Use of shallow groundwater temperature profiles to infer climate and land use change: interpretation and measurement challenges          下载免费PDF全文

Nicolò Colombani  Beatrice Maria Sole Giambastiani  Micòl Mastrocicco 《水文研究》2016,30(14):2512-2524

Temperature is often used to infer the effect of land use and climate conditions on aquifers. Reliable data are needed to examine the temperature behaviour in the subsurface; thus, the use of robust acquisition techniques is unavoidable. Three temperature measurement techniques were applied to assess the sources of bias that could occur during temperature logging in a shallow Quaternary coastal aquifer in Ferrara (Northern Italy). Open borehole temperature logging, multilevel sampling straddle packers isolated temperature measurements within a flow cell above ground and multilevel sampling straddle packers isolated temperature measurements via an in‐well level logger (MLS‐IW) were compared for several coastal monitoring wells to gain insights on the limitations of each technique. Results show that the source of bias between the three applied techniques are different: (i) the open borehole temperature logging method tends to record heat convection through the open borehole and is not representative of the aquifer temperature distribution; (ii) the multilevel sampling straddle packers isolated temperature measurements within a flow cell above ground method is swayed by the air temperature and the heating of the submersible pump used to lift groundwater above ground; and (iii) the MLS‐IW provides the most reliable vertical thermal profiling both in summer and winter, because groundwater temperature is directly measured at the selected monitoring depth. The implementation of a 1D flow model demonstrates that if precise temperature profiles are needed to infer the influence that land use and climate changes have on groundwater, the MLS‐IW method is a reliable method that could be applied to existing monitoring wells. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

The convergence problem of collocation solutions in the framework of the stochastic interpretation     

F. Sansò  G. Venuti 《Journal of Geodesy》2011,85(1):51-63

The problem of the convergence of the collocation solution to the true gravity field was defined long ago (Tscherning in Boll Geod Sci Affini 39:221–252, 1978) and some results were derived, in particular by Krarup (Boll Geod Sci Affini 40:225–240, 1981). The problem is taken up again in the context of the stochastic interpretation of collocation theory and some new results are derived, showing that, when the potential T can be really continued down to a Bjerhammar sphere, we have a quite general convergence property in the noiseless case. When noise is present in data, still reasonable convergence results hold true.

“Democrito che ’l mondo a caso pone” “Democritus who made the world stochastic” Dante Alighieri, La Divina Commedia, Inferno, IV – 136  相似文献   

Diagenetic and thermal history of the Jurassic-Tertiary succession of the Zagros Mountains in the Dezful Embayment (SW Iran): constraints from fluid inclusions     

A. Ceriani  R. Calabrò  A. Di Giulio  R. Buonaguro 《International Journal of Earth Sciences》2011,100(6):1265-1281

To constraint the diagenetic and thermal history in the Mesozoic-Tertiary succession of the Zagros Fold-Belt, a study was performed on fluid inclusions trapped in intergranular, vug, and fracture-filling cements in Jurassic to Miocene outcrop samples collected along the Anneh and Fahliyan Valleys of Khuzestan Province, southwest Iran. Petrographic observations showed at least two systems of fractures that postdate intergranular cementation. Two different types of oil-filled fluid inclusions occur in the intergranular cements and in the first fracture network, but they are absent in the second fracture network. Microthermometry of fluid inclusions was used to determine the temperature and salinity of fluids responsible for mineral precipitation. Within intergranular cements and calcite fillings the oldest fractures, precipitation occurred from high saline fluids in a temperature range of 60–120°C, depending on the stratigraphic depth. The strong correlation between fluid inclusions temperature and stratigraphic depth suggests that the intergranular cementation and the first fracture-filling event occurred prior to structural deformation. Furthermore, this correlation indicates a relatively constant paleogeothermal gradient at the time of cement precipitation of about 28°C/Km. On the contrary, fluid inclusions trapped in cements within the second fracture network lack oil and contain freshwater trapped at low temperatures that do not correlate to the stratigraphic position. This suggests second fracturing event occurred after oil migration and during or after deformation of the Zagros Fold-Belt, when the samples were in a near-surface position.  相似文献   

Re-testing the JET-X Flight Module No. 2 at the PANTER facility     

Daniele Spiga  Gianpiero Tagliaferri  Paolo Soffitta  Oberto Citterio  Stefano Basso  Ronaldo Bellazzini  Alessandro Brez  Wolfgang Burkert  Vadim Burwitz  Enrico Costa  Luca de Ruvo  Ettore Del Monte  Sergio Fabiani  Gisela Hartner  Benedikt Menz  Massimo Minuti  Fabio Muleri  Giovanni Pareschi  Michele Pinchera  Alda Rubini  Carmelo Sgrò  Gloria Spandre 《Experimental Astronomy》2014,37(1):37-53

