Causes of the Occurrence of A-Type Volcanic Rocks in Active Continental Margins (Southern Sikhote-Alin, Russian Far East)

2021 ◽  
Vol 62 (2) ◽  
pp. 207-222
Author(s):  
A.V. Grebennikov ◽  
S.O. Maksimov
Keyword(s):  
Russian Far East ◽  
Far East ◽  
Volcanic Rocks ◽  
Sudden Change ◽  
Apical Part ◽  
Igneous Rocks ◽  
Geochemical Data ◽  
Southern Primorye ◽  
The Pacific ◽  
Active Continental Margins

Abstract ––New isotope-geochemical data on the volcanic complexes of the South Yakut and Martel volcanic depressions in southern Primorye are presented. Their formation in the early Eocene (54.3 Ma) and Late Cretaceous (83.5 Ma), respectively, is evidenced by U–Pb zircon dating (LA-ICP-MS). Based on the geochemical characteristics, it is concluded that the volcanics are typical A-type igneous rocks. Their formation coincides with the sudden change in the vector of motion of the Pacific slab with respect to the continent in the Campanian and Paleocene–Eocene, which caused destruction of the slab with its probable discontinuity and the injection of the subslab asthenosphere. The effect of mantle fluids on the continental lithospheric-rock melting determined the generation of magmas with the specific geochemical features of A-type igneous rocks. The regularities of their composition are due to the deep-seated reduced F-rich fluids that caused the intense differentiation of magmas accumulating fluidized melts enriched in mobile components in the apical part.

scholarly journals Gold in Mineralized Volcanic Systems from the Lesser Khingan Range (Russian Far East): Textural Types, Composition and Possible Origins

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 103
Author(s):  
Nikolai Berdnikov ◽  
Victor Nevstruev ◽  
Pavel Kepezhinskas ◽  
Ivan Astapov ◽  
Natalia Konovalova
Keyword(s):  
Iron Oxide ◽  
Subduction Zones ◽  
Gold Mineralization ◽  
Russian Far East ◽  
Far East ◽  
Volcanic Rocks ◽  
Liquid Immiscibility ◽  
Explosive Volcanism ◽  
Deep Roots ◽  
Scientific Debate

While gold partitioning into hydrothermal fluids responsible for the formation of porphyry and epithermal deposits is currently well understood, its behavior during the differentiation of metal-rich silicate melts is still subject of an intense scientific debate. Typically, gold is scavenged into sulfides during crustal fractionation of sulfur-rich mafic to intermediate magmas and development of native forms and alloys of this important precious metal in igneous rocks and associated ores are still poorly documented. We present new data on gold (Cu-Ag-Au, Ni-Cu-Zn-Ag-Au, Ti-Cu-Ag-Au, Ag-Au) alloys from iron oxide deposits in the Lesser Khingan Range (LKR) of the Russian Far East. Gold alloy particles are from 10 to 100 µm in size and irregular to spherical in shape. Gold spherules were formed through silicate-metal liquid immiscibility and then injected into fissures surrounding the ascending melt column, or emplaced through a volcanic eruption. Presence of globular (occasionally with meniscus-like textures) Cu-O micro-inclusions in Cu-Ag-Au spherules confirms their crystallization from a metal melt via extremely fast cooling. Irregularly shaped Cu-Ag-Au particles were formed through hydrothermal alteration of gold-bearing volcanic rocks and ores. Association of primarily liquid Cu-Ag-Au spherules with iron-oxide mineralization in the LKR indicates possible involvement of silicate-metallic immiscibility and explosive volcanism in the formation of the Andean-type iron oxide gold-copper (IOCG) and related copper-gold porphyry deposits in the deeper parts of sub-volcanic epithermal systems. Thus, formation of gold alloys in deep roots of arc volcanoes may serve as a precursor and an exploration guide for high-grade epithermal gold mineralization at shallow structural levels of hydrothermal-volcanic environments in subduction zones.

New Species of Neotrombicula (Acari: Trombiculidae) from the Southern Primorye Territory, Russian Far East

1995 ◽  
Vol 32 (3) ◽  
pp. 381-383 ◽  
Author(s):  
Teruki Kadosaka ◽  
Akira Tamura ◽  
Irina V. Tarasevich
Keyword(s):  
New Species ◽  
Russian Far East ◽  
Far East ◽  
Southern Primorye

Neolithization and Ancient Landscapes in Southern Primorye, Russian Far East

2014 ◽  
Vol 27 (3-4) ◽  
pp. 247-261 ◽  
Author(s):  
Alexander N. Popov ◽  
Andrei V. Tabarev ◽  
Yuri A. Mikishin
Keyword(s):  
Russian Far East ◽  
Far East ◽  
Southern Primorye ◽  
Ancient Landscapes

