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61.
Friedemann Baur Matias Di Benedetto Thomas Fuchs Carolyn Lampe Simone Sciamanna 《Marine and Petroleum Geology》2009
For the first time, a new approach to petroleum systems analysis is presented which allows full integration of tectonic and palinspastic restoration with three-dimensional (3D), PVT-controlled, multi-component, three-phase petroleum migration analysis through time. A systematic modeling study has been applied to a study area dominated by fold and thrust belts located in the Sub Andean orogeny near Tarija, Bolivia. The project has been performed with a special focus on the simulation technique and on the correct distribution of temperature, source-rock maturity and pressure development through time with reference to its input data. This is the first pilot project presenting a 3D numerical model in a compressional structural regime to which the basin modeling approach has been applied to explain the observed distribution of temperature, pressure, maturity and petroleum accumulations in general. 相似文献
62.
Miroslav Gačić Vedrana Kovačević Simone Cosoli Andrea Mazzoldi Jeffrey D. Paduan Isaac Mancero-Mosquera Sadegh Yari 《Estuarine, Coastal and Shelf Science》2009
Surface patterns of the low-frequency current in a 20 × 30 km region in front of the Venice Lagoon were analysed from a 13-month-long HF radar data set. Surface circulation was related to prevalent wind regimes in the area and to the tidal flow through the lagoon inlet. Three different categories of wind-forcing were defined: bora (NE wind), sirocco (SE wind), and finally the category containing all other wind directions and calms (winds lower than 3 m/sec). Mean flow and vorticity spatial distributions were discussed for different wind conditions. The coastal area about 5 km wide is characterized by a flow field with maximum vorticity. Outside the coastal boundary layer the interior flow is part of the Adriatic basin-wide cyclonic circulation. Two counter-rotating vortices of the dimension of about 4–5 km were evidenced in the average flow field in front of the lagoon inlet (Malamocco inlet) in all situations except for the bora. The vortex-pair is probably associated with the tidal flow through the inlet. The bora wind induces a strong southward coastal jet detached from the coast by about 5 km homogenizing the flow and eliminating the dipole. The average coastal flow pattern in calm wind conditions was also analysed as a function of the strong inflow/outflow (currents in the inlet > 0.7 m s−1) from the lagoon inlet. In both cases the vorticity pattern is similar, with the negative vorticity to the left of the inlet and positive to the right looking seaward. 相似文献
63.
Simone Mantellini Vincenzo Picotti Abbas Al-Hussainy Nicolò Marchetti Federico Zaina 《Geoarchaeology》2024,39(3):268-299
The last two decades witnessed increasing scholarly interest in the history of water management in southern Mesopotamia. Thanks to many geoarchaeological research projects conducted throughout the central and southern Iraqi floodplains, a general understanding of the macrophases of anthropogenic manipulation of this vast hydraulic landscape has been achieved. However, current narratives mostly rely on studies at a regional scale and are based on excessively long chronological phases (often spanning a whole millennium). A finer-tuned analysis at a submillennial scale is needed to better appreciate the dynamics that led to the development of artificial canals and irrigation systems and the creation of harbours in cities and other navigation-related facilities. The Iraqi-Italian QADIS project is addressing this issue through a systematic geoarchaeological investigation in the south-eastern area of the Qadisiyah province. We aim to update the current narrative by analysing case studies involving specific periods of occupation. We performed 17 boreholes to propose a date on the functioning period of the hydraulic works in five selected archaeological sites of this region. This approach allowed us to understand changes in water management strategies in both the short and the medium term (i.e., on a scale of centuries). In this paper, we present the results for the fourth and third millennia B.C.E. This period witnessed a crucial passage from the basic exploitation of natural watercourses for irrigation and occasional navigation to the emergence of the first system of artificial canals and intraurban harbours. 相似文献
64.
Quantitative and qualitative diatom analyses from the north Nile Delta lakes sediments of Egypt were used to evaluate the
paleoenvironmental development of the lakes and climatic changes during the late Holocene. We analyzed 565 samples taken from
19 cores from Manzala, Burullus and Edku lakes. A total of 263 diatom species and varieties were identified. Multivariate
statistical analyses distinguished 17 ecological groups that reflect changes in water salinity, lake-level and trophic state
of the lakes, which in turn are mainly related to climatic changes and anthropogenic impacts. Manzala and Burullus lakes experienced
a series of alternation between fresh, brackish and marine episodes, which were associated with wet and dry climates. Edku
Lake cores, however, contained only three ecological groups that are characteristic of brackish water conditions. The general
depositional regime in the lakes indicated five environmental phases: (a) a deep freshwater phase when the Nile flood water
reach the lakes during humid warm climate; (b) a shallow freshwater phase with some macrophytes during a dry climate; (c)
a shallow brackish water phase when Nile floodwater ceased during a dry climate and the lakes shifted to brackish conditions;
(d) a mixed environmental phase when the seawater mixed with freshwater from drains and canals (water salinity fluctuated
widely from freshwater to estuarine and full marine conditions); (e) a fully marine phase when seawater entered the lakes
at all stages of the tide. 相似文献
65.
