B basalt

From Calas Petiau (1983) B = basaltic glass G = granitic glass... 

Figure 20 Relationship between Si fluxes and runoff from watersheds draining (a) granitic and (b) basaltic...

Titanium is a common constituent of rocks, in concentrations from 0.3 to 14gkg b Basalts and gabbros are rich in titanium... 

Fig. 16.3 The alkali-rich volcanic rocks of the Erebus volcanic province are classified on the total alkali-silica diagram of Le Bas et al. (1986). The rocks in this diagram can be arranged into three series with decreasing alkali content (1) Basanite (Bn), tephrite (Tp), phonotephrite (Ptp), tephriphonolite (Tpp), and phonolite (P) (2) Hawaiite (H), mugearite (M), benmoreite (Bm), and trachyte (T) (3) Basalt (B), basaltic andesite (Ba), andesite (A), and dacite (D). The boundary between the alkali-rich and subalkalic rocks defined by Macdonald and Katsura (1964) is shown as a dashed line (Adapted from LeMasurier (1990) and Wilson (1989))...

B - basalt aggregate, L -limestone aggregate, H -HAREX fibres, 0.0%, 0.7%, 1.3% - fibres volumetric fraction. 

B- basalt aggregate, L- limestone aggregate, H- HAREX fibres. 

Abbr. f-fine(0-.5 mm), c-coarse(l-2.5 mm), s-standard, b-basalt, q-quartz, 12,30,60-average volume amount... 

Figure 1.33. Frequency (number of analyses) histogram for Fc203 (wt%) of epidote from the Kuroko basalt. A epidote coexisting with albite, B epidote coexisting with chlorite, C epidote coexisting with pyrite, D epidote coexisting with hematite and calcite (Shikazono et al., 1995).

Figure 1.34. Frequency histogram for MgO/FeO ratios (in wt%) of chlorite from the basalt studied (A) and MORE (B). Data sources are Shikazono and Kawahata (1987), Humphris and Thompson (1978) (M Mid-Atlantic Ridge) and Kawahata (1984) (C Costa Rica Rift, Galapagos Spreading Centre). The data on chlorite from MORE are taken from typical metabasalt and not from quartz-chlorite breccia and veins which formed in a hydrothermal upflow zone (Shikazono et al., 1987).

Figure 1.46. REE patterns of the altered volcanogenic rocks and Kuroko ores. Data sources Shikazono (1999a). (A) Hydrothermally altered dacite and anhydrite underlying the Kuroko ores. (B) Barite, Kuroko ore and ferruginous chert. (C) Hydrothermally altered basalt overlying the Kuroko ores (Shikazono, 1999a).

Figure 1.47. REE patterns of the fresh volcanic rocks in the Kuroko mine area. Data source Dudis et al. (1983). (a) basalt (b) acidic rocks (Shikazono, 1999a).

Figure 1.164. Distribution of Cenozoic basalts and active rift systems in the northeast China region. Arrows indicate the horizontal convective current in the upper mantle associated with the upwelling of the asthenosphere beneath the region. A Baikal Rift B Shanxi Graben C Tancheng-Lujiang Fault D Okinawa Trough (Tatsumi et al., 1990).

Fig. 2.34. (A) Chondrite-normalized REE pattern of fresh basaltic andesite. (B) Chondrite-normalized REE pattern of altered basaltic andesite. (C) Ratios of REE content in the altered rock normalized to the fresh basaltic andesite (298-R-02). The dashed line is the ratio line of one. (D) Chondrite-normalized REE patterns of hydrothermal fluids from Vienna Wood, Pacmanus and Desmos, Tamagawa and Kusatsu-Yubatake (Gena et al., 2001).

It is shown in Fig. 2.57 that the lead isotopic variation of the Besshi-subtype is similar to that of midoceanic ridge basalt, suggesting the lead in the Besshi-subtype was derived from mantle. The data from the Shimokawa, and Yanahara deposits (Group B) are slightly more radiogenic than Group A, suggesting that crustal lead was involved in the formation of the Shimokawa deposit, and lead isotopic values for the Shimokawa and Yanahara plot between MORB and Cretaceous-Tertiary deposits in Japan (Kuroko, skarn, vein-type deposits). 

Watanabe et al. (1993) have determined a whole rock isochron age of 107 15 Ma (yi b = 1.42 X 10 Vy) for well-preserved pillowed basalts in Western Shikoku with their basalt initial ratio of 0.70401. 

The studies on the hydrothermal systems at midoceanic ridges during the last three decades clearly revealed that the seawater-basalt interaction at elevated temperatmes (ca. 100-400°C) affects the present-day seawater chemistry (Wolery and Sleep, 1976 Edmond et al., 1979 Humphris and Thompson, 1978). For example, a large quantity of Mg in seawater is taken from seawater interacting with midoceanic ridge basalt, whereas Ca, K, Rb, Li, Ba and Si are leached from basalt and are removed to seawater (Edmond et al., 1979 Von Dammet al., 1985a,b). 

Fig. 3.2. (a) The relationship between MgO and CaO contents of basaltic rocks and of (b) dacitic rocks from the Green tuff region in Japan (Shikazono, 1994). 

Boron concentrations and isotopes are also useful geochemical tracers of contamination in MORB. Boron concentrations are low (<2 ppm) in unaltered ocean floor basalt but high in altered basalts (>8 ppm B) (Spivack and Edmond 1987 Ryan and Langmuir 1993). Goldstein et al. (1989) measured B concentrations in their samples and found them to be less than 1.6 ppm, inconsistent with contamination. More recently, B isotopes have been used to assess contamination since large differences in 5 B are known to exist between seawater, sediments, and unaltered MORB. Sims et al. (2002) reported that 6 B for their 9°N EPR samples were inconsistent with incorporation of any seawater or seawater-derived material. 

Bourdon B, Sims KWW (2003)U-series constraints on intraplate basaltic magmatism. Rev Mineral Geochem 52 215-254... 

Landwehr D, Blundy J, Chamorro-Perez E, HiU E, Wood B (2001) U-series disequilibria generated by partial melting of spinel Iherzolite. Earth Planet Sci Leh 188 329-348 Langmuir CH, Hanson GN (1980) An evaluation of major element heterogeneity in the manhe sources of basalts. Phil Trans R Soc London A 297 383-407... 

Vigier N, Bourdon B, Joron J-L, Allegre CJ (1999) U-Th-Ra disequilibria in Ardoukoba tholeiitic basalts (Asal rift) timescales of ciystallization. Earth Planet Sci Lett 174 81-98 Watson S, McKenzie D (1991) Melt generation by plumes a study of Hawaiian volcanism. J Petrol 32 501-537... 

Staudigel H, Plank T, White B, Schmincke H-U (1996) Geochemical fluxes during seafloor alteration of the basaltic upper oceanic crust DSDP Sites 417 and 418. In Subduction Top to Bottom. Bebout GE, Scholl DW, Kirby SH, Platt JP(eds), AGU, Washington DC, p 19-37 Suman DO, Bacon MP (1989) Variations in Holocene sedimentation in the North American Basin determined by °Th measurements. Deep Sea Res 36 869-787... 

---