Petrology, tectonic setting, and 40Ar/ 39Ar (hornblende) dating of the Late Ordovician - Early Silurian Belle Côte Road orthogneiss, western Cape Breton Highlands, Nova Scotia

The Belle Côte Road orthogneiss is a major component of the western Cape Breton Highlands, where it forms a belt approximately 60 km in length. Previous U-Pb dating has shown that the granodioritic to tonalitic protolith of the gneiss crystallized at 442 ± 3 Ma, providing a minimum age for the metavolcanic and metasedimentary units of the Aspy terrane intruded by the orthogneiss. The gneissic fabric in the orthogneiss is mainly conformable with the regional fabric, and generally trends north-south, except in the southern part of the unit where it is oriented east-west. Typical orthogneiss contains quartz, plagioclase, and biotite, with variable amounts of K-feldspar and muscovite and rarely epidote or garnet. A tonalitic variant contains amphibole. The orthogneiss is peraluminous, with A/CNK values of 1to 1.2. Petrochemical characteristics are consistent with syntectonic emplacement in the roots of a volcanic arc built on continental crust. 40Ar/39Ar dating was done on hornblende from three samples of orthogneiss and seven samples of amphibolite from xenoliths in the orthogneiss and an adjacent amphibolite unit. Eight of these samples yielded cooling ages ranging between 384 and 370 Ma. Two younger ages (ca. 363 and 353 Ma) may reflect localized effects of younger plutonism and/or shearing. The 40Ar/39Ar data combined with previous U-Pb data from titanite indicate that the orthogneiss and associated units experienced rapid cooling from ca. 600 to 400°C between ca. 386 Ma and 370 Ma, perhaps related to uplift associated with ongoing terrane amalgamation in Cape Breton Island. RÉSUMÉ Les orthogneiss de Route de Belle Côte est un composant important des hautes terres du Cap Breton occidental, où il forme une ceinture approximative de 60 kilomètres de longueur. Des mesures connues d'U-Pb a prouvé que le granodioritique au protolite tonalitique du gneiss a cristallisé au ± 442 3 Ma, fournissant un âge minimum pour les unités métavolcaniques et métasédimentaires du terrane d'Aspy imposé par les orthogneiss. Le tissu gneissique dans les orthogneiss est principalement conforme au tissu régional, et a une tendance généralement nord-sud excepté dans la partie sud de l'unité où la tendance est est-ouest. Les orthogneiss typiques contient le quartz, le plagioclase, et la biotite, avec des quantités variables de K-feldspath et de muscovite et rarement d'épidote ou de grenat. Une variante tonalitique contient l'amphibole. Les orthogneiss sont péralumineux. avec des valeurs A/CNK de 1 à 1.2. Les caractéristiques p&rochimiques sont conformées a là mise en place syntectonique dans les racines d'un arc volcanique construit sur la croute continentale. La datation d' 40Ar/39Ar à été faite sur la hornblende de trois échantillons d'orthogneiss et de sept échantillons d'amphibolite provenant de xénolites dans les orthogneiss et une unité adjacente d'amphibolite. Huit de ces échantillons ont rapporté des âges de refroidissement s'étendant entre 384 et 370 de Ma. Deux àges plus jeunes (ca. 363 et 353 Ma) peuvent refléter des effets localises des plus jeunes plutonismes et/ou cisaillement. Les données 40Ar/39Ar combing avec des données précédentes d'U-Pb de titanite indiquent que les orthogneiss et les unites associées ont éprouve' le refroidissement rapide ca de 600 a 400°C entre ca. 386 Ma et 370 Ma, peut-ètre assocté au soulèvement en plus d'amalgamation continue de terrane sur Tile du Cap Breton. [Traduit par la rédaction

Performing television history

An expanded conception of performance study can disturb current theoretical and historical assumptions about television’s medial identity. The article considers how to write histories of the dominant forms and assumptions about performance in British and American television drama, and analyses how acting is situated in relation to the multiple meaning-making components of television. A longitudinal, wide-ranging analysis is briefly sketched to show that the concept of performance, from acting to the display of television’s mediating capability, can extend to the analysis of how the television medium ‘performed’ its own identity to shape its distinctiveness in specific historical circumstances

Analysing communication in a complex service process: an application of social network analysis in the Scottish Prison Service

This article utilizes social network analysis (SNA) and associated statistical techniques to examine a complex process known as Sentence Management in a Scottish Prison Service facility. Findings indicate that communication did not always follow the formal hierarchical process defined by that organization, significant fragmentation existed between certain key roles, and four central actors controlled much of the process. This research demonstrates the applicability of the SNA as an operations management tool to analyse structural communication patterns. This case study further suggests that SNA may be particularly applicable to the public service sector, to better understand informal communication networks within operations that are largely dependent on human performance

Identification of the Bloody Creek structure, a possible impact crater in southwestern Nova Scotia, Canada

An approximately 0.4 km diameter elliptical structure formed in Devonian granite in southwestern Nova Scotia, herein named the Bloody Creek structure (BCS), is identified as a possible impact crater. Evidence for an impact origin is based on integrated geomorphic, geophysical, and petrographic data. A near-continuous geomorphic rim and a 10 m deep crater that is infilled with lacustrine sediments and peat define the BCS. Ground penetrating radar shows that the crater has a depressed inner floor that is sharply ringed by a 1 m high buried scarp. Heterogeneous material under the floor, interpreted as deposits from collapse of the transient cavity walls, is overlain by stratified and faulted lacustrine and wetland sediments. Alteration features found only in rim rocks include common grain comminution, polymict lithic microbreccias, kink-banded feldspar and biotite, single and multiple sets of closely spaced planar microstructures (PMs) in quartz and feldspar, and quartz mosaicism, rare reduced mineral birefringence, and chlorite showing plastic deformation and flow microtextures. Based on their form and crystallographic orientations, the quartz PMs consist of planar deformation features that document shock-metamorphic pressures less than or equal to 25 GPa. The age of the BCS is not determined. The low diameter-to-depth ratio of the crater, coupled with anomalously high shock-metamorphic pressures recorded at its exposed rim, may be a result of significant post-impact erosion. Alternatively, impact onto glacier ice during the waning stages of Wisconsinian deglaciation (about 12 ka BP) may have resulted in dissipation of much impact energy into the ice, resulting in the present morphology of the BCS.The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202