scholarly journals Structural and Chemical Controllers of the North and Northwest of Torud Based on Involved Fluid Studies, Structural and Geochemical Analyses

2021 ◽  
Vol 15 (3) ◽  
pp. 339-349
Author(s):  
Fatemeh Baseri ◽  
Arash Gourabjeri Pour ◽  
Nima Nezafati
Keyword(s):  
Volcanic Rocks ◽  
Mining Area ◽  
Hydrothermal Solutions ◽  
Base Metals ◽  
Laboratory Studies ◽  
Scattered Space ◽  
The North ◽  
Geochemical Analyses ◽  
Geochemical Studies ◽  
Semnan Province

Chah Mura mining area in Semnan province is located 30 km southwest of Shahroud and 20 km north of Torud village with an area of 35 km2 and includes a part of 1:250,000 Torud plate. Structurally, this area is located in the northeastern part of Central Iran and in the center of the volcanic-intrusive arc of Torud-Chah Shirin. Rock units of the area are volcanic and pyroclastic, depending on the Eocene age. Exposed assemblages in the Chah Mura area, based on field and laboratory studies, can be divided into basalt, andesite, andesite-basalt, trachyandesite, trachyandesibasalt and small outcrops of pyroclastic units in the form of agglomerates and sediments of sandstone and conglomerate. Volcanic rocks are influenced by sub-volcanic masses younger than Eocene with an intermediate to basic composition, and their predominant textures are granular, porphyroid with microcrystalline to microintragranular background. Finally, the units are cut by dikes. In this area, mineralization is mainly in the control of sub-faults and subvolcanic massifs. Mineralization is in the form of vein-veinlet, filling empty and scattered space in the oxidation-supergen stage. Mineral sequences include pyrite, chalcopyrite, chalcocite, digenite and covellite, cuprite, tenorite, natural copper, malachite, azurite, and iron oxides and hydroxides. Geochemical studies indicate that copper does not correlate well with any of the base metals and depositing elements. Copper shows only a relative correlation with silver. Micrometric studies of fluid inclusions in samples from this area indicate dilution as a result of mixing hydrothermal solutions with atmospheric fluids in formation of this reserve.

Volcanic stratigraphy and structure in the Hunter Creek Fault area, Rouyn–Noranda, Quebec

1990 ◽  
Vol 27 (10) ◽  
pp. 1348-1358 ◽  
Author(s):  
G. Camiré ◽  
D. H. Watkinson
Keyword(s):  
Volcanic Rocks ◽  
Drill Hole ◽  
Volcanic Complex ◽  
Calc Alkaline ◽  
Volcanic Stratigraphy ◽  
The Past ◽  
The North ◽  
Northern Side ◽  
Volcanic Facies ◽  
Geochemical Studies

The Hunter Creek Fault (HCF) has been considered in the past as a major synvolcanic fault marked by a change in volcanic facies and separating two geologically distinct blocks within the Noranda volcanic complex: the North Mine and the Central Mine sequences. Detailed mapping in the HCF area, in conjunction with petrographic and geochemical studies, has revealed that most of the volcanic units defined south of the fault zone also occur on its northern side. Field and drill-hole correlations indicate that the rocks are cut by a N240–N250 reverse-slip fault dipping approximately 70° toward the northwest. Major- and trace-element data suggest that least-altered volcanic rocks are of tholeiitic affinity and that there is no calc-alkaline unit in the HCF area.

scholarly journals NAPPE STRUCTURE OF THE NORTH SPORADES (GREECE): ON THE GEOLOGICAL EVOLUTION OF ALONNISOS ISLAND

2004 ◽  
Vol 36 (4) ◽  
pp. 1636 ◽  
Author(s):  
V. Jacobshagen ◽  
D. Matarangas
Keyword(s):  
Upper Cretaceous ◽  
Volcanic Rocks ◽  
Field Studies ◽  
Geological Mapping ◽  
Published Data ◽  
The North ◽  
Geological Evolution ◽  
Geochemical Analyses ◽  
Pelagonian Zone ◽  
Rock Association

