Mantle evolution in the Variscides of SW England: geochemical and isotopic constraints from mafic rocks

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.The geology of SW England has long been interpreted to reflect Variscan collisional processes associated with the closure of the Rhenohercynian Ocean and the formation of Pangea. The Cornish peninsula is composed largely of Early Devonian to Late Carboniferous volcanosedimentary successions that were deposited in pre- and syncollisional basins and were subsequently metamorphosed and deformed during the Variscan orogeny. Voluminous Early Permian granitic magmatism (Cornubian Batholith) is broadly coeval with the emplacement of ca. 280-295 Ma lamprophyric dykes and flows. Although these lamprophyres are well mapped and documented, the processes responsible for their genesis and their relationship with regional Variscan tectonic events are less understood. Pre- to syn-collisional basalts have intra-continental alkalic affinities, and have REE profiles consistent with derivation from the spinel-garnet lherzolite boundary. εNd values for the basalts range from +0.37 to +5.2 and TDM ages from 595 Ma to 705 Ma. The lamprophyres are extremely enriched in light rare earth elements, large iron lithophile, and depleted in heavy rare earth elements suggesting a deep, garnet lherzolite source that was previously metasomatised. They display εNd values ranging from -1.4 to +1.4, initial Sr values of ca. 0.706, and TDM ages from 671 Ma to 1031 Ma, suggesting that metasomatism occurred in the Neoproterozoic. Lamprophyres and coeval granite batholiths of similar chemistry to those in Cornwall occur in other regions of the Variscan orogen, including Iberia and Bohemia. By using new geochemical and isotopic data to constrain the evolution of the mantle beneath SW England and the processes associated with the formation of these post-collisional rocks, we may be able to gain a more complete understanding of mantle processes during the waning stages of supercontinent formation

Ambient Stable Quantitative PCR Reagents for the Detection of Yersinia pestis

Plague, caused by Yersinia pestis, is one of the oldest and most dangerous diseases in human history, and has claimed millions of lives in the three major historical pandemics. Although panic caused by the Black Death is fading, the threat of the reemergence of plague pandemics still exists, with the additional potential of misuse in biowarfare or bioterrorism. Rapid on-site detection and identification of the pathogen is of paramount significance for timely implementation of effective countermeasures. TaqMan probe-based real-time PCR assays can give quick and accurate identification; however, the need for cold delivery and storage prevents its potential on-site application. The objective of this study was to develop a stable PCR system for easy delivery and storage under room temperature, which is vital for conventional plague surveillance and for preparedness in public health emergencies. We present a solution to this particular issue, hoping that it is helpful to future applications

The Significance of Changes of Source Areas During Carboniferous Turbiditic Deposition (Southwestern Iberia)

U–Pb dating of detrital zircons from the Carboniferous turbidites of southwestern Iberia (the Cabrela, Mértola, Mira, and Brejeira formations) shows that synorogenic sedimentation during the Carboniferous was marked by significant variations in the source areas, involving the denudation of different crustal blocks and a break in synorogenic volcanism. The Visean is characterized by the accumulation of immature turbidites (the Cabrela and Mértola formations and the base of the Mira Formation). These turbidites were probably formed in relation to sources (magmatic arcs) of Mid–Late Devonian age poorly influenced by sedimentary recycling, as indicated by the near-absence of pre-Devonian zircons, ages that are typical of the Gondwana basement. The presence of Carboniferous grains in Visean turbidites indicates that volcanism was active at this time. Later, Serpukhovian to Moscovian turbiditic sedimentation (the Mira and Brejeira formations) included sedimentary detritus derived from mature felsic source rocks situated far from active magmatism. The abundance of Proterozoic and Palaeozoic zircons reveals strong recycling of the pre-Carboniferous basement. A peri-Gondwanan provenance is indicated by zircon populations with Neoproterozoic (the Cadomian–Avalonian and Pan-African zircon-forming events), Palaeoproterozoic, and Archean (the West African Craton zircon-forming events) ages. The presence of Late Ordovician and Silurian detrital zircons in the Brejeira turbidites, which do not correspond to the Gondwana basement of southwestern Iberia, indicates an external source (Laurussia?)

Labor and household mobility: efficiency and equilibrium

H41, H42, J61, R13,