Articoli di riviste: "Petrofabric analysis"

1

HO, T. L. "Petrofabric Analysis by Means of X-Ray1". Bulletin of the Geological Society of China 27, n. 1 (29 maggio 2009): 389–98. http://dx.doi.org/10.1111/j.1755-6724.1947.mp27001027.x.

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Lloyd, Geoffrey E., Colin C. Ferguson e Richard D. Law. "Discriminatory petrofabric analysis of quartz rocks using SEM electron channelling". Tectonophysics 135, n. 1-3 (aprile 1987): 243–49. http://dx.doi.org/10.1016/0040-1951(87)90165-x.

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Ho, T. L. "Petrofabric Analysis of Some Wutal Schist and its Bearing on the Tectonite*". Bulletin of the Geological Society of China 26, n. 1 (29 maggio 2009): 109–19. http://dx.doi.org/10.1111/j.1755-6724.1946.mp26001006.x.

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Ui, Tadahide, Keiko Suzuki-Kamata, Rumi Matsusue, Kei Fujita, Hideya Metsugi e Mami Araki. "Flow behavior of large-scale pyroclastic flows ? Evidence obtained from petrofabric analysis". Bulletin of Volcanology 51, n. 2 (marzo 1989): 115–22. http://dx.doi.org/10.1007/bf01081980.

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Lloyd, Geoffrey E., e Colin C. Ferguson. "A spherical electron-channelling pattern map for use in quartz petrofabric analysis". Journal of Structural Geology 8, n. 5 (gennaio 1986): 517–26. http://dx.doi.org/10.1016/0191-8141(86)90002-7.

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Krzesińska, Agata, Jérôme Gattacceca, Jon M. Friedrich e Pierre Rochette. "Impact‐related noncoaxial deformation in the Pułtusk H chondrite inferred from petrofabric analysis". Meteoritics & Planetary Science 50, n. 3 (marzo 2015): 401–17. http://dx.doi.org/10.1111/maps.12429.

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Philpotts, Anthony R., e Nancy Wilson. "Application of Petrofabric and Phase Equilibria Analysis to the Study of a Potsherd". Journal of Archaeological Science 21, n. 5 (settembre 1994): 607–18. http://dx.doi.org/10.1006/jasc.1994.1060.

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Sychev, S. N., R. V. Veselovskiy, A. K. Khudoley e K. V. Kulikova. "Thrust and strike-slip deformations on the southern part of polar Urals based on the rock magnetic data". Moscow University Bulletin. Series 4. Geology, n. 6 (28 dicembre 2016): 46–55. http://dx.doi.org/10.33623/0579-9406-2016-6-46-55.

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Petromagnetic characteristics rocks croup out in the Main Uralian Fault zone and Voikar- Synya ophiolites confirmed that multistage deformation led to formation of modern structure of Ural. Analysis of the anisotropy of the magnetic susceptibility of rock minerals detects orienta- tion formed by the thrust (reverse faults) and strike-shear strain at an early stage of the Uralian orogeny. The main axes of the ellipsoid of the anisotropy of magnetic susceptibility associated with regional thrusting - the main stage of formation of structure of the Urals have been revealed rarely. It indicates almost complete resetting thrust petrofabric by later shear deformations.

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Lloyd, Geoffrey E., Richard D. Law e Stefan M. Schmid. "A spherical electron channelling pattern map for use in quartz petrofabric analysis: correction and verification". Journal of Structural Geology 9, n. 2 (gennaio 1987): 251–53. http://dx.doi.org/10.1016/0191-8141(87)90031-9.

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Renjith, A. R., e Manish A. Mamtani. "Domainal petrofabric analysis of micaceous quartzite using EBSD data: Role of muscovite in LPO evolution of quartz". Journal of the Geological Society of India 83, n. 5 (maggio 2014): 479–82. http://dx.doi.org/10.1007/s12594-014-0074-6.

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Lee, K. Y., e B. W. Robertson. "Petrofabric study using electron channeling patterns of quartzes and hematites in dual-phase banded iron formations". Proceedings, annual meeting, Electron Microscopy Society of America 53 (13 agosto 1995): 388–89. http://dx.doi.org/10.1017/s0424820100138312.

