Tephra Layers of in the Quaternary Deposits of the Sea of Okhotsk: Distribution, Composition, Age and Volcanic Sources

Quaternary International xxx (2016) 1e25

Contents lists available at ScienceDirect

Quaternary International

journal homepage: www.elsevier.com/locate/quaint

Tephra layers of in the quaternary deposits of the Sea of Okhotsk: Distribution, composition, age and volcanic sources

* Alexander N. Derkachev a, , Nataliya A. Nikolaeva a, Sergey A. Gorbarenko a, Maxim V. Portnyagin b, c, Vera V. Ponomareva d, Dirk Nürnberg b, Tatsuhiko Sakamoto e, Koiji Iijima e, Yanguang Liu f, Xuefa Shi f, Huahua Lv f, Kunshan Wang f a V.I. Il'ichev Paciﬁc Oceanological Institute, FEB RAS, Baltiyskaya st., 43, Vladivostok, 690041, Russia b GEOMAR Helmholtz Centre for Ocean Research, Wischhofstrasse, 3, Kiel, Germany c V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, RAS, Moscow, Russia d Institute of Volcanology and Seismology, FEB RAS, Piip Boulevard, 9, Petropavlovsk-Kamchatsky, 683006, Russia e Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan f First Institute of Oceanography, SOA, Xian-Xia-Ling Road, 6, Qingdao, 266061, China article info abstract

Article history: The fullest summary on composition, age and distribution of 23 tephra layers detected and investigated Available online xxx in the Okhotsk Sea Pleistocene-Holocene deposits is presented. Seven tephra layers are surely identified with powerful explosive eruptions of volcanoes of Kamchatka, Kurile and Japanese Islands. For them, the Keywords: areas of ash falls including which weren't revealed earlier on the land are specified and established. It is Tephra estimated that explosive eruptions of volcanoes of the Kamchatka Sredinny Range were the sources for Tephrostratigraphy three tephra layers. Complex investigations of morphological, mineralogical and chemical composition of Quaternary deposits tephras including composition of rare and earth-rare elements (electron microprobe analysis and laser Sea of Okhotsk Geochemistry of volcanic glasses ablation method - LA ICP MS) have been made for all studied layers. They were a basis for tephrostratigraphic correlation of the regional deposits promoting to specification of stages of volcanic explosive activity in this region. © 2016 Elsevier Ltd and INQUA. All rights reserved.

1. Introduction of their activities that cannot be reliably ascertained without investigating the properties of separate interlayers of tephra. In The interlayers of the volcanic ashes (tephra) in the continental addition, the tephra interlayers are very efﬁcient markers for and marine deposits contain the critical information of history and stratigraphic study of the sedimentary sequences and dating of past character of volcanic eruptions. In the events of the violent volcanic events (Addison et al., 2010; Jensen et al., 2011; Hamann et al., eruptions, an ash falls at spots being at distances of thousands ki- 2008; Hasegawa et al., 2011a, 2011b; Lowe et al., 2008; Lowe, lometers from the eruption centre while the substance related to 2011; Nakagawa et al., 2002, 2008; Nakamura, 2016; Nakamura the eruptive cloud can have effect on the natural environment et al., 2009; Preece et al., 2011; Ponomareva et al., 2015a; Smith including one on the global scale (Ambrose, 1998; Ehrmann et al., et al., 2002, and others). 2007; Hamann et al., 2008). Finally, the catastrophic character of In recent decades, in the entire world, the work on documenting the volcanic explosions and their destructive effect on the envi- and age dating of the greatest explosive eruptions is carried out ronmental situation and human life and activities exact to predict (Crosweller et al., 2012; Newton et al., 2007; Siebert and Simkin, the future behavior of particular volcanoes and to gain the 2002, and others). However, it should be noted that the global knowledge of possible spatial distribution of the harmful products catalog of such eruptions even over the past thousands years is nowhere near full: up to now, many greatest eruptions were not revealed. In addition, even for the established explosive eruptions,

* Corresponding author. the tephra distribution area is often unknown and, as a conse- E-mail addresses: [email protected] (A.N. Derkachev), mportnyagin@ quence, it is impossible to evaluate a volume of products thrown out geomar.de (M.V. Portnyagin), [email protected] (V.V. Ponomareva), by an eruption and to determine the extent of eruptions. This makes [email protected] (T. Sakamoto), xfshi@ﬁo.org.cn (X. Shi). http://dx.doi.org/10.1016/j.quaint.2016.07.004 1040-6182/© 2016 Elsevier Ltd and INQUA. All rights reserved.

Please cite this article in press as: Derkachev, A.N., et al., Tephra layers of in the quaternary deposits of the Sea of Okhotsk: Distribution, composition, age and volcanic sources, Quaternary International (2016), http://dx.doi.org/10.1016/j.quaint.2016.07.004 2 A.N. Derkachev et al. / Quaternary International xxx (2016) 1e25 it difficult to study the productivity and dynamics of the volcanic presented according to a classification (Katoh et al., 2000). A min- activity as well as the impact of volcanism on the environment and eral component of heavy (more than 2.85 g/cm3) fraction of ashes climate. So, the present differences in evaluating a role of volcanism with grain size of 0.05e0.1 mm was determined by the immersion as a factor of influence on the environment result from the method under the polarization microscope with count of not less incompleteness of the explosive eruptions record. Only an identi- than 300 mineral grains. The refraction index of volcanic glasses fication of tephra in the distant sections using data of its age and was determined by K. Iijima in JAMSTEC (Japan) using the material composition offers an opportunity to determine the dis- immersion-thermal method on the RIMS-86 (RI measurement tribution area and volume of tephra as well as magnitudes of system, Kyoto Fission) (Supplement 2), partially under the micro- eruptions which is crucial for understanding of the volcanism dy- scope in the immersion liquids (Derkachev et al., 2012). namics and evolution (Addison et al., 2010; Derkachev and All the layers of tephra from the deposits of the Sea of Okhotsk Portnyagin, 2013; Hasegawa and Nakagawa, 2016; Hasegawa et al., being at our disposal were examined by the unified procedure in 2011a, 2011b; Ponomareva et al., 2013a, 2013b, 2015b, and others). the electron microprobe JEOL JXA 8200 in the Leibniz Institute for The interlayers of tephra were found out in many marine and Ocean Research, now GEOMAR (Helmholtz Centre for Ocean continental deposits of the Pleistocene-Holocene age within the Research, Kiel, Germany) (Supplement 3). Investigations, carried north-west sector of the transition zone from the Asian continent out with the use of this method, allowed also to specify chemical to the Pacific Ocean. They were studied in sufficient detail on land composition of tephra. Volcanic glasses of this tephra were close to the Japanese Islands, Kamchatka and, to a lesser extent, analyzed earlier on electronic microscope Quanta-2000 with the Kurile Islands (Arai et al., 1986; Aoki and Machida, 2006; Braitseva energy-dispersive spectroscopy (EDAX) in FIO (Qingdao, China) and et al., 1993, 1997, 1998; Endo et al., 1989; Hasegawa et al., 2008, microprobe Cameca SX5 (GEOMAR, Kiel, Germany) (Gorbarenko 2009, 2011a, 2011b; Hasegawa and Nakagawa, 2016; Kimura et al., 2002; Derkachev et al., 2012; Kaiser, 2001); data obtained et al., 2015; Machida and Arai, 2003; Melekestsev et al., 1997; were used as additional source for correlation of sediment cores. Nakagawa et al., 2008; Nakagawa and Ohba, 2003; Pevzner, 2015; Using the microprobe JEOL JXA 8200, an analysis of volcanic Ponomareva et al., 2004, 2007; Razzhigaeva et al., 2011, 2016; glasses was performed by the defocused up to 5 mm electron beam Satoguchi and Nagahashi, 2012; Suto et al., 2007; Zaretskaya at accelerating voltage of 15 kV and current of 6 nA. For the device et al., 2001, 2007; Yamamoto et al., 2010, and others). However, calibration and monitoring of analyses quality, the natural certified despite the certain progress in the study of the region tephros- samples of volcanic glasses (basalt glass USNM 113498/1 VG-A99, tratigraphy, the North-West Pacific Ocean including the Sea of rhyolite glasses USNM 72854 VG568 and KN-18) and minerals Okhotsk remains to be poorly understood. (scapolite USNM R6600-1) were used (Jarosewich et al., 1980; Over the past fifteen years, during complex expeditions with the Mosbah et al., 1991). The results of analysis were corrected in participation of the Russian, German, Japanese and Chinese re- accordance with the CITZAF program. Every analytic session searchers in the Sea of Okhotsk, 23 tephra layers of in the including 15e40 h of operation of the instrument in autonomous Pleistocene-Holocene deposits were found out in more than 85 mode in the previously planned coordinates of measurement sediment cores (Fig. 1, Supplement 1). Data on them were pre- points was accompanied by analyses of the basic standards (rhyo- sented with different level of detail in a number of publications lite, basalt and scapolite) at the beginning, every 50e60 analyses (Derkachev et al., 2004; Derkachev and Portnyagin, 2013; and at the end of session. Based on these measurements, the Gorbarenko et al., 2002; Derkachev et al., 2011, 2012; Sakamoto correction factors considering a possibility of a slight calibration et al., 2005, 2006; Aoki, 2008 and others). In this paper, we pre- shift in a time of analysis were calculated for each analytical ses- sent the fullest summary on composition, age and distribution of 23 sion. In most cases, the values of factors did not exceed those of layers of tephra detected and investigated by us in the Sea of standard error of measurements of standards. After introduction of Okhotsk deposits. corrections into the measured data, all analyses of glasses were resulted in the sum of element oxides of 100% and used for con- 2. Materials and methods structing the diagrams presented in this paper and carrying out of the geochemical analysis. Method of microprobe analysis is given in The basis of this work was formed by the study of sediment our publications in detail (Ponomareva et al., 2013a, 2015a). cores taken in the Sea of Okhotsk with respect mainly to the When performing the tephrostratigaphical studies, the high- Russian-Germany project КОМЕХ (1998e2003) on board of quality chemical analyses carried out with quality control in research vessels “Akademik M.A. Lavrentyev”, “Marshal Gelovani”, accordance with international standards are needed (Froggatt, “Sonne” and the Russian-Japanese project on board of research 1992; Hunt et al., 1998; Kuehn et al., 2011). As the results of the vessels “Miray” and “Yokosuka” (2006e2007). In addition, the data international interlaboratory comparison of the accuracy of analytic for two sediment cores taken with respect to the Russian-Chinese investigations of the volcanic glass made upon an initiative of the project (2011) as well as materials of the earlier researches car- INTAV group tephrochronologists have shown, a procedure of the ried out in the Pacific Oceanological Institute, FEB RAS (Fig. 1, glass analysis accepted in GEOMAR is in accord with all the criteria Supplement 1) were used. The composition of tephra from the of high quality of analyses both in accuracy and reproducibility of sediment core MD01-2415 (age is about 1.1 million years) taken results (Kuehn et al., 2011). during voyage of the French research vessel “Marion Dufresne” When considering the chemical composition of the major pet- (2004) with respect to the program IMAGES was also investigated rogenic elements in the volcanic glasses, the representative sample (Nürnberg and Tiedemann, 2004; Levitan et al., 2007). of 885 new microprobe analyses carried out in recent times in Only material of clean and well visually diagnosable interlayers GEOMAR was used (Table 1, Supplement 3). of tephra was used for investigations. Initially, the sample was Determination of rare and rare-earth elements in the volcanic divided using a standard screen set under a water stream. The glasses was made by M. Portnyagin with the use of the laser abla- further studies were carried out with the use of grain-size fractions tion method - LA ICP MS (245 analyses) (University of Kiel, Kiel, of more than 0.05e0.1 and 0.1e0.25 mm. The morphology of ash Germany). For comparison, the data of 45 analyses made by ICP MS particles was examined under the binocular microscope by re- method in A.P. Vinogradov Institute of Geochemistry, Siberian flected light and scanning electronic microscope (FIO, Qingdao, Branch of RAS, Irkutsk (Sakhno et al., 2010) and in FIO, Qingdao, China). The morphological types of the volcanic glasses are China (analyst Chen Jihua) were also used.

Fig. 1. The scheme of study of tephra layers from the Holocene-Pleistocene deposits of the Sea of Okhotsk. 1 -2-sediment columns with tephra layers discovered by: 1-authors, 2- Japanese geologists (Sakamoto et al., 2005, 2006); 3-sediment columns without tephra layers. K. tr - Kashevarov Trough, L.R. eLebed Rise, Ac.S.R. - Academy of Sciences Rise.

To estimate the age of tephra layers we used published data the radiocarbon dating of organic residues. The resulting based on complex of stratigraphic methods: determination of radiocarbon ages were converted into calendar age by using physical parameters of deposits (humidity, density, magnetic the calibration tool Calib Rev 6.0 (Stuiver and Reimer, 1993) susceptibility, paleomagnetic properties), study of diatoms and with the Intcal 09 and Marine 09 data sets (Reimer et al., foraminifera, isotopic-oxygenic analysis of foraminifera, data of 2009).

Table 1 Mean chemical composition of volcanic glasses from tephra layers of the Okhotsk Sea deposits (%).

t Index tephra n SiO2 TiO2 Al2O3 FeO MnO MgO CaO Na2OK2OP2O5 FSO3 Cl Sum KO 38 76.92 0.23 12.83 1.44 0.05 0.23 1.49 4.53 2.06 0.02 0.02 0.01 0.16 97.03 (0.46)** (0.02) (0.21) (0.14) (0.03) (0.04) (0.12) (0.14) (0.11) (0.02) (0.03) (0.01) (0.01) (1.28) N 15 66.71 0.62 14.56 6.50 0.16 1.16 4.80 4.38 0.79 0.12 0.03 0.02 0.16 98.47 (1.82) (0.09) (0.57) (0.77) (0.03) (0.37) (0.65) (0.23) (0.09) (0.03) (0.03) (0.02) (0.02) (0.88) TR(Zv) 15 72.95 0.48 13.37 3.82 0.15 0.57 2.90 4.52 0.93 0.09 0.02 0.01 0.18 97.79 (0.48) (0.02) (0.24) (0.15) (0.04) (0.03) (0.14) (0.03) (0.02) (0.02) (0.01) (0.01) (0.01) (0.99) K2 92 75.38 0.32 12.81 2.29 0.08 0.26 1.61 4.43 2.50 0.03 0.03 0.01 0.25 97.33 (0.36) (0.03) (0.16) (0.23) (0.03) (0.04) (0.15) (0.12) (0.23) (0.02) (0.03) (0.01) (0.02) (1.35) K3 131 75.44 0.32 12.84 2.26 0.08 0.26 1.62 4.36 2.47 0.03 0.04 0.01 0.26 96.98 (0.36) (0.02) (0.21) (0.14) (0.04) (0.03) (0.10) (0.13) (0.06) (0.02) (0.04) (0.01) (0.02) (1.61) T 65 74.42 0.46 12.76 3.13 0.09 0.67 3.51 3.60 1.05 0.09 0.03 0.02 0.15 98.30 (1.05) (0.05) (0.54) (0.34) (0.04) (0.13) (0.42) (0.28) (0.27) (0.03) (0.03) (0.02) (0.03) (1.65) K4 26 72.07 0.58 14.18 2.87 0.12 0.74 3.15 4.65 1.27 0.09 0.04 0.03 0.20 97.68 (0.50) (0.03) (0.41) (0.24) (0.04) (0.08) (0.20) (0.16) (0.05) (0.03) (0.04) (0.02) (0.02) (1.78) MR1 15 70.21 0.54 13.84 4.50 0.10 1.03 4.26 3.90 1.28 0.15 0.04 0.03 0.12 98.38 (0.46) (0.02) (0.13) (0.28) (0.04) (0.05) (0.16) (0.09) (0.03) (0.02) (0.04) (0.02) (0.02) (1.23) Kc2-3 45 77.21 0.34 12.32 1.58 0.09 0.30 1.57 4.30 2.04 0.03 0.03 0.02 0.17 96.91 (0.70) (0.04) (0.33) (0.18) (0.05) (0.04) (0.18) (0.20) (0.20) (0.02) (0.04) (0.01) (0.02) (1.59) Aso4* 13 73.06 0.41 15.27 1.45 0.10 0.42 0.92 3.78 4.58 n.d n.d n.d n.d (0.27) (0.02) (0.1) (0.05) (0.03) (0.03) (0.05) (0.20) (0.17) K5 19 77.51 0.36 12.18 1.58 0.11 0.30 1.47 4.46 1.79 0.03 0.03 0.03 0.17 95.69 (0.19) (0.02) (0.08) (0.12) (0.04) (0.02) (0.04) (0.11) (0.07) (0.02) (0.03) (0.02) (0.01) (1.51) AL7.2a (MR2) 34 75.73 0.40 13.10 1.88 0.08 0.40 1.99 4.36 1.79 0.04 0.05 0.02 0.15 94.85 (0.26) (0.02) (0.11) (0.12) (0.04) (0.03) (0.08) (0.14) (0.04) (0.02) (0.04) (0.01) (0.01) (1.19) AL7.2b 51 77.56 0.13 12.79 0.71 0.06 0.10 0.76 3.95 3.79 0.01 0.02 0.01 0.10 94.41 (0.52) (0.07) (0.14) (0.27) (0.03) (0.08) (0.31) (0.17) (0.55) (0.02) (0.03) (0.01) (0.02) (1.01) AL7.4 39 76.36 0.13 13.33 0.73 0.07 0.06 0.50 4.18 4.51 0.01 0.03 0.02 0.09 93.70 (0.16) (0.01) (0.10) (0.07) (0.03) (0.02) (0.02) (0.11) (0.14) (0.01) (0.03) (0.01) (0.03) (1.23) nMR 58 78.17 0.19 12.25 1.18 0.06 0.20 1.40 3.84 2.50 0.02 0.02 0.01 0.15 94.10 (0.28) (0.04) (0.25) (0.13) (0.04) (0.03) (0.14) (0.23) (0.25) (0.02) (0.03) (0.01) (0.01) (0.71) K6 22 69.15 0.67 14.89 3.98 0.13 0.96 4.05 4.33 1.51 0.13 0.05 0.02 0.12 97.32 (1.83) (0.10) (1.25) (0.70) (0.05) (0.14) (0.82) (0.25) (0.16) (0.05) (0.05) (0.01) (0.02) (1.73) MR3 (AL9.22) 74 75.90 0.28 13.24 1.37 0.06 0.30 1.61 3.89 3.09 0.03 0.03 0.02 0.19 94.30 (0.19) (0.02) (0.16) (0.12) (0.04) (0.03) (0.03) (0.14) (0.08) (0.02) (0.03) (0.01) (0.01) (1.38) AL9.22b 17 61.11 1.01 15.51 8.04 0.22 2.52 6.20 4.13 0.87 0.20 0.04 0.02 0.14 98.36 (0.67) (0.04) (0.25) (0.39) (0.04) (0.17) (0.23) (0.14) (0.06) (0.04) (0.03) (0.01) (0.01) (0.90) MR4 (AL9.24) 60 64.03 1.09 16.13 4.82 0.18 1.59 3.98 5.30 2.27 0.35 0.07 0.06 0.09 97.64 (1.51) (0.09) (0.33) (0.69) (0.05) (0.29) (0.55) (0.20) (0.18) (0.09) (0.05) (0.03) (0.02) (1.70) AL10 22 62.56 1.22 16.06 5.31 0.17 1.98 4.46 5.08 2.40 0.50 0.08 0.09 0.10 97.74 (3.07) (0.23) (0.36) (1.22) (0.05) (0.61) (1.12) (0.23) (0.42) (0.19) (0.04) (0.04) (0.02) (1.50) Md1 20 74.04 0.46 14.06 2.50 0.13 0.40 1.67 4.55 2.01 0.06 0.00 0.02 0.11 93.88 (0.31) (0.02) (0.11) (0.14) (0.04) (0.03) (0.04) (0.28) (0.05) (0.02) (0.00) (0.01) (0.01) (0.88) Md2 22 78.18 0.11 12.63 0.65 0.06 0.10 0.76 3.76 3.62 0.01 0.00 0.01 0.11 94.68 (0.20) (0.01) (0.13) (0.08) (0.04) (0.03) (0.03) (0.13) (0.12) (0.02) (0.00) (0.01) (0.01) (0.81) Md3 20 74.45 0.40 13.48 2.36 0.09 0.33 1.60 4.40 2.64 0.05 0.00 0.02 0.18 95.44 (0.18) (0.02) (0.09) (0.11) (0.04) (0.02) (0.04) (0.16) (0.06) (0.02) (0.00) (0.01) (0.01) (0.64)

