Nakano, S., and Yamamoto, T. (1991). Science 163, 926–927. Additional trace elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), using a Thermo Fisher Scientific X-series II at the Graduate School of Science and Technology, Tokyo Institute of Technology, and a Thermo Fisher Scientific X-series instrument at the Graduate School of Science, Hokkaido University, using the methods described in Yokoyama et al. No use, distribution or reproduction is permitted which does not comply with these terms. The estimates of the individual opx–cpx pairs are represented by the gray plots and the averages with 1σ bars of each stage are represented by the black plots. (2016) and Lu et al. Immer wieder tauchen auf Google Maps die kuriosesten Dinge auf. doi: 10.1016/j.lithos.2008.12.012, Kuritani, T., Kimura, J.-I., Ohtani, E., Miyamoto, H., and Furuyama, K. (2013). Considering that the data of the Group-B2 aphyric samples form a linear trend from low-PC1 and high-PC2 compositions to high-PC1 and low-PC2 compositions, one magmatic process is considered to be crystal differentiation (i.e., fractionation of plagioclase and mafic minerals) of crystal-poor magmas (Figure 8C). Figure 5 shows Harker variation diagrams for some major oxides (TiO2, Al2O3, Fe2O3∗, MgO, CaO, and K2O) plotted against the SiO2 content. The main magmas can remain crystal-poor during the differentiation because compositional evolution proceeds through mixing of the melt. TABLE 2. Izu Ōshima Izu Ōshima is in Japan. 57, 1223–1240. 29, 91–95. Anal. Misonou, Y., Takahashi, M., Yasui, M., and Hayashida, K. (2005). Concomitant separation of strontium and samarium-neodymium for isotopic analysis in silicate samples, based on specific extraction chromatography. This is consistent with the essentially homogeneous 87Sr/86Sr and 143Nd/144Nd ratios of the YOG samples, including those of the basalts and basaltic andesites (Figures 6E,F). J. After the Y1 eruption, relatively large-scale eruptions (in the order of 105–106 m3 of eruption volume) occurred in 1876–77, 1912–14, 1950–51, and 1986–87. FIGURE 9. MAGMA 92, 21–39. Jpn. Find local businesses, view maps and get driving directions in Google Maps. Mineral. Volcano-stratigraphic study of Oshima Volcano, Izu. For whole-rock analysis, rock specimens were crushed to coarse chips 3–5 mm in diameter. 110, 355–369. Nakamura, K. (1964). The sample symbols are identical to those used in Figure 5. (via @g.g.t.m_cynthiaa) . doi: 10.1016/0003-2670(94)00274-6, Pin, C., and Zalduegui, J. F. S. (1997). Bull. Received: 25 July 2018; Accepted: 10 October 2018;Published: 30 October 2018. Data other than those obtained in this study are taken from Ishizuka et al. Zielgenau wird der Hafen angesteuert. However, the composition of the possible aphyric end-member magma for 1986–87a (filled star in Figure 10) was less differentiated than those of Y1L. J. Glass beads were prepared by fusion with an alkali flux (2:1 sample dilution) consisting of a 4:1 mixture of lithium tetraborate and lithium metaborate. Sci. 60, 5–40. A., Kimura, J.-I., and Barmina, G. S. (2013). The volcanic activities of recent eruptions, including those in 1777–78, 1950–51, and 1986–87, were triggered by the injection of porphyritic magmas into the magma chamber at 8–10 km depth. 100, 2172–2184. The high absolute value for Na2O (but opposite sign to those for MgO and Fe2O3∗) can also be explained by the fact that Na is an incompatible element during the crystallization of mafic minerals. J. Mineral. These scoria-fall eruptions were followed by an effusion of lava flows from craters on the caldera floor (Y1L in Figure 1). Petrology of the lavas and ejecta of the November 1986 eruption of Izu-Oshima volcano (in Japanese with English abstract). Sci. Jpn. For a better understanding of the recent basaltic magma plumbing system, we collected plenty of samples for products of the recent eruptions (Y1Ca, Y1Cb, Y1L, 1950–51, and 1986–87a) to determine the compositional variability of each eruption stage. Geoanal. Mass fractionation factors for Sr and Nd were internally corrected using 86Sr/88Sr = 0.1194 and 146Nd/144Nd = 0.7219, respectively. Fujii et al. To help elucidate the current and future state of the volcano’s magma system, the temporal evolution of the recent magma plumbing system was investigated through a petrological and geochemical analysis of its basaltic lavas and pyroclastics (<∼53 wt.