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Research in deformation of rocks requires the understanding of structure-property relationship. The study of structure-property relationships requires knowledge of the crystallographic texture on a local scale. Electron Channeling in scanning microscope has been used to analyze textures of local features in a microstructure, misorientations between grains and the spatial arrangement of grains of individual crystallographic orientations can be determined. This information is critical for a mechanical understanding of microstructure evolution during the deformation of rocks. Petrofabric analysis using Electron Channeling Patterns can use normal geological thin sections and mounted sections, which allows relatively fast and easy interpretation and allows one to determine the relationship between a microstructural feature and the individual orientations of its grains. The most efficient and satisfactory way of accomplishing this task is by direct electronic detection and indexing of Kikuchi patterns, which requires modification of the microscope, at considerable cost. This study, however, has been undertaken using only an unmodified SEM with electron channeling capability.

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Graziani, Riccardo, Chiara Montomoli, Salvatore Iaccarino, Luca Menegon, Laura Nania e Rodolfo Carosi. "Structural setting of a transpressive shear zone: insights from geological mapping, quartz petrofabric and kinematic vorticity analysis in NE Sardinia (Italy)". Geological Magazine 157, n. 11 (20 aprile 2020): 1898–916. http://dx.doi.org/10.1017/s0016756820000138.

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AbstractThe Posada–Asinara Line is a crustal-scale transpressive shear zone affecting the Variscan basement in northern Sardinia during Late Carboniferous time. We investigated a structural transect of the Posada–Asinara Line (Baronie) with the aid of geological mapping and structural analysis. N-verging F2 isoclinal folds with associated mylonitic foliation (S2) are the main deformation features developed during the Posada–Asinara Line activity (D2). The mineral assemblages and microstructures suggest that the Posada–Asinara Line was affected by a retrograde metamorphic path. This is also confirmed by quartz microstructures, where subgrain rotation recrystallization superimposes on grain boundary migration recrystallization. Crystallographic preferred orientation data, obtained using electron backscatter diffraction, allowed analysis of quartz slip systems and estimation of the deformation temperature, vorticity of flow and rheological parameters (flow stress and strain rate) during the Posada–Asinara Line activity. Quartz deformation temperatures of 400 ± 50 °C have been estimated along a transect perpendicular to the Posada–Asinara Line, in agreement with the syn-kinematic post-metamorphic peak mineral assemblages and the late microstructures of quartz. The D2 phase can be subdivided in two events: an early D2early phase, related to the metamorphic peak and low kinematic vorticity (pure shear dominated), and a late D2late phase characterized by a lower metamorphic grade and an increased kinematic vorticity (simple shear dominated). Palaeopiezometry and strain rate estimates associated with the D2late deformation event showed an intensity gradient increasing towards the core of the shear zone. The D2early deformation developed under peak temperature conditions, while the D2late event was active at shallower structural levels.

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JOHNSTON, J. D. "Localization of mid-crustal thrust ramps by metadolerite sheets in the Dalradian of northwest Ireland". Geological Magazine 134, n. 2 (marzo 1997): 199–212. http://dx.doi.org/10.1017/s0016756897006663.

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The Slieve League peninsula in southwest Donegal affords some of the best exposures of the Dalradian Appin/Argyll Group transition available in Ireland. As a result, a refined stratigraphical column is available, allowing resolution of small- (metric-) scale imbrication of parts of the sequence. Large-scale D2 thrust nappes dominate the structure of the region, and the rocks have undergone multiple folding and complex cleavage development. In the Glencolumbkille valley, an imbricate duplex has been mapped in detail. Original intrusive relationships of metadolerite sheets controlled the geometry of subsquent deformation. A major ramp cuts up through the established stratigraphy and is controlled by a pre-D2 metadolerite intrusion. Throughout the region, major and minor ramps are localized by the metadolerite sheets. Within the thrust sheets, analysis of quartz petrofabric and clast fabrics in hangingwall mylonites within the Boulder Bed document kinematics and strain localization within the thrust sheets. Axial ratios in the dolomitic clasts increase up to a maximum of 30 [ratio ] 1 adjacent to the ductile thrusts. However, granite clast axial ratios are less pronounced adjacent to some of the shears, suggesting that strain may have partitioned into the matrix at high strains.

