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Newsletter - June 2012

The full, illustrated newsletter is available as a pdf for download. Text extracts are given below.

Editorial

Welcome to a packed June newsletter! Inside is an article from a new member, a review of a piece of fossil curating software, a field report from the Broadhurst Memorial Walk plus two book reviews. Many thanks to those who have contributed and if you have any articles to contribute for the September newsletter please email them to me by the end of August.

For those members on the internet, please remember to sign up to the MGA's Facebook group, where members can post interesting geological news items as well as getting updates from the association. Details of this and how to join are in the March newsletter. We have had some members join already but it would be great to get some more.

In other news, Derek Brumhead has brought to my attention the Geomap project in the Forest of Dean, which celebrates the geology and industrial history of the Forest. It is a geological map built in the forest, showing the geology of the Forest, made of the actual stones that the map represents, it also includes details of old mines and industry - it looks like it is well worth a visit (more information here).

Council news - We are looking for a new Membership Secretary to take over from Lisa Abbott who has done an excellent job over the last 2 years. If interested please contact us, being membership secretary is an interesting and rewarding role on the council which involves lots of interaction with our members.

James Jepson
Newsletter Editor

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Article

I am a new member of MGA with a rapidly growing interest in geology which has arisen from wanting to discover more about "what's under my feet". As a keen walker, I have become increasingly fascinated with observing geological features and different rock types, collecting the occasional rock samples beneath my feet on my numerous walks in England, Scotland, and Wales, also on the Isle of Skye and in the French Alps. My mini cairns of rock samples are slowly gathering along the garden wall and my wife is just about tolerant of my collections, at least for the moment!

I have recently enjoyed two excellent guided geology walks in both Snowdonia and The Lakes; course details here and here. The extremely knowledgeable guide, Paul Gannon, is the author of three well illustrated books titled Rock Trails: Snowdonia (2008) Lakeland (2009) and Peak District (2010). Each book begins with a general introduction followed by more detailed geological descriptions and explanations of the various landscapes. I have found all the books to be very helpful beginner's guides to geological terms with multiple diagrams and photographs, accompanied by clear and lucid explanations. At the end of each book, there are between 13-15 graded walks with in-depth accounts and portrayals of geological events, features and rock types. I have already had great pleasure in doing several of these walks from all three books, observing and learning about amazing geology along the way shown in the pictures I have taken!

As I approach my final years as a NHS medical practitioner, I hope to increase my knowledge, understanding and appreciation of another science for pleasure and leisure, and look forward to meeting and learning from both like-minded amateur and professional geologists.

Stephen Proctor


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TriloBase, the fossil-specific database software - A fabulous find in The Netherlands

Introduction and background: TriloBase is a database constructed by a field-based palaeontologist/geologist for fellow palaeontologists and fossil collectors. The software is sleek and for the most part intuitive to use. Although TriloBase is frighteningly cheap to buy do not be put off by this - it is well thought out and created by an end-user rather than a techno-geek (my apologies to any palaeo techno-geeks out there).

Why am I going to the trouble of writing a review about databasing software? Well, let me preface what I am about to write by saying that I am an amateur 'fossil nut' rather than a professional palaeontologist or geologist, but I do take my hobby quite seriously. I have collected fossils for many years and still have my very first fossil - a small death plate of Dactylioceras sp. ammonites purchased in 1986 for the princely sum of £4.50. Whilst my collection is hardly a rival for the NHM London I began to realise that I might lose track of what I have, so I embarked on an internet search about fossil collection curating... and databasing. The two most obvious database options were (1) a card index database - I am of that era, the Archeon - or (2) an electronic database, Microsoft Access being the obvious choice. I dislike the clunky Access database, so the quest for a better database began. I scoured the internet and looked at the various options then I happened upon TriloBase, written by Danny Alexandre (DA) in The Netherlands, and what a find it turned out to be! I test drove the trial version available here and discovered that it was exactly what I needed. The full version is available on CD from the same website for the crazily small sum of £12, along with which you will receive a product key that works for a specified period - more of this later.

(The illustrated, full review is available in the newsletter pdf)

Sue Shawcross PhD CBiol MSB


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The 2012 Broadhurst Memorial Walk

The Broadhurst Memorial Walk for 2012, led by Jane Michael, was based on an excursion described by Fred Broadhurst in his guidebook "Rocky Rambles in the Peak District". The walk started at the scenic village of Rowarth, taking in some typical Pennine scenery.