On Alonnisos island detailed field studies were carried out concerning rock sequences and their boundaries, geochemical analyses of mafic volcanic rocks, and geological mapping of key areas in the southwestern and central parts of the island to the scale 1:10 000. In connection with already published data, our results led to a revision of the tectonic structure of the island and of its geological evolution. The deeper parts of Alonnisos are built up by Mesozoic rocks of the Pelagonian zone, locally with outliers of the Eohellenic nappe on top. Both units are covered by the well-known Mesoautochthonous sequence of Upper Cretaceous/Lower Tertiary age. These units are tectonically overlain by relics of the Palouki nappe, which consists of the probably Lower Cretaceous Palouki formation (once called "Palouki series"), followed by Upper Cretaceous marbles and by a metaflysch. This nappe was probably overthrust during the Eocebe (Mesohellenic) orogeny.Relics of the Palouki nappe can be followed from Alonnisos to Skopelos in the SW, over some small islands. As the rock association in its older parts point to a pelagic marine origin, we assume that the Palouki nappe had its origin in a relic of the Vardar ocean. Relations to other nappe ouliers, which hold a comparable position in the Sporades/Pelion region, are discussed.

A new volcanic province: evidence from glacial erratics in western North Greenland

2000 ◽  
pp. 35-41 ◽  
Author(s):  
Peter R. Dawes ◽  
Bjørn Thomassen ◽  
T.I. Hauge Andersson
Keyword(s):  
Volcanic Rocks ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Common Component ◽  
Volcanic Province ◽  
North West ◽  
North East ◽  
The North ◽  
Surficial Deposits ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dawes, P. R., Thomassen, B., & Andersson, T. H. (2000). A new volcanic province: evidence from glacial erratics in western North Greenland. Geology of Greenland Survey Bulletin, 186, 35-41. https://doi.org/10.34194/ggub.v186.5213 _______________ Mapping and regional geological studies in northern Greenland were carried out during the project Kane Basin 1999 (see Dawes et al. 2000, this volume). During ore geological studies in Washington Land by one of us (B.T.), finds of erratics of banded iron formation (BIF) directed special attention to the till, glaciofluvial and fluvial sediments. This led to the discovery that in certain parts of Daugaard-Jensen Land and Washington Land volcanic rocks form a common component of the surficial deposits, with particularly colourful, red porphyries catching the eye. The presence of BIF is interesting but not altogether unexpected since BIF erratics have been reported from southern Hall Land just to the north-east (Kelly & Bennike 1992) and such rocks crop out in the Precambrian shield of North-West Greenland to the south (Fig. 1; Dawes 1991). On the other hand, the presence of volcanic erratics was unexpected and stimulated the work reported on here.

scholarly journals Morphotectonic Analysis along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 102
Author(s):  
Paraskevi Nomikou ◽  
Dimitris Evangelidis ◽  
Dimitrios Papanikolaou ◽  
Danai Lampridou ◽  
Dimitris Litsas ◽  
...  
Keyword(s):  
Fault Zone ◽  
Seismic Activity ◽  
Volcanic Rocks ◽  
Active Tectonics ◽  
Normal Fault ◽  
Aegean Sea ◽  
Northern Margin ◽  
The North ◽  
Eastern Aegean ◽  
Half Graben

On 30 October 2020, a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea, whose earthquake mechanism corresponds to an E-W normal fault dipping to the north. During the aftershock period in December 2020, a hydrographic survey off the northern coastal margin of Samos Island was conducted onboard R/V NAFTILOS. The result was a detailed bathymetric map with 15 m grid interval and 50 m isobaths and a morphological slope map. The morphotectonic analysis showed the E-W fault zone running along the coastal zone with 30–50° of slope, forming a half-graben structure. Numerous landslides and canyons trending N-S, transversal to the main direction of the Samos coastline, are observed between 600 and 100 m water depth. The ENE-WSW oriented western Samos coastline forms the SE margin of the neighboring deeper Ikaria Basin. A hummocky relief was detected at the eastern margin of Samos Basin probably representing volcanic rocks. The active tectonics characterized by N-S extension is very different from the Neogene tectonics of Samos Island characterized by NE-SW compression. The mainshock and most of the aftershocks of the October 2020 seismic activity occur on the prolongation of the north dipping E-W fault zone at about 12 km depth.