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Cao, Yi, Haemyeong Jung, Shuguang Song, Munjae Park, Sejin Jung e Jaeseok Lee. "Plastic Deformation and Seismic Properties in Fore-arc Mantles: A Petrofabric Analysis of the Yushigou Harzburgites, North Qilian Suture Zone, NW China". Journal of Petrology 56, n. 10 (ottobre 2015): 1897–944. http://dx.doi.org/10.1093/petrology/egv053.

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15

Salisbury, Matthew H., e Nikolas I. Christensen. "Olivine fabrics in the Bay of Islands Ophiolite: implications for oceanic mantle structure and anisotropy". Canadian Journal of Earth Sciences 22, n. 12 (1 dicembre 1985): 1757–66. http://dx.doi.org/10.1139/e85-186.

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Petrofabric analysis of oriented ultramafic and mafic rock samples from six traverses representing all four massifs of the Bay of Islands ophiolite complex, Newfoundland, indicate that the ultramafic rocks are tectonites displaying fabrics consistent with high-temperature plastic flow on the olivine (010) [100] and (0kl) [100] slip systems. The fabric orientation is uniform in three of the four massifs but varies between massifs, suggesting differential rotation before or during emplacement. Within North Arm Mountain, the olivine a axes are aligned approximately perpendicular to the sheeted dikes in both the ultramafic tectonites and the overlying gabbroic tectonites. In Blow Me Down Mountain, the olivine a axes in the gabbros are perpendicular to the dikes, but they are parallel to them in the ultramafic rocks. It is concluded that the ultramafic rocks on Blow Me Down Mountain were rotated 90° during emplacement or that local decoupling and rotation occurred between the crust and upper mantle prior to emplacement. Within the Lewis Hills, the olivine fabrics rotate and weaken near the shear zone in the center of the massif. A second deformation, perhaps associated with low-temperature plastic flow, appears to have obliterated the fabric patterns still observed in the ultramafic rocks to the east.

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Xue, Zhenhua, Guillaume Martelet, Wei Lin, Michel Faure, Yan Chen, Wei Wei, Shuangjian Li e Qingchen Wang. "Mesozoic Crustal Thickening of the Longmenshan Belt (NE Tibet, China) by Imbrication of Basement Slices: Insights From Structural Analysis, Petrofabric and Magnetic Fabric Studies, and Gravity Modeling". Tectonics 36, n. 12 (dicembre 2017): 3110–34. http://dx.doi.org/10.1002/2017tc004754.

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Tikhonravova, Yana V., Viktor V. Rogov e Elena A. Slagoda. "Genetic Identification Of Ground Ice By Petrographic Method". GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 14, n. 4 (28 dicembre 2021): 20–32. http://dx.doi.org/10.24057/2071-9388-2021-063.

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The advantages and limitations of the petrography method and the relevance of its use for the study of natural ice are reviewed in the present work. The petrographic method of ground ice study is often used for solving paleogeographic issues. The petrofabric analysis of ground ice is not only useful for descriptive purposes but, like the study of cryostructures, helps to infer growth processes and conditions. Different types of natural ice have specific features that can help us to determine ice genesis. Surface ice, such as glacier ice is often presented by foliation formed by large crystals (50-60 mm); lake ice is characterised by the upper zone of small (6 mm x 3 mm) dendritic and equigranular crystals, which change with increasing depth to large (may exceed 200 mm) columnar and prismatic crystals; segregated ice is composed by crystals forming foliation. Ground ice, such as ice wedge is presented by vertical-band appearance and small crystals (2-2.5 mm); closed-cavity ice is often distinguished by radial-ray appearance produced by elongated ice crystals; injection ice is composed by anhedral crystals, showing the movement of water; snowbank ice is presented by a high concentration of circular bubbles and small (0.1-1 mm) equigranular crystals; icing is described by foliation and mostly columnar crystals. Identification of the origin of ground ice is a complicated task for geocryology because it is difficult to distinguish different types of ground ice based on only visual explorations. The simplest way to get an ice texture pattern is by using polarized light. Distinctions between genetic types of ground ice are not always made in studies, and that can produce erroneous inferences. Petrography studies of an ice object are helpful to clarify the data interpretation, e.g., of isotopic analyses. It is particularly relevant for heterogeneous ice wedges’ study.