Notes. n.d. - the component wasn't deﬁned; n - quantity of analyses; ** in brackets - standard deviation; * according to Kaiser, 2001. All data normalized to 100%. All analyses are executed with the use of the electron microprobe JEOL JXA 8200 in the Leibniz Institute for Ocean Research, now GEOMAR (Helmholtz Centre for Ocean Research, Kiel, Germany). Analysts is A.N. Derkachev and M.V. Portnyagin. Tephra samples for which chemical analyses of volcanic glasses were carried out: KO - Lv29-110 (345e350), Lv55-9 (545); N - GC12-6a (278e279); TR(Zv) - 9301 (453e456); K2 - So178-11-5 (1390e1391), So178-12-3 (1167e1168), M961 (148e151), Lv28-37-1 (342e344), MD01-2415 (410); K3 - 9313 (126e127), K-68 (90e98), Lv27-15-1 (363e367), Ge99-10 (249e250), Lv55-38 (127); T - Lv28-2-4- (470e475), Lv29-72-2 (569e570), Ge99-10 (273e274), So178-3-4 (153e154); K4 - Lv27-15-1 (527e528); MR1 - GC-1A (148e153); Kc2-3 - So178-1-4 (460e470); Aso4* - Lv28-64-5 (1108e1110); K5 - Ge99-38 (273e274); MR2 (AL7.2a) - Lv28-42-4 (656e657); AL7.2b - Lv28-42-4 (660e661), Lv28-40-5 (790?); AL7.4 - Lv28-42-4 (736e737); nMR - MD01-2415 (1681), MR0604-PC5R (1111.5e1113.5); K6 - 9305 (450e455), Ge99-38 (404e405); MR3 (AL9.22) - Lv28-42-4 (926e927), MR0604-PC7R (1517.6e1520.1); AL9.22b - Lv28-42-4 (926e927); MR4 (AL9.24) - Lv28-42-4 (936e937), MR0604-PC6R (1720.6e1725.6); AL10 - Lv28-42-4 (987e988); Md1 - MD01-2415 (2290e2292); Md2 - MD01-2415 (2806e2809); Md3 - MD01-2415 (3863e3866).

3. Results Derkachev et al., 2012). The maximal thickness of tephra (16 cm) is observed at the station LV29-112 located in the lower part of the 3.1. Characteristics of tephra layers continental slope nearby Paramushir Island (Fig.1). In the ash layers of increased thickness, the discernible signs of differentiation of The special features of tephra interlayers are listed in the particles in density and sizes as a consequence of processes of their sequence consistent with their age and stratigraphical position: transport and settling to the bottom are noted. As a result, the signs from young to older ones. of graded bedding are observed. The transparent ﬂuidal-bubbly and KO tephra is presented by the light-gray (to whitish-gray) silt laminated glasses (types B and E according to Katoh et al., 2000) with with admixed ﬁne sandy particles. The layer occurs in the deposits of the refraction index N ¼ 1.501e1.507 (mean of 1.503) predominate. the central and eastern Sea of Okhotsk at many stations (Supplement In the coarse fractions, the light-gray and white pumiceous glass 1, Fig. 2). The tephra is visually observed in the form of white lenses (type B) prevails. Aside from glass, tephra contains also an admixture and laminas of small thickness (0.5e1.0 cm) bioturbated essentially (maximum 25%) of crystalloclastics (plagioclases, rock fragments, by the bottom burrowing organisms (Gorbarenko et al., 2002; pyroxenes, dark ore minerals).

Fig. 2. Areals of ash falls established in deposits from the Sea of Okhotsk. 1 -sediment columns with studied tephra layers; 2-sediment columns without tephra layers; 3- sediment columns with tephra layer Aso4; 4-5-sediment columns with tephra layers according to (Okazaki et al., 2005; Sakamoto et al., 2005); 6-location of volcanoes supplied tephra for the following layers: КО (Kurile Lake, Kamchatka), К2, К3 (Nemo III), Zv (TR) (Zavaritsky, Simushir Island), Т (Mashu, Hokkaido Island); 7-12-estimated areals of tephra distribution: 7- КО;8-К2; 9-К3; 10-Zv (TR); 11-Т; 12-Aso4. Spfa1, Kc-Hb, Kc-Sr - areals of ash falls according to (Machida and Arai, 2003).

Among heavy minerals, the clinopyroxenes and orthopyroxenes of 0.9. A distinctive feature of the KO tephra is an increased con- prevail (mean of 35.5% and 38.8% in terms of the transparent centration of hornblende (up to 10e23% with a mean of 16.0%) minerals, respectively). The ratio of clinopyroxene to orthopyrox- including brown and basaltic hornblende (mean of 1.0%) enclosed ene (Cpx/Opx) is different and varies from 0.57 to 1.4 with a mean often in an “envelope” of volcanic glass. The apatite and mica are

Please cite this article in press as: Derkachev, A.N., et al., Tephra layers of in the quaternary deposits of the Sea of Okhotsk: Distribution, composition, age and volcanic sources, Quaternary International (2016), http://dx.doi.org/10.1016/j.quaint.2016.07.004 6 A.N. Derkachev et al. / Quaternary International xxx (2016) 1e25 also present (amounted to an average of 1.5 and 1.3% respectively). concentrations of amphiboles is low (less than 9.0%; mean of 2.8%), More detailed information on the mineral composition of tephra apatite is present in a small quantity (less than 4.0%; mean of 1.6%) and peculiarities of the chemical composition of minerals is given (Derkachev and Portnyagin, 2013; Derkachev et al., 2016). in the paper (Derkachev et al., 2016). K3 tephra occurs in the sediments of the Academy of Sciences N tephra was found out in the sediment core GC12-6А from the Rise and adjacent areas extending in the sublatitudinal direction as Kashevarov trough in the central Sea of Okhotsk among the Holo- a broad zone at a distance of up to 600 km west of Kurile Islands cene terrigenous-diatomic deposits. The silt-size tephra layer is (Fig. 2). This tephra layer is visible as the strongly expressed against light-grey in color; the layer thickness is about 1 cm; its edges are the background of enclosing sediments grey horizon with the indistinct, with lenticular-spotted structure. The pumiceous fine- predominantly coarse-grain composition represented by sands porous volcanic glass (type A) being light-grey with a greenish from fine- and medium-grained to medium- and coarse-grained, tone predominates. Among the heavy minerals, the clinopyroxenes with a large amount of pumice particles up to 2e7 mm in size. In and dark ore minerals dominate, in the subordinate quantity, the the layers of great thickness (up to 16 cm, station Ge99-38), an orthopyroxene occurs. increase in sizes of particles is observed toward the bottom of ho- TR(Zv) tephra was found out in five sediment cores to the south rizon. In the bottom of the interlayer, a decrease in grade of the of the Academy of Sciences Rise, on the north-eastern slope of volcaniclastic material to fine-grained sand with a considerable Kurile basin (Figs. 1 and 2, Supplement 1). The grey-colored tephra admixture of silt is noted. The characteristic feature of the layer, layer 1e2 cm thick is predominantly presented by the fine-sandy apart from its coarseness and grey color, is a presence of a large particles. In the tephra composition, the colorless, with greyish quantity of the pumice and crystalloclastics fragments (large phe- tint volcanic glasses having a pumiceous-cellular and elongated- nocrystals of plagioclases, pyroxenes and dark ore minerals as well cellular forms (types A and B) predominate; the coarse-cellular- as their clots in the “envelope” of the volcanic glass). In this case, plate grains (types C and E) with refraction index of 1.505e1.507 the crystalloclastics is present in both fine and coarse fractions occur more rarely (Supplement 2). The olive-brown fragmentary reaching 40e50% of total quantity of fractions (Gorbarenko et al., glass with the higher refraction index occurs as an admixture. 2002). The specified features of K3 tephra distinguish it slightly There, the grains with numerous inclusions of microlites of py- from the K2 tephra stratigraphically close to it (see above). roxenes and plagioclases are also present. The distinctive feature of On the other hand, the signs of the similarity of the tephra under tephra is an occurrence of a large crystal clastic admixtures (up to study to K2 tephra are found out. In the first place, the signs of the 15e20%) represented by fragments of plagioclases and pyroxenes similarity are manifested in the morphology of volcanic glasses and as well as glassy shards of the greenish-brown rocks with in- index of their refraction (N ¼ 1.502e1.512; mean of 1.507) as well as clusions of minerals’ microlites. In the mineral assemblage, a pre- in closeness of mineral associations and chemical composition of dominance of orthopyroxene over clinopyroxene is observed (Cpx/ volcanic glasses and minerals (Derkachev and Portnyagin, 2013; Opx ¼ 0.55e0.96). Derkachev et al., 2016). In the mineral assemblage, the associa- K2 tephra is distributed in the sediments of the central Sea of tion of the clino- and orthopyroxenes predominates (on average, Okhotsk and was found out in many sediment cores (Derkachev 46.4 and 43.5%, respectively). The content of hornblende is low (less et al., 2004; Cruise Report …, 1999, 2000, 2003; Derkachev et al., than 7.5%), individual grains of brown hornblende occur. The rela- 2011, 2012; Derkachev and Portnyagin, 2013; Gorbarenko et al., tive enrichment with hornblendes registered in a number of sam- 2002; Sakamoto et al., 2006)(Fig. 2, Supplement 1). In the exam- ples is, probably, a consequence of pollution of these samples with ined sediment cores, it occurs as layers with varying thicknesses of an admixture of the terrigenous material. As a rule, an increase in 1e22 cm (Fig. 2) and small lenses 0.3e0.6 cm in diameter. The the quantity of epidote and other terrigenous fragments is regis- maximum thickness of tephra (up to 22 cm, station M969) was tered in the same samples. As a small admixture, the grayish-brown observed in the sediment cores located in the lows of the bottom glass with numerous inclusions of microlites of pyroxenes and, relief between the Institute of Oceanology and Academy of Sciences rarely, dark-grey glass occur. Rises (Derkachev and Portnyagin, 2013). In most cases, the tephra Т tephra was found out in 6 sediment cores taken in the south- consists of the silt-fine sand sized particles. With increase of dis- western Sea of Okhotsk, on the slope of the Kurile basin west of the tance from the explosive source, the size of ash particles lowers to Academy of Sciences Rise (Figs. 1 and 2, Supplement 1). It is visible that of silt. In the thickest interlayers, the signs of the gravity in cores as small lenses 0.2e0.6 cm in diameter filled in with the sorting of particles as a result of their settling from the ash cloud are yellowish-grey silt. In the composition of tephra, the colorless well noted; the lower levels of the tephra layers are enriched in volcanic glass of pumiceous-fine-cellular form (type A) pre- bigger particles. The bottom interface of ash layers is, as a rule, dominates, the glasses of pumiceous-fluidal form (types B and C) sharp and even or, less frequently, twisting while the top one is are less common and an admixture of crystalloclastics is also irregular and often with marks of deformations and flow structures. observed. As admixtures, the glasses of more basic composition are One of the most important diagnostic properties of this tephra is its noted in this tephra. The refraction index of glasses N is color (grey, with a visible brownish tone). 1.501e1.502. In the mineral assemblage, the orthopyroxene and In the tephra composition, the colorless volcanic glass of the clinopyroxene (Cpx/Opx ¼ 0.22e0.38) dominate (Derkachev and fragmentary-vesicular and fluidal-cellular form (type E) pre- Nikolaeva, 2010; Derkachev et al., 2016). We assume that pres- dominates. In the coarser fraction, the pumiceous particles (type C, ence of a small amount of hornblende (up to 5e10%) in T tephra is rarely, type B) dominate. The refraction index of glasses N is caused by outside impurity because of error during sampling. It is 1.504e1.510 (mean of 1.507) (Supplement 2). In the tephra known, that hornblende is absent in products of explosive erup- composition, the phenocrystals of plagioclases, pyroxenes, dark ore tions of Masyu volcano (Hasegawa et al., 2012). minerals, rarely, hornblende (crystalloclastics) enclosed often in an K4 tephra was found out in the one sediment core Lv27-15 on “envelope” of volcanic glass occur as admixtures (first percents). An the slope of Kurile basin in its north-east closing in the latitude of admixture of resurgent material e fragments of rocks and particles the Shiashkotan Island (Kurile Islands) (Fig. 1, Supplement 1). The of andesite-basalt glass e is also noted. tephra in the core is visible as the isolated grey lenses with thick- In the heavy fraction, a not large predominance of orthopyrox- ness of about 1 cm filled with the silt-sand particles with rare in- enes over clinopyroxenes is observed (Cpx/Opx ¼ 1.02 on average) clusions of the pumice piece of the gravel size. In its composition, at average contents of 44.8 and 48.1%, respectively. The the colorless, predominantly pumiceous volcanic glass with

