295,927 research outputs found
Seismic data reveal eastern Black Sea Basin structure
No full textRifted continental margins are formed by progressive extension of the lithosphere. The development of these margins plays an integral role in the plate tectonic cycle, and an understanding of the extensional process underpins much hydrocarbon exploration. A key issue is whether the lithosphere extends uniformly, or whether extension varies\ud
with depth. Crustal extension may be determined using seismic techniques. Lithospheric extension may be inferred from the waterloaded subsidence history, determined from\ud
the pattern of sedimentation during and after rifting. Unfortunately, however, many rifted margins are sediment-starved, so the subsidence history is poorly known.\ud
To test whether extension varies between the crust and the mantle, a major seismic experiment was conducted in February–March 2005 in the eastern Black Sea Basin (Figure 1), a deep basin where the subsidence history is recorded\ud
by a thick, post-rift sedimentary sequence. The seismic data from the experiment indicate the presence of a thick, low-velocity zone, possibly representing overpressured sediments. They also indicate that the basement and\ud
Moho in the center of the basin are both several kilometers shallower than previously inferred. These initial observations may have considerable impact on thermal models of the petroleum system in the basin. Understanding\ud
the thermal history of potential source rocks is key to reducing hydrocarbon exploration risk. The experiment, which involved collaboration between university groups in the United Kingdom, Ireland, and Turkey, and BP and\ud
Turkish Petroleum (TPAO), formed part of a larger project that also is using deep seismic reflection and other geophysical data held by the industry partners to determine the subsidence history and hence the strain evolution of\ud
the basin
Willamette Basin Irrigation Conference
No full textIrrigation equipment / John W. Wolfe -- Reclamation research / Dr. W.L. Powers -- Fertilization and irrigation / Arthur S. King -- Irrigated pastures / Harold Ewalt -- Cost of irrigating vegetable crops / M. H. Becker -- Irrigation of vegetable crops / Carl Robertson -- Water resource development plans, Bureau of Reclamation / Lee McAllister.This archived document is maintained by the Oregon State Library as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Title from caption.Typescript.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Review of integrated approaches to river basin, planning, development and management
No full textPiecemeal approaches to river basin development and management may not fully recognize the interactions and interdependence among components of a river basin system. River basin management that focuses on a single water use, on a single sector, or on the supply to particular segment of the basin population may inadvertently disrupt other sectors of the economy (in time or space). Hence, advocating for a systems approach to river basin development - for models that could help account for a river basin's key components and help address various objectives. The authors review the literature on such economic models, including models that deal with issues of water quality and quantity or with environmental considerations, recreational demand, countrywide planning, and multiple objective planning. Their review may serve as a source of references for those who need to consider whether they can use a model. Readers can evaluate the suitability, advantages, and disadvantages of particular modeling approaches for specific objectives.Water Conservation,River Basin Management,Water and Industry,Environmental Economics&Policies,Decentralization,Environmental Economics&Policies,Water Conservation,Water Supply and Sanitation Governance and Institutions,Water and Industry,Town Water Supply and Sanitation
Labelled Deduction
No full textPreface - D. Basin, M. D'Agostino, D. M. Gabbay, S. Matthews, L. Viganò.
Labelled Proof Systems for Intuitionistic Provability - V. Balat, D. Galmiche.
Normal Multimodal Logics with Interaction Axioms - M. Baldoni.
The SAT Problem of Signed CNF Formulas - B. Beckert, R. Hähnle, F. Manyà.
Discipline as Logic: Treating Labels as First Class Citizens - P. Blackburn.
Labelled Abduction (I) - K. Broda, D.M. Gabbay.
Labelled Tableaux for Propositional Linear Time Logic over Finite Frames - S. Cerrito, M. Cialdea Mayer.
Fibred Modal Tableaux - D.M. Gabbay, G. Governatori.
Labelled Deduction for the Guarded Fragment - M. Marx, S. Mikulás, S. Schlobach.
Semantics for Temporal Annotated Constraint Logic Programming - A. Raffaetà, T. Frühwirth.
