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Coesite Inclusions: Microbarometers in Diamond
Coesite Inclusions: Microbarometers in Diamond Ren Lu GIA Laboratory, New York Mineral inclusions in diamond provide valuable information for decoding their thermobarometric, mechanical, and mineralogical conditions during and after diamond formation deep within the earth’s mantle. Coesite, a polymorph of silica (SiO2), shares the same chemical composition as quartz but has a different crystal structure and a higher Mohs hardness Anthony et al., 1990). Coesite forms at pressures greater than 2 GPa (i.e., 20,000 times atmospheric pressure). It has been found in high-impact meteorite craters and as inclusions in minerals and diamonds in ecologites in ultrahigh-pressure metamorphic terrains (Sobolev et al., 1999). Mineral inclusions in diamonds record the physical and chemical history of diamond formation; consequently, they provide a window to processes occurring in the deep interior of the mantle. Microscopic Raman spectroscopy is a very effective “fingerprint” technique for identifying unknown materials such as inclusions in gems, because Raman spectral features closely correlate to the crystal structure and chemistry of a material. Furthermore, this technique is nondestructive and requires virtually no sample preparation. We recently examined a suite of high-quality pink diamonds set in a bracelet. These stones were type Ia and exhibited gemological and spectral characteristics typical of the rarest group of high-quality Argyle pink diamonds (refer to table 2 in Shigley et al., 2001). A cluster of mineral inclusions were present in a 0.21 ct marquise in the intense to vivid purple-pink color range (figure 1). Raman spectra were collected with a Renishaw inVia confocal Raman system interfaced with 488, 514, 633, and 830 nm laser excitations. -
Scottish Journal of Geology
Scottish Journal of Geology On the origin and stability of remanence and the magnetic fabric of the Torridonian Red Beds, NW Scotland T. H. Torsvik and B. A. Sturt Scottish Journal of Geology 1987; v. 23; p. 23-38 doi: 10.1144/sjg23010023 Email alerting click here to receive free e-mail alerts when service new articles cite this article Permission click here to seek permission to re-use all or request part of this article Subscribe click here to subscribe to Scottish Journal of Geology or the Lyell Collection Notes Downloaded by on January 24, 2012 © 1987 Scottish Journal of Geology On the origin and stability of remanence and the magnetic fabric of the Torridonian Red Beds, NW Scotland T. H. TORSVIK1 and B. A. STURT2 institute of Geophysics, University of Bergen, N-5014 Bergen-U, Norway 2Geological Survey of Norway, Leif Eirikssons vei 39, P.O. Box 3006, N-7001 Trondheim, Norway SYNOPSIS Primary (compactional) magnetic fabrics and multicomponent rem- anences are recognized in the Stoer and Torridon Groups. Low tempera- ture (LT) blocking remanences are randomized around 400-600°C and relate to a post-Torridonian magnetic overprint, possibly of early Mesozoic age. In the Stoer Group (and some Stoer boulders in the basal Torridon Group) LT remanences are partly or fully carried by magnetite (titanomagnetite). High temperature (HT) remanences are characterized by discrete unblocking above 600°C, having a specular haematite remanence carrier. Results of a conglomerate test of some Stoer boulders provides a positive stability test for HT remanences in the Torridon Group, and a convergence of evidence suggests that remanence acquisi- tion of both the Stoer and Torridon Groups was facilitated by both detrital and early diagenetic processes. -
Relict Zircon Inclusions in Muong Nong-Type Australasain Tektites: Implications Regarding the Location of the Source Crater
