Geochemistry of plutonic spinels from the North Kamchatka Arc: comparisons with spinels from other tectonic settings

1993 ◽  
Vol 57 (389) ◽  
pp. 575-589 ◽  
Author(s):  
Pavel K. Kepezhinskas ◽  
Rex N. Taylor ◽  
Hisao Tanaka
Keyword(s):  
Tectonic Setting ◽  
Transitional Zone ◽  
Late Eocene ◽  
Accessory Mineral ◽  
Volatile Content ◽  
Complex Chemical ◽  
Chemical Zoning ◽  
Magmatic Arc ◽  
The North ◽  
Tectonic Settings

AbstractUltramafic to marie plutons in the Olyutor Range, North Kamchatka, represent the magmatic roots of a late Eocene arc, related to the westward subduction of the Komandorsky Basin beneath the Asian continental margin. Olyutor Range plutons are concentrically zoned with cumulate dunite cores mantled by a wehrlite-pyroxenite transitional zone and, in turn, by a narrow gabbroic rim.Spinel is a common accessory mineral in these arc plutonics, and we present analyses of spinels from a range of lithologies. A continuous compositional trend is observed from Cr-spinel in the ultramafics to Cr-rich magnetite in marginal gabbros. Complex chemical zoning patterns within individual spinel grains suggest an interplay between fO2, fractionation, volatile content and subsequent sub-solidus reequilibration of spinel with co-existing silicates (mainly olivine).In general, the spinels from magmatic arc environments are characterised by high total Fe and high Fe3+ contents compared to MORB and boninitic spinels and higher Cr-values relative to oceanic basin spinels. These differences imply a high oxygen fugacity during arc petrogenesis. Differences are also observed between plutonic spinels from arcs and low-Ti supra-subduction zone ophiolites. Low-Ti ophiolitic spinels are generally poorer in iron and richer in Cr, and hence are similar in composition and perhaps tectonic setting to fore-arc boninitic spinels.

Interpretation of structures in the southeastern Nechako Basin, British Columbia, from seismic reflection, well log, and potential field data1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.2Geological Survey of Canada Contribution 20100002.

2011 ◽  
Vol 48 (6) ◽  
pp. 1000-1020 ◽  
Author(s):  
Nathan Hayward ◽  
Andrew J. Calvert
Keyword(s):  
British Columbia ◽  
Potential Field ◽  
Seismic Reflection ◽  
Middle Eocene ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Late Eocene ◽  
Strike Slip ◽  
Potential Field Data ◽  
The North

The structure and stratigraphy of the southeast Nechako Basin, which are poorly understood primarily because of substantial volcanic cover, are investigated in an analysis of seismic reflection, well, and potential field data. Formation and development of the SE Nechako Basin resulted in sub-basins containing Cretaceous and Eocene rocks. Interpretation reveals that dextral transtension in the Early to Middle Eocene created NNW-trending, en echelon, strike-slip faults linked by pull-apart basins, which locally contain a thickness of Eocene volcaniclastic rocks of >3 km. This structural pattern is consistent with regional observations that suggest the transfer of slip from the Yalakom fault to the north via a series of en echelon strike-slip faults. In the Middle to Late Eocene, faults associated with a change in the direction of stress, echoed by the north-trending right-lateral Fraser fault, reactivated and cut earlier structures. A simple model agrees with local observations, that northeast-directed compression was subparallel to the relic Cretaceous grain. Cretaceous rocks are discontinuous throughout the basin and may be remnants of a broader basin, or a number of contemporaneous basins, formed in a regional transpressional tectonic setting that caused northeast-directed thrusting along the eastern side of the Coast Plutonic Complex. Results suggest that thrusting affected most of the SE Nechako Basin, as observed across the Intermontane Belt to the northwest and southeast. The pattern of deposition of Neogene volcanic rocks of the Chilcotin Group was in part controlled by the Eocene structural grain, but we find no evidence of Neogene deformation.

