 | | Journal (article/letter/editorial) | | SUMMER FIELD MEETING TO WESTERN PART OF THE LLEYN PENINSULA. August 27th to September 10th, 1938. Rep ort...face p. 84. SUMMER FIELD MEETING TO LL.EYN PENINSULA. 85 at various points; it is badly crushed....Cambrian and lower Ordovician rocks of St. Tudwal's Peninsula, Mr. T. C. Nicholas acting as Director. The initial...of Abersoch (as near to the south end of the peninsula as parking space permits) and the party then proceeded...Trwyn Cilan, the southernmost extremity of the peninsula where, in a little hollow above the point, a section |  | | Journal (article/letter/editorial) | | the Lower Paleozoic granitoids of the Lleyn Peninsula, North Wales IAN Department of Geological W. CROUDACE’...revisedfirm December 2, 1981) Abstract-The Lleyn Peninsula of North Wales is penetrated by at least twenty stocks...Paleozoic granitic (sensuo tato) rocks of the Lleyn Peninsula are described. From these features, a discussion...igneous activity in North Wales. The coastal and inland areas of the Lleyn Peninsula have over twenty granitic...Thomas and Briden (1976) has shown that six of the Lleyn intrusions have similar remanence directions to |  | | Journal (article/letter/editorial) | | KENNETH I. II. III. E. University College of Wales, Aberystwyth. (PLATES VIII AND IX.) CONTENTS. WILLIAMS...Cardiganshire. observations on the glaciation of Central Wales in general. In this paper he refers to the glacial...originated " in the Caermarthenshire hills of South Wales, where the Upper Palaeozoic pebbles were obtained...Gwbert, and in a stream near by, a pebble of the riebeckite microgranite of Ailsa Craig was found. Above...the Department of Geology, University College of Wales, Aberystwyth Glacial Drifts of Cardiganshire. |  | | Book | | provided by: Amgueddfa Cymru (National Museum of Wales, Cardiff); British Geological Survey, Edinburgh...tellurob:smu'Ji::eC!ogau andVigramines,nr Oolgellau, Gwynedd, Wales t!.e'.don ra:::ayqJarry,nr o~eha'Tlp'.:i. ...United Kingdom, including England, Scotland and Wales, arc here referred to as Britain. The offshore teITitorics...but two). but these. along with many others in Wales, were swept awa) with the introduction of administn1tive...been found. followed by Benallt mine. Lleyn Peninsula, Gwynedd, Wales (4). Three localities (one in England |  | | Book (edition) | | Hillers, Henry Mountains . intrusive rocks of North Wales have an outcrop which indicates a laccolitic origin...g. , in the English Lake District and in North Wales) . Dykes and Veins. - A dyke is a wall-like mass...Isles. Much of the beautiful scenery of North Wales and of the Lake District owes its origin to the...Isle of Syra, Japan) . Gastaldite is a variety. Riebeckite . Monoclinic. Silicate of soda and iron -... ((See Fig. 44.) Maximum extinction = 59-70. Riebeckite occupies a position among the amphiboles equivalent |  | | Report (edition) | | SURVEY AND MUSEUM BRITISH REGIONAL GEOLOGY NORTH WALES by BERNARD SMITH, M.A., Sc.D., F.R.S. and T. NEVILLE...•• •• •• * II. PRE-CAMBRIAN ROCKS Anglesey and Lleyn; The Bangor and Padam Ridges III. THE CAMBRIAN SYSTEM...SYSTEM The Harlech Dome; The Lleyn Peninsula; Caernarvonshire; Minerals in the Cambrian Rocks. IV. THE...North Wales . 