Simone Vincenzi Graziano Caramori Remigio Rossi Giulio A. De Leo 《Marine pollution bulletin》2007,55(10-12):579
Habitat Suitability (HS) models have been extensively used by conservation planners to estimate the spatial distribution of threatened species and of species of commercial interest. In this work we compare three HS models for the estimation of commercial yield potential and the identification of suitable sites for Tapes philippinarum rearing in the Sacca di Goro lagoon (Italy) on the basis of six environmental factors. The habitat suitability index (HSI) is based on expert opinion while the habitat suitability conditional (HSC) is calibrated on observational data. The habitat suitability mixed (HSM) model is a two-part model combining expert knowledge and regression analysis: the first component of the model uses logistic regression to identify the areas in which clams are likely to be present; the second part applies the same parameter-specific suitability functions of the HSI model only in the areas previously identified as productive by the logistic component.The HS models were validated on an independent data set and estimates of potential yield of the Goro lagoon were compared. The effectiveness of the three approaches is then discussed in terms of predicted yield and identification of suitable sites for farming. 相似文献
66.
67.
Andrew S. Cohen Manuel R. Palacios-Fest James McGill Peter W. Swarzenski Dirk Verschuren Robert Sinyinza Tharcisse Songori Bombi Kakagozo Mutanga Syampila Catherine M. O’Reilly Simone R. Alin 《Journal of Paleolimnology》2005,34(1):1-18
We investigated paleolimnological records from a series of river deltas around the northeastern rim of Lake Tanganyika, East Africa (Tanzania and Burundi) in order to understand the history of anthropogenic activity in the lakes catchment over the last several centuries, and to determine the impact of these activities on the biodiversity of littoral and sublittoral lake communities. Sediment pollution caused by increased rates of soil erosion in deforested watersheds has caused significant changes in aquatic communities along much of the lakes shoreline. We analyzed the effects of sediment discharge on biodiversity around six deltas or delta complexes on the east coast of Lake Tanganyika: the Lubulungu River delta, Kabesi River delta, Nyasanga/Kahama River deltas, and Mwamgongo River delta in Tanzania; and the Nyamuseni River delta and Karonge/Kirasa River deltas in Burundi. Collectively, these deltas and their associated rivers were chosen to represent a spectrum of drainage-basin sizes and disturbance levels. By comparing deltas that are similar in watershed attributes (other than disturbance levels), our goal was to explore a series of historical experiments at the watershed scale, with which we could more clearly evaluate hypotheses of land use or other effects on nearshore ecosystems. Here we discuss these deltas, their geologic and physiographic characteristics, and the field procedures used for coring and sampling the deltas, and various indicators of anthropogenic impact. 相似文献
68.
A global positioning system (GPS)-based online control and alarm system (GOCA) for monitoring of three-dimensional movements
has been developed at the Karlsruhe University of Technology. The GOCA hardware consists of an array of GPS sensors and communication
units to be placed in the monitoring area. The hardware-dependent control software communicates with the GPS sensors and provides
the GPS baseline data and covariance information to the GOCA deformation analysis software. The GOCA center, which comprises
both the control software and the GOCA software, may be linked – for example, over a long distance – to another personal computer
(PC) that serves as a remote control station. GOCA is able to provide the full capabilities of classical deformation analysis
online (with stations grouped into stable points and moving object points). Both types of points may be occupied either continuously
or over short periods at different times. The object points are determined with respect to the stable points. A network adjustment
is performed for each interval of data collection, and the coordinate and covariance information may optionally be transformed
into a specific reference system (e. g., the building system). Unstable reference points are to be detected by statistical
tests. The estimated object point time series are filtered with respect to gross errors using robust estimation techniques.
Online filters are used to smooth the time series data of critical displacements and to predict other deformation functions.
The time series data, as well as prediction results, are displayed graphically for each object point. An example concerning
the online monitoring of a slag heap in a coal-mining area is included. ? 2000 John Wiley & Sons, Inc. 相似文献
69.
Boron recycling in the continental crust of the central Andes from the Palaeozoic to Mesozoic, NW Argentina 总被引:4,自引:2,他引:2
Simone Kasemann Jörg Erzinger Gerhard Franz 《Contributions to Mineralogy and Petrology》2000,140(3):328-343
Whole-rock chemical composition and 11B/10B isotope ratios in tourmaline was investigated to study the geochemical recycling of boron during the evolution of the Andean
basement from the Palaeozoic to Mesozoic. In the basement (Cambrian to Ordovician high-grade paragneisses, migmatites and
orthogneisses, the Eocambrian Puncoviscana Formation, and Paleozoic-Mesozoic granitoid igneous rocks) whole-rock B contents
are generally below 100 ppm, but B contents of ˜1 wt% are found in cogenetic aplite and pegmatite dikes and in tourmaline–quartz
rocks. In the metasedimentary rocks, no systematic variation in B content because of metamorphic grade and no correlation
of B with other incompatible elements are apparent. Tourmalines from the high-grade metamorphic basement yield δ11B values ranging from −11.2 to −6.8‰ and isotope fractionation during migmatisation was small. Metamorphic tourmalines from
the Puncoviscana Formation have δ11B values between −6.3 and −5.8‰. The calculated (corrected for fractionation) δ11B values of −6 to −2‰ for the sedimentary protolith of the metamorphic basement indicate a continental B source with subordinate
marine input. Tourmalines from Palaeozoic and Mesozoic granitoids display an identical range of δ11B values from −12 to −5.3‰ and indicate a similarly homogeneous B source throughout time. Tourmalines from pegmatites and
tourmaline–quartz rocks record the average δ11B values of the parental granitic magma. We assume that B in the Palaeozoic and Mesozoic granitoids is derived from the local
metamorphic basement supporting the hypothesis that recycling of the lower Palaeozoic crust is the dominant process in granitic
magma formation from Palaeozoic to Mesozoic.
Received: 15 December 1999 / Accepted: 11 July 2000 相似文献
70.