The origin and life cycle of ocean islands have been debated since the early days of Geology. In the case of the Canary archipelago, its proximity to the Atlas orogen led to initial fracture-controlled models for island genesis, while later workers cited a Miocene-Quaternary east-west age-progression to support an underlying mantle-plume. The recent discovery of submarine Cretaceous volcanic ro...

The role of the subducting lithospheric slab in the genesis of mantle-derived (primitive) magmas is investigated through a study of volcanic rocks formed in the tectonically strike-slip–dominated western Aleutian arc. Two types of chemically and petrologically distinctive primitive andesites have been found among the Miocene– late Pleistocene–age volcanic rocks in the western Aleutians. These a...

Introduction: Recently published reports on chemical and physical properties of Mars sediments indicate that diagenetically altered volcanic rocks were reworked by sedimentary processes [1]. Furthermore, compositional and petrographic aspects of sediments show varying degrees of elemental enrichment as well as complex interaction between the minerals in partially saturated or saturated conditio...

rocks of the Stuhuni and King Salmon Groups; a pre-.Middlm: Triassic unconformity is found througbmt the North American Cordillera (Read and Okulitch, 1977, Siberling, 1973:. In the Stikine Terrane, late Triassic volcanic rocks ar: dominantly fragmental andcommonly alkalic. Based on bul:: rock chemistry, both extensional, ba:k-arc, and Fore-ar: tectonic settings have been suggested tor these r...

Petrophysical properties of geothermal reservoir rocks are valuable information for many activities, including reservoir characterization, modelling, field test analysis and planning of exploitation techniques. Petrophysical data of rocks from geothermal reservoirs located in volcanic areas is in general very scarce. In particular, no petrophysical data of rocks from the Los Azufres geothermal ...

The high-grade uranium deposits in the Xiemisitan area, northwestern China, are genetically associated with the faulting of felsic volcanic or sub-volcanic rocks. Ferric iron alteration indicates that oxidizing hydrothermal fluids percolated through the rocks. In this study, we measured the gamma-ray intensities of rocks in the Xiemisitan area and we propose a hybrid method for the mapping of f...

Silicic volcanic rocks are associated with most, if not all, continental ×ood basalt provinces and volcanic rifted margins, where they can form substantial parts of the eruptive stratigraphy and have eruptive volumes >104 km3. Poor preservation of silicic volcanic rocks following kilometer-scale uplift and denudation of the volcanic rifted margins, however, can result in only deeper level struc...

This Special Publication provides a snapshot of our understanding of volcanic processes through the use of palaeomagnetic and rock magnetic techniques. Here, we provide a context for the book, placing individual chapters within the milieu of previous work, including some magnetic techniques that were not used in the particular studies described herein. Thermoremanent magnetization is a powerful...