A new species of the genusKogotusRicker from Southern Primorye (The Russian Far East) (Plecoptera: Perlodidae)

1993 ◽  
Vol 15 (3) ◽  
pp. 177-183 ◽  
Author(s):  
Lidija A. Zhiltzova ◽  
Valentina A. Teslenko ◽  
Peter Zwick
Keyword(s):  
New Species ◽  
Russian Far East ◽  
Far East ◽  
Southern Primorye ◽  
A New Species ◽  
The Russian Far East

The tectonic significance of Ordovician basic igneous rocks in the Southern Uplands, southwest Scotland

1995 ◽  
Vol 132 (5) ◽  
pp. 549-556 ◽  
Author(s):  
E. R. Phillips ◽  
R. P. Barnes ◽  
R. J. Merriman ◽  
J. D. Floyd
Keyword(s):  
Volcanic Rocks ◽  
Accretionary Prism ◽  
Igneous Rocks ◽  
Geochemical Data ◽  
Published Data ◽  
Volcanic Material ◽  
Tectonic Significance ◽  
Arc Setting ◽  
Back Arc ◽  
Midocean Ridge

AbstractIn the northern part of the Southern Uplands, restricted volumes of basic igneous rocks occur at or near the base of the Ordovician sedimentary strata. These rocks have previously been interpreted as ocean-floor tholeiites representative of the subducted Iapetus oceanic plate, preserved as tectonic slivers in a fore-arc accretionary prism. The alternative, back-arc basin model proposed for the Southern Uplands on sedimentological evidence raises questions over the origin of these rocks. New geochemical data and previously published data clearly indicate that the volcanic material does not have a simple single source. The oldest (Arenig) volcanic rocks from the Moffat Shale Group associated with the Leadhills Fault include alkaline within-plate basalts and tholeiitic lavas which possibly display geochemical characteristics of midocean ridge basalts. In the northernmost occurrence, alkaline and tholeiitic basalts contained within the Caradoc Marchburn Formation are both of within-plate ocean island affinity. To the south, in the Gabsnout Burn area, the Moffat Shale Group contains lenticular bodies of dolerite and basalt which have characteristics of island-arc to transitional basalts. This complex association of basaltic volcanic rocks is, at the present time, difficult to reconcile with either a simple fore-arc or back-arc setting for the Southern Uplands. However, the increasing arc-related chemical influence on basic rock geochemistry towards the southeast may tentatively be used in support of a southern arc-terrane, and as a result, a back-arc situation for the Southern Uplands basin. An alternative is that these volcanic rocks may represent the local basement to the basin and include remnants of an arc precursor to the Southern Uplands basin.

scholarly journals The Oldest Ceramics of East Asia: Current Research Questions (Materials for the Educational Course “Ceramics as an Archaeological Source”)

2020 ◽  
Vol 19 (7) ◽  
pp. 10-33
Author(s):  
Irina S. Zhushchikhovskaya ◽  
Lyudmila N. Mylnikova
Keyword(s):  
East Asia ◽  
Russian Far East ◽  
Far East ◽  
Northern China ◽  
Ceramic Technology ◽  
Ancient Ceramics ◽  
Cultural Traditions ◽  
The Pacific ◽  
Ceramic Vessels ◽  
The Japanese Archipelago

Purpose. The article presents a historiographical review of the problems of research of ancient ceramics from archaeological sites of East Asia in the chronological interval from 20,000–18,000 to 9,000 years ago. Results. The subject of discussion is the periodization of monuments with early ceramics, the problems of socio-economic conditions of the emergence of pottery technology, its functional role in ancient societies, reconstruction of technological skills and technical levels of pottery, morphology and decor. There are a lot of controversial issues and “blind spots” in this direction. However, the opening of sites with ancient ceramics in East Asia showed that here, on the Pacific (eastern) outskirts of the Eurasian continent, pottery making technology first appeared about 10,000 years earlier than in the Middle East. The invention of ceramics in this region of the world at the turn of the Pleistocene and Holocene should be considered as a result of a combination of natural and social factors. The example of East Asia shows that the relationship between the appearance of ceramic vessels and the development of agriculture, as a technology for food production, is universally, not a mandatory factor. Conclusion. The article discusses certain regional differences in the formation of skills in making the most ancient ceramic vessels of East Asia. It is assumed that the development of ceramic technology in the Japanese archipelago and in the mainland areas of East Asia took place independently. For the Amur region, there are two local cultural traditions – Osipovskaya and Gromatukhinskaya. According to materials from Northern China, there is a version of the existence of a common line in the development of ancient ceramics in the Valley of the Nonny River. There are similarities between the early ceramics of Northeast China, and the Gromatukhinskaya and Osipovskaya cultures of Amur. For the ceramics of South Korea also note similarities with the materials of the Russian Far East, Japanese and Chinese dishes.

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