Intermediate rocks

Elemental bundance of intermediate rocks in China is average of dioritoids and andesitoids Elemental bundance of metapelite in the eastern part of China is average of slate, phylite and micaceous schist. 

ABSTRACT A geochemical analysis of major, trace and rare earth elements was carried out in beach sands collected from the Northeastern coast of Mexico in order to observe the spatial trends along three different beaches. Results show that major elements patterns along the beaches are controlled by heavy minerals and plutonic and sedimentary input towards the coast. In addition, trace elements tendencies indicate that the beach sands are influenced by the presence of magnetite. Finally, the differences in Eu anomalies indicate a mix of felsic to mafic and intermediate rocks and feldspar weathering. 

Granodiorite An intrusive intermediate rock with a composition between that of a granite and a diorite. 

This is divided into a western, a central and an eastern sector. The western Aeolian arc (Alicudi, Filicudi, Salina) consists of calc-alkaline rocks with typical island arc signatures. Mafic and intermediate rocks dominate the volcanic sequence, with minor silicic volcanics. The central islands (Vul-cano and Lipari) are dominated by calc-alkaline to shoshonitic mafic to silicic rocks mafic rocks from this sector show isotopic compositions and incompatible trace element ratios similar to the western islands. The eastern arc (Panarea and Stromboli) consists of calc-alkaline to potassic alkaline rocks. Stromboli shows geochemical and isotopic signatures akin to the Neapolitan volcanoes. The Island of Panarea, located between Stromboli and Lipari, has intermediate characteristics between these two volcanoes (Calanchi et al. 2002a). 

The SiC>2 vs. K2O plot (Fig. 7.8) shows that the Lipari volcanics define a steep increase in K2O from mafic to intermediate rocks, straddling the limits between arc tholeiitic, calc-alkaline and shoshonitic series. Basaltic andesites and andesites have porphyritic textures with phenocrysts of zoned... 

Aeolian Seamounts (Sisifo, Enarete, Eolo, Lame-tini, Alcione, Palinuro) 1.3 to <0.1 - Arc tholeiites (Lametini and southern Marsili basin) to calc-alkaline and shoshonitic mafic to intermediate rocks. 

Igneous rocks can be (i) ultra basic rock, (ii) basic rock, (iii) intermediate rock, (v) acid rock. 

Element Atomic number Earth crust Basic rock (Ba salts) Intermediate rock Acid rock (granites)... 

Apatites from felsic-intermediate rocks display considerable variability on a plot of P/lOO-Si-S (Fig. 4a). The ratio of Si to S is highly variable in the apatite, but the bulk of the analyses cluster crudely near a value of 1, consistent with the substitution Si" + =... 

In a regional summary of the geology of the basement rocks of the Queen Maud Mountains, Stump (1995) stated that the composition of the Granite Harbor Intrusives varies widely from granite to gabbro but noted that intermediate rocks (e.g., granodiorite and... 

Fig. 21. Pb 5Sr2 3Yi, Ca,Cu207, model of a perfect ordering of the Pb(II) and Sr in the intermediate rock salt layers. This idealized drawing shows that 4a xc superstructure can be built up. Other models can be obtained by translation of the adjacent layers. On the left of the figure, the tetragonal subcell axaxc is drawn. The orientation of the Pb(II) lone pair is also drawn.

Thorium is generally associated with acid (and intermediate) rocks. It is very stable and will not dissolve in a solution. As a result of alteration, thorium is deposited only with detrital sediments, never with purely chemical sediments (carbonates, aragonite). Therefore, in carbonate reservoirs, thorium becomes a very important clay indicator. It is found in mudstones where it is adsorbed by clay minerals, and with heavy minerals that are often abundant in the silty fraction. Thorium is generally considered a marine element (Baker Atlas, 1985). 

Uranium is also generally associated with acid (and intermediate) rocks— their average concentration is about 4.65 ppm. As a result of weathering and alteration it forms—unlike potassium and thorium—soluble salts, which are transported in sea and river water. The salts are unstable and go into... 

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