Oxygen isotope geochemistry of the silicic volcanic rocks of the Etendeka-Paraná province: Source constraints

Oxygen and neodymium isotope evidence for source diversity in Cretaceous anorogenic granites from Namibia and implications for A-type granite genesis

“…The mixing hypothesis predicts that the Awahab rhyodacites are nearly 100% crustal, which agrees with earlier conclusions by Harris et al (1990), but conflicts with Ewart et al (1998b), who suggested that the Awahab rhyodacites formed from subequal contributions of mantle and crustal melts. The latter model was based on an assumed crustal component like ''C1''.…”

Nd-, O-, and H-isotopic evidence for complex, closed-system fluid evolution of the peralkaline Ilı́maussaq intrusion, south Greenland

“…In contrast, alkaline to peralkaline silica-oversaturated intrusive rocks typically show signs of contamination with crustal material during emplacement (e.g., Davies and Macdonald, 1987;Heaman and Machado, 1992;Harris, 1995;Mingram et al, 2000;Schmitt et al, 2000;Späth et al, 2001;. For example, studies on silica-undersaturated, oversaturated, and mixed complexes of the Damaraland, Namibia (Harris et al, 1990(Harris et al, , 1999Harris, 1995;Mingram et al, 2000;Schmitt et al, 2000) and from the Gardar province of South Greenland (e.g., support the assumption of Foland et al (1993) that alkaline silica-oversaturated magmas evolved from undersaturated magma via crustal contamination, or that they are products of crustal anatexis.…”

Petrogenetic evolution of the felsic and mafic volcanic suite in the Siang window of Eastern Himalaya, Northeast India

“…Alternatively, Leat et al (1986) considered that the rhyolites of the British Caledonides evolved in the same magma chamber through fractional crystallization of a basaltic magma contaminated with melted crustal material. Furthermore, the silicic volcanics of the Etendeka-Parana province are considered to be derived directly by melting of crustal material (Erlank et al, 1984;Harris et al, 1990). Thus, the petrogenesis of felsic volcanics associated with the voluminous basaltic provinces remains a controversial issue and several models have been proposed to explain their origin.…”