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Wang, Chia-Yin. "Petrofabric Analyses of Quartz Veins in the Hengshan Granodiorite*". Bulletin of the Geological Society of China 26, n. 1 (29 maggio 2009): 121–28. http://dx.doi.org/10.1111/j.1755-6724.1946.mp26001007.x.

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Yeriomina, Natalia, Vladimir Gridin, Zinaida Sterlenko, Yelena Tumanova e Katerina Chernenko. "Structure-texture peculiarities influence on petrophysical properties of Neftekumsk carbonate sediments". E3S Web of Conferences 164 (2020): 01007. http://dx.doi.org/10.1051/e3sconf/202016401007.

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The analysis of structure-texture peculiarities of carbonate sediments of Neftekumsk’ reservoir within the limits of Zimne-Stavkinsko- Pravoberezhny field was realized in the field of massive bioherm buildups and interreef lowerings in accordance with data of the core analyses. The existing pore space was divided into structure-texture classes. The correlations between petrofabrics and petrophysical parameters were determined. The received data can be used for describing of the three- dimensional distribution of petrophysical properties with the aim to increase the quality of three-dimensional (3-D) geological models.

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Pollard, W. H., e H. M. French. "The Internal Structure and Ice Crystallography of Seasonal Frost Mounds". Journal of Glaciology 31, n. 108 (1985): 157–62. http://dx.doi.org/10.1017/s0022143000006407.

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AbstractThe crystal character of the ice core within frost blisters supports the hypothesis that groundwater injection into residual zones of the active layer followed by rapid freezing is the primary growth mechanism for these features. The ice core is characterized by an upper zone of relatively small randomly arranged equigranular ice crystals which change with increasing depth to columnar anhedral crystals, commonly exceeding 200 mm in length, and with crystal diameters ranging between 25 and 35 mm. Petrofabric analyses show that thec-axis orientations are normal to crystal elongations, with crystal growth along the basal plane in ana-axis direction. These observations eliminate ice segregation as a possible growth mechanism, thereby distinguishing seasonal frost mounds from palsas.

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Pollard, W. H., e H. M. French. "The Internal Structure and Ice Crystallography of Seasonal Frost Mounds". Journal of Glaciology 31, n. 108 (1985): 157–62. http://dx.doi.org/10.3189/s0022143000006407.

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AbstractThe crystal character of the ice core within frost blisters supports the hypothesis that groundwater injection into residual zones of the active layer followed by rapid freezing is the primary growth mechanism for these features. The ice core is characterized by an upper zone of relatively small randomly arranged equigranular ice crystals which change with increasing depth to columnar anhedral crystals, commonly exceeding 200 mm in length, and with crystal diameters ranging between 25 and 35 mm. Petrofabric analyses show that the c-axis orientations are normal to crystal elongations, with crystal growth along the basal plane in an a-axis direction. These observations eliminate ice segregation as a possible growth mechanism, thereby distinguishing seasonal frost mounds from palsas.

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Law, R. D., S. S. Morgan, M. Casey, A. G. Sylvester e M. Nyman. "The Papoose Flat Pluton of eastern California: a reassessment of its emplacement history in the light of new microstructural and crystallographic fabric observations". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 83, n. 1-2 (1992): 361–75. http://dx.doi.org/10.1017/s0263593300008026.