Please cite this article in press as: Derkachev, A.N., et al., Tephra layers of in the quaternary deposits of the Sea of Okhotsk: Distribution, composition, age and volcanic sources, Quaternary International (2016), http://dx.doi.org/10.1016/j.quaint.2016.07.004 A.N. Derkachev et al. / Quaternary International xxx (2016) 1e25 7 numerous irregularly located small cavities (type A) dominates lenses (up to 1e2 mm in thickness) observed in the sediment cores while the pumiceous-fluidal glass (type B) is less common. The MR0604-PC6R, and MR0604-PC5R (Derkachev et al., 2012). The ash more basic glass whose color varies from greenish-gray to particles are mainly presented by the colorless glass of the greenish-brown is present as an admixture. The distinctive feature fragmentary-vesicular and, more rarely, fluidal-pumiceous form of the mineral assemblage is a predominance of clinopyroxene over (types E, C and, more rarely, B) with refraction index orthopyroxene (Cpx/Opx ¼ 1.79) and presence of hornblendes (up N ¼ 1.505e1.510 (mean of 1.508). In the composition of heavy to 12%) including a brown hornblende. fraction, the clinopyroxene (mean of 41.6%) dominates over MR1 tephra in the form of beige-colored lenses with thicknesses orthopyroxene (mean of 26.7%) and the increased content of am- of up to 3e4 mm was found at stations MR0604-PC-7R and phiboles (mean of 9.9% on average) is noted. The distinctive feature MR0604-PC6R in the central Sea of Okhotsk. Among the ash par- is a presence of brown mica (biotite) (up to 3.0e10.0%), brown and ticles, the colorless glass of the coarse-cellular form predominates basaltic hornblende (oxyhornblende) (up to 2.2%). On the upper while, in the fine fraction, a fine-porous pumiceous one (types A, F horizons of tephra layer, a notable admixture of terrigenous parti- and, more rarely, type B) was predominantly found out. The cles is recorded (Derkachev et al., 2012, 2016). refraction index of glasses N is 1.511e1.514 (mean of 1.513). Among AL7.2b tephra is observed in the sediment core Lv28-42-4 the heavy minerals, the clinopyroxenes (49.8%) and orthopyrox- several centimeters below the layer MR2 (AL7.2a) as a thin, enes (22.4%) prevail while the content of hornblendes is up to 11%. strongly bioturbated white layer with thickness of about 1 cm As an admixture, the increased content of terrigenous particles (Cruise Report …, 1999). In the composition of tephra, the colorless (epidote, mica, actinolite etc.) is observed (Derkachev et al., 2012, glass (types C, B and, more rarely, E) predominates. The refraction 2016). index of glass N is ~1.497e1.498. The distinctive feature of this Kc2-3 tephra was recovered in the sediment core So178-1-4 tephra is a high content of biotite (up to 45.5e67.4%) and horn- from the south-western part of Kurile basin. In this core, the blendes (up to 12.5e19.6%) with subordinate role of pyroxenes numerous layers of turbidites are registered. Tephra is traced in the (Derkachev et al., 2016). form of badly defined lenses enriched in particles of sand-and- AL7.4 tephra was identified in sediment core Lv28-42-4 (Kaiser, gravel size and represented mainly by pumice. The dispersed vol- 2001; Gorbarenko et al., 2002; Nürnberg and Tiedemann, 2004). It caniclastics occurs in a large amount also among the material of is visible in the form of white layer about 1 cm thick. Later it was turbidites at the depths of 460e470 cm. The white fine-porous found in sediment core MD01-2415 as a thin lens by thickness of particles of the pumiceous shape (types A and B; colorless in thin about 2 mm (Bubenshchikova et al., 2015). The tephra was formed pieces) dominate. As the admixtures, the colorless glasses of frag- by predominantly colorless volcanic glass (types C and E predom- mentary type (fragments of great bubbles of C and E types) and, inate while types B and A are less common) of the silt-fine sand more rarely, the brownish glasses of the same morphological type size). The refraction index of glasses N is 1.490e1.498. The mineral are observed. The occurrence of the considered volcaniclastics in assemblage is presented by pyroxenes (Cpx/Opx ¼ 1.5) with sig- the turbidite sediments suggests its redeposited character. The nificant quantities of hornblendes and biotite (up to 38.4 and 7.3%; well-defined interlayer of this tephra was found in the sediment 34.6 and 5.9% on average respectively). A considerable admixture of core MD01-2412 taken southward, on the slope of the Hokkaido terrigenous minerals (mainly, epidote) is present (Derkachev et al., Island (Sakamoto et al., 2006). 2016). Аso4 tephra was recovered in the lower part of three sediment nMR tephra was recorded in two sediment cores taken on the cores taken on the north-west slope of Kurile basin (Figs. 1 and 2, south slope of the Lebed Rise (central Sea of Okhotsk) (Fig. 1, Supplement 1). It is traced as the readily visible light-grey layers Supplement 1, Table 3). The light-grey (almost white) layer has a with thickness of 0.7e3 cm represented by particles of silt size. This thickness of about 2 cm. In its composition, the colorless glass tephra was also found in the southern Sea of Okhotsk off the (types A and B; more rarely, type E) dominates; the refraction index Hokkaido Island coast (Sakamoto et al., 2006, Aoki, 2008). The of glasses N is 1.499e1.503 (mean of 1.501). The mineral assem- tephra is characterized by the homogeneous composition and blage contains, nearly in equal quantities (Cpx/Opx ¼ 0.9e1.2), the formed by the colorless, predominantly thin-walled volcanic glass clinopyroxenes and orthopyroxenes. For the layer, the high content of fragmentary form (fragments of great bubbles) (types D, E and, of hornblende (up to 20e25%) is characteristic. more rarely, C). The refraction index of glasses N is 1.507e1.510 K6 tephra was found out in two sediment cores from the south (Supplement 2). Among the mineral inclusions, the two-pyroxene slope of the Academy of Sciences Rise (Fig. 1, Supplement 1). The association (Cpx/Opx ¼ 1.03) dominates at relatively high content grey layer formed by glass of sand-silt size is about 5 cm thick. The of amphiboles (up to 29%). The distinctive feature of tephra is a glass is mainly presented by the colorless particles of fine-porous- presence of hornblendes with decreased magnesiality pumiceous and fluidal form (types A and B). A considerable (Mg# ¼ 62.7) which distinguishes them from amphiboles from admixture of the light-grey and grayish-light-brown glasses is other tephra layers of the Sea of Okhotsk (Derkachev et al., 2016). observed while the dark-brown glass of plate shape is less common. K5 tephra was detected in three sediment cores taken in the In the mineral assemblage, the pyroxenes (up to 74e92% in total) Academy of Sciences Rise (Fig. 1, Supplement 1) as the light-grey dominate. layers with thicknesses of 1e6 cm. Tephra consists of the silt- MR3 (AL9.22) tephra is identified as a visible yellowish-grey layer sand particles represented by predominantly colorless volcanic with thickness of 1 cm (station Lv28-42-4) to 6 cm (station MR0604- glass of the fluidal-cellular form (type B and, more rarely, E). In the PC7R) which is represented by the silt-fine-sand particles. Over and mineral assemblage, the pyroxenes dominate at similar contents of under the interlayer, tothe depth of 3e5 cm, the signs of bioturbation clino- and orthopyroxenes (Cpx/Opx ¼ 0.91) and relatively (small lenses of oval shape filled in with the same ash material) are increased content of amphiboles (up to 10%) (Derkachev et al., observed. The volcanic glass is represented by the colorless grains 2016). An admixture of terrigenous particles is present. (types E and B and, more rarely, type A). The refraction index of glass MR2 (AL7.2a) tephra was found in sediment cores (Lv28-42-4 N is 1.504e1.508 (mean of 1.505). In the mineral assemblage, py- and MR0604-PC7R) in the central Sea of Okhotsk as a visible layer roxenes prevail and clinopyroxene dominates slightly over ortho- 1e4 cm thick, represented by particles of the silt-fine sand size. Due pyroxene (mean of 34.9 and 33.5%, respectively). The distinctive to bioturbation, some lenses of this tephra penetrate 3e5 cm below feature of MR3 tephra is an increased content of hornblendes (up to the main level. The possible analog of this tephra is thin layers and 29.2; 26.0% on average) and apatite (up to 3.2%).

On the horizon of 928e930 cm in sediment core Lv28-42-4 alkaline rock series. The glasses of tephras N and AL9.22b and in- under MR3 (AL9.22) tephra, the thin lenses of dark-gray volcanic dividual grains of tephras MR4 (AL9.24) and AL10 conform to the ashes differing markedly from the overlying ashes in their prop- derivates of tholeitic magmas. erties were identified (Cruise Report …, 1999). In view of the As to the chemical composition, the volcanic glasses of the stratigraphical closeness with MR3 (AL9.22) tephra, we assign tephra layers examined are mainly homogenous and belong to these lenses to the independent layer under the name of AL9.22b.In rhyolites (more rarely, rhyodacites) with normal (standard) alka- the composition of this tephra, the greenish-gray volcanic glasses linity of calc-alkaline rock series (Fig. 3, Table 1). Of the majority of of pumiceous shape (type A, rarely type B) predominate, the more them, a predominance of Na2OoverK2O1.3e2.7 times is charac- dark-colored varieties (to dark-brown and black) and, rarely, teristic. The low-alkaline and medium-alkaline tephras are less colorless glasses of the similar shape occur as the admixtures. Many widespread. In the low-alkaline glasses of tephras T, TR (Zv) and, particles of glasses contain numerous microlites of plagioclases and partially, K4, this proportion increases to 3.2e5.5. According to the pyroxenes. Al* ¼ Al2O3/(FeO*þMgO) ratio, the tephras considered belong to MR4 (AL9.24) tephra was found out in two sediment cores as the rather high-aluminous varieties with values Al* ¼ 4.8e7.2 and, layers with thicknesses of 1 cm (station Lv28-42-4) to 5 cm (station more rarely, 7.3e10.7 (KO and nMR tephras) due to their lower MR0604-PC6R) and presented by greenish-gray with yellowish- magnesiality and ferruginosity (Figs. 4 and 5). The glasses of Md2 brown tint silt and fine sand. In the composition of tephra, the tephra (Al* ¼ 16.9e19.6) fall into category of the extremely high- dark-gray with greenish-light-brown tint volcanic glass of pumi- aluminous varieties. The volcanic glasses of the low-potassium ceous shape (type A, rarely type B) predominates. There is a rhyolites-rhyodacites of tephras T and TR (Zv) are characterized by considerable admixture of dark-brown (to black) volcanic glasses the decreased alumina (Al* ¼ 2.1e4.3) (Fig. 4c). Distinctive sign for with numerous inclusions of microlites of minerals. The refraction them is higher ferruginosity of glasses from tephra TR (Zv) (Fig. 4c). index of glasses is high (N > 1.530). In some grains, more acidic Glasses of three tephra layers (AL7.4, AL7.2b, Aso4) belong to the glass is also present in the form of colorless pumiceous particles. In medium-alkaline trachyrhyolites of the calc-alkaline rock series at the composition of tephra, there is in quantities an admixture of relatively increased content of K2O (up to 3.5e4.7%wt of K2O). A crystalloclastics in the envelope of volcanic glass. In the mineral ratio Na2O/K2O for them varies from 0.7 to 0.9 for tephra Aso4 to assemblage, the pyroxenes predominate drastically (up to 0.9e1.2 for tephras AL7.4 and AL7.2b. The volcanic glasses of these 89e96.5%) with slight variations in content of clinopyroxenes and layers belong to rather high-aluminous and extremely high- orthopyroxenes (Cpx/Opx ¼ 0.7e1.2; 0.9 on average). The relatively aluminous varieties with values of Al* equal to 5.9e8.2 and increased content of apatite (up to 3e6.8%) is noted (Derkachev 13.6e17.7 for tephras Aso4 and AL7.4, AL7.2b, respectively (Table 3). et al., 2016). Glasses of the tephras belonging to andesites (AL9.22b), dacites AL10 tephra was identified only in one sediment core Lv28-42-4 and rhyodacites (K6, N, MR1 and, partially, T) (Fig. 3) are less as a dark-gray layer with thickness of about 1 cm (Gorbarenko et al., widespread in the Sea of Okhotsk deposits. Based on relation SiO2- 2002; Kaiser, 2001; Nürnberg and Tiedemann, 2004). Among the Na2O þ K2O, SiO2-K2O, they belong to low-potassium and medium- volcanic glasses, the variety both in morphology and color of grains potassium rocks of normal and low alkalinity (Figs. 3e5, Table 1). is observed. The glasses of types A and C dominate while grains of B According to value of Na2O/K2O, they are characterized by the and E types occur more rarely. The light-gray (to colorless) and light potassium-sodium (K6, MR1) and sodium (N, AL9.22b) specializa- brown glasses occur practically in equal quantities. The deep- tion with the average values of 2.6e3.1 and 4.8e5.7, respectively. To colored (dark brown and black) glasses containing large quanti- the petrochemical features of glasses from these tephras, the ties of inclusions of microlites of minerals occur more rarely. The increased content of FeO (up to 4.6e8.1%wt on average), MgO (up to refraction index of volcanic glasses varies from 1.520 to 1.548. For 1.0e2.5%wt on average) and CaO (up to 4.6e8.1%wt on average) the tephra considered, a predominance of orthopyroxenes over should be assigned. According to value of Al*, they belong to the clinopyroxenes (Cpx/Opx ¼ 0.73) and low content of the horn- high-aluminous (N, AL9.22b) and rather high-aluminous (K6, MR1) blendes are characteristic. rock varieties. Md1, Md2 and Md3 tephras were identified by us in the lower, Glasses of two tephra layers (MR4 (AL9.24) and AL10) belong to most ancient (Early-Middle Pleistocene) part of sediment core medium-potassium (partly, high-potassium) trachyandesite-tra- MD01-2415 on the horizons of 2290e2292, 2806e2809 and chydacites of medium-alkaline rock series (Figs. 3 and 5, Table 1) 3863e3866 cm respectively. In the composition of tephras Md1 and which are related to the rather high-aluminous varieties Md2, the thin-walled, colorless, fragmentary and fluidal-cellular (Al* ¼ 2.0e2.3). Despite the relative proximity of the composition glasses of E and C types and, more rarely, B type dominate. In of volcanic glasses of the considered tephra layers, a number of Md3 tephra, the colorless pumiceous glass (type A and, rarely, type differences is observed. So, of the tephra AL10, the more hetero- B) and fragmentary-cellular (type E) glass predominate. The geneous chemical composition and relatively increased content of distinct feature of tephra Md2 is a presence of biotite admixture. FeO*, MgO, CaO, K2O(Table 1) are characteristic. In a number of the Characteristics of glass chemistry which is the most useful for Harker diagrams, the distinctive features of the chemical compo- identification and correlation, will be shown next chapter. sition of these tephras are clearly visible (Fig. 5). The discriminant analysis is very effective method estimating 3.2. Chemical composition of volcanic glasses degree of distinction of material composition of rocks including a chemical composition of volcanic glasses (Pearce and Cann, 1973; One of the most important diagnostic properties of tephra is the Bourne et al., 2010). We divided preliminarily the initial data on chemical composition of volcanic glasses (Table 1, Supplement 3). chemical composition of glasses from the tephra layers into two arrays grouped in accordance with ages of tephra layers. The first 3.2.1. Distribution of major elements group included data for tephra layers of the Late Pleistocene- The typification of volcanic glasses is given in accordance with Holocene age (less than 120 thousand years). The second group recommendations in paper (Le Bas et al., 1986)(Fig. 3) and addi- contained data for tephra layers of the Middle-Pleistocene age. To tions on (Klassifikatsiya …, 1997). According to the classification these data arrays, a procedure of discriminant analysis was applied diagram AFM (Irvine and Baragar, 1971), the majority of chemical with calculation of equations of discriminant functions and esti- compositions of glasses from the tephra studied resemble calc- mating their significance and efficiency of the division of initial data

Fig. 3. SiO2-NaO þ K2O variation diagram (Le Bas et al., 1986) of glass shards of tephra layers from the Sea of Okhotsk. Notes and indexes of tephra layers see in the text. into groups. During calculation, the programs of the discriminant composition of volcanic glasses was fairly efficient. The compact analysis from the application package of computer programs areas of the scattering of imaging points of the composition for STATGRAPHICS were used. The results obtained were plotted on the separate tephra layers are well-defined. The exception is provided diagrams taking into account the values of the first and second, by a tephra of the heterogeneous composition or tephra with a most significant discriminant functions (Fig. 6). As it follows from similar composition of glasses (for example, K2 and K3, MR4 this Figure, a division of the tephra layers according to chemical (AL9.24) and AL10 tephras).

Fig. 4. Bi-component Harker's diagrams of a chemical composition of volcanic glasses from tephra layers in the Late Pleistocene-Holocene deposits of the Sea of Okhotsk (age less than 220 kyr). Notes and indexes of tephra layers see in the text.