The bedrock hereabouts is Middle and Upper Carboniferous with some glacial cover. From the car park at Rowarth we walked north-north-east on a footpath beside a stream, where the dip in the Rough Rock sandstone was checked to be south-east. From here we continued eastward on to Harthill, where a good view was obtained of the dipping rocks of the Goyt syncline.

In the wall by a stile approaching Matleymoor Farm there is a block of light-coloured ganister, the remnant of a sandy soil leached of minerals by plants growing in it. A Stigmaria root can be seen in the ganister, standing vertically now though originally growing horizontally. Rows of rootlet scars surround the root, which has been compressed from a round to an elliptical shape by later overburden.

From here we turned southwards along the Pennine Bridleway to Lantern Pike, from the summit of which there are extensive views of the surrounding countryside - eastwards across to the Kinderscout Grit exposed in the Kinder Plateau, southwards toward Chinley Churn, with the large quarry at Birch Vale in the westerly-dipping Woodhead Hill Rock.

Retracing our steps to the foot of Lantern Pike, after lunch, we turned north-westwards to join a south-westerly path from Blackshaw Farm, investigating en route extensive rows of pits, which had possibly been sunk into the Yard Coal for coal or to extract stone.

Joining a path heading north-west back to Rowarth we stopped to examine an abandoned quarry in the Woodhead Hill Rock. This is situated near the axis of the syncline, and shows abundant crossbedding and small concretions ca. 2.5cm diameter.

Returning to the footpath, Jane found some glacial erratics in the cobbles beside the path which had weathered to a whitish skin. The range of rock type of the erratics is consistent with them being derived from the Borrowdale Volcanic Group found in the Lake District and provides evidence of the likely course of the glaciers.

The final stretch of the path cuts through the softer mudstones beneath the Woodhead Hill Rock before reaching the Rough Rock again near the inn in Rowarth. In so doing we have returned down-sequence from the Upper to the Middle Carboniferous, passing though the Gastrioceras subcrenatum marine band (not seen).

The Goyt Syncline is a broadly north-south trending structure plunging gently southward. The walk, in summary, provides good views of its structure, starting near the nose of the syncline before moving onto its eastern limb then back towards its axis. Thanks to Jane Michael for a very interesting day.

Jim Spencer


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Book Reviews

Introducing Volcanology: A Guide to Hot Rocks by Dougal Jerram
Dunedin Academic Press - 2011
ISBN 978-1-906-71622-6
Paperback: £9.99


Introducing Volcanology is an introduction to all aspects of volcanology, from melting, to eruption and volcanic hazards. The book is well-illustrated throughout, with many of the diagrams being useful references for the more knowledgeable reader too. New terms are introduced in bold type in the text, with further detail given in a comprehensive glossary at the back of the book.

The first chapter provides a good background on rock types and mineralogy, giving more detail on the common volcanic minerals, and on the classification of volcanic rocks. The Earth's interior is introduced in chapter 2, with discussion on the role of radioactive decay on the rate of the Earth's cooling. The relationship between temperature, pressure and water in the melting of rocks is also explained, as well as what can be learned from the study of crystals, melt inclusions and their related melts. Chapter 3 introduces plate tectonics and palaeomagnetism, explaining the links between plate tectonics, earthquakes, and volcanic activity. This chapter further expands on the mechanisms for inducing melting, and a brief discussion of volcanism on other planets and their satellites is included. Eruption styles are covered in chapter 4, which also includes detailed illustrations showing the relationship between viscosity of magmas, and volcano morphology and eruption style. Discussion on the effects of magma viscosity continues in chapter 5, where the links between the type of lava flow and its silica content and viscosity is explained. Pyroclastic flows, air falls, and their related deposits are introduced in chapter 6, which contains useful illustrations of the pyroclastic classification schemes. Chapter 7 provides a background on igneous intrusions and their emplacement, including sills, dykes, plugs and diapirs. The effect of volcanism on the Earth's climate and life is discussed in chapter 8, with particular reference to the Large Igneous Provinces and their potential links to the major mass extinction events. The effects of the two geologically recent eruptions at Laki, Iceland (1783-4) and Pinatubo, The Philippines (1991) are covered in more detail. Volcanic monitoring is covered in chapter 9, with chapter 10 providing insight into the relationship between volcanoes and man; the book rounds up by covering four eruptions which have affected life on the planet, including the recent (2010) Eyjafjallajökull eruption.

