New Data on the Age, Material Composition, and Geological Structure of the Central Kamchatka Depression (CKD). Part 2. The Mineralogical Composition of Volcanic Rocks and Mantle Xenoliths. Toward a Petrologic Model

This paper studies the original results of the material composition analysis of the Early Silurian terrigenous deposits of the Kordonka formation of the Paleozoic – Early Mesozoic Laoeling-Grodekovo terrane of the South Primorye. The research is aimed at reconstructing paleogeodynamic setting of the deposition of sediments of the formation, and determining the type and mother rock composition of the feed sources based on the complex genetic interpretation of the material composition of rocks. It was established that mineralogically and geochemically formation of the rocks correspond to the typical graywackes and represent petrogenic or “first cycle” rocks formed mainly through the source rock failure. They are characterized by a low maturity, low lithodynamic recycling rate of mother rocks and their rapid burial. The interpretation of the results of the complex study of the material composition of the rocks was carried out on the basis of its comparison with the compositions of ancient rocks and modern sediments formed in the well-known geodynamic settings. The obtained data indicate that deposits of the Kordonka formation accumulated in a sedimentary basin connected with an oceanic island arc. Being built by basic and intermediate volcanic rocks as well as by igneous and sedimentary rocks that constituted its base, this island arc was the source area that supplied clastic material to the aforementioned sedimentary basin.

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Applicability of Ground Penetrating Radar on desert archaeological sites: a case study from the Saqqara necropolis in Egypt

Studia Quaternaria ◽

10.2478/squa-2014-0014 ◽

2014 ◽

Vol 31 (2) ◽

pp. 133-141 ◽

Cited By ~ 1

Author(s):

Fabian Welc ◽

Radosław Mieszkowski ◽

Sebastian Kowalczyk ◽

Jerzy Trzciński

Keyword(s):

Ground Penetrating Radar ◽

Clay Fraction ◽

Mineralogical Composition ◽

Archaeological Site ◽

Geological Structure ◽

Horizontal Resolution ◽

Archaeological Sites ◽

Depth Range ◽

Non Invasive ◽

Ground Penetrating

Abstract This paper presents the preliminary results of ground penetrating radar sounding applied at the desert archaeological site in Saqqara (Egypt). The survey was carried out in 2012 within a project realized by Institute of Archaeology, Cardinal Stefan Wyszyński University in Warsaw and the Faculty of Geology, University of Warsaw. One of the key aims of the research was testing the application of ground penetrating radar to non-invasive surveys of desert archaeological sites. Radargrams obtained for area of so called the Dry Moat channel surrounding the Step Pyramid complex have shown the geological structure of its filling. It comprises among others debris-sand conglomerate of diluval origin characterized by a significant content of the clay fraction and clay minerals. Such lithological content strongly attenuate the propagation of EM waves, restricting the depth range of the GPR survey. The conducted geophysical prospection west to the Step Pyramid in Saqqara has confirmed the high applicability of the GPR method in non-invasive studies of vast architectural structures, such as the monumental ditch surrounding the Step Pyramid known as the Dry Moat. It should summarised that high horizontal resolution obtained during GPR survey is a result of local geological structure of the searched area, i.e. strong lithological contrast of the sediments filling the Dry Moat, which, depending on their mineralogical composition

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Ultramafic mantle xenoliths in the Late Cenozoic Volcanic rocks of the Antarctic Peninsula and Jones Mountains, West Antarctica

Geological Society London Memoirs ◽

10.1144/m56-2019-44 ◽

2021 ◽

pp. M56-2019-44

Author(s):

Philip T. Leat ◽

Aidan J. Ross ◽

Sally A. Gibson

Keyword(s):

