The isotopic evolution of the British lithosphere

A Sm-Nd mineral isochron obtained from an olivine gabbro yields an age of 375 +/- 34 Ma (M.S.W.D. = 0.006) and represents the formation age of the Lizard Igneous Complex. Two magmatic suites are recorded in the complex, an early trace element enriched (ENd375 = + 8.9 - + 10.1) and a late MORB-like( ENd375 = + 9.2 - + 11.7). The early magmatic suite records a decoupling between low Sm/Nd and high (143Nd/144Nd)375 ratios and indicates that the low SW/Nd ratios were generated immediately prior to the petrogenesis of the early magmatic suite, due to either i) L.REE enrichment of the source or ii) enrichment processes during magma genesis.The marked L.REE depletion of the spinel lherzolites, which comprise the majority of the Lizard peridotite, reflects multiple, small percentage (Two suites of metabasaltic rocks occur in the Mona Complex (Anglesey), the Gwna Group ((Ce/Yb)N = 0.6 - 2.1) and New Harbour Group ((Ce/Yb)N = 0.3 - 0.5). The Gwna Group yield a whole-rock Sm-Nd isochron of 595 +/- 86 Ma (M.S.W.D. = 1.5) with an initial ratio equivalent to ENd of 7.1 +/- 1.0. This isochronous relationship and large variation in the degree of L.REE enrichment indicates, as in the case of the early magmatic suite of the Lizard Complex, that the low Sm/Nd ratios were generated immediately prior to the petrogenesis of the metabasalts.Nd model ages of the Mona gneisses, a sediment and the Coedana Granite, in conjunction with the age of the Gwna Group, argue for an origin of the entire Mona Complex during the late Precambrian.The Lower Palaeozoic subduction related volcanism of southeast Ireland occurs in 2 distinct suites, north and south of the Leinster Granite. The southern suite has trace element, Sr and Nd isotope systematics equivalent to the present day calc alkaline volcanism of Java. It is estimated that 80% of the Sr and 50% of the Nd in these rocks are slab derived. The northern tholeiitic suite is markedly trace element enriched, and the rocks show a correlation between their Sm/Nd and (143Nd/144Nd)I ratios, and the % of slab derived Nd. The calculated Sr/Nd ratio of the slab component is 19, such that mixing lines between slab and mantle wedge components are straight lines on an ESr vs ENd diagram. It is not possible to distinguish between an ancient LILE and L.REE enrichment event, circa 1100 Ma, or sediment subduction to account for the isotopic systematics of the slab component.The dioritic primary magma to the Leinster Granite is predominantly derived from juvenile lower crust. The maximum mantle component involved in the diorites' petrogenesis is 30% and the maximum TCHUR age of the lower crust is 720 Ma. The primary dioritic magma assimilated Lower Palaeozoic sediments and fractionated a plagioclase, K feldspar and biotite assemblage, resulting in the production of granitic rocks with more and less radiogenic Sr and Nd isotope ratios respectively.Lower curstal xenoliths from central Ireland and the Midland Valley of Scotland indicate that crustal accretion occurred during both Grenvillian and Late Precambrian ti~es. The N.E. Ox Mount, lins inlier also provides evidence of a Late Precambrian crust forming event (605 +/- 39 Ma). (No evidence of Archaean crust is found in these regions.) The lower crustal garnet granulite xenoliths from Ireland and the Midland Valley represent possible crustal components involved in the petrogenesis of both the pre and post-tectonic Caledonian granites of Central Scotland.The majority of basement rocks of southern Britain formed during the Late Precambrian with only the Rushton Schists and Rosslare Complex having Nd and Sr isotope systematics characteristics of old, >1300 Ma, crust. Late Precambrian and Cambro-Ordovician sediments have Nd isotope systematics equivalent to the majority of the Late Precambrian basement rocks. Subsequent to the closure of the Iapetus Ocean the sedimentary pile within southern Britain records the gradual introduction of an "ancient" crustal component, presumably from the mixed Archean/Proterozoic terrains of northern Europe. A steady state is reached by Jurassic times such that present day coastal sediments have equivalent Nd isotope systematics to those of Jurassic sediments

The Anglo-American military relationship: Institutional rules, practices, and narratives

The Anglo-American military relationship is a vital yet neglected area of study. This article argues that the British military have actively cultivated a relationship with the U.S. military that has contributed to the longevity of the broader so-called "Special Relationship", even in the Trump era. The article contends that the complexities of the military relationship can best be captured by the theoretical lens provided by Lowndes and Roberts that combines different strands of institutionalism to focus on rules, practices, and narratives. The intense linkages between the United States and United Kingdom have become routinized, enabling them to adapt their peacetime cooperation to conflicts, and thereby address post-Cold War security challenges. The article draws upon semi-structured interviews with senior British military officers as well as policy documents to explore how these patterns of collaboration have become ingrained in patterns of both thinking and behavior

An analysis and criticism of the English series of the South African "individual intelligence scale" (Provisional Tests-1925)

In December, 1924, at the Annual Congress Meeting of the Suid Afrikaanse Onderwysers Unie a paper was read by Dr. H. Cruse on "Intelligence Tests and their applications to the Schools". As a result of this paper it was decided to appoint a Committee to attempt to standardize tests for pupils in South African schools, since no set of tests from any one country can be adequately adopted in any other country in view of the vast differences existing in racial and climatic conditions

Coronary haemodynamics in hypertension and left ventricular hypertrophy

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Superoxide radicals can act synergistically with hypochlorite to induce damage to proteins

AbstractActivated phagocytes generate both superoxide radicals via a respiratory burst, and HOCl via the concurrent release of the haem enzyme myeloperoxidase. Amine and amide functions on proteins and carbohydrates are major targets for HOCl, generating chloramines (RNHCl) and chloramides (RC(O)NClR′), which can accumulate to high concentrations (>100 μM). Here we show that superoxide radicals catalyse the decomposition of chloramines and chloramides to reactive nitrogen-centred radicals, and increase the extent of protein fragmentation compared to that observed with either superoxide radicals or HOCl, alone. This synergistic action may be of significance at sites of inflammation, where both superoxide radicals and chloramines/chloramides are formed simultaneously

Possible evidence for the ejection of a supermassive black hole from an ongoing merger of galaxies

Attempts of Magain et al (2005) to detect the host galaxy of the bright QSO HE0450--2958 have not been successful. We suggest that the supermassive black hole powering the QSO was ejected from the observed ULIRG at the same redshift and at 1.5 arcsec distance. Ejection could have either be caused by recoil due to gravitational wave emission from a coalescing binary of supermassive black holes or the gravitational slingshot of three or more supermassive black holes in the ongoing merger of galaxies which triggered the starburst activity in the ULIRG. We discuss implications for the possible hierarchical build-up of supermassive black holes from intermediate and/or stellar mass black holes, and for the detection of coalescing supermassive binary black holes by LISA.Comment: 4 pages, LaTeX, no figures; MNRAS in pres