailed soil structures. In this model, the soil nonlinearity, the soil–nail interaction and the staged construction are all considered. Parametric studies are carried out to investigate some influence factors on the deformation behavior. An engineering case is also analyzed and the predicted soil movements at various stages of excavation are compared with field measurements. Good agreement between the prediction and the measurements proves the reliability of the model.  相似文献   

17.
Arnold, L. J., Roberts, R. G., MacPhee, R. D. E., Haile, J. S., Brock, F., Möller, P., Froese, D. G., Tikhonov, A. N., Chivas, A. R., Gilbert, M. T. P. & Willerslev, E. 2010: Paper II – Dirt, dates and DNA: OSL and radiocarbon chronologies of perennially frozen sediments in Siberia, and their implications for sedimentary ancient DNA studies. Boreas, Vol. 40, pp. 417–445. 10.1111/j.1502‐3885.2010.00181.x. ISSN 0300‐9483 The sedimentary ancient DNA (sedaDNA) technique offers a potentially invaluable means of investigating species evolution and extinction dynamics in high‐latitude environments. An implicit assumption of the sedaDNA approach is that the extracted DNA is autochthonous with the host deposit and that it has not been physically transported from older source deposits or reworked within the sedimentary profile by postdepositional mixing. In this paper we investigate whether these fundamental conditions are upheld at seven perennially frozen wetland sites across the Taimyr Peninsula and coastal lowlands of north‐central Siberia. Optically stimulated luminescence (OSL) and radiocarbon (14C) dating are used to constrain the ages of both the inorganic and organic fractions of perennially frozen deposits from which sedaDNA of extinct and extant species have been recovered. OSL and 14C age/depth profiles, as well as single‐grain equivalent dose (De) distribution characteristics, are used to assess the stratigraphic integrity of these sedaDNA sequences by (i) identifying the presence of primary or reworked organic and inorganic material, and (ii) examining the types of depositional and postdepositional processes that have affected specific sedimentary facies. The results of this study demonstrate that even though DNA preservation and stratigraphic integrity are commonly superior in perennially frozen settings, this does not, in itself, guarantee the suitability of the sedaDNA approach. The combined OSL and 14C chronologies reveal that certain perennially frozen sites may be poorly suited for sedaDNA analysis, and that careful site selection is paramount to ensuring the accuracy of any sedaDNA study – particularly for ‘latest appearance date’ estimates of extinct taxa.  相似文献   

18.
The stability of vertical unsupported circular excavations in rock media, obeying generalized Hoek-Brown yield criterion, has been investigated by using the lower bound finite elements limit analysis. An axisymmetric analysis, composed of a planar domain with a mesh of three-noded triangular elements, has been carried out. The optimization problem is dealt with by using the semidefinite programming technique avoiding the need of either smoothing the yield surface or making any assumption associated with the circumferential stress (σθ). A detailed parametric study has been executed, and the effects of different input material parameters, namely, geological strength index (GSI), yield parameter (mi), and the disturbance factor (D) on the results have been studied. For different height to radius ratios of the excavation, the computed results are presented in the form of nondimensional stability numbers. Failure mechanisms have also been investigated for a few typical cases. The results from the analysis have been compared with that evaluated separately with the application of the software OptumG2.  相似文献   

19.
Palynological investigation is one of the most important tools for reconstructing past vegetation. Some plants have proved to be relatively sensitive indicators of human activity, but most of them are not specific. In this paper we propose a method which can be used for the verification of phases of anthropogenic impact on vegetation distinguished in pollen diagrams. In this work we adopted the existing molecular methods for tracking bacterial ancient DNA of Bifidobacterium and Bacteroides‐Prevotella (known as human‐ and cow‐specific genetic markers) in palynologically and archaeologically associated sediments. This method can be helpful in determining local human presence, especially in those time periods when pollen analysis has not always been very discriminating (Palaeolithic, Mesolithic) and at sites without archaeological evidence. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

20.
Gully erosion is a major threat concerning landscape degradation in large areas along the northern Tanzanian Rift valley. It is the dominant erosion process producing large parts of the sediments that are effectively conducted into the river network. The study area is located in the Lake Manyara—Makuyuni River catchment, Arusha, northern Tanzania. During fieldwork, we measured topographic data of eight gully systems close to Makuyuni Town. The main focus of this study is to assess gully erosion dynamics using improved DEMs with original resolutions of 30 and 20 m, respectively. We assessed terrain characteristics to extract information on environmental drivers. To improve the DEM, we integrated information deduced from satellite images as well as from acquired GPS field data. Topographic indices such as Stream Power Index or Transport Capacity Index were derived from the re-interpolated DEM. To evaluate gully evolution, we assessed also the longitudinal slope profiles. Finally, the gully evolution phases of each gully were classified according to the concept proposed by Kosov et al. (Eksperimental’naya geomorfologiya, vol 3. Moscow University, Moskva, pp 113–140, 1978). The re-interpolated DEMs revealed a positive response especially for the more developed gullies. We show that the extraction of information on this spatial process scale based on “low-resolution” data is feasible with little additional fieldwork and image interpretation. In fact, areas identified as having a greater risk of gully erosion have been confirmed by observations and surveys carried out in the field.  相似文献   

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