排序方式： 共有12条查询结果，搜索用时 31 毫秒
1.
A long-term study on the chemistry of percolating waters in a very large touristic karst cave (Grotta Gigante, northern Italy)
was carried out in order to define recharge zones, flowpaths, and possible anthropogenic contamination from the neighboring
area. On the basis of a multivaried analysis of the chemical parameters, a discrimination of the dripping points was attempted.
Percolation waters whose recharge zone is in the northernmost sector of the cave appeared permanently affected by the anthropic
settlements and agricultural activity on the ground surface.
Received: 28 April 1997 · Accepted: 3 February 1998 相似文献
2.
Pietro Mosca Riccardo Polino Sergio Rogledi Massimo Rossi 《International Journal of Earth Sciences》2010,99(4):833-849
Alps and Apennines are juxtaposed within an approximately 100 km-wide area covered by the Upper Eocene to Miocene successions
of the Tertiary Piedmont Basin. The Upper Eocene–Oligocene evolution of this area was characterized to the north and west
by the propagation of the SE-verging Southalpine thrust-fold belt that can be traced from the Po Plain subsurface until the
Torino Hill-Saluzzese area, and to the south by a high-angle, broadly E–W oriented megashear zone that led to the juxtaposition
of different crustal levels and controlled the development of a mosaic of partly independent sub-basins. Since the latest
Oligocene the N-verging Apenninic tectonics prevailed in the collisional system and the Tertiary Piedmont Basin evolved as
a wide thrust-top basin, bounded to the north by the N-verging Monferrato arc and characterized by a tectono-sedimentary evolution
recording changes of subsidence and shift of depocentres in relation to crustal structures. 相似文献
3.
Petrological constraints on the tectonic setting of the Kathmandu Nappe in the Langtang–Gosainkund–Helambu regions,Central Nepal Himalaya 
下载免费PDF全文
下载免费PDF全文 The Gosainkund–Helambu region in central Nepal occupies a key area for the development of Himalayan kinematic models, connecting the well‐investigated Langtang area to the north with the Kathmandu Nappe (KN), whose interpretation is still debated, to the south. In order to understand the structural and metamorphic architecture of the Greater Himalayan Sequence (GHS) in this region, a detailed petrological study was performed, focusing on selected metapelite samples from both the Gosainkund–Helambu and Langtang transects. The structurally lowest sample investigated belongs to the Lesser Himalayan Sequence; its metamorphic evolution is characterized by a narrow hairpin P–T path with peak P–T conditions of 595 ± 25 °C, 7.5 ± 1 kbar. All of the other samples here investigated belong to the GHS. Along the Langtang section, two tectono‐metamorphic units have been distinguished within the GHS: the Lower Greater Himalayan Sequence (L‐GHS), characterized by peak P–T conditions at 728 ± 11 °C, 10 ± 0.5 kbar (corresponding to a T/depth ratio of 22 ± 1 °C km?1), and the structurally higher Upper Greater Himalayan Sequence, with peak metamorphic conditions at 780 ± 20 °C, 7.8 ± 0.8 kbar (corresponding to a T/depth ratio of 31 ± 4 °C km?1). This confirms the existence of a main tectono‐metamorphic discontinuity within the GHS, as previously suggested by other authors. The results of petrological modelling of the metapelites from the Gosainkund–Helambu section show that this region is entirely comprised within a sub‐horizontal and thin L‐GHS unit: the estimated peak metamorphic conditions of 734 ± 19 °C, 10 ± 0.8 kbar correspond to a uniform T/depth ratio of 23 ± 3 °C km?1. The metamorphic discontinuity identified along the Langtang transect and dividing the GHS in two tectono‐metamorphic units is located at a structural level too high to be intersected along the Gosainkund–Helambu section. Our results have significant implications for the interpretation of the KN and provide a contribution to the more general discussion of the Himalayan kinematic models. We demonstrate that the structurally lower unit of the KN (known as Sheopuri Gneiss) can be correlated with the L‐GHS unit; this result strongly supports those models that correlate the KN to the Tethyan Sedimentary Sequence and that suggest the merging of the South Tibetan Detachment System and the Main Central Thrust on the northern side of the KN. Moreover we speculate that, in this sector of the Himalayan chain, the most appropriate kinematic model able to explain the observed tectono‐metamorphic architecture of the GHS is the duplexing model, or hybrid models which combine the duplexing model with another end‐member model. 相似文献
4.
