Northern Kamchatka Research Articles

Holocene environmental changes in southern Kamchatka, Far Eastern Russia, inferred from a pollen and testate amoebae peat succession record

High resolution palaeoenvironmental records in Far-Eastern Russia are rare, and the Kamchatka Peninsula is among the least studied areas of the region. This paper describes a record spanning the last ca. 11,000yr, obtained from a bog in the southern part of Kamchatka. The radiocarbon dated core was analysed for pollen, testate amoebae, charcoal and loss-on-ignition (LOI).The vegetation during the early Holocene was dominated by grasses (Poaceae), birch (Betula) and heath (Ericaceae p. p.). Around 10,300calyr BP there was a substantial change in the vegetation cover to shrub alder (Alnus viridis s.l.) stands with sedges and ferns (Polypodiophyta) as well as herbs such as meadow rue (Thalictrum) in the understory. In the surroundings of Utka peatlands started to form. The variations in the vegetation cover were most probably caused by climatic changes. At the beginning of sediment accumulation, before 10,300calyr BP, the composition of the vegetation points to cooler summers and/or decreased annual precipitation. Around 10,300calyr BP, changes in vegetation occurred due to rising temperatures and/or changed water regimes. Increased abundancies of dry indicating testate amoebae after 9100calyr BP point to intermediate to dry soil conditions. Between 8600 and 7700calyr BP tree alder (Alnus incana) was widely spread at the site which probably indicates optimal environmental conditions. The tephra layer at 381–384.5cm (ca. 8500calyr BP) produces a strong impact on the testate amoebae assemblages. At 7700calyr BP there was a sudden drop of A. incana in the local vegetation. From this time on, A. incana and also A. viridis decrease continuously whereas Betula gradually increases. The upper part of the sequence (after 6300calyr BP) shows higher abundancies of meadowsweet (Filipendula) and sweet gale (Myrica) pollen. After 6300calyr BP, changes in testate amoebae demonstrate variable soil moisture conditions at the site. Between 3700 and 1800calyr BP, wet conditions dominate as dry indicating testate amoebae decrease. After 1800calyr BP soil conditions become more variable again but this time with dry dominating testate amoebae.In contrast to surrounding regions, there is no evidence of trees such as spruce or larch growing in the surroundings of the site even though those trees are characteristic of many eastern Siberian sites. This difference might be because of the maritime influence of the Okhotsk Sea. Even dwarf pine (Pinus pumila), which is currently widely dispersed in northern Kamchatka, became part of the local vegetation only during the last 700yr.

Geology and stream sediment geochemistry of the Vilyuchinsky gold district, Southern Kamchatka, Russian Federation

The Kamchatka–Kuril island arc forms the northeastern margin of the Eurasian continent, including the Kuril Islands, Kamchatka Peninsula and parts of the Koryak Highlands. This composite island arc, over 2000 km long, contains abundant epithermal gold deposits with total resources currently assessed at approximately 30 Moz of gold. Epithermal gold deposits of the Kamchatka–Kuril arc cluster in several gold districts associated with Neogene volcanism, Koryak, Northern Kamchatka, Central Kamchatka, Kumroch and Southern Kamchatka (Vilyuchinsky), and there are also smaller deposits in the Kuril Islands.The Vilyuchinsky district comprises mainly intermediate and felsic volcanic rocks of Miocene and Pliocene age overlying a sedimentary flysch sequence, and locally overlain by Quaternary basalts. Shallow subvolcanic intrusions represent the roots of Neogene palaeovolcanic structures that were exposed by erosion. Epithermal gold deposits in the Vilyuchinsky district are of the adularia-sericite type and form north west trending linear arrays that are spatially associated with the Vilyuchinsky crustal fault that bounds the district to the North. Mineralisation is spatially associated with, and is commonly hosted by, subvolcanic intrusions of dacite and andesitic-dacite exposed in the deeply eroded palaeovolcanic centres.The Vilyuchinsky district was mapped and explored at a scale of 1 : 50 000. All creeks were systematically sampled at a density of approximately one sample per 500 m along the stream infilled to 1 : 25 000 in geologically favourable areas. Analysis of stream sediment assays indicates that gold has a multi-modal statistical distribution, suggesting the presence of different levels of geochemical anomalies. Gold assays ≥ 20 ppb are classified as anomalous, and values ≥ 100 ppb are classified as highly anomalous. In the Kamchatka region, deposits containing more than 1 Moz of gold coincide with stream sediments that contain ≥ 100 ppb of gold. In the Vilyuchinsky district, such samples are found only around the Porozhistoe deposit. Copper and lead values in stream sediments are classified as anomalous at ≥ 100 ppb and ≥ 30 ppb, respectively.Base metals and gold are commonly distributed in three separate zones surrounding diorite porphyry centres (e.g. at the Balaganchik prospect). Copper anomalies occur in the vicinity of diorite porphyry intrusions, lead is present 2–3 km from the centres, forming an intermediate geochemical halo, and gold veins and related stream sediment anomalies form an outer halo most distant, commonly >5 km from the diorite centres. The zoned nature of the stream sediment anomalies can be used as a geochemical vector to facilitate exploration.