Lunar and Planetary Science XXXI 1196.pdf RELICT ZIRCON INCLUSIONS IN MUONG NONG-TYPE AUSTRALASAIN TEKTITES: IMPLICATIONS REGARDING THE LOCATION OF THE SOURCE CRATER. B. P. Glass, Geology Department, University of Delaware, Newark, DE 19716, USA ([email protected]) Introduction: Over the last thirty years we Australasian tektite samples from which we have have recovered crystalline inclusions from ap- identified inclusions; however, not all of the recov- proximately forty Muong Nong-type tektites from ered inclusions have been identified by XRD. the Australasian tektite strewn field in order to Based on appearance, the percent of inclusion- learn more about the nature of the parent material bearing specimens containing zircon is probably and the formation process [e.g., 1, 2]. More re- 100% or very close to it. Nearly all the zircons cently we have used geographic variations in con- are opaque white and their X-ray patterns show centration (number/gm) of crystalline inclusions to extreme X-ray asterism. However, of the 28 zir- indicate the possible location of the source crater cons identified by X-ray diffraction, only two [3]. The purpose of this abstract is to summarize (both from the same specimen whose place of ori- all the presently available data regarding relict gin is unknown) produced X-ray diffraction pat- zircon inclusions recovered from Australasian terns indicating that baddeleyite may be present. Muong Nong-type tektites and to discuss implica- The X-ray patterns from these two grains con- tions regarding the possible location of the source tained the two strongest lines for baddeleyite and crater which has still not been found. -
A Detrital Zircon and Apatite Provenance Study of the Stac Fada Member and Wider St
On the track of a Scottish impact structure: a detrital zircon and apatite provenance study of the Stac Fada Member and wider Stoer Group, northwest Scotland Gavin G. Kenny1,2*, Gary J. O’Sullivan1, Stephen Alexander1, Michael J. Simms3, David M. Chew1 and Balz S. Kamber1,4 1Department of Geology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland 2Department of Geosciences, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden 3Department of Natural Sciences, National Museums Northern Ireland, Cultra, BT18 0EU Northern Ireland, UK 4School of Earth, Environmental and Biological Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia *[email protected] Abstract The Stac Fada Member of the Stoer Group, within the Torridonian succession of northwest Scotland, is a melt-rich, impact-related deposit that has not been conclusively correlated with any known impact structure. However, a gravity low approximately 50 km east of the preserved Stac Fada Member outcrops has recently been proposed as the associated impact site. Here we aimed to shed light on the location of the impact structure through a provenance study of detrital zircon and apatite in five samples from the Stoer Group. Our zircon U-Pb data is dominated by Archaean grains (>2.5 Ga), consistent with earlier interpretations that the detritus was derived largely from local Lewisian Gneiss Complex, whereas the apatite data (the first for the Stoer Group) display a single major peak at ca. 1.7 Ga, consistent with regional Laxfordian metamorphism. The almost complete absence of Archaean-aged apatite is best explained by later heating of the >2.5 Ga Lewisian basement (the likely source region) above the closure temperature of the apatite U-Pb system (~375-450°C). -
Tracking the Evolution of the Grenville Foreland Basin
Krabbendam et al: Detrital zircon and rutile in the Sleat and Torridon groups Tracking the evolution of the Grenvillian Foreland Basin: constraints from sedimentology and detrital zircon and rutile in the Sleat and Torridon groups, Scotland Maarten Krabbendam a, *, Helen Bonsor a, Matthew S.A. Horstwood b, Toby Rivers c a) British Geological Survey, Lyell Centre, Research Avenue South, Edinburgh EH14 4AP, Scotland, UK b) NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth NG12 5GG, UK c) Department of Earth Sciences, Memorial University of Newfoundland, St. John’s, NL Canada A1B 3X5 * Corresponding author. Email: [email protected] Keywords: foreland basin; provenance; detritus; Grenville Orogen; U-Pb geochronology; Neoproterozoic 1 Krabbendam et al: Detrital zircon and rutile in the Sleat and Torridon groups Abstract The Grenville Orogen, although occupying a key position in the Rodinia supercontinent, lacks a clear foreland basin in its type area in eastern Canada. Early Neoproterozoic siliciclastic rocks in northern Scotland, however, are now interpreted as remnants of a proximal Grenvillian foreland basin. Analysis of the sedimentology and detrital zircon and rutile of the Torridon and underlying Sleat groups provide new constraints on the evolution of this basin. Youngest U-Pb detrital zircon grains yield ages of 1070-990 Ma in both groups, consistent with a Grenvillian source. The proportions of older age components vary throughout the stratigraphy. The lower Sleat Group shows a dominant ca. 1750 Ma peak, likely derived from local Rhinnian rocks in Scotland and Ireland uplifted within the Grenville Orogen. In the upper Sleat Group and Torridon Group, detrital zircon peaks at ca. -