As the indicated diagrams were developed with due consider- earth elements normalized to chondrite (Fig. 7a). The values of La/Yb ation of all the spectrum of content of major elements of the vol- and La/Sm are 0.92e1.24 and 0.88e1.05, respectively. The europium canic glasses and with the following calculation of the values of anomaly is slightly manifested or absent at all (Eu/Eu* ¼ 0.76e0.97). Of discriminant functions, their use accelerates and facilitates K4 tephra, a slightly enhanced background of contents of the light considerably the procedure of carrying out of the comparative lanthanides (LREE) in relation to heavy (HREE) and medium (MREE) analysis of new data on tephra composition, its identification and, ones (La/Yb ¼ 1.29, La/Sm ¼ 1.19) is characteristic (Table 2). therefore, correlation of the deposits under study. According to the nature of REE distribution, the majority of explored tephra layers are close against each other and they were 3.2.2. Distribution of microelements combined into the second (tephras K2, K3, K5, MR2 (AL7.2a), Kc2-3, One of the correct methods of correlation and identification of the Md1, Md3) and third (tephras KO, T, MR1, K6) groups (Fig. 7 b, c, d). tephra layers is an analysis based on microelements and rare-earth Most of them belong to the medium-potassium rhyolites and elements (Aksu et al., 2008; Pearce et al., 2004; Sakhno et al., 2006, dacites-rhyodacites (more rarely). The spectra of REE distribution 2010; Tomlinson et al., 2012 and others). In accordance with results are characterized by low and medium degrees of fractionating of of cluster analysis on the distribution of rare-earth elements, 6 rela- the light lanthanides relative to the heavy and medium ones (La/ ¼ e ¼ e tively independent groups of tephra layers are identified. Into the first Yb 1.67 2.23, La/Sm 1.46 1.95). In most cases, they have the fi e group, the tephras N, Zv (TR), K4 and AL9.22b (low-potassium well-de ned, negative europium anomaly (Eu/Eu* is 0.52 0.74 on rhyodacites-rhyolites, dacites and andesites) are included. They are average) that is more strongly manifested in K2, K3, K5 tephras characterized by unfractionated spectra of distribution of the rare- (Fig. 7b and c). Of the glasses from tephras falling under the third

Fig. 5. Bi-component Harker's diagrams of a chemical composition of volcanic glasses from tephra layers in the Middle Pleistocene deposits of the Sea of Okhotsk (age more than 220 kyr). group, the slightly decreased concentrations of REE (lower than more pronounced degree of fractionating (La/Yb ¼ 2.74e3.61, La/ 75 ppm) as compared with tephras of the second group are char- Sm ¼ 1.7e2.13) are characteristic. The spectra of normalized REE acteristic (Table 2). As it follows from Table 2 and Fig. 7c and d, the T concentrations have a gentle slope in the light part with gradual and K6 tephras contain an admixture of glasses having different flattening in the area of heavy lanthanides (Gd/Yb ¼ 1.21e1.6). The composition which is also confirmed by data of content of major europium anomaly is unexpressed (Eu/Eu* ¼ 0.84e0.96) (Fig. 7e). elements in these glasses (Figs. 3e5). The fifth group contains the glasses from tephra layers of AL7.2b, The fourth group includes the layers of MR4 (AL9.24) and AL10 MR3 (AL9.22), nMR and Md2 which are represented by the tephras which belong to trachyandesites-trachydacites. Of them, in medium-potassium rhyolites. Despite the general similarity of the contrast to previous groups, the spectra of REE distribution with REE distribution curves to ones for previous layers of tephras (fourth

Fig. 6. The discriminant diagram of a chemical composition of volcanic glasses of tephra layers from the Sea of Okhotsk. df1,df2 - values of 1st and 2nd discriminant functions: (A) - for the Late Pleistocene-Holocene tephra layers: df1 ¼0.5866 SiO2-1.128 TiO2-0.757 Al2O3-2.792 FeOþ0.011 MnOþ2.615 MgO-1.963 CaO-0.647 Na2Oþ5.249 K2Oþ55.73; df2 ¼1.287 SiO2þ1.94 TiO2þ0.514 Al2O3þ2.706 FeO-2.196 MnO-3.898 MgO-0.973 CaO-0.865 Na2Oþ4.059 K2Oþ81.46. Oval ﬁgures designate areas characterizing the composition of volcanic glasses found on the land (Aso4, Zavaritsky, Mashu, Kutcharo, Kurile Lake volcanoes); (B) - for the Middle Pleistocene tephra layers: df1 ¼ 1.89 SiO2-6.061 TiO2-1.166 Al2O3-0.355 FeO-2.535 MnO þ 4.264 MgOþ2.821 CaO-0.455 Na2O þ 1.598 K2O-130.69; df2 ¼0.691 SiO2-7.72 TiO2 þ 1.157 Al2O3 þ 0.84 FeO þ 3.511 MnO þ 1.68 MgO-1.907 CaO- 1.215 Na2O þ 4.347 K2Oþ32.19. Indexes of tephra layers see in the text.

Fig. 7. Distribution of REE normalized to chondrite (Sun and McDonough, 1989), in tephra layers from the Okhotsk Sea sediments. Note. Initial data are listed in Table 2. Methods: all data -LA ICP MS, Christian-Albrechts University, Kiel, Germany (M. Portnyagin is analyst); Aso4 - ICP MS A.P. Vinogradov Institute of Geochemistry, Siberian Branch of RAS, Irkutsk (Sakhno et al., 2010) and in FIO, Qingdao, China (analyst is Chen Jihua), Aso4 (1) e (Kimura et al., 2015).

Table 2 Mean composition LA ICP MS analyses of trace and rare earth elements on glass shards in tephra layers of Pleistocene-Holocene deposits from the Sea of Okhotsk.

Sample name Lv29-110 GC12-6a 9301 Lv28-37 Lv55-38 Lv29-72-2 GC-12-1A Lv27-15-1 So178-1-4

Tephra index KO N TR (Zv) K2 К3 T MR1 K4 Kc2-3

n 9 5 13 13 14 9 4 11 7 13 2 La 11.6 5.7 6.9 14.0 13.8 8.2 13.8 9.2 9.1 14.0 13.5 Ce 28.2 14.5 18.6 33.0 34.5 18.8 31.2 21.1 22.2 32.9 29.9 Pr 3.5 2.3 2.8 4.4 4.5 2.5 4.3 2.9 3.2 4.3 3.7 Nd 15.6 12.6 14.6 20.5 20.4 12.2 20.6 14.0 16.8 20.2 15.8 Sm 4.0 4.2 4.8 5.6 5.5 3.6 5.2 3.8 4.9 5.5 4.0 Eu 0.9 1.4 1.4 1.1 1.0 0.9 1.0 1.1 1.7 1.4 0.8 Gd 4.3 5.5 6.7 7.2 6.3 5.2 6.7 5.3 6.5 6.4 4.1 Tb 0.7 0.9 1.1 1.1 1.0 0.8 1.1 0.9 1.1 1.1 0.7 Dy 5.0 6.2 7.5 7.5 7.0 5.3 7.4 5.8 7.1 7.2 4.6 Ho 1.1 1.4 1.7 1.7 1.5 1.2 1.6 1.3 1.6 1.6 1.0 Er 3.5 4.1 5.2 5.3 4.8 3.5 5.1 3.8 5.0 4.9 3.2 Tm 0.5 0.6 0.8 0.8 0.7 0.5 0.7 0.6 0.8 0.7 0.5 Yb 3.8 4.2 5.4 5.5 5.2 3.6 5.6 3.9 5.1 5.2 3.8 Lu 0.6 0.7 0.8 0.9 0.8 0.6 0.9 0.6 0.8 0.8 0.6 Sum REE 83.3 58.6 78.3 108.6 107.0 66.9 105.2 74.3 85.9 106.2 86.2 Cs 2.6 1.4 1.8 3.2 3.2 4.5 3.0 3.8 2.6 2.7 2.8 Rb 41.4 11 13.6 45.6 46.4 29.9 44.1 30.7 24.7 42.3 47 Ba 514 176 218 447 454 432 433 415 347 546 613 Th 2.9 0.8 0.9 4.3 4.1 2.4 4.1 2.8 1.9 4.7 5.7 U 1.3 0.3 0.4 1.6 1.6 1.1 1.5 1.0 0.7 1.4 1.7 Nb 3.1 1.2 1.8 4.3 4.4 3.1 4.1 3.3 1.7 2.7 2.3 Ta 0.2 0.1 0.2 0.3 0.3 0.3 0.3 0.2 0.1 0.2 0.2 Pb 12.6 9.2 10.7 15.7 16.0 44.6 14.7 20.4 16.9 19 15.4 Sr 111 212 166 111 110 194 116 216 242 135 120 Zr 182 98 127 226 207 83 228 115 128 156 167 Hf 5.2 2.6 3.7 6.3 5.7 2.4 6.2 3.4 4.0 4.5 4.6 Y 31.7 38.4 46.3 48.5 43.9 34.6 50.0 37.3 43.7 44.2 30.9

Sample name Ge99-38 Lv28-42-4 Lv28-42-4 MR0604-PC7R Lv28-42-4 MD01-2415 Ge99-38 Lv28-42-4

Tephra index K5 MR2 (AL7.2a) AL7.2b MR3 (AL9.22) AL7.4 nMR K6 MR4

n 13 14 5 22 6 11 7 3 3 5 La 14.3 14.6 20.6 15.5 28.0 10.4 14.0 9.6 14.2 22.3 Ce 33.8 34.4 39.2 32.0 55.4 21.6 31.5 22.2 30.9 50.9 Pr 4.4 4.5 4.0 3.7 6.0 2.5 4.4 2.9 4.3 7.2 Nd 20.9 20.7 14.3 14.6 21.6 9.7 20.5 13.5 20.7 33.4 Sm 5.6 5.6 2.2 3.0 3.9 2.0 6.7 2.8 4.9 8.5 Eu 1.5 1.4 0.4 0.7 0.5 0.5 1.7 1.1 1.6 2.4 Gd 6.8 6.5 2.0 2.8 3.4 1.9 6.9 4.1 6.3 8.5 Tb 1.1 1.1 0.3 0.5 0.5 0.4 1.2 0.7 1.0 1.4 Dy 7.59 7.1 2.2 3.0 3.2 2.3 7.6 4.2 7.3 8.7 Ho 1.7 1.5 0.4 0.6 0.7 0.5 1.6 0.9 1.8 2.0 Er 5.2 4.8 1.5 2.0 2.1 1.7 4.6 3.1 5.5 5.6 Tm 0.8 0.7 0.2 0.3 0.3 0.3 0.7 0.5 0.8 0.8 Yb 5.6 5.2 1.7 2.4 2.4 2.1 5.1 3.4 4.6 5.9 Lu 0.9 0.8 0.3 0.4 0.4 0.3 0.8 0.5 0.8 0.9 Sum REE 110.2 108.9 89.3 81.5 128.4 56.2 107.3 69.5 104.7 158.5 Cs 2.5 2.7 2.4 2.7 2.3 2.6 2.7 1.8 3.0 1.9 Rb 39.7 41.2 86.5 63.9 91.5 42.3 34.8 27.6 40.1 42.2 Ba 55.3 582 679 789 159 568 509 346 507 669 Th 4.8 4.8 6.9 4.7 7.2 3.1 3.9 2.4 4.2 2.8 U 1.6 1.6 3.2 1.9 3.5 1.3 1.2 0.8 1.5 1.2 Nb 2.8 2.8 16.0 4.2 21.2 2.6 2.5 2.0 2.8 8.0 Ta 0.2 0.2 1.5 0.4 1.5 0.2 0.2 0.2 0.2 0.5 Pb 16.1 17.1 12.8 14.8 16.7 11.1 13.6 7.6 16.9 12.2 Sr 126 163 71 156 18 113 232 192 255 332 Zr 167 168 76 193 112 125 150 115 153 263 Hf 5.0 4.9 2.9 4.9 3.5 3.4 4.1 2.6 4.7 6.5 Y 48.0 44.9 13.3 19.7 20.6 16.3 45.6 28.7 47.4 50.3

Sample name Lv28-42-4 Lv28-42-4 MD01-2415 MD01-2415 MD01-2415

Tephra index AL9.22b AL10 Md1 Md2 Md3

n 1292121313 La 6.6 21.6 27.8 12.5 13.7 16.3 Ce 17.0 50.0 62.8 30.7 26.5 37.8 Pr 2.6 7.0 8.0 4.4 2.8 5.2 Nd 13.7 33.7 35.7 20.4 9.6 24.1 Sm 4.1 8.1 8.4 5.6 1.7 6.1 Eu 1.5 2.6 1.9 1.4 0.3 1.3 Gd 5.1 8.3 7.8 6.1 1.5 6.6 Tb 0.9 1.3 1.3 1.0 0.3 1.1

Table 2 (continued )

Sample name Lv28-42-4 Lv28-42-4 MD01-2415 MD01-2415 MD01-2415

Tephra index AL9.22b AL10 Md1 Md2 Md3

Dy 5.7 7.1 8.1 6.8 1.6 7.2 Ho 1.2 1.6 1.8 1.5 0.3 1.6 Er 3.7 4.6 5.0 4.5 1.1 4.8 Tm 0.6 0.7 0.8 0.7 0.2 0.7 Yb 3.8 4.3 5.7 5.0 1.5 5.1 Lu 0.6 0.7 0.9 0.8 0.2 0.8 Sum REE 67.1 151.6 176.0 101.4 61.3 118.7 Cs 1.1 1.6 3.0 2.1 3.7 3.2 Rb 12.2 39.6 77.0 40.0 82.7 60.1 Ba 177 634 891 542 915 746 Th 1.1 3.0 5.2 2.2 4.5 3.8 U 0.5 1.2 2.1 1.3 2.7 1.6 Nb 1.9 7.6 11.7 5.6 3.8 5.4 Ta 0.1 0.5 0.7 0.4 0.4 0.4 Pb 9.1 12.1 14.0 9.9 9.2 10.7 Sr 298 455 177 119 67 106 Zr 85 237 388 196 65 249 Hf 2.5 6.0 9.5 5.2 2.2 6.6 Y 33.5 45.0 47.7 41.9 10.6 44.8

Note. Methods and institutes: LA ICP MS, Christian-Albrechts University, Kiel, Germany (M. Portnyagin is analyst). group), they differ from them in the lower content of both light and known occurrences of explosive volcanism on adjacent land are of a heavy lanthanides (Fig. 7f) at slightly larger values of La/Yb (up to great importance. We used the published materials for a number of 8.82) and La/Sm (up to 6.12). A tendency to increase in heavy lan- standard sediment cores from the Sea of Okhotsk for which the thanides from Ho to Lu is clearly evident. The negative europium complex of methods of deposits correlation was involved as a basis anomaly (Eu/Eu* ¼ 0.57e0.77) (Table 2) was also revealed. of stratigraphic position of the tephra layers under study Into the sixth group, the layers of Aso4 and AL7.4 tephras (tra- (Gorbarenko, 1991; Ivanova and Gorbarenko, 2001; Barash et al., chyrhyodacites-trachyrhyolites) were included. They differ from all 2001, 2006; Derkachev et al., 2004; Levitan et al., 2007; other tephra layers from the Sea of Okhotsk in the highest degree of Gorbarenko et al., 1998, 2002, 2004, 2007, 2010, 2012, 2014; fractionating of REE: La/Yb from 5.09 to 6.89 (Aso4) to 8.48 (AL7.4). Greinert et al., 2002; Kaiser, 2001; Nürnberg and Tiedemann, The higher values are also characteristic of La/Sm: 2.53e3.32 and 2004; Okazaki et al., 2005; Sakamoto et al., 2005, 2006). In addi- 4.67 respectively. The specific feature of the tephras under tion, data of age and chemical composition of known layers of consideration is a well-defined negative europium anomaly (Eu/ tephra in the Pleistocene-Holocene soil-pyroclastic cover of the Eu* ¼ 0.42e0.63) (Fig. 7g) which suggests a higher degree of frac- adjacent land (Kamchatka, Kurile and Japanese Islands) were used tionating for plagioclases in the initial magmas. (Bazanova et al., 2005; Melekestsev et al., 1991,1996,1997; Machida The spectra of distribution of rare and rare-earth elements and Arai, 2003; Machida, 1999; Aoki, 2008; Aoki and Arai, 2000; normalized to the primitive mantle (Sun and McDonough, 1989) Arai et al., 1986; Braitseva et al., 1993, 1995, 1997; Hasegawa exhibit the typically island-arc signs (Churikova et al., 2001; et al., 2008, 2009, 2011, 2012; Hunt and Najman, 2003; Katoh Portnyagin et al., 2005; Duggen et al., 2007; Martynov et al., et al., 1995; Kyle et al., 2011; Kishimoto et al., 2009; Machida and 2010; Miyagi et al., 2012, and others). So, based on key geochem- Arai, 2003; Matsumoto, 1996; Nakagawa et al., 2008; Okumura, ical indices, the analyzed tephras are products of oversubduction 1991; Pevzner, 2015; Ponomareva et al., 2004, 2007; Zaretskaya volcanites of which the high contents of large-ionic lithophils (LILE) et al., 2001, 2007; Yamamoto et al., 2010 and others). The results (Rb, Ba, U as well as Pb) and low concentrations of high field of these comparative complex studies were summarized in the strength elements (HFSE) (Nb, Ta) (Fig. 8) are characteristic. Of the total table which characterizes the basic features of the examined majority of tephras, a presence of the strongly-expressed negative tephra layers of the Sea of Okhotsk and, on the other hand, presents Ta-Nb anomaly is peculiar. A minimum of Sr the value of which the stratigraphic position with estimation of their age over a period decreases (or is entirely absent) in the more basic on silica content of up to 350 thousand years (for station MD01-2415 of RV “Marion tephras (N, TR (Zv), K4, AL10) is also well traced. By the value of Ta- Dufresne” - up to 900 thousand years) (Table 3). The frequency of Nb anomaly, the tephras layers can be sorted (in order of occurrence of the tephra layers in the Sea of Okhotsk deposits descending) in the following sequence: N, TR (Zv), K4, AL9.22b, K6, during different periods of the Pleistocene-Holocene history can be K2-K3, KO, K5, AL7.2a, K6, Kc2-3, N, nMR, MR1, Md1, Md3, MR3, traced in Fig. 10 in which the stratigraphic position of the tephra Md2, AL10, MR4 (Fig. 8). Against this background, the tephras Aso4, layers was compared against the known age isotopic-oxygenic AL7.4 and AL7.2b stand out. In their spider-plots, the negative Ta-Nb curve (Bassinot et al., 1994). anomaly smoothes out almost completely but the Ba minimum Of all examined tephra layers in the Sea of Okhotsk deposits, we appears with simultaneous increasing Sr minimum (Fig. 8e). In have earlier identified the KO, TR (Zv), K2 and K3 tephras more details, the distinctive signs of tephras related to rare and (Derkachev and Portnyagin, 2013; Derkachev et al., 2011, 2012; rare-earth elements are noticeable in the binary diagrams (Fig. 9). Gorbarenko et al., 2002). The stratigraphic position of KO tephra from sediment cores of 4. Discussion the Sea of Okhotsk (Gorbarenko et al., 2002, 2012; Kaiser, 2001)as well as the chemical composition of the volcanic glasses are com- 4.1. Age and identification of tephra layers parable to those of the known KO tephra layer found in the Holo- cene deposits on the adjacent land (Fig. 6, Table 3). This tephra In the process of the tephrostratigraphical studies, data on age of corresponds to the great caldera-forming explosive eruption of the deposits and results of identification of tephra interlayers with Kurile Lake volcano in the south Kamchatka that took place,

Fig. 8. Primitive mantle-normalized (Sun and McDonough, 1989) trace element patterns for glass shards in tephra layers from the Okhotsk Sea sediments. Initial data are listed in Table 2.