High-latitude regions of Siberia and Northeast Russia in the Paleogene: Stratigraphy, flora, climate, coal accumulation

The geological structure and development history of superposed depressions on the Arctic coast of East Siberia and Bering Sea region (Chukotka, Koryakiya, northern Kamchatka) in the Early Paleogene are considered with the analysis of their flora and climatic parameters. The paleofloral analysis revealed thermophilic assemblages that reflect phases of maximum warming at the Paleocene-Eocene transition and in the Early Eocene. The appearance of thermophilic plants (Magnoliaceae, Myrtaceae, Lauraceae, Araliaceae, Loranthaceae, and others) in the Siberian segment of the Arctic region is explained by the stable atmospheric heat transfer from the Tethys to higher latitudes and absence of the latitudinal orographic barrier (Alpine-Himalayan belt). The plants migrated to high latitudes also along the meridional seaway that connected the Tethys with the Arctic Ocean via marine basins of the Eastern Paratethys, Turgai Strait, and West Siberia. The migration from the American continent was realized along the southern coast of Beringia under influence of a warm current flowing from low latitudes along the western coast of North America. The palm genus Sabal migrated to northern Kamchatka and Koryakiya precisely in this way via southern Alaska. In the Oligocene, shallow-water marine sediments in high-latitude regions were replaced by terrestrial facies. The Late Oligocene was marked by maximum cooling. Coal accumulation in Northeast Russia through the Paleogene is reviewed.

Distal tephrochronology in volcanic regions: Challenges and insights from Kamchatkan lake sediments

Kamchatka is one of the world's most active volcanic regions and has hosted many explosive eruptions during the Holocene. These eruptions had the potential to disperse tephra over wide areas, forming time-synchronous markers wherever those tephras are found. Recent research in Kamchatka has begun to focus on the geochemical analysis of individual glass shards in order to characterise tephra layers. We have applied this approach to the study of visible tephras from three lakes – one in central and two in northern Kamchatka – with the aim of identifying key tephras and potential issues in the application of distal (>100km from an active volcano) tephra in volcanically complex regions. In total, 23 tephras from 22 tephra beds have been geochemically analysed, representing products from at least four volcanic systems in Kamchatka. We demonstrate that distal lake sediments in the region can yield reliable tephrostratigraphies, capturing tephra from eruptions that have the greatest potential to disperse volcanic ash beyond the region. We draw attention to issues relating to correlating and distinguishing key marker horizons from the highly active Shiveluch Volcano, namely the need to ensure inter-lab comparability of geochemical data and good chronological control of the proximal and distal tephras. Importantly, we have also extended the known distribution of two key tephra isochrons from the Ksudach volcano. Our work contributes valuable glass geochemical on data several key marker beds that will facilitate future tephra and palaeoenvironmental research within and beyond Kamchatka.