Antarctic Peninsula ◽

Upper Mantle ◽

Lithospheric Mantle ◽

Volcanic Rocks ◽

Oceanic Lithosphere ◽

Incompatible Trace Element ◽

Mantle Xenoliths ◽

South Shetland Islands ◽

West Antarctica ◽

Gondwana Margin

AbstractAbundant mantle-derived ultramafic xenoliths occur in Cenozoic (7.7-1.5 Ma) mafic alkaline volcanic rocks along the former active margin of West Antarctica, that extends from the northern Antarctic Peninsula to Jones Mountains. The xenoliths are restricted to post-subduction volcanic rocks that were emplaced in fore-arc or back-arc positions relative to the Mesozoic-Cenozoic Antarctic Peninsula volcanic arc. The xenoliths are spinel-bearing, include harzburgites, lherzolites, wehrlites and pyroxenites, and provide the only direct evidence of the composition of the lithospheric mantle underlying most of the margin. The harzburgites may be residues of melt extraction from the upper mantle (in a mid-ocean ridge type setting), that accreted to form oceanic lithosphere, which was then subsequently tectonically emplaced along the active Gondwana margin. An exposed highly-depleted dunite-serpentinite upper mantle complex on Gibbs Island, South Shetland Islands, supports this interpretation. In contrast, pyroxenites, wehrlites and lherzolites reflect percolation of mafic alkaline melts through the lithospheric mantle. Volatile and incompatible trace element compositions imply that these interacting melts were related to the post-subduction magmatism which hosts the xenoliths. The scattered distribution of such magmatism and the history of accretion suggest that the dominant composition of sub-Antarctic Peninsula lithospheric mantle is likely to be harzburgitic.

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Redox state of southern Tibetan upper mantle and ultrapotassic magmas

Geology ◽

10.1130/g47411.1 ◽

2020 ◽

Vol 48 (7) ◽

pp. 733-736 ◽

Cited By ~ 1

Author(s):

Weikai Li ◽

Zhiming Yang ◽

Massimo Chiaradia ◽

Yong Lai ◽

Chao Yu ◽

...

Keyword(s):

Upper Mantle ◽

Lithospheric Mantle ◽

Redox State ◽

Volcanic Rocks ◽

Mantle Xenoliths ◽

Continental Plate ◽

Cratonic Mantle ◽

Tectonic Settings ◽

Mantle Condition ◽

Typical Range

Abstract The redox state of Earth’s upper mantle in several tectonic settings, such as cratonic mantle, oceanic mantle, and mantle wedges beneath magmatic arcs, has been well documented. In contrast, oxygen fugacity () data of upper mantle under orogens worldwide are rare, and the mechanism responsible for the mantle condition under orogens is not well constrained. In this study, we investigated the of mantle xenoliths derived from the southern Tibetan lithospheric mantle beneath the Himalayan orogen, and that of postcollisional ultrapotassic volcanic rocks hosting the xenoliths. The of mantle xenoliths ranges from ΔFMQ = +0.5 to +1.2 (where ΔFMQ is the deviation of log from the fayalite-magnetite-quartz buffer), indicating that the southern Tibetan lithospheric mantle is more oxidized than cratonic and oceanic mantle, and it falls within the typical range of mantle wedge values. Mineralogical evidence suggests that water-rich fluids and sediment melts liberated from both the subducting Neo-Tethyan oceanic slab and perhaps the Indian continental plate could have oxidized the southern Tibetan lithospheric mantle. The conditions of ultrapotassic magmas show a shift toward more oxidized conditions during ascent (from ΔFMQ = +0.8 to +3.0). Crustal evolution processes (e.g., fractionation) could influence magmatic , and thus the redox state of mantle-derived magma may not simply represent its mantle source.