Please cite this article in press as: Derkachev, A.N., et al., Tephra layers of in the quaternary deposits of the Sea of Okhotsk: Distribution, composition, age and volcanic sources, Quaternary International (2016), http://dx.doi.org/10.1016/j.quaint.2016.07.004 A.N. Derkachev et al. / Quaternary International xxx (2016) 1e25 17 according to different sources, 7.43e7.98 thousand years (14C) or the slope of the Kurile basin (western Sea of Okhotsk). According to 8.0e8.4 thousand calibrated years ago (Braitseva et al., 1997; the results of litho- and biostratigraphic correlation of sediment Hasegawa et al., 2011; Ponomareva et al., 2004, 2007; Zaretskaya cores from the Sea of Okhotsk and data on oxygen isotopy of et al., 2001, 2007). By the volume of erupted pyroclastic material foraminifera in them, the stratigraphic position of T tephra falls on (about 170 km3), this eruption is one of the greatest in the Kam- the end of isotopic stage 3 (MIS 3) and is very close to position of K3 chatka happened during Holocene. A zone of ash fall has stretched tephra (Ivanova and Gorbarenko, 2001; Derkachev et al., 2004; north-westward and was traced at a distance of more than one Artemova et al., in press). thousand kilometers from the eruption centre (Braitseva et al., A comparison of the composition of volcanic glasses of T tephra 1997; Ponomareva et al., 2004, 2007; Derkachev et al., 2011, with the chemical composition of the tephra found in the Late 2012; Melekestsev et al., 1991)(Fig. 2). Pleistocene deposits on the Hokkaido Island points at their essen- TR (Zv) tephra layer which is tracked in eastern areas of the Sea tial similarity to the products of explosive eruptions of the Mashu of Okhotsk adjacent to a middle part of the Kurile Island arch volcano (Fig. 6a). Here, it is pertinent to note that the low- (Fig. 2) is rather confidently identified. Earlier, this tephra layer potassium volcanic glasses are characteristic of both Holocene called TR was connected with the Holocene eruption of the Tao- rocks and rocks of the older eruptions of this volcano (Kishimoto Rusyr volcano on the Onekotan Island (Derkachev et al., 2004; et al., 2009; Okumura, 1991; Hasegawa et al., 2009, 2012). The Gorbarenko et al., 2002). However, new data on the tephra Late Pleistocene episodes of the strong explosive eruptions of the composition in the soil-pyroclastic cover of the Kurile Islands Mashu volcano (with volume of up to 10 km3)werefixed in the showed that the tephra under consideration belongs to the marker soil-pyroclastic cover to the east and north of this volcano. The layer of Zv-Su tephra (Zavaritsky-Shumshu). The source of this thick pumice layers of the Nakashumbetsu (Upper Nakashumbetsu) tephra is a violent explosive caldera-forming eruption of the series (Nu-r, Nu-p, Nu-n) and, north of the volcano, the pumice Zavaritsky volcano on the Simushir Island (central part of Kurile layers YmP and HkP (Yambetsu and Higashikayano pumice) are Islands) the age of which is estimated about 8.0 thousand calendar confined to the time period to which the T tephra layer is related year (Nakagawa et al., 2008). On a chemical composition of volcanic (Hasegawa et al., 2012; Yamamoto et al., 2010). A formation of these glasses, TR (Zv) tephra is very close to the GA tephra which was pumice deposits has taken place in the time interval of 35e38 found on the Paramushir Island (north part of Kurile Islands) and its thousand calendar years (30.32e34.69 thousand years according to age makes near 8.54 (14C) thousand year (Hasegawa et al., 2011). 14C) (Yamamoto et al., 2010). The layers of tephra Ds-Oh and Kc-Sr This is also confirmed by data of sediment cores recovered in the (KpI) which age is estimated at 32.6 thousand years (14C) are also Sea of Okhotsk (Gorbarenko et al., 1998, 2002; Kaiser, 2001). High additional marking (refining) age reference points (Okumura, 1991; coincidence of the chemical compositions of the rhyolite glasses Hasegawa et al., 2012; Yamamoto et al., 2010). Therefore, this data from TR (Zv) layer and Zv-Su tephra is clearly visible in Figs. 6, 7a of age are in good agreement with the established by us strati- and 9. graphic position of T tephra found in sediment cores of the Sea of The areas of the ash falls for K2 and K3 tephras on land were Okhotsk (Table 3). unknown but, at sea, they were clearly traced in the north-west (K2 The Kc1 (Kc-Sr), Spfa-1 and Kc4 (Kc-Hb) tephras which are tephra) and sublatitudinal (K3 tephra) directions from the eruption connected with the explosive activity of Kutcharo and Shikotsu centers which were located on the Onekotan Island (northern part volcanoes on Hokkaido Island can be placed into the category of of the Kurile Island arc) (Gorbarenko et al., 2002; Derkachev et al., identified tephra layers of the Sea of Okhotsk. Their age is estimated 2011, 2012; Derkachev and Portnyagin, 2013)(Fig. 2). Based on at 34.69e34.9, 39.43e40.12 (14С) and 115e120 thousand years complex studies, it was found that the most probable source of respectively (Table 3)(Yamamoto et al., 2010; Katoh et al., 1995; pyroclastics was the great caldera-forming explosive eruptions of Aoki and Arai, 2000; Hunt and Najman, 2003). These tephra the Nemo volcano in the north part of the Onekotan Island layers were not discovered in sediment cores studied by us. But (Melekestsev et al., 1997; Derkachev and Portnyagin, 2013). Ac- they were found in sediment core MD01-2412 recovered on the cording to the data of radiocarbon analysis, the age of layers with K2 slope of Hokkaido Island: Kc1(Kc-Sr) and Spfa-1 with ages of ~32.5 tephra is estimated at 25.71e26.6 thousand years (14C) and 42e43 thousand calendar years respectively (Okazaki et al., (Gorbarenko et al., 2002, 2007, 2010; Greinert et al., 2002)or 2005; Sakamoto et al., 2006). 30.46e31.2 thousand calendar years respectively (Table 3). The A tephra discovered in sediment core So-178-1-4 recovered in caldera-forming eruption of the Nemo-III volcano being 24.5 the Kurile basin coincides fully with tephra Kc2-3 in sediment core thousand years ago (14C) is most similar in time (age) one among MD01-2412 taken on the slope of Hokkaido Island in the chemical the known in this region great explosive eruptions (Melekestsev composition of volcanic glasses (Okazaki et al., 2005; Sakamoto et al., 1997). According to our calculations, the volume of pyro- et al., 2006). This tephra is similar in composition of both major clastics of this explosive eruption is about 9 km3 (Derkachev and and rare and rare-earth elements to the pumice deposits KpII/III on Portnyagin, 2013) which is consistent with data of paper Hokkaido Island identified near the Kutcharo volcano (Hasegawa (Melekestsev et al., 1997). et al., 2011; Hoang et al., 2011). According to different sources, It was suggested (Derkachev and Portnyagin, 2013) that the the age of these pumice deposits is estimated at the interval of caldera-forming eruption of the Nemo-II volcano relatively close in 84e90 thousand years (Machida and Arai, 2003; Machida, 1999; time to the following strong eruption of Nemo-III could be the Yamamoto et al., 2010). In this case, the series of pumice KpII/III source of explosive material when forming the K3 tephra is stratigraphically situated above the marker layer of Aso4 tephra (Melekestsev et al., 1997). According to researches of these authors, (about 88 thousand years) well represented on the Japanese Islands the directed explosion took place north-westward, toward the Sea and adjacent seas (Aoki, 2008; Oba et al., 2006; Hasegawa et al., of Okhotsk. The material traces of this strong eruption were not 2012; Okumura, 1991; Machida and Arai, 2003). In sediment core kept on land due to the denudation processes. It was stated that K3 MD01-2412, Kc2-3 tephra comparable with KpII/III is also strati- tephra in sediment core Ge99-10 is younger than the T tephra layer graphically higher (i.e. younger) than the Aso4 tephra in the de- (Artemova et al., pers. com.) and the age of the latter is about 35e38 posits of isotopic stage 5.2 (Sakamoto et al., 2006). According to the thousand years (see below). age scale for this core, the age of Kc2-3 tephra is about 79e80 The T tephra, represented by the low-potassium rhyolites- thousand years (Okazaki et al., 2005; Sakamoto et al., 2006). Thus, rhyodacites, was recorded in several sediment cores recovered on the performed comparison of the composition of volcanic glasses of

Fig. 9. Indicative variations of ratios among rare and rare earth elements characterizing a contribution of different sources into the processes of magma genesis. Arrows show the trends of intensified influence of elements supply in fluid phase and due to melting of subducting sediments (Duggen et al., 2007). tephra from sediment core So-178-1-4 affords ground to identify and Arai, 2000; Hunt and Najman, 2003; Sakamoto et al., 2006). this tephra with the caldera-forming eruption of Kutcharo volcano According to the latest data, the age of Aso4 tephra falls on the on Hokkaido Island. isotopic stage MIS 5.2 and is estimated at 86.6e87.3 thousand years A layer of Aso4 tephra belonging to the greatest Late-Pleistocene (Aoki, 2008; Oba et al., 2006) while the age of tephra from sediment explosive eruption of the Aso volcano on Kyushu Island is well core MD01-2412 is about 88 thousand years (Okazaki et al., 2005; identified (Machida and Arai, 2003). This tephra layer was revealed Sakamoto et al., 2006). in the deposits of the southern Sea of Okhotsk (Fig. 2). As was For the majority of other tephra layers (16 of 23 studied by us), shown above, (Figs. 3, 5e9), it differs markedly in geochemical the sources of volcanic explosions remain unknown due to our characteristics from composition of tephras, the sources for which incomplete knowledge about the volcanic activity of the adjacent were the explosive eruptions of volcanoes of the Sea of Okhotsk land. Even with availability of the highly representative database framing. The results of our investigations of this tephra are in good which are available at our disposal (about 20 thousand microprobe agreement with data on composition of Aso4 tephra widespread chemical analyses) of the chemical composition of tephras (pre- both in deposits of land (Japanese Islands, southern Kurile Islands) dominantly Holocene volcanic eruptions in Kamchatka and, more and in the adjacent areas of the Sea of Japan and north-western rarely, on Kurile Islands), we failed to find the close analog in the Pacific Ocean (Fig. 6)(Aoki, 2008; Machida and Arai, 2003; Aoki deposits of land and, consequently, the source of explosive

Table 3 Characteristic features of tephra layers from the Okhotsk Sea Quaternary deposits.

Index of Thickness of Color of Mineral Geochemical Chemical Color of Age, kyr Supposed tephra tephra layer, tephra complex series composition volcanic source Marine Terrestrial layer cm layer of volcanic glass glass.

14 14 KO 0.5e16 white Opx Cpx: Med-K SiO2 - 75.8e8.4 colorless 7.8 ( C) - 8.6 7.5-7.98 ( C) Kurile Lake Hb rhyolite (76.9%)** (cal. kyr) kyr- 8.0-8.4 caldera

K2O - 1.96e2.6 (Gorbarenko (cal. kyr) (Braitseva (South (2.1%) et al., 2002) et al., 1995, 1997; Kamchatka) 14 TiO2 - 0.17e0.28 7.4 ( C) - 8.4 Melekestsev (0.23%) (cal. kyr) (Sakamoto et al., 1991; et al., 2005) Ponomareva 8.0e8.1 (cal. kyr) et al., 2004, 2007; (Kaiser, 2001) Zaretskaya 8.2e8.6 (cal. kyr) et al., 2001) (Barash et al., 2005) 7.43 (14C) (Hasegawa et al., 2011)

N ~1 (lenses) light grey Cpx > Opx Low-K SiO2 - 64.5e69.9 grey ~8.5 kyr n.d Gamchen dacite (66.7%) (?), Kamchatka

K2O - 0.6e0.9 (0.8%)

TiO2 - 0.46e0.72 (0.62%) 14 TR (Zv) 1e2 grey Opx > Cpx Low-K SiO2 - 71.7e73.7 colorless, 8.0 ( С)(Gorbarenko 8.0 cal kyr Zavaritsky rhyolite (73.0%) light grey et al., 1998, 2002) (Nakagawa caldera 14 K2O - 0.9e1.0 8.0e8.05 ( C) et al., 2008) (Simushyr, (0.9%) (Kaiser, 2001) ~8.54 (14C) Middle

TiO2 - 0.45e0.51 kyr- (Hasegawa Kurile Island) (0.48%) et al., 2011) 14 14 K2 1e22 grey with Cpx Opx: Med-K SiO2 - 73.4e76.3 colorless 25.71 ( C) kyr 24.5 ( C) kyr Nemo-III reddish (Hb) rhyolite (75.4%) (Greinert et al., 2002) (Melekestsev (Onekotan, 14 shade K2O - 2.3e2.7 26.6 ( C) - 31.2 et al., 1997) North Kurile) (2.5%) (cal. kyr) (Gorbarenko

TiO2 - 0.14e0.44 et al., 2004) (0.32%) 30.46e30.49 (cal. kyr) (Gorbarenko et al., 2007, 2010)

K3 grey Cpx Opx: Med-K SiO2 - 73.5e77.2 colorless; Late Pleistocene, Late Nemo-II? (Hb) rhyolite (75.4%) crystallo- the end of MIS 3 - Pleistocene - (Onekotan,

K2O - 2.3e2.7 clastics (Kaiser, 2001; (Melekestsev North Kurile) (2.5%) Derkachev et al., 2004; et al., 1997)

TiO2 - 0.25e0.41 Derkachev and (0.32%) Portnyagin, 2013)

T 0.2e0.6 yellowish- Opx > Cpx Low-K SiO2 - 65.7e77.1 colorless, Late Pleistocene, 30.32e34.69 Mashu (lenses) grey rhyolite (74.4%) light the end of MIS 3 - (14C) - 35e38 volcano,

K2O - 0.5e1.1 brown (rare); (Kaiser, 2001; (cal. kyr) - Hokkaido (1.0%) crystallo- Ivanova and (Hasegawa Is., Japan

TiO2 - 0.29e0.78 clastics Gorbarenko, 2001; et al., 2009, 2012; (0.46%) Derkachev et al., 2004) Yamamoto et al., 2010)

Kc1 (Kc-Sr)* 17 dark grey Opx > Cpx Med-K SiO2 - 78.2%* 32.5 (cal. kyr) 30-32 Kutcharo (top), rhyolite K2O - 2.5% (Okazaki et al., 2005; (cal. kyr) caldera, light grey TiO2 - 0.26% Sakamoto et al., 2006) (Okumura, 1991; Hokkaido (base) Arai et al., 1986; Is., Japan Machida and Arai, 2003) 34.69e34.9 (14C) - 40.03e40.23 (cal. kyr) - (Yamamoto et al., 2010)

Spfa1* 5 light grey Opx: Hb Med-K SiO2 - 77.9%* ~42e43 39.43e40.12 Shikotsu 14 rhyolite K2O - 2.7% (cal. kyr) - MIS 3.13 ( C) kyr (Katoh caldera, TiO2 - 0.14% (Sakamoto et al., 2006) et al., 1995) Hokkaido 39.5e40.1 Is., Japan (cal. kyr) (Aoki and Arai, 2000; Hunt and Najman, 2003)

K4 ~1 (lenses) grey Cpx > Opx: Low-K SiO2 - 70.6e73.1 Colorless; ~50 kyr - MIS 3.3 unknown unknown Hb rhyolite (72.1%) green-grey (Kaiser, 2001)

K2O - 1.1e1.3 (rare), light (1.3%) brown (rare)

TiO2 - 0.46e0.72 (0.58%) (continued on next page)

Table 3 (continued )

MR1 0.3e0.5 beige Cpx > Opx: Hb Med-K SiO2 - 69.4e71.0 colorless ~65e67 unknown unknown (lenses) dacite (70.2%) kyr - MIS 4

