Compared to other Aleutian basalts of similar silica content, these lavas are less LREE enriched and have lower overall abundances. The geochemical characteristics of these basalts suggest they represent true liquid compositions despite their highly porphyritic nature. Published phase relations indicate ...
In contrast, iron-rich smectite formation was not observed in three 13.5-Ma core samples, which suggests that iron-rich smectite formation may be affected by the dilution of aqueous silica supplied from basalt dissolution by actively circulating fluid. As iron-rich smectite from the 33.5-Ma and ...
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aRegional setting of the Cretaceous alkaline magmatism (modified of Castañares et al.2001).bSimplified geological map and distribution of volcanic rocks in the Biscay synclinorium.cExposition of the basaltic lava flow at Armintza.dPillow-lava lobeseContact of the pillow lava with the flysch. ...
The kaolinization is decided by aluminum within the parental rocks, which is, to begin with, changed over to kaolinite through the combination with the accessible silica, which any encourages weathering (i.e., silica loss) past this condition, in this manner, marks the organize of the ...
Over the past decade, extensive efforts have been devoted to experimentally studying the rheological changes of melts feeding eruptions under disequilibrium conditions, with a specific focus on basaltic compositions. Basalts are characterized by low silica content (i.e., 48–52 wt.% of SiO2) and ...
The andesites and cogenetic rocks of the intraoceanic island arc systems vary in silica content from 4950% SiO2 to about 76% SiO2. The most primitive compo... S Maal?E,TS Petersen - 《Journal of Geophysical Research Solid Earth》 被引量: 47发表: 1981年 ...
Silica-saturated basaltic magma is the source of the voluminous lava flows, erupted frequently and rapidly in the primitive shield-building stage of activity, that form the bulk of each Hawaiian volcano. This magma may be available in batches that differ slightly in free silica content from batch...
Proust D, Fontaine C (2007b) Amethyst geodes in the basaltic flow from Triz quarry at Ametista do Sul (Rio Grande do Sul): magmatic source of silica for the amethyst crystallisations. Geol Mag 144:731–739. : 10.1017/S0016756807003457...
Over the past decade, extensive efforts have been devoted to experimentally studying the rheological changes of melts feeding eruptions under disequilibrium conditions, with a specific focus on basaltic compositions. Basalts are characterized by low silica content (i.e., 48–52 wt.% of SiO2) and ...