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“Trachytes” from Sardinia: Geoheritage and Current Use

Sustainability ◽

10.3390/su11133706 ◽

2019 ◽

Vol 11 (13) ◽

pp. 3706 ◽

Cited By ~ 1

Author(s):

Nicola Careddu ◽

Silvana Maria Grillo

Keyword(s):

Volcanic Rocks ◽

Mineralogical Composition ◽

Building Stone ◽

Step Method ◽

Public And Private ◽

Current State ◽

Igneous Activity ◽

Mineral Components ◽

Granitoid Rocks ◽

The Aesthetic

Sardinia was affected by an intense igneous activity which generated calc-alkaline products during the Oligo-Miocene period. The volcanic substance shows large variations, ranging from pyroclastic flow deposits, lava flows and domes. By composition, the deposits are all primarily dacites and rhyolites, with subordinate andesites and very scarce basalts. The rhyolite lavas show porphyritic and ash-flow tuffs. Ignimbrite structures are found in the dacitic domes and rhyolitic lavas. These rocks—commercially known as “Trachytes of Sardinia”—used to be quarried in all historical provinces, mainly in the central part of the island to be used as ornamental and building stone. They continue to be commonly used nowadays, but their use dates back to the prehistoric age. They are easily found in many nuraghi, “domus de janas”, holy wells, Roman works (mosaics, paving, roads, bridges), many churches built in Sardinia and practically in all kinds of structural elements in public and private buildings, such as walls, houses, and bridges. Contrary to the granitoid rocks, whose appearance is largely influenced by the mineralogical composition, the aesthetic feature of volcanic rocks is rather affected by the widest range of colors, structure and texture, i.e., shape, size and distribution of mineral components, porphyric index, etc. “Trachyte” is quarried opencast with the “single low step” method, with descending development, with prevalent use of double-disc sawing machines. Whenever the stone deposit allows higher steps, the chain cutting machine, in combination with diamond wire, becomes the preferred extraction solution. This study aims to at look Sardinian “trachytes” from a geoheritage perspective. After a geological-petrographic framework, the paper discusses the historical uses of “trachyte” in Sardinia. The current state of the art of “trachyte” quarrying, processing and usage in the Island is also described. An analysis of the “trachyte” production has been carried out. Finally, a consideration about how to enhance geotourism in the area is suggested.

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II.—On the Origin of certain Banded Gneisses

Geological Magazine ◽

10.1017/s0016756800190405 ◽

1887 ◽

Vol 4 (11) ◽

pp. 484-493 ◽

Cited By ~ 3

Author(s):

J. J. H. Teall

Keyword(s):

Flow Structure ◽

Volcanic Rocks ◽

Mineralogical Composition ◽

Plutonic Rock ◽

Parallel Structure ◽

Present Purpose ◽

Parallel Arrangement ◽

Plutonic Rocks ◽

Chemical And Mineralogical Composition

The term gneiss as generally used by geological writers signifies a rock of granitic composition in which a parallel structure in the arrangement of the constituents is more or less apparent. For our present purpose it is important to note that other plutonic rocks besides granite (e.g. diorite, gabbro, and peridotite) have their gneissose equivalents, so that, if we use the term gneiss in a structural rather than in a mineralogical sense, we may speak of diorite-gneiss, gabbro-gneiss, and so on. Now the parallel structure of gneissose rocks is of two kinds. It may consist (1) of a parallel arrangement of certain constituents (e.g. mica plates or porphyritic felspars), or (2) of an alternation of bands of varying chemical and mineralogical composition. It is agreed on all hands that a parallel structure of the first kind may be due either to the deformation of a mass of half-consolidated plutonic rock at the time of intrusion, in which case it is strictly analogous to the flow structure in many volcanic rocks, or to deformation produced by earth-stresses operating on the mass after consolidation.