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ABSTRACTOne of the most outstanding apparent examples in N America of a forcibly emplaced pluton is the Papoose Flat Pluton of eastern California. Sideways expansion of this granitic pluton, during emplacement into a series of Cambrian shelf strata, has been regarded by early workers as resulting in the observed intense crystal plastic deformation of the pluton's mylonitic border facies and surrounding country rocks. This deformation is evidenced by up to 90% thinning of individual stratigraphic layers within the pluton's metamorphic aureole, although such intense penetrative deformation of the country rocks is not observed outside the aureole.Previously published quartz c-axis fabrics associated with this deformation (and presented on projection planes oriented perpendicular to lineation) were interpreted as being symmetrical with respect to foliation and lineation, implying almost coaxial deformation histories. Such fabrics could be interpreted as indicating that the pluton evolved by “ballooning” as a result of new magma being intruded into its core during emplacement. However, a major problem with applying the strict ballooning model to the Papoose Flat Pluton is that while oblate strains would be expected to develop in association with a ballooning mechanism, the mylonitic rocks of this elongate WNW-ESE-trending pluton and its aureole are characterised by both a strongly developed foliation, which is concordant with the pluton's margin, and an intense, NW-SE trending, shallow plunging stretching lineation.Previously published fabrics from the Papoose Flat Pluton and its metamorphic aureole have been rotated on to a projection plane oriented parallel to lineation and perpendicular to foliation. Examination of the fabrics in this projection plane has revealed that they are in fact dominantly asymmetric, and that a constant sense of asymmetry is detected across the pluton, suggesting a consistent (top-to-the-SE) shear-sense. This new interpretation is strongly supported by microstructural and petrofabric analysis of additional L-S tectonites collected, during recent fieldwork, from both the aureole and quartz veins within the pluton's gneissic border facies. Thus mylonite formation around the Papoose Flat Pluton could have involved large-scale consistently oriented translation and associated shearing, rather than passive “blister-like” coaxial deformation associated with pluton ballooning. It should be noted that mylonitic deformation is restricted to the western half of the pluton, features indicative of a more “permitted” emplacement mechanism being found in the eastern portion of the pluton.The detected top-to-the-SE shear-sense could be interpreted as indicating that the granitic material forming the western part of the pluton was forcibly intruded in a northwestward direction from the pluton source as a nearly solidified wedge beneath a static cover of sedimentary rocks. Alternatively, the detected shear sense could also be interpreted as indicating SE-directed thrusting of the cover rocks over the underlying pluton, the western margin of the pluton suffering intense mylonitic deformation, while the eastern margin was located in a “stress-shadow” region. If this alternative interpretation is correct, then the deformation temperatures indicated by the pattern of quartz c-axis fabrics dictate that thrusting must either be synchronous with pluton emplacement, or at least have commenced during the early stages of pluton cooling.

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Aravadinou, E., e P. Xypolias. "Evolution of a passive crustal-scale detachment (Syros, Aegean region): Insights from structural and petrofabric analyses in the hanging-wall". Journal of Structural Geology 103 (ottobre 2017): 57–74. http://dx.doi.org/10.1016/j.jsg.2017.09.008.

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Lane, Larry S., Edward D. Ghent, Mavis Z. Stout e Richard L. Brown. "P–T history and kinematics of the Monashee Décollement near Revelstoke, British Columbia". Canadian Journal of Earth Sciences 26, n. 2 (1 febbraio 1989): 231–43. http://dx.doi.org/10.1139/e89-019.

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Microstructural and petrofabric analyses of mylonites from the Monashee Décollement demonstrate that the hanging wall was displaced eastward over the footwall. Microstructural kinematic indicators include shear-band foliation, asymmetric strain shadows, and S–C fabrics. Quartz c axes locally exhibit asymmetric fabrics that are consistent with the microstructural evidence for sense of shear. The kinematic evidence is reliable because multiple criteria coexist within individual specimens.Metamorphic assemblages from footwall Monashee Complex pelites at the Revelstoke damsite indicate that the peak metamorphic assemblage was sillimanite–K-feldspar–biotite–almandine–quartz ± plagioclase. Biotite–garnet geothermometry and garnet–plagioclase–sillimanite–quartz geobarometry set broad constraints on metamorphic temperatures but closer constraints on pressures, near 650 °C and 630 MPa.Comparison of these data with Late Cretaceous hornblende cooling ages from the same locality indicates that the metamorphism is at least as old as Late Cretaceous. Complex microstructures relating to repeated mylonitization and annealing render difficult the correlation of metamorphic conditions with mylonitic fabrics. Early mylonitic textures predate the metamorphic equilibration and thus are pre-Late Cretaceous in age. Postmetamorphic mylonites are well preserved, but their ages are poorly constrained. The present interpretation favours a Late Cretaceous to Paleocene age relating to compressional tectonics. However, an Early Eocene age relating to extensional shearing cannot be excluded.

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Mahmoudi Sivand, Siamak, Ali Faghih, Saeede Keshavarz e Masoumeh Soleimani. "Characterizing syn-convergent extension along the Neybaz-Chatak detachment shear zone, Central Iran: Insights from microstructures, quartz petrofabrics and flow vorticity analysis". Journal of Structural Geology 143 (febbraio 2021): 104270. http://dx.doi.org/10.1016/j.jsg.2020.104270.

