Mantle Sources and Melting Dynamics in the British Palaeogene Igneous Province

The North Atlantic igneous province offers an unrivalled opportunityto study mantle sources contributing to flood basalt magmatism,and melting dynamics associated with active and passive upwellingof hot mantle beneath the lithosphere. In this study, Palaeogenebasalts sampled at localities across the British Isles (fromthe Hebrides in the north to Lundy Island in the south) areshown to have concentrations of Nb, Zr and Y consistent withderivation from two mantle sources: ‘Icelandic’(plume) mantle and hot N-MORB-like mantle forming an outer envelopeto the plume. These sources were sampled over the period 61–58Ma (chrons 26R–26N). Values of     

ALEXANDER VON HUMBOLDT'S IMAGE AND INFLUENCE IN NORTH AMERICAN GEOGRAPHY, 1804–2004

ABSTRACT. Alexander von Humboldt is universally identified as a key figure in laying the foundations for modern geography. His main sites of research and scholarly production were centered on Europe, Latin America, and Russia. He drew on global sources of geographical data and knowledge in constructing and producing his voluminous works. Although he only briefly knew North America firsthand—at the outset of his career, in the late spring of 1804—he maintained a lifelong interest in the realm, especially in the United States. In turn, many North American scholars were admirers and followers of his perspectives, practices, and publications. Although geography did not emerge as an institutionally based discipline in the United States until the late nineteenth century, Humboldt's influence and impact on its antecedents were considerable. Contrary to conventional wisdom, his authority and influence in geography persisted well beyond Humboldt's death in 1859. His vision of demonstrating nature's unity in diversity and his enlightened views on social issues have continued to appeal to select sectors and actors in North American geography, especially Latin Americanists, historians of the discipline, and, more recently, proponents of an engaged, critical geography.     

Near-solidus Melting of the Shallow Upper Mantle: Partial Melting Experiments on Depleted Peridotite

We present the results of melting experiments on a moderatelydepleted peridotite composition (DMM1) at 10 kbar and 1250–1390°C.Specially designed experiments demonstrate that liquids extractedinto aggregates of vitreous carbon spheres maintained chemicalcontact with the bulk charge down to melt fractions of     

WRITING THE MIDWEST: HISTORY,LITERATURE, AND REGIONAL IDENTITY

ABSTRACT. In this article I discuss the function of history in constructing regional identity and explore the ways in which the American Midwest differs from other widely recognized regions—New England, the South, and the West—in the kinds of historical figures and narratives that create a regional distinctiveness in the eyes of residents and writers. Whereas other regions tend to locate identity in a limited number of well-known figures and events from the past and to generalize them to the region as a whole, in the Midwest meaning is discerned on a more limited, place-by-place basis, in terms of more strictly local events and personages. This understanding of a particular kind of historically based identity is made especially clear in contemporary nonfiction from the Midwest, which collectively creates a dense mosaic of local meanings in a landscape conventionally seen by outsiders as largely empty of interest and significance.