Orcadian Basin Devonian Extensional Tectonics Versus Carboniferous
Journal of the Geological Society Devonian extensional tectonics versus Carboniferous inversion in the northern Orcadian basin M. SERANNE Journal of the Geological Society 1992; v. 149; p. 27-37 doi:10.1144/gsjgs.149.1.0027 Email alerting click here to receive free email alerts when new articles cite this article service Permission click here to seek permission to re-use all or part of this article request Subscribe click here to subscribe to Journal of the Geological Society or the Lyell Collection Notes Downloaded by INIST - CNRS trial access valid until 31/05/2008 on 31 March 2008 © 1992 Geological Society of London Journal of the Geological Society, London, Vol. 149, 1992, pp. 21-31, 14 figs, Printed in Northern Ireland Devonian extensional tectonics versus Carboniferous inversion in the northern Orcadian basin M. SERANNE Laboratoire de Gdologie des Bassins, CNRS u.a.1371, 34095 Montpellier cedex 05, France Abstract: The Old Red Sandstone (Middle Devonian) Orcadian basin was formed as a consequence of extensional collapse of the Caledonian orogen. Onshore study of these collapse-basins in Orkney and Shetland provides directions of extension during basin development. The origin of folding of Old Red Sandstone sediments, that has generally been related to a Carboniferous inversion phase, is discussed: syndepositional deformation supports a Devonian age and consequently some of the folds are related to basin formation. Large-scale folding of Devonian strata results from extensional and left-lateral transcurrent faulting of the underlying basement. Spatial variation of extension direction and distribution of extensional and transcurrent tectonics fit with a model of regional releasing overstep within a left- lateral megashear in NW Europe during late-Caledonian extensional collapse. -
OUGS Journal 32
Open University Geological Society Journal Volume 32 (1–2) 2011 Editor: Dr David M. Jones e-mail: [email protected] The Open University Geological Society (OUGS) and its Journal Editor accept no responsibility for breach of copyright. Copyright for the work remains with the authors, but copyright for the published articles is that of the OUGS. ISSN 0143-9472 © Copyright reserved OUGS Journal 32 (1–2) Edition 2011, printed by Hobbs the Printers Ltd, Totton, Hampshire Committee of the Open University Geological Society 2011 Society Website: ougs.org Executive Committee President: Dr Dave McGarvie, Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA Chairman: Linda Fowler Secretary: Sue Vernon, Treasurer: John Gooch Membership Secretary: Phyllis Turkington Newsletter Editor: Karen Scott Events Officer: Chris Arkwright Information Officer: vacant at time of going to press Branch Organisers East Anglia (EAn): Wendy Hamilton East Midlands (EMi): Don Cameron East Scotland (ESc): Stuart Swales Ireland (Ire): John Leahy London (Lon): Jenny Parry Mainland Europe (Eur): Elisabeth d'Eyrames Northumbria (Nor): Paul Williams North West (NWe): Mrs Jane Schollick Oxford (Oxf): Sally Munnings Severnside (Ssi): Janet Hiscott South East (SEa): Elizabeth Boucher South West (SWe): Chris Popham Walton Hall (WHa): Tom Miller Wessex (Wsx): Sheila Alderman West Midlands (WMi): Linda Tonkin West Scotland (WSc): Jacqueline Wiles Yorkshire (Yor): Geoff Hopkins Other officers (non-OUGSC voting unless otherwise indicated) Sales Administrator (voting OUGSC member ): vacant at time of going to press Administrator: Don Cameron Minutes Secretary: Pauline Kirtley Journal Editor: Dr David M. Jones Archivist/Reviews: Jane Michael Webmaster: Stuart Swales Deputy Webmaster: Martin Bryan Gift Aid Officer: Ann Goundry OUSA Representative: Capt. -