Late Holocene expansion of Siberian dwarf pine (Pinus pumila) in Kamchatka in response to increased snow cover as inferred from lacustrine oxygen-isotope records

Holocene records of cellulose-inferred lake-water δ18O were produced from two lake-sediment sequences obtained in central and northern Kamchatka, Russian Far East. The sediment records share similar fluctuations in δ18O during the interval of ca. 5000–800calyr BP that correspond (inversely) with changes in K+ content of the GISP2 ice-core record from Greenland, a proxy for the relative strength of the Siberian High, suggesting control by climate-related variability in δ18O of regional precipitation. The dramatic expansion of Siberian dwarf pine (Pinus pumila) in northern and central Kamchatka between ca. 5000 and 4000calyr BP, as inferred from pollen records from the same and neighbouring sites, appears to have occurred at a time of progressively declining δ18O of precipitation. This development is interpreted as reflecting a regional cooling trend accompanied by increasing winter snowfall related to gradual intensification of the Siberian High from ca. 5000 to ca. 3000calyr BP. A thicker and more long-lasting snow cover can be assumed to have favoured P. pumila by providing a competitive advantage over other boreal and subalpine tree and shrub species in the region during the later part of the Holocene. These results, which are the first of their kind from Kamchatka, provide novel insight into the Holocene vegetational and climatic development in easternmost Asia, as well as long-term atmospheric circulation dynamics in Beringia.

«Если нет культуры, то нет и истории…»: традиционная культура оленеводов северной Камчатки в постсоветский период

Oliutorskii Chauchu, the Koryak reindeer herders of Northern Kamchatka, have faced serious economic and social hardships since the collapse of the Soviet Union. They had to adapt their traditional reindeer herding, maintenance of village infrastructures and production to a free-market economy. Previously, they based these on the principles of state control. Despite the social changes during the Soviet era, they maintained not only their worldview but also various rituals connected with reindeer herding. Even though some Koryak reindeer herders – the local intelligentsia – received a Soviet education based on materialism, they openly expressed their conviction in religious traditions and discussed spiritual ties between reindeer herders, reindeer, nature and Koryak mythology even in the early 1990s. They saw no contradictions between science and Koryak religion and tried to explain some religious elements by means of science. They thought that finding rational explanations behind traditional beliefs was the purpose of science. They also believed that it was necessary to practice traditional Koryak knowledge and pass it, along with their rituals, to younger generations.This paper aims to study how deeply religion was rooted in the everyday life of reindeer herders in the Oliutorsk Region (Northern Kamchatka). It also shows how religious experience helps young Koryak people form ethnic identity. The paper is based on the author’s observations and interviews, which he collected during his fieldwork among the reindeer herders in the Oliutorsk Region during the early 1990s.

Linguistic Expedition to Kamchatka Documenting the Koryak Language, December 2012–August 2013

This project is titled “Koryak Ethnopoetics: Stories from Herders and Maritime Villagers” and emerges from my long interest in oral narratives in Koryak. It is funded by a grant from the Endangered Language Documentation Project (ELDP).1 The general goal of the project is to document spoken Koryak, especially oral narratives, primarily by speakers of less studied dialects. Koryak varies quite a bit from one dialect to another, and this project will provide a better set of linguistic data for Koryak. In my previous fieldwork, I found that many people wanted me to share the realities of their traditions, their stories, their lives with the wider world. More Koryaks are concerned about having their name spelled correctly in my publications than being anonymous. This documentation project is ultimately about addressing the inequalities of voice as discussed by Dell Hymes (1996). I have found it rare that my academic research makes a real difference in people’s lives. However, that is exactly the feeling I got when talking to Koryaks about our documentation project in northern Kamchatka; it is work that makes a difference for many people in Kamchatka. Indigenous Kamchatkans face great struggles to have their voices heard but soon there will be an open and easily accessible archive of nearly 200 hours of what they want to say. The majority of participants we recorded had the goal of putting their native born language on record. They wanted their language, the language that their grandchildren don’t understand, recorded so that someone, anyone could hear it even after their death. Most people we approached had a clear sense of legacy. A few treasured the opportunity to speak with with my research partner, who was an excellent conversational partner in Koryak and is honestly interested in what the elder had to say.

