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Wyszukujesz frazę "Gneisses" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Qualitative evaluation of aeromagnetic data of Mmaku area, Nigeria, by means of upward continuation, band pass, highs pass and low pass filtering actions
Autorzy:
Umeanoh, Daniel C.
Ugwu, S. A.
Ofoha, Chimezie C.
Powiązania:
https://bibliotekanauki.pl/articles/1163849.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Gneisses
faults
filtered maps
qualitative
structural trends
Opis:
The focus of this research is to delineate subsurface structures as well as their edges by interpreting a high resolution aeromagnetic data via qualitative approach. The study area lies between Latitude 6°00’- 6°30’N and Longitude 7°00’ - 7°30’E in Enugu state, south-east Nigeria. Regional-residual separation algorithm was applied on the total magnetic intensity aeromagnetic map in order to generate the residual and regional maps. On the resulting residual data, further enhancement techniques like the upward continuation at 5 km, 10 km and 20 km, band pass, high pass and low pass enhancement technique/filtering actions were undertaken. Result of the qualitative analysis shows that the study area is characterized by numerous faults and fractures expressed as NNE-SSW, E-W, N-S, NE-SW, NW-SE, and ENE-WSW tectonic trends. The NE-SW and NW-SE tectonic trends indicate that the area is affected by the charcot and oceanic fractures that existed within offshore Niger Delta, Nigeria while the ENE-WSW. NNE-SSW, E-W and N-S tectonic trends exemplify that the separation of Africa from South America affected the area.
Źródło:
World Scientific News; 2018, 108; 74-86
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In situ gamma-ray measurements of 40K, 232Th and 238U in high-grade metamorphic rocks from the Sowie Mountains (Sudetes, SW Poland)
Autorzy:
Malczewski, Dariusz
Żaba, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/2058572.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
gneisses
Sowie Mountains
Sudetes
natural radioactivity
in situ measurements
Opis:
This paper reports on the abundance of primordial radionuclides (40K,232K and 238U) in characteristic lithologies from the Sowie Mountains (SW Poland). In situ gamma-ray measurements were conducted at 12 localities hosting exposed augen gneiss, flaser gneiss, granulite, homophanized gneiss, hornblendite, layered gneiss, layered migmatite, migmatic gneiss, mylonitic gneiss and mylonitic granulite. The activity concentration of 40K varied from 180 Bq kg-1 (mylonitic granulite) to 845 Bq kg-1 (layered gneiss). The activity concentrations associated with 228Ac (232Th) varied from 10 Bq kg-1 (mylonitic granulite) to 53 Bq kg-1 (homophanized gneiss), while activity associated with 226Ra (238 U) varied from 9 Bq kg-1 (mylonitic granulite) to 43 Bq kg-1 (layered gneiss). An augen gneiss adjacent to the Intra-Sudetic Fault showed the highest combined Th + U activity (89 Bq kg-1). The average Th/U ratio (3.6) calculated for gneiss outcrops of the Sowie Mountains falls within the range reported for biotite gneiss (3.5-4). Subsurface outcrops from the Walim-Rzeczka underground complex did not give noticeably higher 238U activities. The results obtained forthe Sowie lithologies are compared with those obtained by similar methods for similar rocks as reported in literature sources.
Źródło:
Geological Quarterly; 2019, 63, 3; 493--504
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wstępne wyniki badań petrograficznych archaicznych gnejsów Uivak (Prowincja Nain, Labrador)
Preliminary petrographic studies of the Archaean Uivak gneisses, Nain Province, Labrador
Autorzy:
Sałacińska, A.
Kusiak, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/2075612.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Ziemia
gnejs
archaik
blok Saglek
Labrador
early Earth
gneisses
Archean
Saglek Block
Opis:
The Saglek Block of the Nain Complex in Northern Labrador forms the westernmost part of the North Atlantic Craton. It is one of the few regions on Earth where early Archaean crust is preserved. It consists of regionally metamorphosed gneisses to either granulite-facies from 2.74 to 2.71 Ga or amphibolite-facies at ca. 2.70 Ga. The Saglek Block is dominated by two suites of metaigneous gneisses: the Uivak I TTG suite (>3.6 Ga) and the Uivak II augen gneisses (ca. 3.4 Ga). Four samples offelsic Uivak I orthogneiss were selected to petrographi- cal and mineralogical studies: Johannes Point Cove (L1419), TigigakyukInlet (L1434; L1440) and Big Island (L1443). Sample composition (granodiorite-tonalite) and mineralogy (mostly plagioclase and quartz, with minor K-feldspar and biotite, and accessory zircon and apatite) for three of the four samples are consistent with published data of the Uivak I gneiss. Sample L1434 contains ferroean diopside and hornblende, which are absent in the other samples. Based on detailed mineralogical analyses, authors concluded that more mafic sample, can not belong to the suite of the Uivak I gneisses. Most probably it represents the younger Uivak II. Further, geochronological study is going to be conducted to characterise both, Uivak I and Uivak II gneisses isotopically.
Źródło:
Przegląd Geologiczny; 2017, 65, 6; 383--391
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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