Stratigraphical Framework for the Devonian (Old Red Sandstone) Rocks of Scotland South of a Line from Fort William to Aberdeen
Stratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen Research Report RR/01/04 NAVIGATION HOW TO NAVIGATE THIS DOCUMENT ❑ The general pagination is designed for hard copy use and does not correspond to PDF thumbnail pagination. ❑ The main elements of the table of contents are bookmarked enabling direct links to be followed to the principal section headings and sub-headings, figures, plates and tables irrespective of which part of the document the user is viewing. ❑ In addition, the report contains links: ✤ from the principal section and sub-section headings back to the contents page, ✤ from each reference to a figure, plate or table directly to the corresponding figure, plate or table, ✤ from each figure, plate or table caption to the first place that figure, plate or table is mentioned in the text and ✤ from each page number back to the contents page. Return to contents page NATURAL ENVIRONMENT RESEARCH COUNCIL BRITISH GEOLOGICAL SURVEY Research Report RR/01/04 Stratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen Michael A E Browne, Richard A Smith and Andrew M Aitken Contributors: Hugh F Barron, Steve Carroll and Mark T Dean Cover illustration Basal contact of the lowest lava flow of the Crawton Volcanic Formation overlying the Whitehouse Conglomerate Formation, Trollochy, Kincardineshire. BGS Photograph D2459. The National Grid and other Ordnance Survey data are used with the permission of the Controller of Her Majesty’s Stationery Office. Ordnance Survey licence number GD 272191/2002. -
TORRIDON Gikoup /~ L Purnpellgik~, E.Pidol'e R. I
Downloaded from http://mem.lyellcollection.org/ by guest on September 24, 2021 Chapter 5 Overview General aspects of the Torridonian briefly reviewed in the following instability and fault activity is evident from the time the earliest paragraphs include the significance of the similarity in depositional Stoer and Torridon Group sediments were deposited (pp. 20 & 44), style shown by the three component groups, their burial history, even though the soft-sediment contortions which formed during palaeocontinental setting and regional correlation. sedimentation and thought to be seismically induced, are noticeably absent from the lowest units (Clachtoll and Diabaig Formations). Contortions are also absent from the basal Sleat Group (Rubha Depositional style Guail and Loch na Dal Formations). The reason for the lack of contorted bedding in the lowermost formations and their abundance The Stoer, Sleat and Torridon Groups are thick fluvial succes- at other stratigraphic levels remains a mystery. sions, each of which tends to become finer upwards. The last two The tectonic instability recorded in the sediments, taken together groups both show an upward progression from locally derived basal with the palaeocurrent directions and evidence for decelerating breccias into lake deposits, followed by a thick fluvial sequence, subsidence, suggests rifting. The rift-bounding faults are surmised to as if they were deposited in a regime of decelerating subsidence. have dipped mainly eastwards, so that some of them were trans- In addition, both were derived from progressively more acid source formed into thrusts by Caledonian compression (Brewer & Smythe rocks, as the source terrain expanded to embrace not just local basic 1984; Blundell et al. -
Edinburgh Geologist No. 31. Autumn 1998
The Edinburgh Geologist Magazina of tho Edinburgh Gaological Soclaly Issue No. 31 Autumn 1998 Incorporating the Proceedings of the Edinburgh Geological Society for the 163rd Session 1996·1997 THE EDINBURGH GEOLOGIST Issue No. 31 Autumn 1998 Cover Illustration The cover illustration shows a drawing of Hemiarges iflghami, a trilobite from the Ordovician Stinchar Limestone ncar Girvan. This species lived along the coast of Laurentia, but found Avalonia a bit on the cool side. (see article by Phil SlOne, 'The Geology of Devolution' on page 8) The drawing is taken from a paper by R P Tripp (Pa laeolltology, 1979, Vol. 22, 339-361) and is reproduced by kind permission of the Palaeontological Association. Acknowledgements Publication of THE EDINBURGH GEOWGIST is supported by grants from the Peach and Horne Memorial Fund and the Sime