Feldspar Pb-isotope ratios for earliest Pleistocene sediments of the sub-polar North Atlantic Ocean

Relatively little is known in detail about the locations of the early Pleistocene ice-sheets responsible for ice-rafted debris (IRD) inputs to the sub-polar North Atlantic Ocean during intensification of northern hemisphere glaciation (iNHG). To shed new light on this problem, we present the first combined in-depth analysis of IRD flux and geochemical provenance of individual sand-sized IRD deposited in the sub-polar North Atlantic Ocean during the earliest large amplitude Pleistocene glacial, marine isotope stage (MIS) 100 (~2.52 Ma), arguably the key glacial during iNHG. IRD provenance is assessed using laser ablation lead (Pb) isotope analyses of single feldspar grains. We find that the Pb-isotope composition (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb) of individual ice-rafted (>150 µm) feldspars deposited at DSDP Site 611A, ODP Site 981 and IODP Site U1308 during MIS 100 records a shift from predominantly Archaean-aged circum-North Atlantic Ocean continental sources during early glacial ice-rafting events to dominantly Palaeozoic and Proterozoic-aged sources during full glacial conditions. The distribution of feldspars in Pb-Pb space for full glacial MIS 100 more closely resembles that documented for feldspars deposited at the centre of the last glacial IRD belt (at IODP/DSDP Site U1308/609) during ambient (non-Heinrich-event) ice-rafting episodes of MIS 2 (~23.8 ka) than that documented for MIS 5d (~106 ka). Comparison of our early Pleistocene and last glacial cycle datasets suggests that MIS 100 was characterised by abundant iceberg calving from large ice-sheets on multiple continents in the high northern latitudes (not just on Greenland).

IR spectra from mapping of diamond sample JH7b

This data set contains 1851 infrared (IR) spectra, forming a single IR map of diamond sample JH7b. This data set is used to show the application of DiaMap, a computer routine written using PERL, to automatically process diamond IR spectra to obtain quantitative impurity data from them. Full abstract will be added after acceptance of publication.

Hombres, poder y conflicto : Estudios sobre la frontera colonial sudamerica y su crisis

Tabla de contenidos: Nota introductoria / Emir Reitano, Paulo Possamai. Del Tajo al Amazonas y al Plata. Las repercusiones atlánticas de las 12 guerras entre las coronas española y portuguesa en la Edad Moderna / Juan Marchena Fernández. El presidio de Buenos Aires entre los Habsburgo y los Borbones: el ejército regular en la frontera sur del imperio español / Carlos María Birocco. Los soldados indígenas del Rey Católico: los misioneros en las guerras por la Colonia del Sacramento / Paulo César Possamai. Ataque de la flota combinada anglo portuguesa a la Colonia del Sacramento.El hundimiento del navío Lord Clive (1763) / Marcelo Díaz Buschiazzo. Travessías difíceis: Portugal, Colónia do Sacramento e o projeto Montevidéu (1715-1755) / Victor Hugo Abril. Beresford e D. Joao VI ? Uma inesperada confluencia / Fernando Dores Costa. La guerra: una situación límite. Una aproximación al tema: Batalla de India Muerta, noviembre 1816 / Juan Carlos Luzuriaga. Fortalezas imperiais: Arquitetura e cotidiano (Fronteira Oeste da América Portuguesa, século XVIII) / Otávio Ribeiro Chaves. Resistência e cotidiano da tropa militar do presídio de Miranda: Aspectos da defesa da fronteira sul da capitania de Mato Grosso (1797-1822) / Bruno Mendez Tulux. Os índios Payaguá: guerra e comércio na fronteira oeste da América portuguesa / Maria De Jesus Nauk. De Yatay a Cerro- Corá. Consenso e Dissenso na resistência militar paraguaia / Mario Maestri. Extraños en los confines del imperio: los portugueses ante la corona española en el Río de la Plata / Emir Reitano. Incidências da guerra en uma fronteira imperial: Rio Grande de Sao Pedro (1750-1825) / Helen Osorio. Armas y control. El ?negro delito de la deserción? en la Banda Oriental (1811-1816) / Daniel Fessler. Cruzar fronteiras, conectar mundos. As missoes austrais na pampa bonaerense (Século XVIII) / María Cristina Martins. Las guerras coloniales en la historiografía uruguaya de orientación nacionalista / Tomás Sansón. Las estatuas al Almirante Brown y la ?construcción de la Nación Argentina? / Diego Téllez Alarcia.