Along-arc variations in lithospheric mantle compositions in Kamchatka, Russia: First trace element data on mantle xenoliths from the Klyuchevskoy Group volcanoes

We provide results of a detailed study of the first peridotite xenoliths of proven mantle origin reported from Bezymyanny volcano in the Klyuchevskoy Group, northern Kamchatka arc. The xenoliths are coarse spinel harzburgites made up mainly of Mg-rich olivine as well as subhedral orthopyroxene (opx) and Cr-rich spinel, and also contain fine-grained interstitial pyroxenes, amphibole and feldspar. The samples are unique in preserving the evidence for both initial arc mantle substrate produced by high-degree melt extraction and subsequent enrichment events. We show that the textures, modal and major oxide compositions of the Bezymyanny xenoliths are generally similar to those of spinel harzburgite xenoliths from Avacha volcano in southern Kamchatka. However, coarse opx from the Bezymyanny harzburgites has higher abundances of light and medium rare earth elements and other highly incompatible elements than coarse opx from the Avacha harzburgites. We infer that (1) the sub-arc lithospheric mantle beneath both Avacha and Bezymyanny (and possibly between these volcanoes) consists predominantly of harzburgitic melting residues, which experienced metasomatism by slab-related fluids or low-fraction, fluid-rich melts and (2) the degrees of metasomatism are higher beneath Bezymyanny. By contrast, xenolith suites from Shiveluch and Kharchinsky volcanoes 50–100km north of the Klyuchevskoy Group include abundant cumulates and products of reaction of mantle rocks with silicate melts at high melt/rock ratios. The high melt flux through the lithospheric mantle beneath Shiveluch and Kharchinsky may be related to the asthenospheric flow around the northern edge of the sinking Pacific plate; lateral propagation of fluids in the mantle wedge south of the plate edge may contribute to metasomatism in the mantle lithosphere beneath the Klyuchevskoy Group volcanoes.

A chronology of the Holocene eruptions from the northern Kamchatka volcanoes based on linking major C14-dated tephra sequences with the help of EMPA glass data

A chronology of the Holocene eruptions from the northern Kamchatka volcanoes based on linking major C14-dated tephra sequences with the help of EMPA glass data

Postcollision exhumation of Northern Kamchatka complexes (Lesnovskii uplift)

The Eocene collision of the Cretaceous Achai� vayam–Valagin ensimatic island arc with the north� eastern margin of the Asian continent was an impor� tant event in the tectonic history of development of the northwestern framework of the Pacific. The collision was diachronic: collision of the southern part of the island arc with the continental margin occurred in the Early Eocene (55–53 Ma); collision of the northern part of the island arc with the continental margin was com� pleted by the Middle Eocene (about 45 Ma ago) [1, 2]. The age of the collision and the lateral variability of collision structures has been studied well [2]. The col� lision zone in North Kamchatka (an area of the Kam� chatka Isthmus) is one of the most thoroughly studied areas in Kamchatka (Fig. 1). In this area, the boundary between the Lesnovskii–Ukelayat and Achaivayam– Valagin terrains is represented by the Lesnovskii– Vatynskii thrust fault, formation of which was com� pleted about 45 Ma ago [3]. In order to reconstruct the postcollision geological history of the region, the fis� sion track dating method was first applied. This method allowed us to estimate the exhumation rate of complexes of the Lesnovskii uplift. Thus, the rates of the Post–Middle Eocene Orogeny in Northern Kam� chatka were calculated for the first time.