% of SiO2) that were erupted during the last ∼1.5 kyr. Available at: http://www.data.jma.go.jp/svd/vois/data/tokyo/STOCK/kaisetsu/CCPVE/izu/izu-01.pdf, Mikada, H., Watanabe, H., and Sakashita, S. (1997). How has the magma plumbing system evolved, in particular, in recent volcanic history? The Group B1 samples have relatively higher Al2O3 contents compared with the Group B2 samples (Figure 8A). What processes have been responsible for forming the basaltic products with variable compositions and phenocryst contents? The data can be largely divided into those with basaltic compositions (<∼53 wt.%) and those with basaltic andesitic compositions (>∼53 wt.%). Hamada, M. (2016). The whole-rock major and trace elements and Sr and Nd isotopic ratios of the YOG samples (S2, N4, N3, N1, Y5, Y4, Y3, Y2, Y1Ca, Y1Cb, Y1L, 1950–51, 1986–87a, and 1986–87b) are listed in Supplementary Table S1. Some phenocrysts are homogeneous or normally zoned in terms of Mg# [100 × Mg/(Mg + Fe)], while others rarely show reverse zoning. The distributions of the products of the S1, N2, Y6, Y1Ca, 1876–1877, and 1912–1914 eruptions are not shown because those of S1, N2, and Y6 mainly occur as scoria fall deposits, those of Y1Ca are entirely covered by those of Y1Cb, and those of the 1876–1877 and 1912–1914 eruptions were mainly ejected inside the summit crater of Mt. The scattered compositional diversity would have been established by polybaric fractional crystallization with variable melt water contents (e.g., Almeev et al., 2013). Here are 17 mysterious shipwrecks you can see on Google Earth. Japan: a guide to magma chamber volume. (2015). In the 1986–87b samples, the An content of plagioclase phenocrysts is positively correlated with the Mg# of clinopyroxene phenocrysts, with few outlying data. Concentrations of whole-rock major elements and some trace elements (Sc, V, Cr, Co, Ni, Rb, Sr, Y, Zr, and Ba) were obtained by XRF spectrometry using a Rigaku RIX 2100 at the Graduate School of Science, Osaka City University (Suda et al., 2010, 2011), and a Spectoris MagiX PRO at the Graduate School of Science, Hokkaido University. We suggest that this observation is attributed to the progressive evolution of the aphyric magmas in the 8–10 km-deep magma chamber after caldera formation (Figure 10). Kawanabe, Y. Some products from N3, S2, and Y5 also have basaltic andesitic compositions. Am. The magma plumbing system, consisting of shallower and deeper magma chambers, is similar to that of the Miyake-jima volcano located near the Izu-Oshima volcano in the Izu arc (Amma-Miyasaka and Nakagawa, 2003; Kuritani et al., 2003). Petrological constraints on the magma plumbing system of Izu-Oshima Volcano. Because the data are distributed to the lower-PC1 side of the linear trend formed by the Group-B2 samples, the other process would be either plagioclase accumulation or mixing of plagioclase-rich magmas. (2015). (1998). In this case, the injection of relatively large amounts of primitive magma would have been required to change the compositions of the aphyric end-member magmas (i.e., from the filled star to the open star in Figure 10) during the interval between 1951 and 1986. SiO2 variation diagrams for (A) Ni, (B) Sr, (C) Zr, (D) Ba, (E) 87Sr/86Sr, and (F) 143Nd/144Nd measured in samples from the Younger Oshima Group. Impact Factor 2.689 | CiteScore 3.3More on impact ›, University of California, San Diego, United States, Natural History Museum (United Kingdom), United Kingdom. Mihara, and their products were ejected mainly inside the crater. Res. The eigenvalues of PC1 and PC2 exceed 1; therefore, only these two components are significant. doi: 10.2465/jmps.090825, Pin, C., Briot, D., Bassin, C., and Poitrasson, F. (1994). Doch wieso liegt es da und wie kann es sein, dass es bisher nicht entdeckt wurde? The trace element concentrations of primitive mantle are from Sun and McDonough (1989). Mineral. 263, 182–192. It is expected that the injection would have triggered an eruption of aphyric magmas from the 8–10 km-deep magma chamber. The phenocryst-rich Y1Ca, Y1Cb, 1950–51, and 1986–87a magmas, produced by mixing of the porphyritic and aphyric magmas, erupted from the summit crater of the volcano (Figures 11C,D). *Correspondence: Takeshi Kuritani, kuritani@sci.hokudai.ac.jp, Front. Petrol. It has been suggested that the recent magma plumbing system for the main basaltic magmas consists of a magma chamber located at 8–10 km depth (estimated by an analysis of seismic waveforms by Mikada et al., 1997) and a deeper magma chamber (Meteorological Agency, 2008). The plagioclase-melt thermometer of Waters and Lange (2015) with a melt water content of 5 wt.