K2O - 1.2e1.4 (Gorbarenko (1.3%) et al., 2010, 2012, 2014)

TiO2 - 0.52e0.57 (0.54%)

Kc2-3 turbidite light grey Opx > Cpx Med-K SiO2 - 73.9e78.1 colorless; ~79e80 kyr - MIS 5.2 ~84e90 kyr - Kutcharo rhyolite (77.2%) a lot of pumice (Sakamoto et al., 2006) (Machida,1999; caldera,

K2O - 1.7e2.4 Machida and Hokkaido (2.0%) Arai, 2003) Is., Japan

TiO2 - 0.26e0.56 ~85e86 kyr - (0.34%) (Yamamoto et al., 2010)

Aso4 0.7e3 light grey Hb > Cpx High-K SiO2 - 72.7e73.6 colorless 88 kyr - MIS 5.2 86-90 kyr - Aso caldera, Opx trachy- (73.1%) (Okazaki et al., 2005; (Machida and Kyushu

rhyolite K2O - 4.3e4.9 Sakamoto et al., 2006) Arai, 2003) Is., Japan (4.6%) MIS 5.2 - 86.8e87.3 kyr -

TiO2 - 0.38e0.43 (Ivanova and (Oba et al., 2006; (0.41%) Gorbarenko, 2001; Aoki, 2008) Cruise Report, 2003) ~89 kyr - (Matsumoto, 1996)

Kc4 (Kc-Hb)* 13.5 yellowish- Opx > Cpx: Med-K SiO2 - 78.0%* ~115 kyr (Okazaki 100-130 kyr Kucharo grey (Hb) rhyolite K2O - 2.1% et al., 2005; Sakamoto (Machida caldera, (top), dark TiO2 - 0.31% et al., 2006) and Arai, 2003) Hokkaido grey (base) 115-120 kyr e Is., Japan (Hasegawa et al., 2008; 2011; Yamamoto et al., 2010)

K5 1e6 light grey Opx > Cpx Med-K SiO2 - 77.2e77.8 colorless ~115e120 kyr - unknown unknown rhyolite (77.5%) MIS 5.4

K2O - 1.7e2.0 (Gorbarenko, 1991; (1.8%) Gorbarenko

TiO2 - 0.32e0.4 et al., 2002; Barash (0.36%) et al., 2001)

MR2 1e4 light grey Cpx > Opx: Med-K SiO2 - 74.9e76.3 colorless ~206 kyr - MIS 7.2 unknown unknown (AL7.2a) Hb rhyolite (75.7%) (Kaiser, 2001;

K2O - 1.7e1.9 Nürnberg and (1.8%) Tiedemann, 2004)

TiO2 - 0.36e0.46 ~200e210 kyr - (0.4%) MIS 7.2 (Barash et al., 2006) ~199.7 kyr - MIS 7.1 (Gorbarenko et al., 2010, 2014)

AL7.2b 1 white Bi > Hb > Med-High-K SiO2 - 76.7e76.6 colorless ~206e210 kyr - unknown Volcanoes Cpx > Opx trachy- (77.6%) MIS 7.2 (Kaiser, 2001; of Kamchatka

rhyolite K2O - 3.6e4.2 Nürnberg and Sredinny (3.8%) Tiedemann, 2004) Range

TiO2 - 0.08e0.15 (0.13%)

AL7.4 1 white Hb > Cpx > High-K SiO2 - 76.0e76.6 colorless ~229 kyr - MIS 7.4 Magadan city Volcanoes Opx trachy- (76.4%) (Nürnberg and (Uptar mine) - of Kamchatka

rhyolite K2O - 4.3e5.0 Tiedemann, 2004) (Melekestsev Sredinny (4.5%) ~230e235 et al., 1991) Range

TiO2 - 0.09e0.15 kyr - MIS 7.4 (0.13%) (Barash et al., 2006; Levitan et al., 2007)

nMR 2 very light Cpx Opx: Med-K SiO2 - 77.4e78.6 colorless ~290e300 kyr - unknown unknown grey Hb rhyolite (78.2%) MIS 8.6 (Nürnberg

(almost K2O - 2.3e2.7 and Tiedemann, 2004; white) (2.5%) Levitan et al., 2007)

TiO2 - 0.15e0.22 (0.19%)

K6 5 grey Opx Cpx Med-K SiO2 - 65.1e72.1 colorless, ~310e320 kyr - unknown unknown dacite (69.2%) light grey, MIS 9.1e9.2

K2O - 1.1e1.7 dark brown (Derkachev et al., 2004) (1.5%) (rare)

TiO2 - 0.4e0.81 (0.67%)

MR3 1e6 yellow-grey Cpx Opx: Med-K SiO2 - 75.3e76.2 colorless ~311 kyr - MIS 9.22 unknown unknown (AL9.22) Hb rhyolite (75.9%) (Nürnberg and

K2O - 2.9e3.3 Tiedemann, 2004)

Table 3 (continued )

(3.1%) ~290e310 kyr - MIS

TiO2 - 0.24e0.37 9.1e9.2 (Barash (0.28%) et al., 2006) ~307 kyr - MIS 9.1e9.2 (Gorbarenko et al., 2010, 2012, 2014)

AL9.22b 0.5e0.9 dark grey n.d. Low-K SiO2 - 60.2e62.4 green-grey, ~310e315? kyr - unknown unknown (lenses) andesite (61.1%) light-brown MIS 9.1e9.2 - (Cruise

K2O - 0.8e1.0 and dark Reports, 1999) (0.9%) brown

TiO2 - 0.94e1.08 (rare) - both (1.01%) with microlites of minerals

MR4 1e5 grey with Opx Cpx Med-K SiO2 - 60.6e68.3 dark grey, ~319e320 kyr - unknown unknown (AL9.24) yellowish- trachy- (64.02%) greenish-light MIS 9.24 (Nürnberg

brown andesite- K2O - 1.8e2.7 brown, dark and Tiedemann, 2004) shade trachyda-cite (2.3%) brown ~320 kyr - MIS 9.2

TiO2 - 0.77e1.32 (rare) with (Barash et al., 2006) (1.09%) microlites MIS 9.2 (Cruise of minerals Report, 2003)

AL10 0.5e0.9 dark grey Opx > Cpx Med-K trachy- SiO2 - 58.7e69.2 light and ~330 kyr - MIS 10 unknown unknown andesite- (62.6%) dark grey, (Nürnberg and

trachyda-cite K2O - 1.9e3.5 dark brown Tiedemann, 2004) (2.4%) (rare) with

TiO2 - 0.7e1.5 microlites (1.22%) of minerals

Md1 2 yellow- Cpx Opx: Med-K SiO2 - 73.6e74.8 colorless ~400e410 kyr - unknown unknown grey Hb rhyolite (74.0%) with yellowish (Nürnberg and

K2O - 1.9e2.1 shade Tiedemann, 2004); (2.0%) MIS 11 (Levitan

TiO2 - 0.42e0.5 et al., 2007) (0.46%)

Md2 3 beige Cpx Opx: Med-K SiO2 - 77.8e78.4 colorless ~530e540 kyr - unknown Volcanoes Bi, Hb rhyolite (78.2%) (Nürnberg and of Kamchatka

K2O - 3.4e3.9 Tiedemann, 2004); Sredinny (3.6%) MIS 14 (Levitan Range

TiO2 - 0.08e0.13 et al., 2007) (0.11%)

Md3 3 beige Opx > Cpx: Med-K SiO2 - 74.0e74.9 colorless ~890e900 kyr - unknown unknown Ap rhyolite (74.5%) with light (Nürnberg and

K2O - 2.5e2.7 grey shade Tiedemann, 2004); (2.6%) MIS 23? (Levitan

TiO2 - 0.36e0.44 et al., 2007) (0.4%)

Stations where tephra layers were found: KO: M946, Lv27-8-4, Lv28-42-5, Lv28-43-5, Lv28-44-3, Lv29-106-2, Lv29-108-4, Lv29-110-2, Lv29-112-2, Lv55-9, MD01-2415, MR0604-PC6R, V34-98, XP98-PC1. N: GC12-6A. TR(Zv): 9301, 9304, Lv27-10-5, Lv27-15-1, V34-90. K2: 9306, 9307, M918, M924, M927, M934, M945, M961, M968, M969, Ge99-32, Ge99-36, K-68, K-72, K-74, K-78, K-105, Lv27-5-5, Lv27-6-2, Lv27-7-3, Lv27-8-3, Lv27-8-4, Lv28-37-1, Lv28-40-4, Lv28-40-5, Lv28-41-4, Lv28-41-5, Lv28-42-4, Lv28-42-5, Lv28-43-5, Lv29-53-1, Lv29-56-1, Lv29-63-1, Lv29-100-1, Lv29-114-2, Lv32-21, Lv32-25, Lv40-03, Lv40-04, Lv40-09, Lv40-15, Lv40-16, Lv40-17, Lv40-18-2, Lv40-19, Lv40-20, MD01-2415, MR0604-PC6R, MR0604-PC7R, So178-11-5, So178-12-3, So178-62-1, GC-12-1B, GC-12-5A, GC-12-6A, XP98-PC1, XP98-PC2. K3: 9313,

Ge99-10, Ge99-38-5, K-68, Lv27-9-4, Lv27-10-5, Lv27-12-3, Lv27-12-4, Lv27-15-1, Lv55-38. T: Ge99-10, Lv28-2-4, Lv28-64-5, Lv29-70-2, Lv29-72-2, So178-3-4. Kc1 (Kc-Sr): MD01-2412*. Spfa1: MD01-2412*. K4: Lv27-15-1, XP98-PC1. MR1: MR0604-PC6R, GC-12-1A. Kc2-3: MD01-2412*, So178-1-4. Aso4: Ge99-10, Lv28-64-5, Lv29-70-2, MD01- 2412. Kc4 (Kc-Hb): MD01-2412*. K5: 9305, Ge99-38-5, K-68, Lv29-114-2 (?). MR2 (AL7.2a): Lv28-42-4, MR0604-PC7R. AL7.2b: Lv28-42-4. AL7.4: Lv28-42-4, MD01-2415. nMR: MD01-2415, MR0604-PC5R. K6: 9305, Ge99-38-5. MR3 (AL9.22): Lv28-42-4, MR0604-PC7R. AL9.22b: Lv28-42-4. MR4 (AL9.24): Lv28-42-4, MR0604-PC6R. AL10: Lv28- 42-4. Md1: MD01-2415. Md2: MD01-2415. Md3: MD01-2415. *- data of Sakamoto et al., 2006. **- minimum-maximum values, in brackets - mean values. Minerals: Cpx - clinopyroxene, Opx - ortopyroxene, Hb - hornblende, Bi-biotite, Ap-apatite. volcanism. This applies especially to identifying the tephra layers of et al., 1997; Churikova et al., 2001; Smith et al., 2002; Portnyagin the Pleistocene age as their traces on the adjacent land were not et al., 2005 ; Duggen et al., 2007; Jensen et al., 2008, 2011; preserved due to denudation processes during Pleistocene- Addison et al., 2010; Martynov et al., 2010; Preece et al., 2011, and Holocene periods. others). In the volcanites of the frontal zone of the island arcs, a A certain assistance in the questions of the further identiﬁcation predominance in the composition of phenocrysts of clinopyroxene can be rendered by an analysis of the mineral and chemical com- and olivine is marked; at the same time, the subordinate role of positions of tephra if the known tendencies in the cross orthopyroxene which quantity increases gradually as the volcanic mineralogical-geochemical zonality of the volcanism products of front moves away from the trench axis with the appearance of the the island-arc systems are taken into account (Kuno, 1959; Geptner orthopyroxene-clinopyroxene mineral parageneses is noted. As a and Ponomareva, 1979; Volynets et al., 1990; Volynets, 1994; rule, the hornblende is absent here or is rare. In the rocks (espe- Avdeyko et al., 1991; Podvodny Vulkanizm …, 1992; Braitseva cially, with increased silica content) of the backarc of island arcs,

Fig. 10. Tephrostratigraphic scheme of the Pleistocene-Holocene deposits from the Sea of Okhotsk. the quantity of hydrous silicates (amphiboles) in phenocrysts and, In this article, we do not present a detailed analysis of the dis- in a number of cases, biotite with subordinate role of pyroxenes tribution of microelement composition in the studied volcanic increases (Podvodny Vulkanizm …, 1992; Volynets et al., 1990, ashes of the Sea of Okhotsk with estimating their belonging to Braitseva et al., 1995, 1997; Smith et al., 2002, and others). volcanites of the frontal or backarc parts of the island arcs. It is a The signs of geochemical zonality cross strike of arc based on the subject-matter of independent publication. Here, the only microelement composition are visible for the volcanic rocks of following can be noted. Taking in consideration the above ten- Kamchatka in the direction from the East volcanic front (EVF) dencies, the tephras AL7.2b, Md2, nMR and AL7.4 in which the through (across) the Central-Kamchatka Depression (CKD) to the mineral associations with high content of amphiboles and biotite backarc of the Kamchatka Sredinny Range (SK) (Churikova et al., (especially, for AL7.2b and Md2 tephras) are clearly discovered can 2001; Portnyagin et al., 2005). be unambiguously assigned to the backarc volcanites (Derkachev