The Joint European X-ray Telescope (JET-X) was the core instrument of the Russian Spectrum-X- γ space observatory. It consisted of two identical soft X-ray (0.3–10 keV) telescopes with focusing optical modules having a measured angular resolution of nearly 15 arcsec. Soon after the payload completion, the mission was cancelled and the two optical flight modules (FM) were brought to the Brera Astronomical Observatory where they had been manufactured. After 16 years of storage, we have utilized the JET-X FM2 to test at the PANTER X-ray facility a prototype of a novel X-ray polarimetric telescope, using a Gas Pixel Detector (GPD) with polarimetric capabilities in the focal plane of the FM2. The GPD was developed by a collaboration between INFN-Pisa and INAF-IAPS. In the first phase of the test campaign, we have re-tested the FM2 at PANTER to have an up-to-date characterization in terms of angular resolution and effective area, while in the second part of the test the GPD has been placed in the focal plane of the FM2. In this paper we report the results of the tests of the sole FM2, using an unpolarized X-ray source, comparing the results with the calibration done in 1996.  相似文献   

A multidisciplinary investigation of deep-seated landslide reactivation triggered by an extreme rainfall event: a case study of the Monesi di Mendatica landslide,Ligurian Alps     

Notti  Davide  Wrzesniak  Aleksandra  Dematteis  Niccolò  Lollino  Piernicola  Fazio  Nunzio Luciano  Zucca  Francesco  Giordan  Daniele 《Landslides》2021,18(7):2341-2365

Landslides - In November 2016, an extreme rainfall event affected the Ligurian Alps (NW Italy). Consequently, several landslides and debris flows occurred in the upper Tanarello stream basin. In...  相似文献   

Physical controls on sand composition and relative durability of detrital minerals during ultra‐long distance littoral and aeolian transport (Namibia and southern Angola)          下载免费PDF全文

Eduardo Garzanti  Alberto Resentini  Sergio Andò  Giovanni Vezzoli  Alcides Pereira  Pieter Vermeesch 《Sedimentology》2015,62(4):971-996

Sediment in coastal Namibia to southern Angola is supplied dominantly from the Orange River with minor additional fluvial input and negligible modifications by chemical processes, which makes this a great test case for investigating physical controls on sand texture and composition. This study monitored textural, mineralogical and geochemical variability in beach and aeolian‐dune sands along a ca 1750 km stretch of the Atlantic coast of southern Africa by using an integrated set of techniques, including image analysis, laser granulometry, optical microscopy, Raman spectroscopy and bulk‐sediment geochemistry. These results contrast with previous reports that feldspars and volcanic detritus break down during transport, that sand grains are rounded rapidly in shallow‐marine environments, and that quartzose sands may be produced by physical processes. Mechanical wear is unable to modify the relative abundance of detrital components, including pyroxene and mafic volcanic rock fragments traditionally believed to be destroyed rapidly. The sole exceptions are poorly lithified or cleaved sedimentary/metasedimentary rock fragments, readily lost at the transition to the marine environment, and slow‐settling flaky micas, winnowed and deposited offshore. Coastal sediments tend to be depleted in relatively mobile amphibole, preferentially entrained offshore or re‐deposited in sheltered beaches, while less mobile garnet is retained onshore. No detrital mineral displays a significant increase in grain roundness after 300 to 350 km of longshore transport in high‐energy littoral environments from the Orange mouth to south of the Namib Erg, but all minerals get rapidly rounded after passing into the dunefield. Pyroxene and opaques get rounded faster than harder quartz and garnet, but sand mineralogy remains unchanged. Excepting strong transient selective‐entrainment effects, physical processes are unable to modify sand composition significantly. Selective mechanical breakdown can be largely neglected in quantitative provenance analysis of sand and sandstone even in the case of ultra‐long‐distance transport in high‐energy environments dominated by strong persistent winds and waves.  相似文献   

Reclamation influence and background geochemistry of neutral saline soils in the Po River Delta Plain (Northern Italy)     

Dario Di Giuseppe  Barbara Faccini  Micòl Mastrocicco  Nicolò Colombani  Massimo Coltorti 《Environmental Earth Sciences》2014,72(7):2457-2473

