Search results for "mass"
showing 10 items of 9693 documents
Does second phase content control the evolution of olivine CPO type and deformation mechanisms? A case study of paired harzburgite and dunite bands i…
2021
Abstract We have examined the microstructures and crystallographic preferred orientations (CPOs) of six “paired” harzburgite and dunite samples from a small (~ 1 km2) area in the Ellis Stream Complex, Red Hills Massif, Dun Mountain ophiolite belt in New Zealand. Here, banded peridotites with isoclinal folds, E-W striking vertical foliations and vertical lineations are inferred to result from shear on vertical planes that overprint previous mantle structures. The samples contain five different olivine CPOs: typically known as A, C, D, E and AG-types. The co-located harzburgite and dunite of each pair show different CPOs (e.g., A vs E type). In each pair, dunite generally has larger grain siz…
Lamproites as indicators of accretion and/or shallow subduction in the assembly of south-western Anatolia, Turkey
2010
IntroductionThe Western Anatolian region of Tur-key is tectonically one of the mostcomplex parts of the Alpine–Himala-yan orogenic belt (Fig. 1) because ofits long accretional palaeotectonicevolution. One of the major tectonicfeatures shaping the structure ofwestern Anatolia is the Menderesmetamorphic massif, which consistsof several assembled and imbricatedterranes exhumed during the exten-sion that affected the entire Aegeanprovince during the Late Miocene(Yilmaz et al., 2000; Okay, 2002).The Menderes Massif is usually inter-preted as a core complex delineated bylow-angle detachment faults (Bozkurtand Park, 1994; Hetzel et al., 1995;Ring et al., 2003). An alternativeexplanation associates …
Serbo-Macedonian revisited: A Silurian basement terrane from northern Gondwana in the Internal Hellenides, Greece
2009
Abstract New geochronological and geochemical data on basement orthogneisses from the Vertiskos Unit of the Serbo-Macedonian Massif (SMM), Internal Hellenides, northern Greece, are used in order to constrain the pre-Alpine tectonic history of the basement units in the metamorphic hinterland of the Hellenides. The prevailing rock types in the Vertiskos crystalline basement are coarse-grained biotite augengneisses with subordinate leucocratic muscovite gneisses and two-mica gneisses. Zircon Pb–Pb and U–Pb ages on 20 samples range from 425.9 ± 4.2 Ma to 443.4 ± 5.5 Ma with a mean of 432.2 ± 3.2 Ma and are interpreted as primary crystallisation ages of the basement granites on the basis of the …
A fault-related coalification anomaly in the Blanzy-Montceau Coal Basin (Massif Central, France)
1997
Abstract The Stephanian intramontane Blanzy-Montceau Coal Basin is situated along a Variscan fault complex bordering the Upper Paleozoic Blanzy-Le Creusot-Bert graben. The deposition of coal-bearing strata was controlled by a complex of early faults known as the “Faille de Bordure” (FB, Border Fault). Another complex of Permian faults known as the “Faille de l'Est” (FE, Eastern Fault) is situated along the more central part of the coal basin. Coalification in the basin follows three main trends: (1) Increasing rank from upper to lower coal seams in accordance with a general vertical trend (Hilt, 1873). The gradient of volatile matter is higher than normal, ranging from 3% to I I% Vdaf per 1…
Palaeozoic arc magmatism in the Central Asian Orogenic Belt of Kazakhstan: SHRIMP zircon ages and whole-rock Nd isotopic systematics
2008
Abstract Early Palaeozoic tonalite to granodiorite intrusions in northern Kazakhstan are associated with lode gold mineralization and have SHRIMP zircon ages of 457.3 ± 6.6 Ma (Aksu), 452.9 ± 5.6 Ma and 447.4 ± 5.4 Ma (both Zholymbet). The Stepnyak intrusion contains large xenoliths with an age of 480.6 ± 5.0 Ma. One early Palaeozoic zircon from a porphyritic diorite at Stepnyak has a core with a near-concordant 207Pb/206Pb age of 3888 ± 1.5 Ma, whereas other xenocrystic grains are between 983 and 2698 Ma old. The early Archaean age is probably inherited from unexposed basement of the Kokchetav Massif and represents the oldest crustal material so far known from the Asian continent. It appea…
A study of major and trace element accumulation in humic acids
2015
It has been widely studied recent as well as historic accumulation of elements in peat profiles depending on intensity of anthropogenic pollution and thereby peat profiles serve as archives for research of environmental change. Peat ability to accumulate major and trace elements depends on the character of element supply, potency of metal ions to bind functionalities in the peat structure, pH reaction, oxygen presence, presence of complexing compounds, inorganic ions and many other factors. The aim of this study is to assign major and trace element distribution in humic acids (HA) for two well characterized ombrotrophic peat profiles of Eipurs and Dzelve Bog and analyse factors affecting el…
Stages in the compaction of peat; examples from the Stephanian and Permian of the Massif Central, France
1987
Thick coal seams in the intramontane basins of the Massif Central allow a detailed study of peat/coal compaction. Three stages of compaction can be detected. Stage 1—occurred during the deposition of the peat. Coal beds which thicken and dip away from penecontemporaneous sandstones suggest rapid compaction. Stage 2—compaction of peat related to overburden pressure in some cases resulted in the formation of lakes over peat beds. The thickness of the lacustrine deposits may give an indication of the amount of compaction that took place. One possibility is that the early compaction was related to the progradation of siliciclastics over the peat. Stage 3—occurred after the organic sediment achi…
The carbonates of the Permian Lakes of North Massif central, France
1992
During the Permian, large fluvio-lacustrine basins occurred within the West European Hercynian chain. The deposits were mainly detrital (conglomerates, sandstones and pelites). The two studied sites, Couy borehole and Aumance basin contain several dolomitic beds alternating with pelites containing Ostracods. The carbonate layers constitute various dolomitized facies with dolosparite, laminated and bituminous dolomites, oolites, oncolites and stromatolites, and pedological nodules. Microfacies are varied. The dolomite crystals can be either isolated rhombs scattered in pelites or rhombs and xenomorphic crystals cementing sandstones; in dolomicrites, dolomicrosparites and dolosparites, crysta…
Polycyclic Aromatic Hydrocarbons (PAH) in Volcano island (Aeolian archipelago) mud utilized for therapeutic purpose
2007
This paper examines the possible presence, distribution, nature and sources of 18 Polycyclic Aromatic Hydrocarbons (PAH) as constituents of the mud pools collected in Vulcano Aeolian Island. PAH are important from environmental and toxicological point of view. Analysis was performed by gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring (SIM). The total concentration of Polycyclic Aromatic Hydrocarbons ranged from 112 to 154 μ g/Kg of dry matrix. The volcanic mud, used for therapeutic purposes, are moderately contaminated.