75 78 IV ILLUSTRATIONS FIGURES IN TEXT PAGE The rock succession in North Wales Geological...lateral variations in the Cambrian rocKs ot .North Wales Map and section of the Cambrian rocks in the neighbourhood |  | | Journal (article/letter/editorial) | | presence of glaciers in the mountain valleys of North Wales, much has been written concerning the glaciation...stretches south-westwards as the broad promontory of Lleyn between Carnarvon Bay and Cardigan Bay. Western...account of the Drift deposits over the whole of Lleyn, but various references to the glaciation of the...scattered in the literature dealing with the geology of Wales. Among these one of the most interesting and most...the " Diluvial Deposits of North Wales " (p. 398). Concerning Lleyn he says : " The promontory which | | | Report (edition) | | British Regional Geology TOM c o s t e s North Wales THIRD EDITION By Bernard Smith, MA, ScD, FRS, and...Geological Research II. PRE-CAMBRIAN ROCKS Anglesey and Lleyn; The Bangor and Padam Ridges 1 7 III. THE CAMBRIAN...CAMBRIAN SYSTEM The Harlech Dome; The Lleyn Peninsula; Caernarvonshire; Minerals in the Cambrian Rocks...North Wales 89 iv ILLUSTRATIONS FIGURES IN TEXT FIG. 1PAGE The rock succession in North Wales Geological...of Pre-Cambrian rocks on the mainland of North Wales 5. Cambrian fossils 6. Geological map of the Harlech |  | Stephenson, D., Bevins, R. E., Millward, D., Highton, A. J., Parsons, I., Stone, P., Wadsworth, W. J. (1999) References, Glossary & Index. In Caledonian Igneous Rocks of Great Britain (Geological Conservation Review Series - Geological Conservation Review No. 17. Joint Nature Conservation Committee, Peterborough. p.575-648. | Book (chapter) | | Survey, Edinburgh R.E. Bevins National Museum of Wales, Cardiff D. Mi award British Geological Survey,...Townsend Tuff Bed (Lower Old Red Sandstone) in South Wales and the Welsh Borders. Journal of the Geological... R. (1982) The Devonian geology of the Walls Peninsula, Shetland. Unpublished PhD thesis, University... (1979) Summer (1973) field meeting in Central Wales, 31 August to 7 September 1973. Report by the organising...Volcanic Group, Snowdonia, North 576 References Wales. British Geological Survey Research Report, No. |  | | Book | | rnernoi.r covers the central area of the Llyn Peninsula in north-west \i\lales. It lies on the north coast...Precarnbrian in the west, Cambrian on St Tudwal's Peninsula a nd Ordovician underlying most of the area. This...lead, zi nc, copper and silver on St Tudwal's Peninsula, and the rnajor resources of sand and gravel that...the fa·mous Cambria n rocks of the St Tudwal's Peninsula, with its superb sub-Ordovician ang1.1lar unconformity...unconformity at T rwyn Llech-y-doll, St Tudwal's Peninsula. The cliffs in the background are of Aren ig sandstones | | | Report (edition) | | F4 Fs iL a7 aa me | _ ae a | ' 4 | Piz 4 Wales, d ae ae 4 ; Front cover Aber Falls. Face...Research Council British Regional Geology North Wales THIRD EDITION By Bernard Smith, MA, and T. Neville...Anglesey and Lleyn; The Bangor and Padarn Ridges THE CAMBRIAN SYSTEM The Harlech Dome; The Lleyn Minerals...in the Cambrian Rocks IV. THE ORDOVICIAN Peninsula; Caernarvonshire; SYSTEM Basal Unconformity;...publications relating to the geology a of North Wales 82 89 iv ILLUSTRATIONS FIGURES FIG. 1. 2. | | | Report (edition) | | Research Council British Regional Geology North Wales THIRD EDITION By Bernard Smith, MA, ScD, FRS, and.... .. .. .. II. PRE-CAMBRIAN ROCKS Anglesey and Lleyn; The Bangor and Padam Ridges • • • • III. THE...THE CAMBRIAN SYSTEM The Harlech Dome; The Lleyn Peninsula; Caemarvonshire; .. Minerals in the Cambrian...important publications relating to the geology of North Wales .. .. .. .. .. .. . . 