Pole to equator temperature gradient for coniacian time, late cretaceous: Oxygen and carbon isotopic data on the Koryak upland and Hokkaido

The purpose of this study was to estimate the Coniacian latitudinal thermal gradient in the Northern Hemisphere. Both hemipelagic (ammonoids) and benthic (brachiopods and bivalves)  18 O and  13 С records were used. They originated from Coniacian shallow-water sequences across a wide range of paleolatitudes, from the Koryak upland (northern Kamchatka, Russian Far East) in the north, to Hokkaido (Japan) in the south. Among Coniacian ammonoids, both migrants from Hokkaido living in high latitudes (Kamchatka) and endemic forms dwelling in middle-low latitudes (Hokkaido) indicate seemingly close optimal growth temperatures. Nevertheless, certain differences in climatic conditions, prevailing during high-latitude coldest seasons, undoubtedly provoked growth cessation in some groups of ammonites. Our isotopic study suggests latitudinal temperature changes of only 0.12 ℃ per degree of latitude for the Northern Hemisphere in Coniacian times, while the average annual tem- perature in North Kamchatka seems about 3.3 ℃ lower than that in Hokkaido.

Eocene arc-continent collision in northern Kamchatka, Russian Far East

The collision of the Cretaceous Olutorsky Island Arc with eastern Eurasia margin in the northwest Pacific is a critical event in Cenozoic evolution of the Pacific Rim. The timing of synorogenic flysch deposition (Paleocene–Middle Eocene, as young as 45–50 Ma), cross-cutting Shamanka pluton (45 Ma), and an overlap sequence of the Kinkil volcanics (45 Ma) tightly bracket the timing of collision of the far-traveled Olutorsky terrane to the Middle Eocene. This collision may have driven change in plate movement that resulted in the establishment of the Aleutian Arc at this time, which trapped a fragment of the Kula plate (now in the Bering Sea).

Deep neogene structure and modern seismicity of the southern part of the Koryak Highland academician

The Northern Kamchatka and southern part of the Koryak Highland is considered to be an accretion-collision system in the Late Cretaceous and Cenozoic the development of which was caused by the subsequent accretion of various large terranes to the Asian continental margin. The Paleogene Goven Terrane accreted in the Miocene closes this system. Its boundary with the Olyutor Terrane is hidden under the Cenozoic sediments of the Il’pino-Pakhachino interarc trough. The destructive Khaily (March 8, 1991) and Olyutor (April 20, 2006) earthquakes are characterized by an aftershock area extended in the northeastern direction along the axial part of the Il’pino-Pakhachino trough. The aftershock area was intersected by a profile of the earthquake converted-wave method (ECWM) the interpretation of which reveals a correlation loss of the deep reflecting horizons under this area and three faults dipping to the southeast on seismograms.

A geological study of the epicentral area of the April 20(21), 2006 Olyutorskii earthquake

Primary and secondary earthquake effects were investigated (surface breakage and felt effects in the villages of Tilichiki, Korf, and Khailino) in the epicentral area of a large earthquake occurring in northern Kamchatka Krai. The primary effects include an extended surface break that can be followed for a length of about 140 km. The secondary (gravitational and vibrational) effects include soil slides and minor rockfalls, snow flows on slopes, resonant cracks, soil liquefaction phenomena consisting of mud cones, mud gryphons, and discharges of soil from cracks. Detailed maps showing the main types of earthquake surface effects have been made. Paleoseismic data show traces of several large earthquakes that have occurred in the Olyutorskii earthquake zone. Radio carbon dating of soil samples from these paleoseismic scarps revealed a history of great earthquakes occurring in Koryakia. In all, four seismic events with magnitudes about that of the 2006 Olyutorskii earthquake have occurred there during 8000 years, the return period of such events being 1000–2500 years.