% (Hamada et al., 2011) yields the crystallization temperature of the plagioclase phenocrysts of 890–910°C at 4.4–6.1 kbar, which is much lower than the estimates of 1050–1100°C (Figure 9). Geology of the Oshima District. TK, AY, SF, AM, and TY carried out the analyses. MAGMA 93, 19–32. Based on the petrological analysis and previous geophysical studies, we propose that the main magma plumbing system consisted of magma chambers located at, most plausibly, 13–18 km depth and 8–10 km depth. So auch in diesem Fall vor der japanischen Küste. Plagioclase phenocrysts, up to 3 mm in length, are commonly euhedral. Shift and rotation of composition trends by magma mixing: 1983 eruption at Miyake-jima Volcano, Japan. those with higher abundance of plagioclase phenocrysts (Table 1) have higher Al2O3 contents. Ebenfalls im Meer wurde auch diese unglaubliche Entdeckung gemacht. The scoria fall deposits can be divided into the lower “A spatter layer” and upper “B spatter layer,” with distinct whole-rock compositions (Misonou et al., 2005), which are referred to as “Y1Ca” and “Y1Cb,” respectively, in this study. Because PC1 and PC2 represent 65 and 20% of the variance, respectively (Table 2), Figure 8C represents 85% of the observed variability in the data. Phenocryst contents of the representative samples of the Younger Oshima Group. The temporal evolution of the magma plumbing system for the YOG is summarized in Figure 11. Altair off Brazil (Image credit: Google) The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (1988) suggested that primary magma has not been supplied from the source mantle to the crustal levels since the caldera formation at 1.3–1.5 ka, on the basis of the observation that the YOG products tend to evolve progressively over time. Mineral compositions were determined using a JEOL JXA-8800 electron microprobe, located at the Graduate School of Science, Hokkaido University. Petrological and geochemical studies have been conducted, in particular, on the products of the 1986–87 eruption. Because recent eruptions have been triggered by the ascent of porphyritic magma from the 13–18 km-deep magma chamber, and its injection into the 8–10 km-deep magma chamber, it is important to monitor the deeper magma chamber to predict future volcanic activity. Estimating proportions in petrographic mixing equations by least-squares approximation. The application of principal component analysis on the whole-rock major element data suggests that one magmatic process was crystal fractionation of crystal-poor magmas, and the other process was either plagioclase accumulation or mixing of plagioclase-rich magmas. . Petrol. Petrological evolution of Izu Oshima volcano (in Japanese with English abstract). At the Y1 and later eruption stages, porphyritic magmas stored in the deeper magma chamber played more important roles. Street View. Mit seinem originellen Heiratsantrag auf Google Maps beeindruckte ein Mann nicht nur seine Freundin, sondern auch Menschen auf der ganzen Welt. The compositional variations in the basalts resulted from the mixing of the differentiating aphyric magmas with variable proportions of the porphyritic magmas, derived from the 13–18 km-deep magma chamber. 32, 345–350. doi: 10.1016/j.epsl.2015.08.004. Petrol. Oshima Island. (1969). More than 30 years have passed since the last eruptions in 1986–1987, and the crystal-poor magmas in the 8–10 km-deep magma chamber are expected to have evolved since the last eruption. “Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes,” in Magmatism in the Ocean Basins, Vol. By integrating the results of the preceding petrological and geophysical studies, Meteorological Agency (2008) proposed that the recent magma plumbing system at the Izu-Oshima volcano comprises a main magma chamber located at 8–10 km depth and small magma chambers at 4–5 km depth, and new magmas have been supplied to the main magma chamber from a deeper magma chamber. 69, 61–120. Therefore, it is important to monitor the discharge of porphyritic magma from the magma chamber located at 13–18 km depth to predict future eruptions of the Izu-Oshima volcano. Doch die Frage, die sich nach wie vor stellt: Wie kam das Schiff dort hin und war es beabsichtigt, es genau im Hafenbecken sinken zu lassen? Mihara (scoria cone). Both oxide and natural mineral standards (quartz, rutile, corundum, hematite, manganosite, periclase, wollastonite, jadeite, K-feldspar, and eskolaite) were used, and data were obtained using the ZAF correction method. They also showed that the plagioclase phenocrysts equilibrated with melt at different depths: at the near surface level, at ∼4 km depth, and at 8–10 km depth. Earthquake Res. Relationship between the Mg# of clinopyroxene phenocrysts and An content of coexisting plagioclase phenocrysts in 1950–51, 1986–87a, and 1986–87b products. Although the aphyric end-member magmas for the 1950–51 eruptions did not erupt, the possible