After twenty years of parliamentary democracy in Spain the Basque liberation movement ETA is still using violent methods. Considerable support for ETA has persisted in the Spanish Basque Country. Based on voting patterns in Euskadi the persistent support for ETA is studied. ETA support through voting for its political wing Herri Batasuna is concentrated in specific areas. Through ecological analysis the relative weight of cultural, socio-economic, demographic and locational factors in voting patterns is determined. At a local level particular cultural contexts reproduce support for violent separatism. The continuity of violence legitimisation is a Spanish Basque phenomenon as it is confined to the Basque-speaking parts of Spain. The small-size settlements of the Basque Country offer a context of social control which enables mass legitimisation of political violence. 相似文献
This paper presents an overview of the ways that natural radionuclides have been used as tracers of biogeochemical processes occurring in the coastal ocean. The radionuclides involved include those in the uranium and thorium decay series and those produced in the atmosphere by the interaction of cosmic rays with atmospheric gases (i.e., cosmogenic radionuclides). The property of radioactivity provides a chronometer with which to measure the rates of oceanic processes, and the fundamental biogeochemical behavior of the radionuclide determines which process(es) it may be used to trace. Examples from recent research will be presented in the talk. 相似文献
Extended X-ray absorption fine-structure (EXAFS) spectroscopy is used to characterize the local coordination of selected rare-earth elements (Nd3+, Sm3+, Dy3+, Yb3+) coprecipitated with calcite in minor concentrations from room-temperature aqueous solutions. Fitting results confirm substitution in the Ca site, but first-shell Nd-O and Sm-O distances are longer than the Ca-O distance in calcite and longer than what is consistent with ionic radii sums for sixfold coordination in the octahedral Ca site. In contrast, first-shell Dy-O and Yb-O distances are shorter than the Ca-O distance and are consistent with ionic radii sums for sixfold coordination. Comparison of Nd-O and Sm-O bond lengths with those in lanthanide sesquioxides and with ionic radii trends across the lanthanide series suggests that Nd3+ and Sm3+ have sevenfold coordination in a modified Ca site in calcite. This would require some disruption of the local structure, with an expected decrease in stability, and possibly a different charge compensation mechanism between Nd and Sm vs. Yb and Dy. A possible explanation for the increased coordination for the larger rare-earth elements involves bidentate ligation from a CO3 group. Because trivalent actinides such as Am3+ and Cm3+ have ionic radii similar to Nd3+, their incorporation in calcite may result in a similar defect structure. 相似文献
A stock of biotite-muscovite-garnet leucogranite crops out in the lower course of Río Cisnes as an unusual minor lithology within the predominantly dioritic to tonalitic North Patagonian Batholith. Foliated and unfoliated varieties are present—the former are nearer to the main lineament of the Liquin˜e-Ofqui Fault Zone (LOFZ). Two-feldspar thermometry indicates equilibration temperatures above 600°C, for pressures probably not over 3 kbar, as suggested by the Mn-rich garnet composition. A Rb-Sr whole-rock isochron age of 9.6 ± 0.4 Ma (1σ error) probably indicates the time of magma crystallization. 40Ar-39Ar ages of 6.6 ± 0.3 Ma on muscovite and 5.5 ± 0.4 Ma on biotite are cooling ages from which a moderate average uplift/denudation rate ( 1 mm/yr) may be calculated. Paucity of occurrence, distribution close to the LOFZ and a near minimum-melt composition all suggest that the leucogranite magma was derived by partial melting of the lower crust, perhaps by decompression melting at a time when uplift/denudation rates were high (4 mm/yr or more are required). Regional evidence for rapid Holocene uplift in the immediate vicinity of the LOFZ substantiates the feasibility of the proposed petrogenetic model, which may be valid in other strike-slip orogenic environments. 相似文献
The objective of this study was to assess the possible impact of deep well disposal operations, conducted between 1958 and 1974, on the ground water quality in a shallow fresh water aquifer beneath Sarnia, Ontario, Canada. Because of the breakout of formation fluids in Sarnia and Port Huron, Michigan, in the early 1970s, it had been hypothesized that liquid waste from the disposal zone in bedrock had leaked through numerous abandoned oil, gas, and salt wells in the area up to the shallow fresh water aquifer and from there to the surface. A monitoring well network of 29 5cm (2 inch) diameter piezometers was established in the thin sand and shale aquifer system, which exists between 30 and 70m (100 and 230 feet) below ground surface. In addition, a 300m (1000 foot) deep borehole was drilled and instrumented with a Westbay multilevel casing, which permitted sampling of the disposal zone. Ground water samples from the shallow monitoring wells and the Westbay multilevel casing were analyzed for volatiles by GC/MS. Those volatile aromatics that were conspicuously present in the deep disposal zone, e.g., ethyl toluenes and trimethyl benzene, were not detected in the shallow monitoring wells. Thus, if contaminants from the disposal zone did indeed migrate to the shallow aquifer, contamination was not widespread and probably consisted mostly of displaced chloride-rich formation waters. 相似文献
The Malloryville Wetland Complex, a small kettle-hole peatland, contains a diversity of peatland types. The wetland has a ‘rich’ side that contains wetland vegetation associated with solute-rich, near-neutral pH (minerotrophic) water, and a ‘poor’ side containing vegetation that grows in solute-poor and acidic (ombrotrophic) water. Vertical head gradients at piezometer clusters located in the rich side clearly show that groundwater is moving upwards towards the land surface, consistent with the vegetation types and surface water quality. In contrast, vertical head gradients also show that groundwater is moving upward in the poor side even though the vegetation and surface water chemistry are not minerotrophic. An incipient raised bog in the center of the poor side is the only site where groundwater moves consistently downward.
A peat core collected at the bog center shows that the bog site was initially covered by minerotrophic vegetation, typically found in groundwater discharge zones, which was later replaced by ombrotrophic bog vegetation. Theoretical computer simulation experiments of the bog hydrogeologic setting through time suggest that the direction of vertical groundwater flow at the bog site permanently changed from up to down when a water table mound developed under a convex-shaped fen peat mound that probably formed because of differential peat accumulation. Ombrotrophic conditions and bog vegetation probably began when the fen water table mound grew sufficiently large enough to divert the upward movement of regional groundwater. The transition from rich to poor environments probably occurred when the wetland water table was substantially below the elevation of the surrounding regional water table. 相似文献
—The 12 November 1996 Mw 7.7 Peru subduction zone earthquake occurred off the coast of southern Peru, near the intersection of the South American trench and the highest topographical point of the subducting Nazca Ridge. We model the broadband teleseismic P-waveforms from stations in the Global Seismic Network to constrain the source characteristics of this subduction zone earthquake. We have analyzed the vertical component P-waves for this earthquake to constrain the depth, source complexity, seismic moment and rupture characteristics. The seismic moment determined from the nondiffracted P-waves is 3–5 × 1020 N·m, corresponding to a moment magnitude Mw of 7.6–7.7. The source time function for the 1996 Peru event has three pulses of seismic moment release with a total duration of approximately 45–50 seconds. The largest moment release occurs at approximately 35–40 seconds and is located ~90km southeast of the rupture initiation. Approximately 70% of the seismic moment was released in the third pulse.¶We find that the 1996 event reruptured part of the rupture area of the previous event in 1942. The location of the 1996 earthquake corresponds to a region along the Peru coast with the highest uplift rates of marine terraces. This suggests that the uplift may be due to repeated earthquakes such as the 1996 and 1942 events. 相似文献