Saint Mary's University

About: Saint Mary's University is a education organization based out in Halifax, Nova Scotia, Canada. It is known for research contribution in the topics: Population & Stars. The organization has 1931 authors who have published 4993 publications receiving 143226 citations.

The South Aegean active volcanic arc: relationships between magmatism and tectonics

Abstract: Two principal volcanic associations, together with a third minor association, occur in the South Aegean active volcanic arc, differing in magma type, age, spatial distribution, relationship to faulting, and petrogenesis, even though geophysical data indicate a continuous subducted slab at 130 – 150 km beneath the volcanic centres. Variation in magmatism is related to changes in tectonics during the evolution of the arc, as a result of collision of African continental crust with the Aegean-Anatolian microplate, that set up changing patterns of strike-slip faulting in the arc. A synthesis is presented of the age and the variation in major and trace elements and radiogenic isotopes of the rocks of the arc. The western part of the arc (including Aegina, Methana, and the older rocks of Milos and Santorini) has typical arc-related andesite – dacite volcanism, predominantly of Pliocene age, associated with E-W listric faulting with slow slip rates. Nd and Sr isotopes and trace elements show that magmas resulting from volatile-induced melting in the asthenospheric mantle wedge subsequently either underwent assimilation with fractional crystallisation (AFC) or mixed with local partial melts within the lithospheric mantle. Viscous felsic magmas were likely trapped in the lower crust. In contrast, the mid to late Quaternary of the central and eastern part of the arc (Milos, Santorini, Nisyros) consists of lavas and voluminous pyroclastics, with lava compositions including both tholeiitic and calc-alkaline minor basalt, andesite, dacite and minor rhyolite. These younger magmas resulted from melting both of hydrated mantle (calc-alkaline magmas) and depleted asthenospheric mantle (tholeiitic magmas), influenced by regional extension, which is greatest in the central part of the arc. This young volcanism began at the same time as the ENE-trending strike-slip faulting that resulted from collision with an indentor of thinned continental crust of the African plate. Stepover faulting and extension on early Quaternary NE-trending strike slip faults as a result of this mid- to late Quaternary ENE-trending sinistral strike slip motion provided pathways for magmas (including mantle-derived felsic magmas) to rise and fractionate and also pathways for water to enter shallow magma chambers. The third minor group of rocks comprises felsic lavas at Crommyonia and Kos, principally of Pliocene age, derived from mid-crustal anatexis. The ultimate cause of magmatism in the South Aegean active volcanic arc is subduction-related release of hydrous volatiles, but there are important differences between the petrogenesis of the older western and younger eastern parts of the arc.

Adolescents' perceptions of family communication patterns and some aspects of their consumer socialization

Abstract: This study examined the effects of family communication patterns (FCP) on adolescent consumers' decision-making styles and influence in family purchase decisions. Two underlying dimensions of FCP (concept-orientation and socio-orientation) were measured separately for mother–child communication and father–child communication and regressed on adolescents' use of the selected decision-making styles and influence in purchase decisions involving durable products and nondurable products for their own use. Results show that only mother–child communication patterns have significant associations with adolescents' decision-making styles and family purchase influence. Specifically, mothers' concept-oriented communication was positively linked to children's use of utilitarian decision-making styles (e.g., careful and deliberate decision making) and social/conspicuous decision-making styles (e.g., recreational and hedonic decision making) as well as to children's influence in family purchase decisions involving both durable and nondurable products for themselves. On the other hand, mothers' socio-oriented communication was linked positively to children's use of undesirable decision-making styles (e.g., confusion by overchoice) and negatively to children's influence in family purchase decisions. This study also investigated the presence (or absence) of a same-gender effect in the relationships between parent–child communication orientations and children's consumer socialization outcome. If present, a same-gender effect would be indicated by a greater influence from the same-sex parent's communication orientations on the adolescent's decision-making styles and influence in family decisions relative to that of the opposite-- sex parent's communication orientations. Comparisons of the two gender-group regression results revealed no systematic pattern that suggests the presence of such an effect. © 2009 Wiley Periodicals, Inc.

Chronology of Devonian to early Carboniferous rifting and igneous activity in southern Magdalen Basin based on U–Pb (zircon) dating

Abstract: Fifteen U–Pb (zircon) radiometric age determinations have been made on igneous rocks of Middle Devonian to Early Carboniferous age from the southern margin of the Magdalen basin in Cape Breton Island and northern mainland Nova Scotia. Volcanic rocks interbed with early rift-basin sedimentary rocks with some palynological biostratigraphy; dated intrusive rocks cut these sedimentary units. Our biostratigraphically constrained ages are in close agreement with the current Devonian time scale. Combined with previously published data, the age determinations show that igneous activity occurred in four pulses: Middle Devonian (390–385 Ma), early Late Devonian (375–370 Ma), latest Devonian to early Tournaisian (365–354 Ma), and late Tournaisian to early Visean (ca. 339 Ma). Middle Devonian (385–389 Ma) volcanic rocks are confined to the Guysborough Group. The Fisset Brook Formation (basalt and minor rhyolite) in the type area and elsewhere in Cape Breton Island and northern mainland Nova Scotia is Late Devonian (c...