Oceanic crust generation in an island arc tectonic setting, SE Anatolian orogenic belt (Turkey)

2004 ◽  
Vol 141 (5) ◽  
pp. 583-603 ◽  
Author(s):  
OSMAN PARLAK ◽  
VOLKER HÖCK ◽  
HÜSEYİN KOZLU ◽  
MICHEL DELALOYE
Keyword(s):  
Late Cretaceous ◽  
Subduction Zones ◽  
Wide Spectrum ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Orogenic Belt ◽  
Mature Stage ◽  
Magmatic Arc ◽  
The North ◽  
Suprasubduction Zone

A number of Late Cretaceous ophiolitic bodies are located between the metamorphic massifs of the southeast Anatolian orogenic system. One of them, the Göksun ophiolite (northern Kahramanmaraş), which crops out in a tectonic window bounded by the Malatya metamorphic units on both the north and south, is located in the EW-trending nappe zone of the southeast Anatolian orogenic belt between Göksun and Afşin (northern Kahramanmaraş). It consists of ultramafic–mafic cumulates, isotropic gabbro, a sheeted dyke complex, plagiogranite, volcanic rocks and associated volcanosedimentary units. The ophiolitic rocks and the tectonically overlying Malatya–Keban metamorphic units were intruded by syn-collisional granitoids (∼ 85 Ma). The volcanic units are characterized by a wide spectrum of rocks ranging in composition from basalt to rhyolite. The sheeted dykes consist of diabase and microdiorite, whereas the isotropic gabbros consist of gabbro, diorite and quartzdiorite. The magmatic rocks in the Göksun ophiolite are part of a co-magmatic differentiated series of subalkaline tholeiites. Selective enrichment of some LIL elements (Rb, Ba, K, Sr and Th) and depletion of the HFS elements (Nb, Ta, Ti, Zr) relative to N-MORB are the main features of the upper crustal rocks. The presence of negative anomalies for Ta, Nb, Ti, the ratios of selected trace elements (Nb/Th, Th/Yb, Ta/Yb) and normalized REE patterns all are indicative of a subduction-related environment. All the geochemical evidence both from the volcanic rocks and the deeper levels (sheeted dykes and isotropic gabbro) show that the Göksun ophiolite formed during the mature stage of a suprasubduction zone (SSZ) tectonic setting in the southern branch of the Neotethyan ocean between the Malatya–Keban platform to the north and the Arabian platform to the south during Late Cretaceous times. Geological, geochronological and petrological data on the Göksun ophiolite and the Baskil magmatic arc suggest that there were two subduction zones, the first one dipping beneath the Malatya–Keban platform, generating the Baskil magmatic arc and the second one further south within the ocean basin, generating the Göksun ophiolite in a suprasubduction zone environment.

scholarly journals Oligocene-Pleistocene Paleogeography within Banyumas Basin and implication to petroleum potential

2018 ◽  
Vol 1 ◽  
pp. 00006 ◽  
Author(s):  
Eko Bayu Purwasatriya ◽  
Sugeng Sapto Surjono ◽  
Donatus Hendra Amijaya
Keyword(s):  
Depositional Environment ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Source Rocks ◽  
Petroleum Potential ◽  
Magmatic Arc ◽  
The North ◽  
Potential Source ◽  
Back Arc ◽  
Exploration Activity

<p>This study attempts to reconstruct paleogeography of Banyumas Basin in association with magmatic arc evolution and its implication to petroleum potential. Based on the volcanic rocks distribution, their association and relatives age, there are three alignments of a magmatic arc, that are: (1) Oligo-Miocene arc in the south (2) Mio-Pliocene arc in the middle (3) Plio-Pleistocene arc in the north. The consequences of the magmatic arc movement were tectonic setting changing during Oligocene to Pleistocene, as well as their paleogeography. During Oligo-Miocene where magmatic arc existed in the southern part, the Banyumas tectonic setting was a back-arc basin. This tectonic setting was changing to intra-arc basin during Mio-Pliocene and subsequently to fore-arc basin since Plio-Pleistocene until today. Back-arc basin is the most suitable paleogeography to create a depositional environment for potential source rocks. Exploration activity to prove the existence of source rocks during Oligo-Miocene is needed to reveal petroleum potential in Banyumas Basin.<br></p>

scholarly journals Tectonic setting of the middle-late cambrian deposits of isl. Bolshevik and isl. Troynoy (Russian Arctic): a case of clastic rocks from metaterrigeneous complexes

2019 ◽  
pp. 65-77
Author(s):  
P. A. Fokin ◽  
V. O. Yapaskurt ◽  
A. M. Nikishin
Keyword(s):  
Tectonic Setting ◽  
Source Area ◽  
Size Composition ◽  
Orogenic Belt ◽  
Clastic Rocks ◽  
The North ◽  
Late Cambrian ◽  
Coastal Marine ◽  
Tectonic Settings ◽  
Severnaya Zemlya