V. A. Kudryavtsev N. J. C. Spooner P. K. Lightfoot J. W. Roberts M. J. Lehner T. Gamble M. J. Carson T. B. Lawson R. Lüscher J. E. McMillan B. Morgan S. M. Paling M. Robinson D. R. Tovey N. J. T. Smith P. F. Smith G. J. Alner S. P. Hart J. D. Lewin R. M. Preece T. J. Sumner W. G. Jones J. J. Quenby B. Ahmed A. Bewick D. Davidge J. V. Dawson A. S. Howard I. Ivaniouchenkov M. K. Joshi V. Lebedenko I. Liubarsky J. C. Barton G. Gerbier J. Mallet L. Mosca C. Tao 《Astroparticle Physics》2002,17(4):79-408
The status of dark matter searches with inorganic scintillator detectors at Boulby mine is reviewed and the results of tests with a CsI(Tl) crystal are presented. The objectives of the latter experiment were to study anomalous fast events previously observed and to identify ways to remove this background. Clear indications were found that these events were due to surface contamination of crystals by alphas, probably from radon decay. A new array of unencapsulated NaI(Tl) crystals immersed either in liquid paraffin or pure nitrogen atmosphere is under construction at Boulby. Such an approach allows complete control of the surface of the crystals and the ability to remove any surface contamination. First data from the unencapsulated NaI(Tl) do not show the presence of anomalous fast events. 相似文献
5.
S. Pcourt B. Chambon M. de Jsus D. Drain G. Gerbier J. Mallet M. Massaq L. Mosca C. Pastor C. Tao L. Vagneron 《Astroparticle Physics》1999,11(4):52-462
The quenching factor of cesium and iodine nuclei recoiling in a CsI(Tl) scintillator is measured by scattering of 3 to 6 MeV neutrons. This factor increases when recoil energy decreases, from 7% at 150 keV to 15% at 25 keV. This relatively high efficiency could be useful in experiments dealing with very low recoil energies like the WIMP direct detection. These values are well explained by the Birks model. Pulse shape discrimination between electron and nuclei recoils is also investigated. Results are sufficiently good to allow a significant statistical rejection of radioactive background. This rejection capability is shown to be better than for NaI(Tl), at the same electron equivalent energy. 相似文献
6.
The Ligurian Alps segment of the Alpine–Apennine orogen in NW Italy is unconformably covered by Upper Eocene to Holocene sediments in the Tertiary Piedmont Basin (TPB) and Po Plain. These sediments dip towards the north demonstrating the erosional nature of the southern border of the succession and implying that the adjacent orogenic belt formed the substratum rather than the margin of the sedimentary basin. Apatite (U–Th)/He and fission track thermochronology shows that the orogen first subsided and was buried at >4 km from 30 to 26 Ma and began its exhumation thereafter. From 26 Ma to present, this upward movement was contemporaneous with subsidence in the northern TPB. The couple exhumation in the S and subsidence in the N migrated northwards through time. Vertical movements in the area are similar to those reconstructed in Corsica. In both cases, the onset of exhumation becomes younger away from the Ligurian‐Provençal basin and has little correlation with the opening of the surrounding oceanic basins. 相似文献
7.
Y. Messous B. Chambon V. Chazal M. De J sus D. Drain C. Pastor A. de Bellefon M. Chapellier G. Chardin E. Gaillard-Lecanu G. Gerbier Y. Giraud-H raud D. Lhote J. Mallet L. Mosca M. -C. Perillo-Isaac C. Tao D. Yvon 《Astroparticle Physics》1995,3(4):361-366
The ionization deposited in a Ge crystal by the scattering of ≈ 1 MeV neutrons on Ge nuclei is measured and its lowenergy behavior is investigated down to recoil energies of 3 keV. This calibration study is fundamental for the discrimination of Weakly Interacting Massive Particles (WIMPs) from the radioactive background. Experimental results are compared with theoretical predictions. 相似文献
8.
Mainly on the basis of seismic data, we reconstruct magnitude and timing of Miocene to Present vertical movements in the region of the Savigliano basin, an up to 4 km thick succession of Neogene to Quaternary sediments accumulated inside the Alpine arc at the western termination of the Po Plain. We focus, in particular, on the margins of the basin which are the link between the mountain range and the subsiding basin. Seismic data from these regions allow for the definition of upward and downward vertical movements (uplift-exhumation and subsidence) with a spatial and temporal resolution which cannot be attained by other methods. The eastern, southern and western margins of the Savigliano basin display very different geometries of the sedimentary bodies and, therefore, document different vertical movements during Miocene to Present times. The eastern part of the Savigliano basin, and the regions to the E, experienced subsidence followed by exhumation. The southern margin of the basin, in the Cuneo area, was much more stable with Miocene to present formations all pinching-out close to the present day outcropping position of the basement-sedimentary cover contact. In the W, seismic sections record a stage of tilting until the Burdigalian, followed by generalized subsidence which affected also the adjacent regions of the SW Alps. The overall pattern of vertical movements is essentially controlled by the NW-ward migration of a syncline–anticline couple with the synclinal axis presently located in the center of the Savigliano basin. The width of the folds is in the order of 30–60 km (1/2 wavelength). In map view, the trace of the fold axes changes from N–S in the Savigliano basin to E–W in the Alessandria basin. 相似文献
9.
10.
Mosca I. Sargeant S. Baptie B. Musson R. M. W. Pharaoh T. C. 《Bulletin of Earthquake Engineering》2022,20(2):633-675
Bulletin of Earthquake Engineering - We present updated seismic hazard maps for the United Kingdom (UK) intended for use with the National Annex for the revised edition of Eurocode 8. The last... 相似文献