East-northeast extension ca. 24 Ma at Rodeo and Nazas, México, was accompanied by eruption of hawaiites, marking some of the earliest intraplate-type mafic alkalic volcanism associated with development of the southern Basin and Range Province. An earlier extensional pulse, 32.3–30.6 Ma, concurrent with subductionrelated rhyolitic volcanism of the Sierra Madre Occidental, is the earliest establi...

This paper describes occurrences of low grade, disseminated gold in sedimentary rocks and alkalic intrusions in the vicinity of the Howell Creek Structure (HCS; Price,1964) of southeastern British Columbia. The study is part of the B.C. Geological Survey’s ongoing Sediment-hosted Gold Project, which is examining occurrences throughout the province which may have similarities to gold deposits in...

Mesozoic granitic plutons are found throughout the Indochina terrane of eastern Cambodia and southern Vietnam. The rocks range in age from Early Triassic (240 Ma) to Late Cretaceous (80 record distinct tectonomagmatic periods associated with subduction Paleotethys Paleo-Pacific oceans. Samples collected Snoul pluton, composed silicic intermediate dioritic rocks, basalt. quartz diorites magnesia...

BECAUSE OCEANIC ISLANDS in general have an underlying volcanic platform which can be expected to include a primary feeder pipe containing recrystallized magma , the gravity field observed will reflect both the topographic mass effect of the platform rising from the sea floor and a contribution from the feeder pipe presumably having a filling of denser material. Certainly the early study of Oahu...

Syenites are relatively rare within the Nigerian Basement Complex. As a result of their rarity, these rocks have been given less research attention over time and consequently poorly understood. The syenitic at Igarra were studied to ascertain tectonic evolution using geochemistry. Sampling was carried out survey-type geological field mapping approach. A total 10 samples collected for laboratory...

Abstract Mineral inclusions within native gold are features of lode occurrences that preserved in detrital particles. Inclusion assemblages populations particles placers from specific localities revealed through inspection polished sections, and assimilation robust data sets permits reconstruction the source mineralogy. differ considerably according to deposit type, various approaches have been...