Volcanology Commons^™

Correlation Of The Andesitic Ignimbrites Of Northern Dominica Lesser Antilles Caribbean, Lauren Main

Honors Theses

Dominica, a 750 km2 island in the Lesser Antilles volcanic arc, has numerous volcanic centers. One of the more active volcanoes is Morne Diablotins, the proposed source of the Grande Savanne ignimbrite. However, reconnaissance geologic mapping suggests that several other pyroclastic deposits in northern Dominica erupted from Morne Diablotins (Smith and Roobol, 2013): Wesley ignimbrite, Bense ignimbrite, and Pointe Ronde ignimbrite. The Grande Savanne deposit is ~70 m thick and includes a block and ash flow overlain by a baked ash layer, and welded and unwelded tuff. The Wesley ignimbrite is a ~27 m thick, layered deposit with a basal …

Geochemistry And Petrogenesis Of The Bonanza King Mafic Intrusive Complex, Trinity Terrane Ophiolite, California, Keith R. Willse

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Bonanza King mafic intrusive complex (MIC) (>25 km^2₎ of the Trinity terrane ophiolite, northern California, consists of cogenetic plutonic and dike lithologies. Steep intrusive contacts exist between cumulate pyroxenite, isotropic gabbro, and peridotite country rock. Near vertical east-west trending, bimodal dikes intruded gabbro and are centered within the complex. Geochemical modeling indicates taht accumulation/fractionation of a gabbroic parental magma produced lithologic trends of cumulate pyroxenite and fractionated gabbro and dike lithologies. Similarities between all lithologies suggest cogenetic formation of all the elements of the Bonanza King MIC during the Late Silurian (431 +/- 3).

Parental magma …