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Physical-Chemical Studies of the Process of Condensation of a Clinker-Free Binder

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.906.47 ◽

2022 ◽

Vol 906 ◽

pp. 47-52

Author(s):

Maria Badalyan ◽

Amalya Karapetyan ◽

Hovsep Hoveyan

Keyword(s):

Portland Cement ◽

Calcium Hydroxide ◽

Water Resistance ◽

Volcanic Rocks ◽

Mineralogical Composition ◽

Free Lime ◽

Hardening Process ◽

Chemical Studies ◽

The Difference ◽

Physical And Chemical

The possibility of using a clinker-free binder as an alternative to expensive and energy-intensive Portland cement is being considered. The pozzolanizing effect of volcanic rocks is presented, where along with the binding of calcium hydroxide by silica to hydrosilicates, the binding of calcium hydroxide by “free” alumina to hydroaluminates also takes place. In the process of hardening of the clinker-free binder, the phase mineralogical composition of the formed new formations differs from the new formations that are synthesized during hardening of traditional Portland cement, which explains the difference in their properties. The new formations that are formed during the hardening process of clinker-free cements are mainly low-basic hydrosilicates, and alkaline aluminosilicates give the cast-in-place stone water resistance, frost resistance, waterproofing, etc., in a word, durability. Physical and chemical studies of the hardening process of clinker-free lime-igneous cements have been carried out, which indicates the possibility of replacing the energy-intensive Portland cement with cheaper clinker-free cement.

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Fe-Cu-S rich melts in the subcontinental lithospheric mantle: insight from the Lower Silesian (SW Poland) xenoliths

10.5194/egusphere-egu2020-18544 ◽

2020 ◽

Author(s):

Hubert Mazurek ◽

Jakub Ciążela ◽

Magdalena Matusiak-Małek ◽

Jacek Puziewicz ◽

Theodoros Ntaflos

Keyword(s):

Lithospheric Mantle ◽

Volcanic Rocks ◽

Oceanic Lithosphere ◽

Mantle Xenoliths ◽

Subcontinental Lithospheric Mantle ◽

Origin And Evolution ◽

Depleted Mantle ◽

Group A ◽

Sw Poland ◽

Group B

Migration of strategic metals through the lithospheric mantle can be tracked by sulfides in mantle xenoliths. Cenozoic mafic volcanic rocks from the SW Poland (Lower Silesia, Bohemian Massif) host a variety of subcontinental lithospheric mantle (SCLM) xenoliths. To understand metal migration in the SCLM we studied metal budget of peridotites from the Wilcza G&#243;ra basanite and their metasomatic history.The Wilcza G&#243;ra xenoliths are especially appropriate to study metasomatic processes as they consist of 1) peridotites with OlFo=89.1-91.5 representing depleted mantle (group A); 2) peridotites with OlFo=84.2-89.2 representing melt-metasomatized mantle (group B), as well as 3) hornblende-clinopyroxenites and websterites with OlFo=77.2-82.5 representing former melt&#160; channels (group C; Matusiak-Ma&#322;ek et al., 2017). The inherent sulfides are either interstitial or enclosed in the silicates. High-temperature exsolutions of pyrrhotite (Po), pentlandite (Pn) and chalcopyrite (Ccp) indicate magmatic origin of the sulfides.The three peridotitic groups differ by sulfide mode and composition. The sulfide modes are enhanced in group C (0.022-0.963 vol.&#8240;) and group B (<0.028 vol. &#8240;) with respect to group A (<0.002 vol.&#8240;). The sulfides of group C are Ni-poor and Fe-Cu-rich as reflected in their mineral composition (Po55-74Ccp1-2Pn24-44 in group A, Po67-85Ccp1-6Pn14-33, in group B and Po80-97Ccp1-7Pn2-20 in group C) and major element chemical composition. Ni/(Ni+Fe) of pentlandite is the lowest in group C (~0.25) and the highest in group A (0.54-0.61). Cu/(Cu+Fe) of chalcopyrite is 0.32-0.49 in group C contrasting to~0.50 in groups A and B.&#160;The sulfide-rich xenoliths of group C indicate an important role of pyroxenitic veins in transporting Fe-Cu-S-rich melts from the upper mantle to the crust. However, the moderately enhanced sulfide modes in melt-mantle reaction zones represented by xenoliths of group B demonstrate that the upper continental mantle is refertilized with these melts during their ascent. Hence, significant portion of S and metals remains in the mantle never reaching the crust, as has been previously observed in the oceanic lithosphere (Ciazela et al., 2018).&#160;Acknowledgments: This study was supported by the NCN project no. UMO-2014/15/B/ST10/00095. The EPMA analyses were funded from the Polish-Austrian project WTZ PL 08/2018.&#160;References:Ciazela, J., Koepke, J., Dick, H. J. B., Botcharnikov, R., Muszynski, A., Lazarov, M., Schuth, S., Pieterek, B. & Kuhn, T. (2018). Sulfide enrichment at an oceanic crust-mantle transition zone: Kane Megamullion (23 N, MAR). Geochimica et Cosmochimica Acta, 230, 155-189Matusiak-Ma&#322;ek, M., Puziewicz, J., Ntaflos, T., Gr&#233;goire, M., Kuku&#322;a, A. & Wojtulek P.&#160;&#160; M. (2017). Origin and evolution of rare amphibole-bearing mantle peridotites from Wilcza G&#243;ra (SW Poland), Central Europe. Lithos 286&#8211;287, 302&#8211;323.