Geotouristic attractions of the Klyuchevskoy group volcanoes, North Kamchatka, Russia

The paper describes the geotouristic valours of the Klyuchevskaya group of volcanoes in the Northern Kamchatka. The relationships are presented between the Kamchatka and the recent boundaries of crustal plates, then the genesis and the structure are explained of the Koryak-Kamchatka volcanic belt. The geotectonic position of Kamchatka as a part of the “Circumpacific Ring of Fire” enables us to recognize the manifestations of the recent volcanism (shield volcanoes, stratovolcanoes, lava domes, calderas, ignimbrites, lahars, gas and vapour exhalations, native sulphur encrustations). Apart from volcanic activity, the exceptional tourist value of the Northern Kamchatka is the highmountain relief shaped by glaciers, weathering and river erosion.

The optimal sacrifice: A study of voluntary death among the Siberian Chukchi

ABSTRACTIn the Siberian North, “voluntary death,” that is, a person, who—often because of illness and old age—requests to die at the hands of close relatives, has traditionally been explained as a form of suicide resulting from the region's harsh living conditions. In this article, I suggest an alternative interpretation. Drawing on ethnographic data collected among the Chukchi of northern Kamchatka, I argue that voluntary death is effectively a ritual blood sacrifice. In making this argument, I recast long‐standing debates about sacrifice by suggesting that behind the triangular relationship of sacrificer, deity, and victim lies a structure of ideal sacrifice, which is the impossible act of self‐sacrifice. This structure, in turn, makes it possible to conceive of voluntary death as categorically different from suicide—indeed, as a ritual inversion of suicide.

Tectonic position and geological manifestations of the 2006 olyutor earthquake in Koryakia

The results of seismotectonic study of the epicentral zone of the major earthquake in northern Kamchatka oblast are presented. Primary and secondary surface seismic dislocations were revealed. The exposed seismic source as a complex system of seismic faults up to 140 km in total length was found and mapped in detail. The system consists of three en echelon arranged NE-oriented segments about 16, 45, and 75 km long. The general strike of the fault system coincides with the orientation of the ridges in the Koryak Highland. The kinematics of the longest northeastern segment is reverse faulting of the southeastern wall combined with right-lateral strike-slip faulting. The maximum vertical and horizontal separations are 3 and 1.5 m, respectively. Vibration fractures, griffons, landslides, and rockfalls were revealed and documented as secondary seismic dislocations. The indications of paleoseismic dislocations were studied and documented as well. The age of paleoseismic events was determined with radiocarbon method from soil samples. The seismic source is confined to the boundary of the North American and Bering Sea lithospheric plates and exhibits its internal structure for a long distance. Seismic events testify to recent geological activity of the zone of interaction between the lithospheric plates. The collected data provide insights into the structure of the seismic source and its tectonic setting at the active continental margin of Asia.

Seismotectonics of the Chersky Seismic Belt, eastern Sakha Republic (Yakutia) and Magadan District, Russia

Abstract. The Chersky seismic belt represents a zone of deformation between the North American and Eurasian plates in northeast Russia. The belt extends from the Laptev Sea into the Chersky Range where it splits into two branches. One branch extends to Kamchatka and the Aleutian-Kurile Junction, while the other branch extends south towards Sakhalin Island. Focal mechanisms indicate a change from extension to transpression in the northern Verkhoyansk Range and generally left-lateral transpression in the Chersky Range extending to northern Kamchatka. The few focal mechanisms on the second branch suggest right-lateral transpression. A large number of faults, sub-parallel to the seismicity and presumed to be strike-slip, are visible in satellite imagery and topographic maps and are also associated with seismically generated landslides. These data support a model in which the Sea of Okhotsk forms the core of a separate Okhotsk microplate surrounded by diffuse boundaries on the north and west. Microseismicity in continental northeast Russia is most heavily concentrated within and between the fault systems along the northern boundary of the proposed Okhotsk plate and indicates a high level of deformation. The sense of slip on the faults (both from focal mechanisms and geology) are also generally consistent with the extrusion of the Okhotsk plate to the southeast as it is compressed between its larger neighbors. The northernmost part of the Okhotsk plate may be decoupled to some degree from the more stable central Sea of Okhotsk.