89 lV ILLUSTRATIONS FIGURES...PAGE .. .. .. .. .. The rock succession in North Wales .. Geological map of Anglesey .. .. .. .. .. .. |  | | Book (edition) | | Surv. , 1904, p. 209. ) intrusive rocks of North Wales have an outcrop which indicates a laccolithic origin...example, Cornwall, the English Lake District, North Wales, Western Isles of Scotland, and Fife. The Whin...British Isles. Much of the beautiful scenery of North Wales and of the Lake District owes its origin to the...soda-amphiboles and soda-pyroxenes occur (e.g., riebeckite, arfvedsonite, cossyrite, ægirine). Potash also...Isle of Syra, Japan). Gastaldite is a variety. Riebeckite. Monoclinic. Silicate of soda and iron : Na |  | | Book (edition) | | Igneous Geol. Surv., 1904, p. 209.) rocks of North Wales have an outcrop which indicates a laccolithic origin... example, Cornwall, the English Lake District, Wales, Western Isles of Scotland, and Fife. The Whin Sill...British Isles. Much of the beautiful scenery of North Wales and of the Lake District owes ment of erupted...and soda-pyroxenes occur (e.g., arfvedsouite, riebeckite, Potash also enters into cossyrite, the...microgranites and trachytes (Socotra, Mynydd Mawr in Wales, Ailsa Craig and Eildon Hills in Scotland). Crocidolite |  | | Journal (article/letter/editorial) | | gneiss quart z-K-feldspar-plagioclase-hornblende, riebeckite-acmite-zircon-sphene 638 *z Vellingiri Bhavani...Streckeisen (1976). Greenish pleochroic hornblende, riebeckite, aegifine and acmite occur in some of the samples...and subalkaline granite plutons of the Lleyn Peninsula, North Wales, U.K. (Croudace, 1982 ). The normalised...these are similar to the patterns in albitised riebeckite granites reported by Bowden and Whitley (1974)...lower Palaeozoic granitoids of the Llyen Peninsula, North Wales. Geochim. Cosmochim. Acta, 46: 609-622 |  | | Book (edition) | | Isle of Syra, Japan) . Gastaldite is a variety. Riebeckite . Monoclinic. Silicate of soda and iron - Na...Occurs in certain felsites ( Socotra, Myndd Mawr in Wales, Ailsa Craig in Scotland) . Crocidolite is a variety...hope (augite- granite) . Wales. St. Davids , and many places in North Wales and Anglesey ; e.g. , Twt...g. , the quartz-porphyries of St. Davids, South Wales ; the Armboth dyke in the Lake District ; and the...known in South Wales ; for example, at St. Davids, Ramsey I., Skomer I. In North Wales, felsites of Lower |  | | Book | | BASIN VOLC DOC) MARGINAL SM IN SNO (NORTH-WEST WALES) ONIA .. .. • • Front co11er Tryfan, viewed...marginal basin volcanism in Snowdonia (north-west Wales). (London : HMSO for the British Geological Survey...based on Ordnance Survey mapping. Printed in the UK for HMSO Dd 291125 ClO W91 ... lU CONTENTS ...plutons 125 Dolerite and basalt intrusions 127 Lleyn Teyrn andesite intrusion 139 Petrogenesis of the...map of Wales xi Representation of Harker's diagram, NW Wales 1 Disposition of England and Wales, and Scotland |  | | Journal (article/letter/editorial) | | the northern foot of Crib Goch, " unmatched in Wales for wildness," as Ramsay says, containing two small...essay on the" Old Glaciers of Switzerland and North Wales" (r860). From the Pen-y-Pass, the P.-y-G. track...serves many of the chief slate-quarries of North Wales and provides the lighting of many villages. Structurally...south to the Harlech Dome and west along the Lleyn peninsula was 194 HOWEL WILLIAMS, indescribably grand...the valley to collect specimens of this famous riebeckite-granite, rejoining the main party a few hours |  | | Report (issue) | | REPORTS: (A)-ENGLAND AND WALES: 1 . South... West England and South Wales District (a) South-West England...South Wales . .. • • • • 2. South-Eastern District •• • • • • 3. West Midlands and Central Wales District...re-survey of the six-inch geological maps of England, Wales and