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The Geology of the British Virgin Islands

Geological Magazine ◽

10.1017/s0016756800086581 ◽

1924 ◽

Vol 61 (8) ◽

pp. 339-351 ◽

Cited By ~ 3

Author(s):

K. W. Earle

Keyword(s):

Dominican Republic ◽

Volcanic Rocks ◽

Virgin Islands ◽

Geological Structure ◽

Lesser Antilles ◽

Greater Antilles ◽

Igneous Intrusion ◽

British Virgin Islands ◽

The Caribbean ◽

Granitoid Intrusions

The geological structure of the British Virgin Islands correlates them indisputably with the Greater and not with the Lesser Antilles. The latter are composed essentially of Tertiary volcanic rocks of andesitic or basaltic type, with or without development of sedimentary strata which, when present, only dip at gentle angles and never show the violent effects of such dynamic forces as have been responsible for the folding and “up-ending” of the strata in the Virgin Islands. The tremendous depth of the channel separating the British Virgin Islands from the Lesser Antilles lias been ascribed to faulting, probably initiated in Pliocene times.The work of Cleve (1), Hill (4), Vaughan (5), and others (6) in the American Virgin Islands, Porto Rico, the Dominican Republic, Cuba, Haiti, and Jamaica, indicates that the British Virgin Islands form geologically only the eastern termination of that main group of islands and have been subjected to the same earth movements as them. The evidence for attributing a Cretaceous age to the sedimentary series has already been referred to.With regard to the age of the folding and igneous intrusion, Vaughan considers that the folding took place between upper Eocene and middle Oligoccne times, and that the intrusion of the diorites took place at approximately the same date. (7)Wythe Cooke considers that the igneous basal complex in the Dominican Republic certainly dates from Cretaceous time, but that part is probably older. He also considers that the stresses that folded and sheared these rocks were probably active during Eocene time or earlier, and that the intrusion of the great masses of dioritic rocks probably occurred before the deposition of the Eocene sediments.According to Hill (4), however, “in mid-Tertiary times granitoid intrusions were pushed upward into the sediments of the Greater Antilles, the Caribbean, Costa Eican, and Panamic regions.” Frazer, on the other hand (8), considered the nuclear axis of Cuba and San Domingo, and possibly of all the Caribbean islands, to be Archaean, a view upheld also by Dr. W. Bergt. (9)There is no doubt that the key to these problems lies in the larger islands of the Greater Antilles, for it is only there that unaltered fossiliferous sediments occur and can be studied in relation to the igneous intrusion and metamorphism. There appears, however, to the writer to be nothing either in the geological or faunal evidence necessarily indicating previous land connexion at any time between the Virgin Islands and the Lesser Antilles, ahd on this matter it is hoped to furnish further evidence at a later date.

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