Please cite this article in press as: Derkachev, A.N., et al., Tephra layers of in the quaternary deposits of the Sea of Okhotsk: Distribution, composition, age and volcanic sources, Quaternary International (2016), http://dx.doi.org/10.1016/j.quaint.2016.07.004 A.N. Derkachev et al. / Quaternary International xxx (2016) 1e25 23 et al., 2016). The geochemical characteristics of volcanic glasses of References these tephras differ also from those of other tephras and corre- spond, to a greater extent, to the backarc volcanites (Table 2, Figs. 5, Addison, J.A., Beget, J.E., Ager, T.A., Finney, B.P., 2010. Marine tephrochronology of fi e the Mt. Edgecumbe volcanic eld, southeast Alaska, USA. Quat. Res. 73 (2), 7 9). The most probable source of the pyroclastic material for these 277e292. tephras is the volcanoes of the Kamchatka Sredinny Range Aksu, A.E., Jenner, G., Hiscott, R.N., Isler, E.B., 2008. Occurrence, stratigraphy and (Churikova et al., 2001; Portnyagin et al., 2005). Unfortunately, it is geochemistry of late quaternary tephra layers in the aegean sea and the mar- e fi mara sea. Mar. Geol. 252, 174 192. not possible to perform now the perfect identi cation of the above Ambrose, S.H., 1998. Late Pleistocene human population bottlenecks, volcanic tephras. The most probable sources can be the explosions of the winter, and the differentiation of modern humans. J. Hum. Evol. 34, 623e651. Khangar, Alney-Chashakondzha, Opala, Ichinsky volcanoes. The Aoki, K., 2008. Revised age and distribution of ca. 87 ka Aso-4 tephra based on new fi e volcanic glasses similar in composition to AL7.4 tephra were found evidence from the northwest Paci c Ocean. Quat. Int. 178 (1), 100 118. Aoki, K., Arai, F., 2000. Late Quaternary tephrostratigraphy of marine core KH94-3, among the lacustrine deposits near Magadan over a distance of LM-8 off Sanriku, Japan. Quat. Res. Jpn. Assoc. Quat. Res. 39, 107e120 (in Jap- more than one thousand kilometers from the supposed source anese with English abstract). (Melekestsev et al., 1991). Aoki, K., Machida, H., 2006. Major element composition of volcanic glass shards in the Late Quaternary widespread tephras in Japan - distinction of tephras using K2O-TiO2 diagrams. Bull. Geol. Surv. Jpn. 57 (7/8), 239e258 (in Japanese with 5. Conclusion English abstract). Arai, F., Machida, H., Okumura, K., Miyauchi, T., Soda, T., Yamagata, K., 1986. Catalog for Late Quaternary Marker-tephras in Japan II: Tephras Occurring in Northeast The fullest information on distribution, composition and age of 23 Honshu and Hokkaido. Geographical Reports of Tokyo Metropolitan University tephra layers in the Pleistocene-Holocene deposits of the Sea of 21, pp. 223e250 (in Japanese). Okhotsk is presented. The integrated data including the mineralogical Artemova A.V., Gorbarenko S.A., Ivanova E.D. Reaction of carbonaceous and silica- ceous organisms from Okhotsk Sea south-eastern part on the changes of and numerous microprobe chemical analyses (among them, analyses environment and climate during last 100 ka, Geol. Geophys., in press of rare and rare-earth elements) is a reliable basis for the tephros- Avdeyko, G.P., Volynets, O.N., Antonov, A.Yu, Tsvetkov, A.A., 1991. Kurile island arc tratigraphical correlation of the regional deposits. The tephras KO, TR volcanism: structural and petrological aspects. Tectonophysics 199 (2e4), e fi fi 271 287. (Zv), K2 and K3, T, Kc2-3, Aso4 are identi ed with the most con - Barash, M.S., Bubenshchikova, N.V., Kazarina, G.Kh, Khusid, T.A., 2001. Paleo- dence. For them, the sources of pyroclastic material were established ceanography of the central part of the Sea of Okhotsk over the past 200 ky (on and they include the volcanoes of the Kurile Lake (Kamchatka), the basis of micropaleontological data). Oceanology 41 (5), 723e735. Zavaritsky (Simushir Island, Kurile Islands), Nemo (Onekotan Island, Barash, M.S., Matul, A.G., Kazarina, G.Kh, Khusid, T.A., Abelmann, A., Biebow, N., Nürnberg, D., Tiedemann, R., 2006. Paleoceanography of the central sea of Kurile Islands), Mashu and Kutcharo (Hokkaido Island), Аsо (Kyushu Okhotsk during the middle Pleistocene (350-190 ka) as inferred from micro- Island). An assumption of the effect of explosions of the Kamchatka paleontological data. Oceanology 46 (4), 501e512. Sredinny Range volcanoes on the formation of the tephra layers AL7.4, Barash, M.S., Chekhovskaya, M.P., Biebow, N., Nurnberg, D., Tiedeman, R., 2005. On the Quaternary Paleoceanology of the southeastern part of the Sea of Okhotsk AL7.2b, Md2 was made. The areas of ash falls for a number of the great from lithology and planktonic foraminifera. Oceanology 45 (2), 257e268. explosive eruptions of volcanoes located in Kamchatka and Kurile Bassinot, F.C., Labeyrie, L.D., Vincent, E., Quidelleur, X., Shackleton, N.J., Lancelot, Y., Islands were specified and established. 1994. The astronomical theory of climate and the age of the Brunhes-Matuyama magnetic reversal. Earth Planet. Sci. Lett. 126 (1e3), 91e108. The obtained results of the complex investigations of tephras Bazanova, L.I., Braitseva, O.A., Dirksen, O.V., Sulerzhitskii, L.D., Danhara, T., 2005. allow us to essentially supplement the data on the great explosive Peplopady krupneyshikh golotsenovykh izvergeniy na traverse Ust'-Bol'sher- eruptions of volcanoes in the region and offer an opportunity to etsk-Petropavlovsk-Kamchatskiy: istochniki, khronologiya, chastota. Vulkanol. i Seismol. 6, 30e46 (in Russian with English Abstract). develop the generalized tephrochronological scale of the Quater- Bourne, A., Lowe, J.J., Trincardi, F., Asioli, A., Blockley, S.P.E., Wulf, S., Matthews, I.P., nary deposits of this region which is necessary for the strati- Piva, A., Vigliotti, L., 2010. Distal tephra record for the last ca. 105,000 years from graphical correlation of deposits, estimation of environmental core PRAD 1-2 in the central Adriatic Sea: implications for marine tephrostratigraphy. Quat. Sci. Rev. 29, 3079e3094. changes caused by these eruptions, paleooceanological and paleo- Braitseva, O.A., Sulerzhitsky, L.D., Litasova, S.N., Melekestsev, I.V., 1993. Radiocarbon geographical reconstructions. dating and tephrochronology in Kamchatka. Radiocarbon 35 (3), 463e476. Braitseva, O.A., Melekestsev, I.V., Ponomareva, V.V., Sulerzhitsky, L.D., 1995. Ages of Acknowledgements calderas, large explosive craters and active volcanoes in the Kurile-Kamchatka region, Russia. Bull. Volcanol. 57 (6), 383e402. Braitseva, O.A., Ponomareva, V.V., Sulerzhitsky, L.D., Melekestsev, I.V., Bailey, J., 1997. This work was conducted within International Russian-German Holocene key-marker tephra layers in Kamchatka, Russia. Quat. Res. 47 (2), e (KOMEX), RussianeJapan (Grant no 06-05-91576 of JP, JSPS) and 125 139. Braitseva, O.A., Bazanova, L.I., Melekestsev, I.V., Sulerzhitskiy, L.D., 1998. Large Ho- National Nature Science Foundation of China (Grant no U1406404, locene eruptions of avacha volcano, Kamchatka (7250-3700 14C years B.P. Vol- 40431002), China National Programme on Global Change and Air- canol. Seismol. 20 (1), 1e27. Sea Interaction (GASI-01-02-01-04). Analytical investigations Bubenshchikova, N.V., Ponomareva, V.V., Portnyagin, M., Nürnberg, D., fi Tiedemann, R., 2015. Composition and origin of tephra and cryptotephra laers in were nancially supported by both the Russian-German Project the Okhotsk Sea sediments (core MD01e2415) over the last 300 kyr: primary KALMAR and the Russian Foundation for Basic Research (Project no fallout vs redeposition. Geology of seas and oceans. In: Proceedings of XXI In- 11-05e00506a, 16-55-53048, 16-05-00127). M. Portnyagin and V. ternational Conference on Marine Geology, vol. IV. GEOS, Moscow, pp. 346e349. Churikova, T., Dorendorf, F., Worner,€ G., 2001. Sources and fluids in the mantle Ponomareva acknowledge support from the Russian Science wedge below Kamchatka, evidence from across-arc geochemical variation. Foundation grant #16-17-10035. J. Petrology 42 (8), 1567e1593. The authors thank Dieter Garbe-Schonberg€ (University of Kiel) Crosweller, H.S., Arora, B., Brown, S.K., Cottrell, E., Deligne, N.I., Ortiz, N., Hobbs, L.K., € Kiyosugi, K., Loughlin, S.C., Lowndes, J., Nayembil, M., Siebert, L., Sparks, R.S.J., and Mario Thoner (GEOMAR) for their help with the microprobe Takarada, S., Venzke, E., 2012. Global database on large magnitude explosive analyses. volcanic eruptions (LaMEVE). J. Appl. Volcanol. 1 (4), 1e13. We are grateful to the participants of cruises on the R/V Aka- Cruise Reports, 1999. R/V Professor Gagarinsky 22 and R/V Akademik M.a. Lav- e demik M.A. Lavrentyev, Marshal Gelovani, Sonne, Miray, and rentyev 28, vol. 82, pp. 148 178. Kiel, Geomar Report. Cruise Reports, 2000. KOMEX V and VI, R/V Professor Gagarinsky 26 and R/V Yokosuka for their help and for the opportunity to obtain bottom Marshal Gelovany 1, vol. 88, pp. 189e209. Kiel, Geomar Report. sediments cores. Cruise Report, 2003. KOMEX II, R/V Akademik M.a. Lavrentyev 29, Leg 1 and Leg 2. Kiel, Geomar Report 110, 190 pp. Derkachev, A.N., Nikolaeva, N.A., 2010. Mineralogicheskie indikatory Obstanovok Appendix A. Supplementary data prikontinental'nogo Osadkoobrazovaniya zapadnoy chati Tikhogo Okeana. Dalnauka, Vladivostok, Russia (in Russian with English Abstract). Supplementary data related to this article can be found at http:// Derkachev, A.N., Portnyagin, M.V., 2013. Marker tephra layers from the catastrophic eruptions of the Nemo caldera complex (onekotan island, kurile islands) in the dx.doi.org/10.1016/j.quaint.2016.07.004.

late quaternary deposits of the sea of Okhotsk. Stratigr. Geol. Correl. 21 (5), Islands: evaluation of Holocene eruptive activity and temporal change of 553e571. magma system. Quat. Int. 246 (1e2), 278e297. Derkachev, A.N., Nikolaeva, N.A., Gorbarenko, S.A., 2004. Osobennosti postavki i Hasegawa, T., Nakagawa, M., Itoh, J., Yamamoto, T., 2011b. Deposition ages of raspredeleniya klastogennogo materiala v Okhotskom more v Pozdnechetver- Quaternary sequences in Kushiro region, eastern Hokkaido, Japan: correlations tichnoe vremya (na osnove analiza assotsiatsiy tyazhelykh mineralov). and chronology on the basis of high-resolution tephro-stratigraphy. J. Geol. Soc. Tikhookeanskaya Geol. 23 (1), 37e52 (in Russian with English Abstract). Jpn. 117, 686e699 (in Japanese with English abstract). Derkachev, A.N., Nikolaeva, N.A., Gorbarenko, S.A., Portnyagin, M.V., Hasegawa, T., Nakagawa, M., Kishimoto, H., 2012. The eruption history and silicic Ponomareva, V.V., Sakhno, V.G., Nürnberg, D., Sakamoto, T., Iijima, K., Liu, H.H., magma systems of caldera-forming eruptions in Eastern Hokkaido, Japan. Sci- Wang, K., Chen, Z., 2011. Volcanic ash layers in the Okhotsk sea holocene- ence 107, 39e43. pleistocene deposits. In: Proceedings of 7th Biennual Workshop on Japan- Hasegawa, T., Nakagawa, M., 2016. Large scale explosive eruptions of Akan volcano, Kamchatka-Alaska Subduction Processes: Mitigating Risk through Interna- eastern Hokkaido, Japan: a geological and petrological case study for estab- tional Volcano, Earthquake, and Tsunami Science. Petropavlovsk-kamchatsky, lishing tephro-stratigraphy and -chronology around a caldera cluster. Quat. Int. Russia, p. 271. 397 (18), 39e51. Derkachev, A.N., Nikolaeva, N.A., Gorbarenko, S.A., Harada, N., Sakamoto, T., Hoang, N., Itoh, J., Miyagi,I., 2011.Subduction components in Pleistocene to recent Kurile Iijima, K., Sakhno, V.G., Liu, H.H., Wang, K., 2012. Characteristics and ages of arc magmas in NE Hokkaido, Japan. J. Volcanol. Geotherm. Res. 200, 255e266. tephra layers in the central Okhotsk Sea over the last 350 kyr. Deep-Sea Hunt, J.B., Najman, Y.M.R., 2003. Tephrochronological and tephrostratigraphical Research-II 61e64, 179e192. potential of Pliocene-Pleistocene volcanoclastic deposits in the Japan forearc, Derkachev, A.N., Nikolaeva, N.A., Portnyagin, M.V., 2016. Mineral composition of ODP Leg 186. In: Suyehiro, K., Sacks, I.S., Acton, G.D., Oda, M. (Eds.), Proceedings tephra layers in the quaternary deposits of the sea of Okhotsk: heavy mineral of the Ocean Drilling Program, Scientific Results, vol. 186, pp. 1e29. associations and geochemistry. Geochem. Int. 54 (2), 167e196. Hunt, J.B., Clift, P.D., Lacasse, C., Vallier, T.L., Werner, R., 1998. Interlaboratory Duggen, S., Portnyagin, M., Baker, J., Ulfbeck, D., Hoernle, K., Garbe-Schoenberg, D., comparison of electron probe microanalysis of glass geochemistry. In: Grassineau, N., 2007. Drastic shift in lava geochemistry in the volcanic-front to Saunders, A.D., Larsen, H.C., Wise Jr., S.W. (Eds.), Proceedings of the Ocean rear-arc region of the Southern Kamchatka subduction zone: evidence for the Drilling Program, Scientific Results, vol. 152, pp. 85e90. transition from slab surface dehydration to sediment melting. Geochim. Cos- Irvine, T.N., Baragar, W.R.A., 1971. A guide to the chemical classification of the mochim. Acta 71 (2), 452e480. common volcanic rocks. Can. J. Earth Sci. 8 (5), 481e497. Ehrmann, W., Schmiedl, G., Hamann, Y., Kuhnt, T., Hemleben, Ch, Siebel, W., 2007. Ivanova, E.D., Gorbarenko, S.A., 2001. Kompleksy bentosnykh foraminifer materi- Clay minerals in late glacial and Holocene sediments of the northern and kovogo sklona yuzhnoy chasti Okhtskogo morya. Tezisy Dokl. XIV Shkoly po southern Aegean Sea. Palaeogeogr. Palaeoclimatol. Palaeoecol. 249 (1e2), 36e57. morskoy Geol. Moskva, Russia 51e53 (in Russian). Endo, K., Sumita, M., Uno, R., 1989. Late- Holocene tephra sequences in Eastern Jarosewich, E.J., Nelen, J.A., Norberg, J.A., 1980. Reference samples for electron Hokkaido and their source volcanoes. J. Geogr. (Chigaku Zasshi) 98 (4), 506e510 microprobe analysis. Geostand. Newsl. 4 (1), 43e47. (in Japanese). Jensen, B.J.L., Froese, D.G., Preece, S.J., Westgate, J.A., Stachel, T., 2008. An extensive Froggatt, P.C., 1992. Standardization of the chemical analyses of tephra deposits. middle to late Pleistocene tephrochronologic record from east-central Alaska. Report of the ICCT working group. Quat. Int. 13e14, 93e96. Quat. Sci. Rev. 27 (3e4), 411e427. Geptner, A.P., Ponomareva, V.V., 1979. Primenenie mineralogicheskogo analiza dlya Jensen, B.J.L., Preece, S.J., Lamothe, M., Pearce, N.J.G., Froese, D.G., Westgate, J.A., korrelyatsii peplov vulkana Shiveluch. Byulleten' Vulkanol. stantsiy 56, Schaefer, J., Beget, J., 2011. The variegated (VT) tephra: a new regional marker 126e130 (in Russian). for middle to late marine isotope stage 5 across Yukon and Alaska. Quat. Int. Gorbarenko, S.A., 1991. The stratigraphy of the upper quaternary sediments in the 246, 312e323. central part of the sea of Okhotsk and its paleoceanology according to data Kaiser, A., 2001. Ozeanographie, Produktivitat€ und Meereisverbreitung im Ochot- obtained by the 18O and other methods. Oceanology 31 (6), 761e766. skischen Meer wahrend€ der letzten ca. 350 ka. Dissertation zur Erlangung des Gorbarenko, S.A., Chekhovskaya, M.P., Souhton, J.R., 1998. On the paleoenvironment Doktorgrades der Mathematisch-Naturwissenschaftlichen Fakultat der of the central part of the Sea of Okhotsk during the past Holocene glaciation. Christian-Albrechts-Universitat, Kiel, Germany (in German). Oceanology 38 (2), 277e280. Katoh, S., Yamagata, K., Okumura, A., 1995. AMS-14C dates of Late Quaternary tephra Gorbarenko, S.A., Nürnberg, D., Derkachev, A.N., Astakhov, A.S., Southon, J.R., layers erupted from the Shikotsu and Kuttara volcanoes. Jpn. Assoc. Quat. Res. Kaiser, A., 2002. Magnetostratigraphy and tephrochronology of the Upper 34 (4), 309e313 (in Japanese with English Abstract). Quaternary sediments in the Okhotsk Sea: implication of terrigenous, volca- Katoh, S., Nagaoka, S., Wolde Gabriel, G., Renne, P., Snow, M.G., Beyene, Y., Suwa, G., nogenic and biogenic matter supply. Mar. Geol. 183 (1e4), 107e129. 2000. Chronostratigraphy and correlation of the plio-pleistocene tephra layers Gorbarenko, S.A., Southon, J.R., Keigwin, L.D., Cherepanova, M.V., Gvozdeva, I.G., of the konso formation, southern main ethiopian Rift, ephiopia. Quat. Sci. Rev. 2004. Late PleistoceneeHolocene oceanographic variability in the Okhotsk Sea: 19, 1305e1317. geochemical, lithological and paleontological evidence. Palaeogeogr. Palae- Kimura, Jun-Ichi, Nagahashi, Y., Satoguchi, Y., Chang, Q., 2015. Origins of felsic oclimatol. Palaeoecol. 209 (1e4), 281e301. magmas in Japanese subduction zone: geochemical characterizations of tephra Gorbarenko, S.A., Goldberg, E.L., Kashgarian, M., Velivetskaya, T.A., Zakharkov, S.P., from caldera-forming eruptions <5 Ma. Geochem. Geophys. Geosystems. http:// Pechnikov, V.S., Bosin, A.A., Psheneva, O.Yu, Ivanova, E.D., 2007. Millennium dx.doi.org/10.1002/2015GC005854. scale environment changes of the Okhotsk Sea during last 80 kyr and their Kishimoto, H., Hasegawa, T., Nakagawa, M., Wada, K., 2009. Tephrostratigraphy and phase relationship with global climate changes. J. Oceanogr. 63, 609e623. eruption style of Mashu volcano, during the last 14 000 years, eastern Hok- Gorbarenko, S.A., Psheneva, O.Yu, Artemova, A.V., Matul, A.G., Tiedemann, R., kaido, Japan. Bull. Volcanol. Soc. Jpn. 54 (1), 15e36 (in Japanese with English Nürnberg, D., 2010. Paleoenvironment changes in the NW Okhotsk Sea for the Abstract). last 18 thousand years by micropaleontological, geochemical, and lithological Nedra, Moskva, Russia (in Russian). Klassifikatsiya Magmaticheskikh (izvergen- data. Deep-Sea Research-I 57, 797e811. nykh) porod i slovar' Terminov, 1997. Gorbarenko, S.A., Harada, N., Malakhov, M.I., Velivetskaya, T.A., Vasilenko, Y.P., Kuehn, S.C., Froese, D.G., Shane, P.A.R., 2011. The INTAV intercomparison of electron- Bosin, A.A., Derkachev, A.N., Goldberg, E.L., Ignatiev, V.A., 2012. Responses of the beam microanalysis of glass by tephrochronology laboratories: results and Okhotsk Sea environment and sedimentology on global climate changes at the recommendations. Quat. Int. 246 (1e2), 19e47. orbital and millennial scale during the last 350 kyr. Deep-Sea Research-II 61, Kuno, H., 1959. Origin of Cenozoic petrographic provinces of Japan and surrounding 73e84. areas. Bull. Volcanol. 20, 37e76. Gorbarenko, S., Chebykin, E., Goldberg, E., Stepanova, O., Lu, H., 2014. Chronicle of Kyle, P.R., Ponomareva, V.V., Schluep, R.R., 2011. Geochemical characterization of regional volcanic eruptions recorded in Okhotsk Sea sediments over the last marker tephra layers from major Holocene eruptions, Kamchatka Peninsula, 350 ka. Quat. Geochronol. 20, 29e38. Russia. Int. Geol. Rev. 53 (9), 1059e1097. Greinert, J., Bollwerk, S., Derkachev, A.N., Bohrmann, G., Suess, E., 2002. Massive Le Bas, M.J., Le Maitre, R.W., Streckeisen, A., Zanettin, B., 1986. A chemical classifi- barite deposits and carbonate mineralization in the Derugin Basin, Sea of cation of volcanic-rocks based on the total alkali-silica diagram. J. Petrology 27 Okhotsk: precipitation processes at cold seep sites. Earth Planet. Sci. Lett. 203 (3), 745e750. (1), 165e180. Levitan, M.A., Tolmacheva, A.V., Luksha, V.L., 2007. History of sedimentation in the Hamann, Y., Ehrmann, W., Schmiedl, G., Krüger, S., Stuut, J.-B., Kuhnt, T., 2008. northern sea of Okhotsk during the last 1.1 myr. Lithology Mineral Resour. 42 Sedimentation processes in the Eastern Mediterranean Sea during the Late (3), 203e220. Glacial and Holocene revealed by end-member modeling of the terrigenous Lowe, D.J., 2011. Tephrochonology and its application: a review. Quat. Geochronol. 6 fraction in marine sediments. Mar. Geol. 248 (1e2), 97e114. (2), 107e153. Hasegawa, T., Ishii, E., Nakagawa, M., 2008. Correlations of distal ash layers in the Lowe, J.J., Rasmussen, S.O., Bjorck,€ S., Hoek, W.Z., Steffensen, J.P., Walker, M.J.C., Akan pyroclastic deposits, eastern Hokkaido, with large-scale pyroclastic flow Yu, Z., INTIMATE group, 2008. Synchronization of palaeoenvironmental events deposits distributed in central Hokkaido, Japan. J. Geol. Soc. Jpn. 114, 366e381 in the North Atlantic region during the Last Termination: a revised protocol (in Japanese, with English abstract). recommended by the INTIMATE group. Quat. Sci. Rev. 27, 6e17. Hasegawa, T., Kishimoto, H., Nakagawa, M., Itoh, J., Yamamoto, T., 2009. Eruptive Machida, H., 1999. The stratigraphy, chronology and distribution of distal marker- history of post-caldera volcanoes of Kutcharo caldera, eastern Hokkaido, Japan, tephras in and around Japan. Glob. Planet. Change 21, 71e94. as inferred from tephrostratigraphy in the Konsen and Shari areas for the period Machida, H., Arai, F., 2003. Atlas of Tephra in and around Japan. University of Tokyo 35-12 ka. J. Geol. Soc. Jpn. 115 (8), 369e390 (in Japanese with English Abstract). Press, Tokyo, Japan (in Japanese). Hasegawa, T., Nakagawa, M., Yoshimoto, M., Ishizuka, Y., Hirose, W., Seki, S., Martynov, YuA., Khanchuk, A.I., Kimura, J.-I., Rybin, A.V., Martynov, A.Yu, 2010. Ponomareva, V., Rybin, A., 2011a. Tephrostratigraphy and petrological study of Geochemistry and petrogenesis of volcanic rocks in the kurile island arc. Chikurachki and Fuss volcanoes, western Paramushir Island, northern Kurile Petrology 18 (5), 489e513.