At ten chapters long, the book is an accessible and well-written introduction to the field of volcanology, and is also a good basic reference text for those who already have some knowledge on the subject area. Introducing Volcanology aims to be a concise introduction to the topic for those readers with little or no previous knowledge, and as such it doesn't go into great depth in any area, but does provide a good basic background to many areas of volcanology. As an entry level text, a "Further Reading" section may have been a useful addition, to point the enthusiastic reader in the direction of more detailed literature. A few of the figure captions and tables would have benefited from more thorough proof-reading, but these small errors do not detract from the overall text.

Introducing Volcanology is well-priced at £9.99, making it an ideal starting point for the interested reader. The book is part of a new series of geology texts, which aims to provide a concise introduction to different geological topics, including volcanology, plate tectonics, and palaeontology. Introducing Palaeontology will be reviewed in the September newsletter.

Lisa Abbott
University of Manchester

Geology for Dummies by Alecia M. Spooner
John Wiley & Sons - 2011
ISBN 978-1-118-02152-1
Paperback £15.99


My initial concerns were that Geology for Dummies would be just another one of those watered-down, American-style text books on Geology that tried to do too much and fell short of being useful. My fears were somewhat unfounded and I found the reality very readable, informative and, though lacking detail, never-the-less a good sound introduction for students new to the subject.

The book comprises 25 separate chapters organised under six main headings:

1 . Studying the Earth: 4 chapters providing an introduction to geological science giving an overview of the scope and practise of the subject involved with its laws and principles. The later part gives a basic outline of the earth's systems and structure from the atmosphere to the core.

2. Elements, Minerals and Rocks: 3 chapters outlining the physical and chemical properties of minerals and in particular the structure of silicate minerals. Igneous, sedimentary and metamorphic rocks are then explained with reference to their mineralogy, texture and mode of formation within the rock cycle. Within 30 pages rocks are identified, classified and their processes briefly explained using jargon-free language that is easy to access for later reference.

3. One Theory to explain it all: Plate Tectonics: 3 chapters reviewing current understanding of plate theory and the evidence. This is a good section with a basic but full outline of the evidence for the various boundaries and processes involved, including partial melting, earthquakes and current models for mantle convection.

4. Superficially speaking : About Surface Processes: 5 chapters which inevitably cover all the surface processes (above and below ground) in the rock cycle as in most physical geology texts for the American market. This is in more detail than is really needed for UK geology specifications (e.g. geomorphology of braided streams, meandering streams, straight channels, oxbow lakes etc. all included in detail) though useful background. Whilst glacial, aeolian and fluvial and coastal sedimentary environments are included, sadly shallow (coral reef) and deep marine environments and processes (turbidity currents) are not mentioned or are poorly covered. Interestingly, in the chapter on glaciers, the author briefly deals with Milankovic cycles and climate change.

5. Long, long ago, in this galaxy right here: 7 chapters covering the 4.6 billion years of geological time. This section includes geochronological principles and absolute dating methods in some detail (isotopic and dendrochronological methods). It also covers basic palaeontology, the evolution of animals and plants and their increasing diversity through time along with theories of mass extinctions. As a basic grounding of the stratigraphic column it is excellent, even mentioning the Burgess Shale lagerst├Ątten and Snowball Earth theory though this book does not attempt to cover fossil morphology and many faunal groups are not mentioned (e.g. graptolites, brachiopods or bivalves).

6. The part of tens: This short section of 2 chapter briefly deals with the human influence of man on geology (building dams, fracking for gas, climate change etc. ) and vice versa (hazards associated with earthquakes, landslides, and volcanic eruptions). There are few case studies and this section is more a note to refer you other sources.

The book is presented in the format of other Dummies publications, written in a clear, often humorous style and illustrated with a large number of black and white line drawings to visually illustrate an idea. Some of these are good but often they are over stylised and sometimes they detract and give a false impression, particularly when they are devoid of scales and annotation. In addition there are 8 pages of excellent colour photos. As yet I have not found any glaring howlers in the text that would endorse the misconceptions already given by other sources, though I did wince when I read that "The line where the material in the earth's lithosphere changes from the crustal rock to the mantle rock (the asthenosphere) is named the Moho..."

Like all books in the dummies series, Geology for Dummies is not meant to be anything other than a general course introduction to the extensive subject that encompasses geology, and as such it does its job well. So whilst being superficial in its depth, it is cheap and there is enough in here for me to recommend it to anyone starting the subject from scratch.

Indeed, there is little excuse for them feeling like "dummies" for too long with this as a guide.

Pete Loader
Geology Master, St Bede's College


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