Basaltic andesite

Eastern Manus Basin Desmos cauldron (3 42 S, 151°52 E) 2000 Caldera of basalt/basaltic andesite at an intersection of a spreading center and a transform fault Sulfide ores were not recovered. Megaplume-like methane anomalies in water column over the caldera. Ferruginous oxide deposits. Pyrite and native sulfur disseminated in basaltic andesite. 

Western Woodlaik Basin Franklin Seamount (9°55 S, 151L50 W) 2143-2366 Westernmost propagating tip of spreading center. Basaltic andesite and inferred sodic rhyolite. Spires aud mounds of Fe-Mn-Si oxide up to several meters thick and 200 m in extent. Venting 20-30 C clear solution. Inactive barite silica chimneys contain up to 21 ppm Au. vSi-bearing Fe oxyhydroxide. 

A few REE data on hydrothermal solutions are available (Fig. 2.34). Chondrite normalized REE patterns of hydrothermal solutions from Vienna Wood, Pacmanus and Desmos, Manus Basin exhibit positive Eu anomaly and LREE enrichment are similar to midoceanic ridge solution and Kuroko ore fluids. This positive Eu anomaly (Fig. 2.35) may have been caused by the selective leaking of Eu due to the interaction of an ascending hydrothermal solution and footwall volcanic rocks (Gena et al., 2001). It is interesting to note that altered basaltic andesite has a negative Eu anomaly and this feature is the same as that found in the Kuroko mine area (Shikazono, 1999). 

Gena et al. (2001) reported advanced argillic alteration of basaltic andesite from the Desmos caldera, Manus back-arc basin which was caused by interaction of hot acid hydrothermal fluid originated from a mixing of magmatic gas and seawater. It is noteworthy that the acid alteration is found in back-arc basins (Manus, Kuroko area) but not in midoceanic ridges. 

Grove TL, Parman SW, Bowring SA, Price RC, Baker MB (2002) The role of an H20-rieh fluid eomponent in the generation of primitive basaltic andesites and andesites from the Mt. Shasta region, N. California. Contrib Mineral Petrol 142 375-396... 

Sigmarsson O, Chmeleff J, Morris J, Lopez-Escobar L (2002) Origin of Tla- °Th disequilibria in arc lavas from southern Chile and magma transfer time. Earth Planet Sci Lett 196 189-196 Sisson TW, Layne GD (1993) H2O in basalt and basaltic andesite inclusions from four subduction-related volcanoes. Earth Planet Sci Lett 117 619-635... 

In chernozems formed on serpentinite diluvium, Co content is in the range of 10-30 mg/kg, while in chestnut and chestnut vertic soils, Co concentrations vary from 3-15 and 15-45 mg/kg, respectively. Soils on basalt, andesite and gabbro contain 15-68 mg/kg total Cu. Total Mn in chernozems is in the range of 520-850 mg/kg. Chestnut soils have 42-106 mg/kg Zn content. Total Zn in saline alkali soils is in the range of 40-60 mg/kg Zn. Bioavailable Zn (ammonium acetate-extractable Zn) in chernozems, chestnut soils and saline alkali soils of the steppe zones varies from trace amounts to 3.8 mg/kg (1-8.3% of total Zn). In chernozems of Northern Bulgaria, total B is in the range of 25-53 mg/kg. Boron increases in saline soils and saline alkali soils. 

Bulk rock geochemistry of the Lac Cinquante deposit shows that the Archean volcanic rocks (both the mafic volcanic flows and the bimodal volcanic suite) are dominantly tholeiitic high-Fe basalts and basaltic andesites. The alternating felsic units in the bimodal suite are dacitic and rhyolitic in composition (Fig. 2). 

The first studies of Li isotopes in subduction zones concentrated on young convergent margin lavas. Moriguti and Nakamura (1998b) reported correlated Li isotope and fluid-mobile element (notably boron) concentration variations in the Izu arc, southeastern Japan (8 Li = +1.1 to +7.6), consistent with significant incorporation of Li from altered oceanic crust into arc lava sources (Fig. 6). A similar trend has been reported in samples of basalts and basaltic andesites from Mt. Shasta, California (5 Li = +2.5 to +6.5 Magna et al. 2003). 