Abstract The new data on the tectonic settings and sedimentational circumstances of the Middle-Late Cambrian deposits of the southern part of the North Kara terrane, presented in our research, the data induced from the studies of clastic rocks in the basement metaterrigeneous complexes of Troynoy island (archipelago Izvestia CEC) and the northern part of Bolshevik island (archipelago Severnaya Zemlya). The sandstones of both regions are similar in the lithic wacke composition and contain the same groups of rocks fragments. Clastic zircons and Cr-spinels from sandstones of both regions have the same Zr/Hf and TiO2/Al2O3 ratios, respectively. The similarity of even-aged sediments from both regions can be explained by their accumulation due to the demolition of detrital material from a single source eroded area, which is a segment of the accretionary uplift of the Timan‒Severnaya Zemlya orogenic belt, with the newly formed continental Neoproterozoic-Cambrian crust. The low and medium-grade metamorphosed terrigeneous complexes dominated in the structure of the source area. Presence of volcanic and intrusive complexes in the source area is marked by clastic Cr-spinels with geochemical signatures of volcanic arc and suprasubductional ophiolites origin. By the beginning of the Ordovician, the Middle Late Cambrian sediments were also crushed, metamorphosed, and included in the structure of the Timan‒ Severnaya Zemlya orogenic belt. Peculiarities of petrographic and grain-size composition and sorting of the sandstones from the north of Bolshevik island are more typical for the sediments of gravity turbidite flows, in deep or relatively deep water conditions. The deposits of Troynoy island could be formed at shallow and coastal-marine environments.

scholarly journals U - Pb geochronology and composition of zircon mineral from granodiorite in the G18 Gold mine, Quang Nam and its significance in regional tectonics

2021 ◽  
Vol 62 (2) ◽  
pp. 1-11
Author(s):  
Thanh Xuan Ngo ◽  
Hau Vinh Bui ◽  
Hai Thanh Tran ◽  
Binh Van Phan ◽  
Bat Van Dang ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Trace Element Composition ◽  
Gold Mine ◽  
Middle Cambrian ◽  
Middle Ordovician ◽  
Magmatic Arc ◽  
The North ◽  
Continental Magmatic Arc ◽  
Zircon Mineral ◽  
Ophiolitic Complex

The Tam Ky - Phuoc Son suture zone (TPSZ) is located in central Indochina and is referred to as a amalgamation site between the Truong Son and Kon Tum terranes during the early Paleozoic. The amphibolite and ultramafic rocks within the region were considered as a part of the Tam Ky - Phuoc Son ophiolitic complex. In this study, the authors present results of the U - Pb dating and trace element composition of the zircon grains derived from a granodioritic sample collected in the G18 gold mine in Quang Nam province in order to clarify the timing of magma emplacement and tectonic setting. The U - Pb dating data indicates that the granodioritic rocks formed at 447,4±2,9 Ma while the U/Yb ratio is ̴1 (average: 1.32) and the Sc/Yb ratio is ̴ 1.04, high Hf content (Average Hf: 10937 ppm) and low Yb content (Average Yb: 308 ppm). These geochemical values are comparable with the zircon, which is formed in the continental magmatic arc. Combination with the pre - existing data allowed us to confirm the existence of two contrast magma members in the North Kontum massif: The Middle Cambrian island arc complex and the Middle Ordovician continental complex.

Granites in the tectonic evolution of the Himalaya, Karakoram and southern Tibet

1988 ◽  
Vol 326 (1589) ◽  
pp. 281-299 ◽  
Keyword(s):  
Small Volume ◽  
Tectonic Setting ◽  
Southern Tibet ◽  
The North ◽  
Anatectic Granite ◽  
Regional Tectonic ◽  
Lower Palaeozoic ◽  
Intracontinental Subduction ◽  
Tectonic Settings ◽  
The Himalaya

Four major plutonic belts are related to the Meso-Cainozoic orogenic evolution of the Himalaya—Transhimalaya—Karakoram realm: the Transhimalaya belt and its satellite Kohistan arc, the Karakoram batholith, the High Himalaya belt and the North Himalaya belt. A fifth one results from the lower Palaeozoic epirogenic events: the ‘Lesser Himalaya’ belt. The tectonic settings of their production and emplacement are successively reviewed. Among the first four, two result from oceanic subduction along an Andean margin locally branching into an island arc and two result from intracontinental subduction after closure of the oceanic realm. Both Andean belts are made up of very large quantities of highly diversified granitoids produced more or less continuously during 70 Ma at least, whereas the intracontinental ones are limited to a small volume of very uniform anatectic granite produced during a 10—15 Ma period. The production and emplacement in the Andean belts is partly controlled by the obliquity of the convergence between India and Eurasia. The emplacement of the intracontinental belts is even more dependent on the regional tectonic setting. These contrasting belts are case studies probing the depths and mechanisms of their production and giving adequate models for older geodynamic frames.