Scotland was continued mainly in the areas of...to the field staff, South-West England and South Wales District, to replace Mr.. R. A. Downing who returned...Mr. A. Horton (West Midlands, Central and North Wales District), Mr. J. H. Hull (North-Eastern District) |  | | Report (chapter) | | the British province, viz. Scotland, England and Wales. The geographical separation has been retained for...activity. South of the suture, in the Dingle Peninsula of southwest Ireland, and in one of the Blasket...Longford-Down massif, particularly on the Ards Peninsula, the metabentonites of the Birkhill Shales represent...Britain From the ornament on Plate 1 across mainland UK three main sectors can be distinguished. The northernmost...most of northern and central England and all of Wales. The third, southern sector, formed of southwest |  | | Report (issue) | | ••• ••• • •• DISTRICT REPORTS(A)-ENGLAND AND WALES. Introduction by T. EASTWOOD, ... . .. A.R.C.S...South Wales and Bristol District, by R. W. .. . ... ... ... . .. PococK, D.Sc. 3. North Wales and Midlands...PLATE Index to the Geological Map of E;ngland and Wales (1 : 63,360) •• • FACING PAGE TEXT FIGURES FIG...position may be summarised as follows:- England and Wales · 1 .. Primary six-inch survey: Chatham Sheet (272)...(273) and Yeovil Sheet (312) commenced. 2. SOUTH WALES AND BRISTOL DISTRICT. Primary six-inch survey: Chepstow |  | | Book | | AlTa04, E Orth. Adamantine colorless. Kola Peninsula, USSR. H= 7.5-8, Djj4=?, D(.= 5.623, IVD 14a....Vitreous green, greenish-white. Anapa, Taman Peninsula, Russia, USSR. H=3.5, Djjj= 2.816, D(.= 2.811...white, grey, yellow, green, blue. Isle of Anglesey, Wales. H= 2.5-3, 6.38, Dc= 6.321, VIA 07. Beudant, 1832...colorless. Khibina massif, Vuonnemi river, Kola Peninsula, USSR. H= 5, Djjj=3.13, Dq—3.19, VIIB 18. Khomyakov...Translucent colorless, light brown. Kimba, Eyre Peninsula, South Australia, Australia. H= 3.5, Djj4= 4 |  | | Book (edition) | | Iceland 83. Riebeckite-microgranite, Ailsa Craig, Firth of Clyde, Scotland 84. Riebeckite-microgranite...e, Mynydd Mawr, Carnarvonshire, North Wales 85. Devitrified porphyritic pitchstone, Petit Porte/et, Jersey...Jersey, Channel Islands 86. Spherulitic riebeckite-rhyolite, near Ayaka Leru, North Nigeria 87. Some...Variolitic basalt, near Rhobell Fawr, Merionethshire, Wales Olivine-basalts from the Auvergne, France Map of...South Hill, St. Helier, Jersey Vogesite, Ards Peninsula, Ireland Hortonolitite, Mooihoek, Bushveld Complex |  | | Journal (article/letter/editorial) | | magnetite-keratophyres described by Benson 1 from New South Wales. The porphyritic types are admirably exemplified...felspathic basalts. 1 2 Pror. Linn. Soc. X.S. Wales, xliii, 1918, .'{72. Sil. Mem., 44o. The Ballantrae...by Professor Bonney from Penarfynydd in the Lleyn peninsula, Carnarvonshire, and that it resembled certain...number of the dykes that there intersect the riebeckite micro-granite. Upon examination, these rocks |  | | Book (edition) | | strongly coloured amphiboles-arfvedsonite or riebeckite-often in reaction relationship. Itis instructive...arfvedsonite, the very distinctive glaucophane and riebeckite, again end-members of yet another variable series...traces. One significant point here is that while riebeckite and glaucophane both have much the same extinction...associated with aegirine-augite in some cases, but riebeckite in others. These brown amphiboles contain approximately...sphene would suggest kaersutite. Glaucophane and riebeckite are chemically related sodic amphiboles but differ |
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