Augite (Ca,Mg,Fe,Al)2(Si,Al)206 Basalts, andesites, tephrites, limburgites gabbros, dolerites, ultramafic rocks. Sometimes in granites... 

Upper member dacite-rbyodacite-rhyolile end IgmI basaltic andesite (transiUonai to catc-alkaline)... 

Although ore zones are stacked in the stratigraphy, the main ore lenses are located along a key horizon at the contact between two distinct rhyolites and a basaltic-andesite unit ... 

Moore, G.M. Carmichael, I.S.E. 1998. The hydrous phase equilibria (to 3kbar) of an andesite and basaltic andesite from western Mexico constraints on water content and conditions of phenocrysts growth. Contributions to Mineralogy and Petrology, 130, 304-319. 

They have diameters of 2 to more than 8 cm. The substratum of the nodules is shark teeth, basalts, andesites, and more rare varieties of weathered volcanic rocks. 

Alkalis versus silica diagram used for geochemical classification of volcanic rocks. Martian meteorites, Gusev crater rocks and soils analyzed by the Spirit rover, and Bounce Rock analyzed by the Opportunity rover generally plot in the field of basalts, as does the average Mars Odyssey GRS analysis. Compositions derived from TES spectra (Surface Types 1 and 2) and the Mars Pathfinder dust-free rock plot in the basaltic andesite and andesite fields. After McSween et at. (2009). 

Basalt, andesite LA-ICP-MS, Elan 6000 (solution based calibration) 27 0.0006 pLgg-1 (U) Pickhardt et al.8... 

Basaltic andesites to andesites (subduction zone, Northeastern Japan, 4 samples)... 

Basalts (subduction zone, Klychevskoi Volcano, Kamchatka, Russia) Basalts (subduction zone, Simcoe, Washington, USA, 2 samples) Basalts (subduction zone, Tolbachik Volcano, Kamchatka, Russia) Basalts to basaltic andesites (subduction zone, Central America, 19 samples)... 

Aeolian arc (1 or 0.4 Ma to Present) Alicudi (0.06-0.03), Filicudi (1( )-0.04), Salma (0.4-0.013), Vulcano (0.12-1888 AD), Lipari (0.2-580 AD), Panarea (0.15-0.05), Strombo-li (0.2 — Present) - Stratovolcanoes with dominant calc-alkaline (basalt-andesite-rhyolite) and shoshonitic (basalt to rhyolite) compositions, with a few potassic alkaline products. 

The volcanoes in the Campania Province, Pontine Islands and Vulture are composed of a wide variety of magma types. Silica undersaturated ultrapo-tassic volcanism is restricted to Somma-Vesuvio, whereas mildly undersaturated to oversaturated potassic rocks occur at Campi Flegrei, Ischia, Procida and Ventotene. In the latter two islands, low potassium compositions close to calc-alkaline basalts are found among lavas and lithic ejecta. Pliocene calc-alkaline rocks are found as rhyolites at Ponza and as basalts and basaltic andesites beneath the Campanian Plain. At Vulture, volcanism is highly enriched in both Na and K, a composition that is distinct from any other volcano in the Italian peninsula. 

The Vulture, Campania and Pontine volcanoes are characterised by magmas that vary from calc-alkaline to ultrapotassic compositions. Calc-alkaline rocks occur as rhyolites at onza and as basalt to basaltic andesites beneath the Campanian plain. Both these occurrences are older than the potassic and ultrapotassic magmas, indicating an overall time-related increase in potassium on a regional basis. 

Lipari 220 ka to 580 AD - Multicenter volcano formed of calc-alkaline and high-K calc-alkaline basaltic andesite and andesite, followed by latite and abundant rhyolite lava flows, domes and pyroclastic rocks. 

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