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Saha, Dilip. "Universal stage measurements in petrofabric analysis revisited". Journal of Earth System Science 130, n. 3 (7 giugno 2021). http://dx.doi.org/10.1007/s12040-021-01618-x.

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"Discriminatory petrofabric analysis of quartz rocks using SEM electron channelling". International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 24, n. 5 (ottobre 1987): 179. http://dx.doi.org/10.1016/0148-9062(87)90918-1.

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Griffin, S., L. Daly, T. Keller, S. Piazolo, L. V. Forman, M. R. Lee, R. J. Baumgartner et al. "Constraints on the emplacement of Martian nakhlite igneous rocks and their source volcano from advanced micro‐petrofabric analysis". Journal of Geophysical Research: Planets, 16 maggio 2022. http://dx.doi.org/10.1029/2021je007080.

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Eftekhari, Negar, Parviz Holakooei, Elena Marrocchino e Carmela Vaccaro. "To be or not to be local: a provenance study of archaeological ceramics from Shahr-i Sokhta, eastern Iran". Archaeological and Anthropological Sciences 13, n. 4 (27 marzo 2021). http://dx.doi.org/10.1007/s12520-021-01307-2.

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AbstractFindings from the archaeological site of Shahr-i Sokhta in eastern Iran include a wide range of undecorated, monochrome, and polychrome ceramics with gray, red, and buff-colored bodies that date back to a period spanning from 3200 to 1800 B.C.E. Given the large number and variety of ceramics unearthed from Shahr-i Sokhta, the provenance of these wares has remained a subject of controversy. Based on compositional data obtained from quantitative wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy studies and petrographic observations, findings from this study provide information that can be used to determine whether the ceramics from Shahr-i Sokhta were manufactured locally or were imported from elsewhere. We show here that the chemical components of a large group of ceramics with gray, red, and buff-colored bodies are similar to those found in local clay sources and kiln wasters, suggesting local production of these wares. However, one group of red and gray-colored wares demonstrated entirely different chemistry, suggesting a different origin. In support of the quantitative WDXRF data, petrofabric analysis of the first group of buff, gray, and red wares revealed poorly sorted basaltic clasts similar to those found randomly distributed in the matrix of local clays. By contrast, the non-local gray and red wares exhibited fine-grained clay bodies with sorted distribution of fine-grained quartz within the clay matrix.

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Lawrence, A., M. Maffione e C. T. E. Stevenson. "Mush ado about the Ratagain Complex, NW Scotland: Insights on Caledonian granitic magmatism and emplacement from magnetic fabric analyses". Scottish Journal of Geology, 19 aprile 2022, sjg2021–018. http://dx.doi.org/10.1144/sjg2021-018.

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The anisotropy of magnetic susceptibility (AMS) is used to reveal subtle mineral alignment fabrics in apparently isotropic crystalline lithologies, including granites. Such petrofabrics can be produced by emplacement-related magma flow or post-emplacement tectonic strain. However, discriminating between flow-related and tectonic fabrics using field observations alone may be challenging and is usually a broad and arbitrary interpretation. In this contribution, we employ a range of magnetic analyses to characterize the origin of the petrofabric in the ∼425 Ma Ratagain Complex, NW Scotland, a composite Late Caledonian granitic intrusion. Our detailed magnetic analyses reveal that whilst all intrusive units carry an ambient tectonic overprint, critically, this has not developed into an obvious tectonic fabric and contains a horizontal shortening component indicative of transpression. This appears at odds with the well-defined Silurian (Scandian phase) regional transtensional tectonic regime from c.420 – 415 Ma onwards. Accordingly, we suggest that either the complex is younger than previously thought or that it existed as a crystal-mush close to the magmatic solidus for a protracted period after its initial emplacement. This study lays the foundations for much-needed further investigations into the detailed emplacement-mechanisms, timescales and petrogenesis of individual granitic intrusions, to aid understanding of Late Caledonian tectonics.Thematic collection: This article is part of the Early Career Research collection available at: https://www.lyellcollection.org/cc/SJG-early-career-researchSupplementary material:https://doi.org/10.6084/m9.figshare.c.5941375

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Articoli di riviste sul tema "Petrofabric analysis"

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