Reclaimed neutral saline sulphate soils constitute a large part of the eastern part of Po Plain lowlands, where intensive agricultural activities take place. The knowledge of their geochemical features is essential to develop the best management practices capable to preserve this threatened environment. With this aim, three boreholes were drilled in an agricultural field and a typical reclaimed soil profile has been characterized for major and trace element, pH, electrical conductivity, redox conditions and water-soluble anions and ammonium. Statistical analysis (cluster analysis and principal component analysis) has been used to understand the relationship between elements and grain size. The soil profile is characterized by high salinity and high organic matter contents responsible for high chloride, sulphate, and ammonium concentrations. Heavy metal content is naturally high, since Po Plain sediments are the result of ultramafic rocks erosion; in addition, organic matter tends to concentrate heavy metals by adsorption, mainly in peaty horizons. As a consequence of chemical and zootechnical fertilization, high NO₃ ^? contents have been found in the top soil, thus enhancing the risk of nitrate discharge in the water system, especially in relation to extreme climatic events.  相似文献   

Thermodynamic modeling assisted by multivariate statistical image analysis as a tool for unraveling metamorphic P-T-d evolution: an example from ilmenite-garnet-bearing metapelite of the Peloritani Mountains, Southern Italy     

Patrizia Fiannacca  Deborah Lo Pò  Gaetano Ortolano  Rosolino Cirrincione  Antonino Pezzino 《Mineralogy and Petrology》2012,106(3-4):151-171

An ilmenite-garnet-bearing schist from the medium-grade metapelite complex of the Mandanici Unit in the Peloritani Mountains has been investigated to constrain the P-T conditions attained in this sector of the southern European Hercynian chain. Microprobe investigations assisted by statistical handling of X-ray maps via principal component analysis allowed us to better elucidate the porphyroblast-matrix relationships, the geometry of the elemental distribution in garnet porphyroblasts and the average volume percentage of the reactant garnet during retrograde metamorphic evolution. Selected microprobe data were then used to constrain, by means of P-T pseudosections, the main P-T stages of the metamorphic evolution, using the XRF bulk-rock chemistry as the equilibrium chemical composition for the prograde and peak stages and an effective bulk-rock composition for the retrograde one. Peak metamorphic P-T estimates (~530?°C; 0.9?GPa) are consistent with a Hercynian crustal thickening stage at middle-lower crustal conditions, while subsequent evolution, constrained at 420–460?°C; 0.30–0.60?GPa, depicts a retrograde clockwise P-T trajectory linked to exhumation under likely extensional shearing conditions. The results obtained in this paper lead to envisage a new scenario for the crustal evolution of the Peloritani Mountains and stimulate a revision of previous interpretations in the light of the new investigation techniques.  相似文献   

Grain-size dependence of sediment composition and environmental bias in provenance studies     

Eduardo Garzanti  Sergio Andò  Giovanni Vezzoli 《Earth and Planetary Science Letters》2009,277(3-4):422-432

This article investigates both experimentally and theoretically the compositional changes associated with textural effects and hydraulic sorting during sediment transport and deposition, which cause systematic distortion in quantitative provenance analysis (“environmental bias”). Traditional procedures aimed at eliminating textural noise find limited success. The Gazzi–Dickinson method cannot remove hydrodynamic-related modal variability. Multiple size-window strategies are time-consuming. Narrow or moving size-window strategies represent misleading or impractical short cuts, being less convenient options than simply analysing each sample in bulk. New concepts introduced here unravel the superposed causes of compositional variability in modern sediments. Intrasample modal variability, fundamentally explained by settling-equivalence relationships, can be accurately modelled mathematically. Intersample modal variability, principally resulting from selective entrainment, can be assessed and removed by a simple principle. In absence of provenance changes and environmental bias, the weighted average density of terrigenous grains (SRD index) should be equal, for each sample and each grain-size class of each sample, to the weighted average density of source rocks. By correcting relative abundances of detrital minerals in proportion to their densities, we can restore the appropriate SRD index for any provenance and subprovenance type in each sample or grain-size class. Modal variability is effectively reduced by this procedure, which can be applied confidently to modern sediments deposited by tractive currents in any environment. Good results are obtained even for placer sands and finest classes where heavy-mineral concentration is strongest. Such “SRD correction” also successfully compensates for biased narrow-window modes, thus providing a numerical solution of general validity to the problem of environmental bias in sedimentary petrology. After compensating for settling-equivalence and selective-entrainment effects, residual size-dependent compositional variability may be provenance-related. Minor in Ganga–Brahmaputra sediments, provenance-related effects are spectacularly displayed in the Nile basin, where volcaniclastic silt mixes with basement-derived quartzofeldspathic sand and wind-blown Saharan quartz.  相似文献   

Defining Geodetic Reference Frame using Matlab®: PlatEMotion 2.0     

Flavio Cannavò  Mimmo Palano 《Pure and Applied Geophysics》2016,173(3):937-944

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