The geology of the lewisian complex near Poolewe, Ross-shire

The Lewisian rocks near Poolewe are part of an acid gneiss complex; the complex includes subordinate amounts of basic and ultra-basic gneiss (early basites) and also rocks of presumed metasedimentary origin (the Gleann Tulacha and Gruinard metasediments). Two hornblende schist bodies (the Beinn Airigh Charr and Gruinard basites) are intimately associated with the metasediments. Members of a suite of basic igneous rocks (the Scourie dykes) have intruded the gneisses, early basites and also the Gruinard metasediments and basite; the chronological status of the Gleann Tulacha metasediments and Beinn Airigh Charr basite is in doubt since no member of the Scourie dyke suite intrudes them. All of the basic igneous rocks have been metamorphosed and converted into amphibolites. Petrological variation within each of the main rock groupings is more a function of the metamorphic fabric domain in which a rock occurs than of pre-metamorphic lithological heterogeneities. Presentation of detailed petrological descriptions is therefore based upon the metamorphic fabric sequences recognised, attention being focussed upon shape rather than orientation fabrics. These fabric sequences are used for purposes of structural correlation. Structural sequences are also established using the evidence of interfering fold sets and the structural relationships between members of the basic dyke suite and the country rocks. Dyke intrusion involved at least three phases of injection; these are however envisaged as stages in a single protracted event. The period of dyke intrusion is therefore used as a stratigraphical marker within the complex. Structural correlations based upon fabric criteria are consistent with the hypothesis that dyke intrusion was a single protracted event. Development of the complex is therefore considered in terms of a pre-dyke (Scourian) complex and a post-dyke (Laxfordian) complex. Deformational events D2, D3, D4 and D5 have been recognised in the Scourian complex whilst D6, D7 and D8 events affected the Laxfordian complex. The original nature of the S1 surface is unknown. Most of the rocks show evidence of metamorphism in amphibolite facies, although evidence is cited which implies that the M3 event was, in part, in granulite facies. This pre-D4 high-grade metamorphic complex is correlated with the Badcallian (Park 1970), whilst later Scourian events are considered to be of Inverian age. A detailed geometrical analysis of the small-scale structures is presented. In addition, the areas mapped permit the study of parts of three large-scale Lewisian structures, namely the Carnmore antiform, the Letterewe synform and the Tollie antiform. The N.E. limbs of the Carnmore and Tollie antiforms are considered to be large-scale Inverian structures, whilst the S.W. limb of the Carnmore antiform and the adjacent Letterewe synform are of Laxfordian age. The metasediments neither contain any evidence of the Badcallian fabrics nor show the effects of pre-Inverian migmatisation, apparent elsewhere in the complex. It is therefore concluded that the metasediments were originally deposited upon a Badcallian basement, but were involved in Inverian structural and metamorphic events. Both groups of metasediments occur at similar structural levels and are associated with large hornblende schist bodies. It is thus likely that the metasediments are stratigraphically equivalent and that the hornblende schist bodies probably represent post-Badcallian, pre Inverian meta-volcanic assemblages. 29 Samples of dyke material were analysed for major elements using "wet" techniques; 27 of these samples were analysed for Ni, Cr, Ba, Sc, V, Sr, Co, Zr and Cu by emission spectroscopy. The results of these geochemical analyses are presented. It is concluded that the chemical variation exhibited can be explained in terms of the differentiation of a magma having tholelitic affinities. Igneous structures in the dykes are discussed with respect to possible differentiation mechanisms. Consideration of the dyke fabrics and the structural relationships between dykes and country rock leads to the conclusion that the dykes were emplaced into a hot, but cooling, Inverian complex in which the Inverian structures exerted considerable control over dyke emplacement

A fluid control system for nuclear reactors

This thesis presents both an experimental and analytical analysis of the scram characteristics of a fluid control system for a nuclear reactor. This control system utilizes a control tube containing a neutron-absorbing fluid. The level of the fluid inside of the tube is then regulated by means of\u27 a pressurized gas and offers a number of unique advantages over the conventional control rod system using linear absorber rods. The effect of varying the level-control pressure and initial height of the fluid column is determined and evaluated. The time required to complete a scram with the fluid control system is compared to the rod drop times of an operating reactor. The dynamic response of the liquid control system during scram was found to be as fast or faster than a linear-control-rod system of an operating reactor --Abstract, page iii

Low Mass Companions for Five Solar-Type Stars from the Magellan Planet Search Program

We report low mass companions orbiting five Solar-type stars that have emerged from the Magellan precision Doppler velocity survey, with minimum (Msini) masses ranging from 1.2 to 25 Mjup. These nearby target stars range from mildly metal-poor to metal-rich, and appear to have low chromospheric activity. The companions to the brightest two of these stars have previously been reported from the CORALIE survey. Four of these companions (HD 48265-b, HD 143361-b, HD 28185-b, HD 111232-b) are low-mass Jupiter-like planets in eccentric intermediate and long-period orbits. On the other hand, the companion to HD 43848 appears to be a long period brown dwarf in a very eccentric orbit.Comment: Accepted for publication on ApJ, 26 pages, 10 figures, 7 table

The Ursinus Weekly, January 14, 1971

Ursinus enrollment tops 2000 mark • 1971 dictionary honors Howard • Ted Taylor leaves Ursinus for Drexel • Ursinus raises tuition, stops PHEAA credit • Campus Chest pursues profit • Ursinus sponsors mock UN session • Parking problem relief envisioned • Final Forum features Fox • Editorial: the continuing struggle • Quotation of the week • Focus: Mason Williams • Unconditional courses • Boars and sows • Final examination schedule • Bears lose twice: Fall to F&M and LVC • Hockey members honored • Grapplers improve with recruitinghttps://digitalcommons.ursinus.edu/weekly/1136/thumbnail.jp

The Ursinus Weekly, November 19, 1970

Dr. Pettit inaugurated as Ursinus President • Students, Board deliberate U.C. changes, Union plans • Ad Hoc Committee sets parameters • Ursinus\u27 single mailbox relocated at college administration building • Editorial: Campus unrest report • Focus: Alan Novak • The $100,000 night • Faculty portrait: Miss Blanche Schultz • Letters to the editor: Anti-open dorms; Zopo zapped • Hoopmen meet Fords in December debut • U.C. passing attack nets 35-14 final grid victoryhttps://digitalcommons.ursinus.edu/weekly/1133/thumbnail.jp