Late Pleistocene - Holocene Volcanism on the Kamchatka Peninsula, Northwest Pacific Region

Late Pleistocene-Holocene volcanism in Kamchatka results from the subduction of the Pacific Plate under the peninsula and forms three volcanic belts arranged in en echelon manner from southeast to northwest. The cross-arc extent of recent volcanism exceeds 250 km and is one of the widest worldwide. All the belts are dominated by mafic rocks. Eruptives with SiO2>57% constitute ~25% of the most productive Central Kamchatka Depression belt and ~30% of the Eastern volcanic front, but <10% of the least productive Sredinny Range belt. All the Kamchatka volcanic rocks exhibit typical arc-type signatures and are represented by basalt-rhyolite series differing in alkalis. Typical Kamchatka arc basalts display a strong increase in LILE, LREE and HFSE from the front to the back-arc. La/Yb and Nb/Zr increase from the arc front to the back arc while B/Li and As, Sb, B, Cl and S concentrations decrease. The initial mantle source below Kamchatka ranges from N-MORB-like in the volcanic front and Central Kamchatka Depression to more enriched in the back arc. Rocks from the Central Kamchatka Depression range in 87Sr/86Sr ratios from 0.70334 to 0.70366, but have almost constant Nd isotopic ratios (143Nd/144Nd 0.51307–0.51312). This correlates with the highest U/Th ratios in these rocks and suggest the highest fluid-flux in the source region. Holocene large eruptions and eruptive histories of individual Holocene volcanoes have been studied with the help of tephrochronology and 14C dating that permits analysis of time-space patterns of volcanic activity, evolution of the erupted products, and volcanic hazards

Giant Late Pleistocene paleolake in Central Kamchatka depression (Kamchatka Peninsula, Russian Far East)

A number of tephrochronologically correlated and dated sedimentary sections provide evidence for the existence of a giant lake filled the Central Kamchatka depression 30-11 thousand years ago. The lake extent bounded by CKD borders is estimated to be ~10 000 km2. This estimate makes this lake comparable in size to the famous Late Pleistocene glacial Lake Missoula

Large-volume silicic volcanism in Kamchatka: Ar–Ar and U–Pb ages, isotopic, and geochemical characteristics of major pre-Holocene caldera-forming eruptions

The Kamchatka Peninsula in far eastern Russia represents the most volcanically active arc in the world in terms of magma production and the number of explosive eruptions. We investigate large-scale silicic volcanism in the past several million years and present new geochronologic results from major ignimbrite sheets exposed in Kamchatka. These ignimbrites are found in the vicinity of morphologically-preserved rims of partially eroded source calderas with diameters from ∼ 2 to ∼ 30 km and with estimated volumes of eruptions ranging from 10 to several hundred cubic kilometers of magma. We also identify and date two of the largest ignimbrites: Golygin Ignimbrite in southern Kamchatka (0.45 Ma), and Karymshina River Ignimbrites (1.78 Ma) in south-central Kamchatka. We present whole-rock geochemical analyses that can be used to correlate ignimbrites laterally. These large-volume ignimbrites sample a significant proportion of remelted Kamchatkan crust as constrained by the oxygen isotopes. Oxygen isotope analyses of minerals and matrix span a 3‰ range with a significant proportion of moderately low-δ18O values. This suggests that the source for these ignimbrites involved a hydrothermally-altered shallow crust, while participation of the Cretaceous siliceous basement is also evidenced by moderately elevated δ18O and Sr isotopes and xenocryst contamination in two volcanoes. The majority of dates obtained for caldera-forming eruptions coincide with glacial stages in accordance with the sediment record in the NW Pacific, suggesting an increase in explosive volcanic activity since the onset of the last glaciation 2.6 Ma. Rapid changes in ice volume during glacial times and the resulting fluctuation of glacial loading/unloading could have caused volatile saturation in shallow magma chambers and, in combination with availability of low-δ18O glacial meltwaters, increased the proportion of explosive vs effusive eruptions. The presented results provide new constraints on Pliocene–Pleistocene volcanic activity in Kamchatka, and thus constrain an important component of the Pacific Ring of Fire

Magnesian Basalts of Shiveluch Andesite Volcano, Kamchatka

The eruptive history of the Shiveluch andesite volcano included two Holocene events, during which the volcano erupted unusual rocks: medium-potassium, amphibole-bearing magnesian basalts (7600 years ago) and high-potassium magnesian basalts with phlogopite and amphibole (3600 years ago). The volumes of tephra were approximately 0.1 and 0.3 km3, respectively. Some of the mineralogical and geochemical features of the Holocene basalts were inherited by the subsequent basaltic andesites and andesites. These are similar in Mg variation ranges of olivine, clinopyroxene, and amphibole phenocrysts, high Mg contents, and high Cr and Ni concentrations. This and the results of mass-balance calculations do not contradict the view that the Shiveluch volcanic rocks originated during the crystal fractionation of Holocene basalt melts. However, the other geochemical features of the Shiveluch rocks, e.g., their similar REE contents, cast doubt on the formation of the magnesian basaltic andesites through fractional crystallization of magnesian basalt magma and suggest that they originated as a result of interaction between magnesian basalt magma and a depleted mantle material at a shallow depth. At the same time, the different mineral compositions of the Holocene medium- and high-potassium basalts and the results of mass-balance calculations indicate that their parental magmas might be produced by the melting of different rocks

The ages of calderas, large explosive craters and active volcanoes in the Kuril-Kamchatka region, Russia

The ages of most of calderas, large explosive craters and active volcanoes in the Kuril-Kamchatka region have been determined by extensive geological, geomorphological, tephrochronological and isotopic geochronological studies, including more than 600 14C dates. Eight ‘Krakatoa-type’ and three ‘Hawaiian-type’ calderas and no less than three large explosive craters formed here during the Holocene. Most of the Late Pleistocene Krakatoa-type calderas were established around 30 000–40 000 years ago. The active volcanoes are geologically very young, with maximum ages of about 40 000–50 000 years. The overwhelming majority of recently active volcanic cones originated at the very end of the Late Pleistocene or in the Holocene. These studies show that all Holocene stratovolcanoes in Kamchatka were emplaced in the Holocene only in the Eastern volcanic belt. Periods of synchronous, intensified Holocene volcanic activity occurred within the time intervals of 7500–7800 and 1300–1800 14C years BP

PROBLEMS OF DETERMINING THE BALANCE OF RIGHTS BETWEEN THE AUTHOR AND THE SOCIETYABOUT THE USE OF INTELLECTUAL PROPERTY IN THE HISTORY OF LEGAL STUDIES

The article is dedicated to the problem of defining the boundaries of fair use of the composition. By the end of the 18th century compositions became unique and original. Authorship wasn't evaluated from the standpoint of traditionalism. It was connected with genius of the author, originality of creativity. Philosophers, for example I. Kant, J. G. Fichte, G. W. F. Hegel, started considering the concepts of author, ideas, and forms of the composition. The article explains what the idea and form is, comparison of these concepts, and why forms of the composition should be protected by law while the idea can be spread easily. Also the article explains the factors and legal grounds of non-classical concept's appearance due to the increasing complexity of public relations

Radiocarbon dating and tephrochronology in Kamchatka

We discuss results of 14C dates obtained from areas of young volcanoes in Kamchatka. We apply these dates to reconstructing regional volcanic activity during the Holocene