Ozone content over the Russian Federation in the second quarter of 2009

Total ozone (TO) norms for the period from April to June (i.e., the multiyear TO means over Russia and contiguous territories determined for 1974–1984) were given in [1]. Similarly to the first quarter of 2009, quarterly TO means in the second quarter over the territory under control were generally close to the multiyear means (Fig. 1a). Apparently, the return of the ozone layer characteristics to norms of a 30-year past is largely connected with the abnormally strong and long-lasting warming in the stratosphere in the high-latitudes of the Northern Hemisphere observed in winter 2008–2009 [3], which substantially reduced the area under the Arctic circumpolar vortex over Russia. The maximum TO deviations from normal in the second quarter of 2009 were observed at the stations located in Irkutsk and Ekaterinburg. In Ekaterinburg, the quarterly TO mean abnormally exceeded the multiyear mean and reached 8% or 2.8 standard deviations (SD). An anomalous deficiency of the quarterly TO mean value was observed at the station in Irkutsk: 7% or 2.8 SD. The lowest quarterly mean TO values (320–375 DU) were recorded over the southern regions of European Russia, Central Asia, Kazakhstan, and the south of Siberia. Over the central and northern regions of European Russia, the Urals, Siberia, and Chuckchi Peninsula, quarterly TO means were 375–420 DU. The highest TO values were observed over the Far East, northern Eastern Siberia and Kamchatka: 420– 440 DU. In this review, for the total ozone maps compiling, data collected at the UkrNIGMI station were used instead of those from the network station in Kiev, which is located in about 30 km from the UkrNIGMI station. Data collected at Vladivostok, Vitim, Odessa, Chardzhou, Ashkhabad, the Aral Sea, Nagaevo, Petropavlovsk-Kamchatski stations were not used for the ozone field analysis in the second quarter of 2009 because of their low quality. In April 2009, monthly mean TO values determined over the major part of the territory under control were close to the multiyear means (Fig. 1b). The only exception was the station in Ekaterinburg, where the anomalous exceeding of the mean TO value was recorded; it amounted to 14% or 2.8 SD. The maximum deficiency of the monthly mean TO value was recorded in Irkutsk (10% or 2.2 SD). If over European Russia the TO was slightly above the norm, over the south of Siberia, it was slightly below the norm. It is interesting to note that reduced TO values were observed over the major part of Western Siberia, south of Scandinavia, and north of Canada. In May, monthly TO means estimated over the major part of the considered territory were close to the multiyear means (Fig. 1c) except for the Markovo station, where the anomalous deficiency of the monthly TO mean was recorded (10% or 2.7 SD). The maximum exceeding of the monthly mean TO value was observed at the Turukhansk and Nikolaevsk-on-Amur stations (7% or 1.9 and 1.7 SD, respectively). In June, monthly mean TO values over the territory under control were nearly normal. The maximum monthly mean TO deficiency was recorded at the Tsimlyansk station (8% or 2.5 SD). The greatest exceeding of the norm was observed at the Murmansk station (8% or 2.0 SD). ISSN 1068-3739, Russian Meteorology and Hydrology, 2009, Vol. 34, No. 8, pp. 561–563. Allerton Press, Inc., 2009.

Geodynamic settings and magma sources of the Late Cretaceous-Early Paleocene magmatic complexes of northern Kamchatka

Geochemical and isotopic studies showed that the Late Cretaceous-Early Paleocene magmatic rocks of northern Kamchatka were formed in different geodynamic zones of a Late Cretaceous-Early Paleocene suprasubduction system: from a volcanic front to a back-arc rift basin. Suprasubduction magmas were derived from upper mantle garnet or spinel lherzolites variably depleted in terms of Nd isotopic composition or enriched in HFSE and showing varying Th/La, Th/Ta, Zr/Nb, and Nb/U ratios. Subduction-related fluids played an active role in this process. The suprasubduction mantle melts were not contaminated by crustal materials enriched in radiogenic Nd. A weak imprint of contamination was identified only in the lavas of Karaginsky Island.