compositions of the end-member magmas (open star in Figure 10) are more differentiated compared with those of Y1L. 104, 257–269. An index map showing the location of the Izu-Oshima volcano, and a geological map of the volcano (after Kawanabe, 1998). Nakano and Yamamoto (1991) suggested that the plagioclase-phyric high-Al2O3 magmas erupted in the past 200 years, including those from the A crater in the 1986–87 eruption, were produced by the accumulation of plagioclase in a magma chamber. Anal. Fujii et al. The Mg# contents of the phenocryst cores commonly range from 65 to 75, and those of the rims are as low as ∼60. The whole-rock compositions are significantly scattered in the Harker variation diagrams, suggesting that the compositional diversity was established by at least two independent magmatic processes. We show that compositional variations in the basalts resulted from mixing of differentiating aphyric magmas in a shallower magma chamber with variable proportions of porphyritic magmas derived from a deeper magma chamber, and propose a new scenario for the recent magma plumbing system at Izu-Oshima. The whole-rock compositions of the basaltic samples are scattered at a given SiO2 content in the Harker variation diagrams (Figures 5, 6), which should reflect complex magmatic processes and their temporal evolution beneath the volcano. FIGURE 7. Therefore, the compositional diversity of the basalts was established primarily by crystal fractionation and/or magma mixing. FIGURE 1. Products of the younger syn- and post-caldera volcanism (Younger Oshima Group; YOG) consist of the Sashikiji Formation (S1 and S2), Nomashi Formation (N1–N4), and Yuba Formation (Y1–Y6) (Figure 1). The compositions of these aphyric samples change systematically from low-PC1 and high-PC2 compositions to high-PC1 and low-PC2 compositions as the eruption ages progress from the S and N stages through the Y2–6 stages to the Y1 stage (Figure 8C). Zeugen überraschen mit neuen Details, Übergroßes Tier aus Kanalisation geborgen: Arbeiter und Passanten bei Anblick im ersten Moment wie versteinert, Corona in Deutschland: Alarmierende Zahlen aus NRW - 1700 Menschen nach privater Feier in Quarantäne, Google Maps das Missgeschick eines Paketboten, irre Entdeckung bei Google Earth erscheint in Corona-Zeiten. Report on Volcanic Activity of Izu-Oshima (Eruption Scenario of Izu-Oshima), the Coordination Committee for Prediction of Volcanic Eruption. The compositions of the aphyric magmas (<3 vol.% phenocrysts), stored in the 8–10 km-deep magma chamber, show a tight negative trend in the PC1–PC2 diagram (Figure 8D), which can be explained by the fractionation of plagioclase and mafic minerals, as discussed previously. Suda, Y., Koizumi, N., and Okudaira, T. (2011). 236, 13–26. Mihara. As discussed above, the YOG basalts were derived from a single parental magma, and the essentially homogeneous 87Sr/86Sr and 143Nd/144Nd ratios of the basalts suggests that crustal assimilation did not significantly occur. The data can be divided into two groups: Group A with lower PC1 and PC2, consisting mainly of Y1Cb; and Group B with higher PC1 and PC2. (2014) examined the compositional variations of melt for all volcanic activity at Izu-Oshima, and found that the melt compositions fall within the area comprised between higher- and lower-Al/Si trends in compositional variation diagrams. 91, 41–54. In addition, the mixing of the fractionated interstitial melt from the mush zone suppresses the crystallization of the main magma, due to the effect of the liquidus depression (Kuritani, 2009). The Izu-Oshima volcano, located on the volcanic front of the Izu arc (Figure 1), is one of the most active volcanoes in Japan, and younger volcanism (<∼1.5 ka) has produced mainly basaltic magmas with minor basaltic andesitic magmas. 41, 221–242. However, fundamental questions still remain unsolved about the main basaltic magma system: Where is the deeper magma chamber located? Result of the principal component analysis. Oder wurde es vielleicht doch entdeckt? Fujii et al. Solidification fronts and magmatic evolution. The Group B2 samples are considered to represent aphyric end-member magmas with compositional diversity produced by fractional crystallization, and the Group A samples would have been magmas with a relatively high proportion of the porphyritic end-member magmas. (2015). Figure 4 shows the relationship between the Mg# of clinopyroxene phenocrysts and An content of the coexisting plagioclase phenocrysts (i.e., the clinopyroxene and the plagioclase showing evidence of contemporaneous growth) in products from recent eruptions (1950–51 and 1986–87) (Figure 2).