Matsumoto, A., 1996. KeAr age determinations of young volcanic rocks - correction 2015a. Tephra from andesitic Shiveluch volcano, Kamchatka, NW Pacific: for initial 40Ar/39Ar ratios and its application. Chishitsu News 501, 12e17 (in chronology of explosive eruptions and geochemical fingerprinting of volcanic Japanese with English Abstract). glass. Int. J. Earth Sci. 104, 1459e1482. Melekestsev, I.V., Glushkova, O.Yu, Kirianov, V.Yu, Lozhkin, A.V., Sulerzhitsky, L.D., Ponomareva, V., Portnyagin, M., Davies, S., 2015b. Tephra without borders: far- 1991. Proiskhozhdenie i vozrast magadanskikh vulkanicheskikh peplov. Dokl. reaching clues into past explosive eruptions. Front. Earth Sci. 3 (38) http:// Akad. Nauk. USSR 317 (5), 1188e1192 (in Russian with English Abstract). dx.doi.org/10.3389/feart.2015.00083. Melekestsev, I.V., Braitseva, O.A., Bazanova, L.I., Ponomareva, V.V., Sulerzhitsky, L.D., Portnyagin, M., Hoernle, K., Avdeiko, G., Hauff, F., Werner, R., Bindeman, I., 1996. A particular type of catastrophic explosive eruptions with reference to the Uspensky, V., Garbe-Schonberg,€ D., 2005. Transition from arc to oceanic mag- Holocene subcaldera eruptions at Khangar, Khodutka Maar, and Baraniy matism at the Kamchatka-Aleutian junction. Geology 33 (1), 25e28. Amfiteatr volcanoes in Kamchatka. J. Volcanol. Seismol. 18 (2), 135e160. Preece, S.J., Pearce, N.J.G., Westgate, J.A., Froese, D.G., Jensen, B.J.L., Perkins, W.T., Melekestsev, I.V., Volynets, O.N., Antonov, A.Yu, 1997. Nemo III caldera (Onekotan I., 2011. Old Crow tephra across eastern Beringia: a single cataclysmic eruption at the Northern Kurile): structure, 14C age, dynamics of the caldera-forming the close of Marine Isotope Stage 6. Quat. Sci. Rev. 30 (17e18), 2069e2090. eruption, evolution of juvenile products. J. Volcanol. Seismol. 19 (1), 41e64. Razzhigaeva, N.G., Ganzey, L.A., Grebennikova, T.A., Belyanina, N.I., Kuznetsov, V.Yu, Miyagi, I., Itoh, J., Hoang, N., Morishita, Y., 2012. Magma systems of the Kutcharo and Maksimov, F.E., 2011. Last interglacial climate changes and environments of the Mashu volcanoes (NE Hokkaido, Japan): petrogenesis of the medium-K trend Lesser Kuril arc, north-western Pacific. Quat. Int. 241, 35e50. and excess volative problem. J. Volcanol. Geotherm. Res. 231e232, 50e60. Razzhigaeva, N.G., Matsumoto, A., Nakagawa, M., 2016. Age, source, and distribution Mosbah, M., Metrich, N., Massiot, P., 1991. PIGME fluorine determination using a of Holocene tephra in the southern Kurile Islands: evaluation of Holocene nuclear microprobe with application to glass inclusions. Nucl. Instrum. Methods eruptive activities in the southern Kurile arc. Quat. Int. 297 (18), 63e98. Phys. Res. Sect. B 58 (2), 227e231. Reimer, P.J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk Nakagawa, M., Ishizuka, Y., Kudo, T., Yoshimoto, M., Hirose, W., Ishizaki, Y., Ramsey, C., Buck, C.E., Burr, G.S., Edwards, R.L., Friedrich, M., Grootes, P.M., Gouchi, N., Katsui, Y., Solovyow, A.W., Steinberg, G.S., Abdurakhmanov, A.I., Guilderson, T.P., Hajdas, I., Heaton, T.J., Hogg, A.G., Hughen, K.A., Kaiser, K.F., 2002. Tyatya volcano, southwestern Kuril arc: recent eruptive activity inferred Kromer, B., McCormac, F.G., Manning, S.W., Reimer, R.W., Richards, D.A., from widespread tephra. Isl. Arc 11, 236e254. Southon, J.R., Talamo, S., Turney, C.S.M., van der Plicht, J., Weyhenmeyer, C.E., Nakagawa, M., Ohba, T., 2003. Minerals in volcanic ash. 1: primary minerals and 2009. IntCal09 and Marine09 radiocarbon age calibration curves, 0-50,000 glass. Glob. Environ. Res. 6 (2), 41e51. years cal. BP. Radiocarbon 51, 1111e1150. Nakagawa, M., Ishizuka, Y., Hasegawa, T., Baba, A., Kosugi, A., 2008. Preliminary Sakamoto, T., Ikehara, M., Aoki, K., Iijima, K., Kimura, N., Nakatsuka, T., Report on Volcanological Research of KBP 2007-08 Cruise by Japanese Volca- Wakatsuchi, M., 2005. Ice-rafted debris (IRD)-based sea-ice expansion events nology group. Hokkaido University, Sapporo, Japan. during the past 100 kyrs in the Okhotsk Sea. Deep-Sea Res. 52, 2275e2301. Nakamura, Y., Nishimura, Y., Nakagawa, M., Kaistrenko, V.M., Iliev, A.Ya, 2009. Ho- Sakamoto, T., Ikehara, M., Uchida, M., Aoki, K., Shibata, Y., Kanamatsu, T., Harada, N., locene marker tephras in the coastal lowlands of kunashiri and shikotan Iijima, K., Katsuki, K., Asahi, H., Takahashi, K., Sakai, H., Kawahata, H., 2006. islands, southern kuril islands. Bull. Volcanol. Soc. Jpn. (Kazan) 54, 263e274 (in Millennial scale variations of sea-ice expansion in the southwestern part of the Japanese, with English abstract). Okhotsk Sea during the past 120 kyr: age model and ice-rafted debris in IM- Nakamura, Y., 2016. Stratigraphy, distribution, and petrographic properties of Ho- AGES CORE MD01-2412. Glob. Planet. Change 53, 58e77. locene tephras in Hokkaido, northern Japan. Quat. Int. 397 (18), 52e62. Sakhno, V.G., Bazanova, L.I., Glushkova, O.Yu, Melekestsev, I.V., Ponomareva, V.V., Newton, A.J., Dugmore, A.J., Gittings, B.M., 2007. Tephrabase: tephrochronology and Surnin, A.A., Olaf, J., 2006. Origin of Pleistocene-Holocene ashes of the Russian the development of a centralized European database. J. Quat. Sci. 22 (7), northeast based on trace and rare earth element data. Dokl. Earth Sci. 411A (9), 737e743. 1351e1356. Nürnberg, D., Tiedemann, R., 2004. Environmental change in the Sea of Okhotsk Sakhno, V.G., Derkachev, A.N., Melekestsev, I.V., Razzhigaeva, N.G., Zarubina, N.V., during the last 1.1 million years. Paleoceanography 19 (4), 1e23. PA4011. 2010. Volcanic ash in sediments of the Sea of Okhotsk: identification based on Oba, T., Irino, T., Yamamoto, M., Murayama, M., Takamura, A., Aoki, K., Kawahata, H., minor and rare earth elements. Dokl. Earth Sci. 434 (1), 1156e1163. 2006. Paleoceanographic change off central Japan since the last 144,000 years Satoguchi, Y., Nagahashi, Y., 2012. Tephrostratigraphy of the pliocene to middle based on high-resolution oxygen and carbon isotope records. Glob. Planet. Pleistocene series in honshu and Kyushu islands, Japan. Isl. Arc 21, 149e169. Changes 53, 5e20. Siebert, L., Simkin, T., 2002. Volcanoes of the World: an Illustrated Catalog of Ho- Okazaki, Y., Takahashi, K., Katsuki, K., Ono, A., Hori, J., Sakamoto, T., Uchida, M., locene Volcanoes and Their Eruptions. Smithsonian Institution. Global Volca- Shibata, Y., Ikehara, M., Aoki, A., 2005. Late Quaternary paleoceanographic nism Program, Digital Information Series, GVP-3, available at: http://www. changes in the southwestern Okhotsk Sea: evidence from geochemical, radio- volcano.si.edu/world/. larian, and diatom records. Deep-Sea Research-II 52, 2332e2350. Smith, V.C., Shane, P., Smith, I.E.M., 2002. Tephrostratigraphy and geochemical Okumura, K., 1991. Quaternary tephra studies in the Hokkaido district, northern fingerprinting of the mangaone subgroup tephra beds, okataina volcanic centre, Japan. Quat. Res. 30 (5), 379e390 (in Japanese with English Abstract). New Zealand. N. Z. J. Geol. Geophys. 45 (2), 207e219. Pearce, J.A., Cann, J.R., 1973. Tectonic setting of basic volcanic rocks determined Stuiver, M., Reimer, P.J., 1993. Extended 14C database and revised Calib3.0 14C age using trace element analyses. Earth Planet. Sci. Lett. 19, 290e300. calibration program. Radiocarbon 35, 215e230. Pearce, N.J.G., Westgate, J.A., Perkins, W.T., Preece, S.J., 2004. The application of ICP- Sun, S.S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic MS methods to tephrochronological problems. Appl. Geochem. 19, 289e322. basalts; implications for mantle composition and processes. In: Saunders, A.D., Pevzner, 2015. Holocene volcanism of Sredinny Range of Kamchatka. GEOS, Mos- Norry, M.J. (Eds.), Magmatism in the Ocean Basins. Geological Society of Lon- cow, 252 pp. (in Russian). don, London 42, pp. 313e345. Podvodny vulkanizm i zonal'nost' Kuril'skoy Ostrovnoy dugi, 1992. Nauka, Moskva, Suto, S., Inomata, T., Sasaki, H., Mukoyama, S., 2007. Data base of the volcanic ash Russia (in Russian). fall distribution map of Japan. Bull. Geol. Surv. Jpn. 58 (9/10), 261e321 (in Ponomareva, V.V., Kyle, P.R., Melekestsev, I.V., Rinkleff, P.G., Dirksen, O.V., Japanese with English Abstract). Sulerzhitsky, L.D., Zaretskaia, N.E., Rourke, R., 2004. The 7600 (14C) year BR Tomlinson, E.L., Kinvig, H.S., Smith, V.C., Blundy, J.D., Gottsmann, J., Müller, W., Kurile Lake caldera-forming eruption, Kamchatka, Russia: stratigraphy and field Menzies, M.A., 2012. The Upper and Lower Nisyros Pumices: Revisions to the relationships. J. Volcanol. Geotherm. Res. 136 (3), 199e222. Mediterranean tephrostratigraphic record based on micron-beam glass Ponomareva, V., Melekestsev, I., Braitseva, O., Churikova, T., Pevzner, M., geochemistry. J. Volcanol. Geotherm. Res. 243e244, 69e80. Sulerzhitsky, L., 2007. Late pleistocene-holocene volcanism on the Kamchatka Volynets, O.N., 1994. Geochemical types, petrology, and genesis of Late Cenozoic peninsula, northwest pacific region. In: Eichelberger, J., Gordeev, E., Izbekov, P., volcanic rocks from the Kurile-Kamchatka island-arc systems. Int. Geol. Rev. 36 Kasahara, M., Lees, J. (Eds.), Volcanism and Subduction: the Kamchatka Region. (4), 373e405. American Geophysical Union, pp. 165e198. AGU Geophysical Monograph Series Volynets, O.N., Avdeyko, G.P., Tsvetkov, A.A., Antonov, A.Yu, Markov, I.A., 172. Filosofova, T.M., 1990. Mineral zoning in the quaternary lavas of the kurile is- Ponomareva, V., Portnyagin, M., Derkachev, A., Juschus, O., Garbe-Schonberg,€ D., land arc. Int. Geol. Rev. 32 (2), 128e142. Nürnberg, D., 2013a. Identification of a widespread Kamchatkan tephra: a Yamamoto, T., Itho, J., Nakagawa, M., Hasegawa, T., Kishimoto, H., 2010. 14C ages for middle Pleistocene tie-point between Arctic and Pacific paleoclimatic records. the ejecta from Kutcharo and Mashu calderas, eastern Hokkaido, Japan. Bull. Geophys. Res. Lett. 40 (14), 3538e3543. Geol. Surv. Jpn. 61 (5/6), 161e170 (in Japanese with English Abstract). Ponomareva, V., Portnyagin, M., Derkachev, A., Pendea, I., Bourgeois, J., Reimer, P., Zaretskaya, N.E., Ponomareva, V.V., Sulerzhitsky, L.D., Dirksen, O.V., 2001. Radio- Garbe-Schonberg,€ D., Krasheninnikov, S., Nürnberg, D., 2013b. Early Holocene carbon dating of the Kurile Lake caldera eruption (south Kamchatka, Russia). M~6 explosive eruption from Plosky volcanic massif (Kamchatka) and its tephra Geochronometria 20, 95e102. as a link between terrestrial and marine paleoenvironmental records. Int. J. Zaretskaya, N.E., Ponomareva, V.V., Sulerzhitsky, L.D., 2007. Radiocarbon dating of Earth Sci. 102 (6), 1673e1699. large Holocene volcanic events within south Kamchatka (Russian far east). Ponomareva, V., Portnyagin, M., Pevzner, M., Blaauw, M., Kyle, Ph, Derkachev, A., Radiocarbon 49 (2), 1065e1078.