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Alluvial fans and shallow carbonate lakes interfered in the Teruel half‐graben during the Late Miocene–Pliocene. Tectonic influence is recorded in alluvial and lacustrine–palustrine successions, with long‐term climate changes being recorded in detail in the isotopic signatures of carbonates. Episodes of tectonic activity induced alluvial fan progradation and lake retraction in the whole basin. Three lacustrine stages have been identified, which support the idea that climate also exerted an important control on sedimentation. The transition between stages 1 and 2 occurred during a tectonically calm episode due to an increase in aridity in the Early Turolian; small fans with source areas next to the lake margin prograded, inducing lake‐shore retraction. The transition from stage 2 to 3 was caused by the superimposition of increasing tectonic activity and aridity effects. Our study demonstrates that discrimination of allogenic factors controlling sedimentation in continental closed basins is possible using sequence stratigraphy in combination with other techniques such as geochemistry of carbonates.  相似文献   
2.
This article analyzes the geochemical and mineralogical composition of the roofing slate deposits of the Iberian Peninsula. Most roofing slate deposits are found on Middle and Upper Ordovician terrains, although there are also deposits in the Ediacaran, Cambrian and Devonian terrains. Samples of slate were taken in most of the active quarries of the Iberian Peninsula, and being analyzed by X-ray Diffraction and Fluorescence. Each lithotect or slate productive formation has its own specific proportions of major and trace elements, being able to differentiate between them by using these relationships. This fact is particularly interesting in geological exploration and prospecting, as it allows knowing exactly the slate lithotect, and also for restoration work in the architectural heritage, due to the ability of identifying the source of the original slate tiles.  相似文献   
3.
X-ray Computed Tomography (X-ray CT) has been used to study the petrophysical characteristics of a Jurassic sandstone from Asturias (Northern Spain) used as building stone in several monuments in the region. CT monitoring of water capillarity tests has made it possible to visualize the movement of water inside the samples, to relate this movement with texture characteristics, and to measure the height reached in successive images, thereby determining the capillary penetration coefficient; based on this coefficient, the effective capillary pore radius has also been estimated. An advantage of the use of CT is that, as the information comes from the sample interior, border effects that can be generated in the external faces can be avoided.The CT was also used to visualize how a commercial organosilicon consolidant penetrates inside the rock by means of capillarity, a usual way of consolidant application in stone restoration processes. The coefficient of capillary penetration of the product, determined on the basis of the measurements made on the tomographic images, is 53% less than that of water. The influence of rock texture characteristics on the capillarity both of the consolidant and the water was also observed.The samples underwent CT water capillarity studies before and after the consolidant application, proving that the treatment improves the rock's hydric properties. The coefficient of capillary penetration decreased by 24% following the application of the consolidant, whereas the effective pore radius decreased by more than 40%.  相似文献   
4.
In palaeoseismological trench studies, precise correlation of sedimentary units between fault blocks has an unquestionable value for accurately inferring the amounts of coseismic displacement and hence for assessing seismic hazard. A methodology based on laser analysis of particle size and mineralogic composition by X-ray diffraction is proposed in order to strengthen the correlation of sedimentary units in a trench excavated across the Concud Fault (central Iberian Chain, Spain). The surveyed sediments show sharp and multiple lateral facies changes, as well as inconsistent optically stimulated luminescence (OSL) ages. The results reinforce the correlation based on field inspection of lithologic and sedimentologic features. Moreover, they allow interpretation of rejuvenation of OSL ages of samples in the upthrown fault block, which has been attributed to partial erosion of sedimentary units, as evidenced by their smaller thickness and erosive boundaries. The correlated units are then used to estimate coseismic displacements for three palaeoseismic events.  相似文献   
5.
The Bàlitx area is located on the steep coastal side of the Tramuntana Range (Majorca), a mountainous region which was declared a World Heritage Site by UNESCO in 2011 in the cultural landscape category. The Bàlitx site was occupied by farming areas with dry stone constructions and water storing systems of both Roman and Islamic origin. The coastal landscape is characterised by a large fault escarpment of up to 260 m in height. Lateral spreading processes are favoured by local stratigraphy and tectonics in an energetic coastal dynamics scenario. Block spreading morphologies are identified along the escarpment, with large, rocky blocks of volumes up to 60?×?103 m3 moving very slowly until their collapse. Consequently, a thick and highly karstified breccia deposit is accumulated at the base of the scarp. The lowest, oldest breccia outcrop has been dated (Th/U), and an age of 82.5?±?5.6 kyr was obtained, reflecting the time span this process has been active. Additionally, numerous geomorphological slope features are identified in the area: landslides, rockfalls, and, more specifically, long and deep cracks in the hanging wall block of the fault, which also reveal active lateral spreading processes. Coastal dynamics have been investigated by interpreting offshore geophysical studies, bathymetry data and borehole information to determine the role of wave energy in the stability of the slope. Additionally, 14 SAR images from the ALOS PALSAR satellite have been exploited for the present work, covering a period spanning from 2007 to 2010, an anomalous rainy period in the region. Images were processed using the Persistent Scattered Interferometry (PSI) technique. PSInSAR results reveal that the rate of movement for the Bàlitx lateral spreading is extremely low (??5.2 mm/year on average), but major activity has been detected in the NE sector, where velocity rates can reach values of up to ??16 mm/year Coastal dynamics in the area can explain this, as a small island generates wave refraction and reflection determining more intense erosive processes in the NE part, which lead to a greater destabilising effect on the slopes. A simple vulnerability approach has been developed to take the elements of cultural heritage into account. Vulnerability increases from SW to NE, in accordance with landslide activity. The Bàlitx case study could provide a testimony to the effects of mass movements and coastal dynamics in an exceptional example of Mediterranean agricultural landscape.  相似文献   
6.
Landslides - When an active landslide is first identified in an artificial reservoir, a comprehensive study has to be quickly conducted to analyse the possible hazard that it may represent to such...  相似文献   
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