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.

Mesozoic Tectonic Setting of SE Sundaland After Magmatism and Suture Evidences in JS-1 Ridge Area

2021 ◽  
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Tectonic Setting ◽  
Plate Boundary ◽  
Early Jurassic ◽  
The South ◽  
Magmatic Arc ◽  
Plate Convergence ◽  
Ridge Area ◽  
Cretaceous Subduction

Mesozoic plate convergence in SE Sundaland has been a source of debate for decades. A determination of plate convergence boundaries and timing have been explained in many publications, but not all boundaries were associated with magmatism. Through integration of both plate configurations and magmatic deposits, the basement can be accurately characterized over time and areal extents. This paper will discuss Cretaceous subductions and magmatic arc trends in SE Sundaland area with additional evidence found in JS-1 Ridge. At least three subduction trends are captured during the Mesozoic in the study area: 1) Early Jurassic – Early Cretaceous trend of Meratus, 2) Early Cretaceous trend of Bantimala and 3) Late Cretaceous trend in the southernmost study area. The Early Jurassic – Early Cretaceous subduction occurred along the South and East boundary of Sundaland (SW Borneo terrane) and passes through the Meratus area. The Early Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo and Paternoster terranes) and pass through the Bantimala area. The Late Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo, Paternoster and SE Java – South Sulawesi terranes), but is slightly shifted to the South approaching the Oligocene – Recent subduction zone. Magmatic arc trends can also be generally grouped into three periods, with each period corresponds to the subduction processes at the time. The first magmatic arc (Early Jurassic – Early Cretaceous) is present in core of SW Borneo terrane and partly produces the Schwaner Magmatism. The second Cretaceous magmatic arc (Early Cretaceous) trend is present in the SW Borneo terrane but is slightly shifted southeastward It is responsible for magmatism in North Java offshore, northern JS-1 Ridge and Meratus areas. The third magmatic arc trend is formed by Late Cretaceous volcanic rocks in Luk Ulo, the southern JS-1 Ridge and the eastern Makassar Strait areas. These all occur during the same time within the Cretaceous magmatic arc. Though a mélange rock sample has not been found in JS-1 Ridge area, there is evidence of an accretionary prism in the area as evidenced by the geometry observed on a new 3D seismic dataset. Based on the structural trend of Meratus (NNE-SSW) coupled with the regional plate boundary understanding, this suggests that both Meratus & JS-1 Ridge are part of the same suture zone between SW Borneo and Paternoster terranes. The gradual age transition observed in the JS-1 Ridge area suggests a southward shift of the magmatic arc during Early Cretaceous to Late Cretaceous times.

scholarly journals PEMODELAN BAWAH PERMUKAAN MANIFESTASI MINERAL DENGAN METODE GEOMAGNETIK DAERAH PACITAN JAWA TIMUR

KURVATEK ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 25-33
Author(s):  
Fatimah Fatimah
Keyword(s):  
Image Data ◽  
Geological Structure ◽  
Magnetic Data ◽  
Magnetic Intensity ◽  
Magmatic Arc ◽  
The North ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Extensional Structure ◽  
Anomaly Map

Tulakan Subdistrict, Pacitan Regency, East Java Province. This area is part of the Southern Mountain Zone of East Java, which is the Sunda-Banda magmatic arc of Oligo-Miocene age, where there are alterations and indications of valuable ore minerals. Field magnetic data is taken in an area of 1 x 1 km, with the looping method on the grid trajectory within 200 x 100 m. Then, magnetic data correction and data processing were carried out with Oasis Montaj. From the magnetic anomaly map, the value of high magnetic intensity in the southern part is fresh (intrusive) andesit-dasitic rock as host rock which causes alteration, in the middle has a low magnetic intensity value which is in the direction of the relatively NE-SW river direction, whereas in the north with high intensity is fresh andesite lava. From the image data, it can be seen that the straightness pattern of the geological structure which is dominated by the extensional structure with the direction of NE-SW and E-W is the main trap of epithermal veins carrying ore mineralization mainly Cu, Pb in the study area.

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