The Logic of Reusable Propositional Output with the Fulfilment Constraint - L. van der Torre
River basin trajectories: societies, environments and development
No full textRiver basin management / River basin development / Hydrology / Water governance / Water use / History / Water allocation / Water transfer / Water quality / Irrigation management / Groundwater management / Surface irrigation / Water lifting / Pumping / Middle East / Jordan / South Africa / Mexico / Tunisia / Tanzania / Iran / India / China / USA / Australia / Lower Jordan River Basin / Olifants River Basin / Lerma-Chapala River Basin / Mediterranean River Basin / Great Ruaha River / Zayandeh Rud River Basin / Krishna River Basin / Bhavani River Basin / Yellow River Basin / Colorado River Basin / Murray Darling River Basin / Merguellil Basin
Structure and evolution of the intracratonic Congo Basin
No full textSurface wave tomography, heat flow, and crustal thickness measurements have demonstrated that the thickness of the continental lithosphere varies by at least a factor of 2. Since the thermal time constant of the lithosphere depends upon the square of its thickness, subsidence records of extensional sedimentary basins offer a potential way of extending these observations into the past. Here we examine the Congo basin, a large and iconic intracratonic sedimentary basin in Central Africa. This roughly circular basin covers an area in excess of 1.4 × 106 km2 with more than 5 km thickness of sedimentary rocks, the oldest parts of which are late Precambrian in age. First, we assess the thickness of the lithosphere. We have estimated its thickness across Africa using maps of shear wave velocity obtained by inversion of fundamental and higher-mode surface waveforms. The Congo Basin sits on 220 ± 30 km thick lithosphere and appears to be part of a southern core to the continent encompassing both Archean cratons and Proterozoic mobile belts. This thickness is consistent with published estimates from kimberlites. Reappraisal of legacy seismic reflection images demonstrates that the sedimentary section is underlain by a Late Precambrian rift zone and that the basin is still subsiding today. Subsidence modeling of two deep wells is consistent with uniform extension and cooling of the lithosphere by a factor of 1.2 during latest Precambrian and Cambrian time; we argue that the exceptional 0.55 Ga history of the basin is a direct consequence of the lithospheric thermal time constant being a factor of 4 longer than normal. Today, the basin coincides with a long-wavelength −30 to −40 mGal gravity anomaly. We interpret this gravity anomaly as the surficial manifestation of 400–600 m of recent mantle convective drawdown in response to the onset of upwelling plumes around the flanks of the southern African continent. The alternative explanation, that it is the static manifestation of locally thick lithosphere, is inconsistent with global trends of mantle density depletion. Our interpretation is consistent with fast seismic velocities observed throughout the sublithospheric upper mantle underneath the basin and recent geodynamic modeling
Understanding sedimentation in the Song Hong–Yinggehai Basin, South China Sea
No full textThe Cenozoic Song Hong–Yinggehai Basin in the South China Sea contains a large volume of sediment that has been used in previous studies, together with regional geomorphology, to argue for the existence of a large palaeodrainage system that connected eastern Tibet with the South China Sea. To test this and to understand the significance of sediment volumes deposited in the Song Hong–Yinggehai Basin, this study compared erosion histories of source regions with sediment volumes deposited during the two main stages in basin evolution spanning active rifting and subsidence (30–15.5 Ma) and postrift sedimentation (15.5 Ma to present). The study of basin provenance by detrital zircon U-Pb dating revealed Hainan was an important and continuous source of sediment, and a bedrock thermochronological study quantified its overall contribution to basin sedimentation. Comparison between the accumulated mass of basin sediment and volumes of eroded bedrock, calculated from apatite thermochronometry across the modern Red River drainage in northern Vietnam as well as Hainan Island, accounted for the bulk of sediment deposited since 30 Ma. Consequently, if an expanded paleodrainage ever existed it must have predated the Oligocene
Delaware River Basin Commission Annual Report 1998
No full textThe Delaware River Basin Compact, between the federal government and the four signatory states (Delaware, New Jersey, New York, and Pennsylvania) ensures that water resource decisions are based on a majority vote among the five signatory parties. The instrument through which the Compact's terms are implemented is the Delaware River Basin Commission. The Commission addresses plans, projects, and policies dealing with water supply, pollution control, flood protection, conservation, watershed management, recreation, and, on a rare occasion, hydroelectric power. This 1998 annual report discusses changes in the Commission's membership, water regulations and monitoring of water quality in the Delaware River, public educational information, and a financial summary for the Commission.This report covers calendar year 1998. It was compiled and edited by Christopher M. Roberts, the Commission's public information officer. Material for the report was generated by Commission staff.Purpose: To summarize the activities of the Delaware River Basin Commission in 1998
Delaware River Basin Commission Annual Report 1999
No full textThe Delaware River Basin Compact, between the federal government and the four signatory states (Delaware, New Jersey, New York, and Pennsylvania) ensures that water resource decisions are based on a majority vote among the five signatory parties. The instrument through which the Compact's terms are implemented is the Delaware River Basin Commission. The Commission addresses plans, projects, and policies dealing with water supply, pollution control, flood protection, conservation, watershed management, recreation, and, on a rare occasion, hydroelectric power. This 1999 annual report discusses changes in the Commission's membership, water regulations and monitoring of water quality in the Delaware River, public educational information, and a financial summary for the Commission.This report covers calendar year 1999. It was compiled and edited by Christopher M. Roberts, the Commission's public information officer. Material for the report was generated by Commission staff.Purpose: To summarize the activities of the Delaware River Basin Commission in 1999
The middle Waikato Basin and hills
No full textThe middle Waikato (or Hamilton) Basin is a roughly oval-shaped depression more than 80 km north to south and more than 40 km wide. The basin, except in the south, is almost completely surrounded by ranges up to 300 m high, broken by only a few gaps. In the south the basin floor rises gradually and merges with the dissected plateaux of the King Country
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