Bequest Published October 1998 by The Edinburgh Geological Society Editor Alan Fyfe British Geological Survey Murchison Hou se Edinburgh EH93LA ISSN 0265-7244 Price £ 1.50 net Editorial by Alan Fyfc It is my pleasure to have been appointed as the editor of THE EDINBURGH GEOLOGIST and to welcome you to the thirty-first edition. I follow a long line of illustrious editors and hope that I am able to maintain the standard of the publication. My thanks are due to the outgoing editor, Andrew Highton for filling me in on the pitfalls and helping to get me started. This issue sees a slightly altered format, though the changes are largely cosmetic and I have attempted to maintain the general look and feel that has evolved over the years. -
The Dalradian Rocks of the North-East Grampian Highlands of Scotland
Revised Manuscript 8/7/12 Click here to view linked References 1 2 3 4 5 The Dalradian rocks of the north-east Grampian 6 7 Highlands of Scotland 8 9 D. Stephenson, J.R. Mendum, D.J. Fettes, C.G. Smith, D. Gould, 10 11 P.W.G. Tanner and R.A. Smith 12 13 * David Stephenson British Geological Survey, Murchison House, 14 West Mains Road, Edinburgh EH9 3LA. 15 [email protected] 16 0131 650 0323 17 John R. Mendum British Geological Survey, Murchison House, West 18 Mains Road, Edinburgh EH9 3LA. 19 Douglas J. Fettes British Geological Survey, Murchison House, West 20 Mains Road, Edinburgh EH9 3LA. 21 C. Graham Smith Border Geo-Science, 1 Caplaw Way, Penicuik, 22 Midlothian EH26 9JE; formerly British Geological Survey, Edinburgh. 23 David Gould formerly British Geological Survey, Edinburgh. 24 P.W. Geoff Tanner Department of Geographical and Earth Sciences, 25 University of Glasgow, Gregory Building, Lilybank Gardens, Glasgow 26 27 G12 8QQ. 28 Richard A. Smith formerly British Geological Survey, Edinburgh. 29 30 * Corresponding author 31 32 Keywords: 33 Geological Conservation Review 34 North-east Grampian Highlands 35 Dalradian Supergroup 36 Lithostratigraphy 37 Structural geology 38 Metamorphism 39 40 41 ABSTRACT 42 43 The North-east Grampian Highlands, as described here, are bounded 44 to the north-west by the Grampian Group outcrop of the Northern 45 Grampian Highlands and to the south by the Southern Highland Group 46 outcrop in the Highland Border region. The Dalradian succession 47 therefore encompasses the whole of the Appin and Argyll groups, but 48 also includes an extensive outlier of Southern Highland Group 49 strata in the north of the region. -
Ore Bin / Oregon Geology Magazine / Journal
The ORE BIN Volume 27, No.4 April, 1965 THE WALLS OF PORTLAND By Ralph S. Mason* Much publicity has been given in recent years to new construction in the Portland area, particularly to those sections undergoing urban renewal. Very little me!1tion has been made, however, of the role played by the min erai industry in the creation of attractive, long-lasting, economical, fire proof structures. Almost without exception, the recent advances in building construction have been concerned with improved techniques in the handl ing, fabrication, and erection of mineral industry products. lift slabs, tilt-up walls, prestressed and post-tensioned structural members, and slip forms are but a few examples of these developments. Anybody who has watched a multi-silo grain elevator rising into the air in one long, continuous move ment, or has seen a large, singfe-floor commercial building suddenly sprout walls overnight, has witnessed some of the more spectacular achievements made possible by the use of minerals in modern construction. The most noticeable part of any building is'usually its walls. Walls must be functional, giving support and protection to the building, but they can also be an ornament not only to the building but to the area as well. For the first time in history, the architect has no limitations as to length, width, or thickness of his materials. He has a wide choice of natural ag gregates and cut stone, a great variety of ceramic and concrete pre-cast units, and numerous methods for incorporating them into a wall. Brick Walls Historically, the first use of a manufactured mineral product for the construction of a wall was the laying of one sun-dried clay brick upon another by a Persian bricklayer more than 5,000 years ago.