scholarly journals Statherian (ca. 1714–1680 Ma) Extension-Related Magmatism and Deformation in the Southwestern Korean Peninsula and Its Geological Significance: Constraints from the Petrological, Structural, Geochemical and Geochronological Studies of Newly Identified Granitoids

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 557
Author(s):  
Byung-Choon Lee ◽  
Weon-Seo Kee ◽  
Uk-Hwan Byun ◽  
Sung-Won Kim
Keyword(s):  
Korean Peninsula ◽  
Tectonic Setting ◽  
Alkali Feldspar ◽  
Ductile Deformation ◽  
Southwestern Part ◽  
The North ◽  
Deformation Event ◽  
Geochemical Analyses ◽  
A Minor ◽  
T Values

In this study, petrological, structural, geochemical, and geochronological analyses of the Statherian alkali feldspar granite and porphyritic alkali feldspar granite in the southwestern part of the Korean Peninsula were conducted to examine petrogenesis of the granitoids and their tectonic setting. Zircon U-Pb dating revealed that the two granites formed around 1.71 Ga and 1.70–1.68 Ga, respectively. The results of the geochemical analyses showed that both of the granites have a high content of K2O, Nb, Ta, and Y, as well as high FeOt/MgO and Ga/Al ratios. Both granites have alkali-calcic characteristics with a ferroan composition, indicating an A-type affinity. Zircon Lu-Hf isotopic compositions yielded negative εHf(t) values (−3.5 to −10.6), indicating a derivation from ancient crustal materials. Both granite types underwent ductile deformation and exhibited a dextral sense of shear with a minor extension component. Based on field relationships and zircon U-Pb dating, it was considered that the deformation event postdated the emplacement of the alkali feldspar granite and terminated soon after the emplacement of the porphyritic alkali feldspar granite in an extensional setting. These data indicated that there were extension-related magmatic activities accompanying ductile deformation in the southwestern part of the Korean Peninsula during 1.71–1.68 Ga. The Statherian extension-related events are well correlated with those in the midwestern part of the Korean and eastern parts of the North China Craton.

Implication of dating of Early Tertiary volcanic rocks from the north-Chilean Precordillera

1992 ◽  
Vol 202 (1) ◽  
pp. 55-81 ◽  
Author(s):  
K. Hammerschmidt ◽  
R. Döbel ◽  
H. Friedrichsen
Keyword(s):  
Volcanic Rocks ◽  
The North ◽  
Early Tertiary

Equilibrium Temperature Calculation of the Sulfur Isotope in Dongzhongla Pb-Zn Deposit in Tibet

2015 ◽  
Vol 1092-1093 ◽  
pp. 1394-1397
Author(s):  
Guang Chun Fei ◽  
Yi Fan Yu ◽  
Ke Qiang Hua
Keyword(s):  
Sulfur Isotope ◽  
Equilibrium Temperature ◽  
Mining Area ◽  
Isotopic Equilibrium ◽  
The North ◽  
Geological Conditions ◽  
Typical Type ◽  
Lead Zinc ◽  
Block Based ◽  
Exploration Area

The Dongzhongla Pb-Zn deposit, a newly-discovered medium-sized deposit, is located in the north margin of the eastern Gangdese, central Lhasa block. Based on the analysis of the ore-forming geological conditions in this deposit, sulfur isotope of this deposit were analyzed, and S isotopic equilibrium temperature of mineral pairs (sphalerite and galena) were calculated. This study has shown that the sulfur isotopic equilibrium temperature of sphalerite and galena in Dongzhongla Pb-Zn deposit ranged from 185℃ to 296℃. It indicated that the equilibrium temperature decreased gradually from the skarn stage to sulfide stage. The equilibrium temperature can be used as the reference of metallogenic temperature for Dongzhongla Pb-Zn deposit. DongzhongLa deposit is the typical type of skarn Lead-zinc deposit. East of the Dongzhongla mining area is the priority exploration area.

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