Programme: 2011 - 2012

© Craven & Pendle Geological Society

Indoor Meetings

Friday: 14 October 2011
Why Microfossils?
John Varker Ph.D., University of Leeds (retired)

Friday: 11 November 2011
Miocene vegetation and climate: from the Brassington Formation of Derbyshire to global distributions Matthew Pound, MSci. (Geology), University of Leeds

Friday: 9 December 2011
Members Evening

Friday: 13 January 2012
Life and death at high latitudes: marine biodiversity, environmental change and extinction in latest Cretaceous Antarctica James Witts, MEarthSci. (Earth Science), University of Leeds

Friday: 9 March 2012
Meteorites, Stardust and the Early Solar System Professor Jamie Gilmour, University of Manchester

Friday: 30 March 2012
Strange places, the dales - the shaping of the Lakes and Pennines by huge landslips and rockslides
David Jarman, Mountain Landform Research, Stirling, Scotland

Friday: 20 April 2012
Death in a cold climate: Permian extinctions in Svalbard, Norway Professor Paul Wignall, University of Leeds

Field Meetings and Public Lecture

Sunday, 27 May
Penistone Hill Country Park (Haworth): rocks, quarrying, and landscape
Guides: Steve Birch & Karen Ashworth

Friday and Saturday, 22 - 23 June
Permian geology from South Shields to Seaham
Guide: Professor Paul Wignall

Free Public Lecture at the University of Leeds, 7pm, Tuesday, 3 July
A seismological journey to the centre of the Earth
Speaker: Professor Ed Garnero, Arizona State University, USA

Saturday, 14 July
Great Scar Limestone Group: Conistone Dib and the Cracoe reefs
Guide: Paul Kabrna

Sunday, 12 August
Geology and mineralogy of Grassington Moor
Guides: Alan French & Paul Kabrna

Saturday, 8 September
Geology of Ilkley Moor
Guide: David Leather


Why Microfossils?
John Varker

No diagnostic measurement exists for ‘microfossils’ since there is continuous overlap in species from the smallest microfossils to the largest macrofossils. Some species of Foraminifera for example are larger than some species of Trilobite, even though most would regard the former as microfossils and the latter as macrofossils. The clearest distinction is in the way in which these fossils are applied, since microfossils are primarily used to date drill chippings during continuous drilling operations, whilst macrofossils are seen as the tool of the field geologist and map drawer, i.e. microfossils are used in industrial geology, particularly by the oil industry. Techniques are also markedly different in that micropalaeontology usually involves the collection and chemical destruction of rock samples in order to release the microfossils, whereas macrofossils would usually be collected and identified in the field. Finally, the historical development of the two subjects has been very different. Macrofossils were initially the preserve of naturalists, but the work of William Smith and others led to the development of stratigraphy and therefore to geology itself. During the second half of the 19th century the stratigraphic time scale became established, based upon the evolution of macrofossils. However, after this period of pre-eminence, macropalaeontology waned in importance as zonal schemes reached the limits of refinement. The 20th century therefore saw ‘palaeontology’ (as it was) superseded in terms of fundamental research, by newly developing branches of geology. In complete contrast, although the invention of the microscope by Antonio van Leuwenhoek in 1660 did lead to a few early descriptions of microfossils, the subject of micropalaeontology developed out of necessity along with the oil industry and is therefore primarily a product of the 20th century.

Microfossils occur in all of the 5(6) Kingdoms of Life recognised by most biologists (see above diagram). Several important groups are Protists, including Foraminifera, Radiolaria, Diatoms and Coccoliths, all of which have at some stage a mineral skeleton of some sort. The latter are usually calcareous (Forams., Coccoliths) or siliceous (Radiolaria, Diatoms). Acritarchs are Protists but since they have an organic skeleton they are frequently grouped with plant spores under the umbrella of Palynology. Plant spores and pollen, which have taken over from Forams as the mainstay of oil industrial dating etc., are the sex cells, almost always male, of photosynthetic macro-plants. Fungal spores are released by ‘plant-like’ organisms that do not photosynthesize and are consequently dependent upon the presence of decomposed organic material within their environment. These spores do however perform much the same function as plant spores. Similarly animals in general could not have existed before free oxygen became available in the atmosphere. There are also several groups of microfossils that are multicellular animals. Ostracods are for example complex Crustaceans that happen to be small. Extreme sexual dimorphism in certain groups of Ostracods has led to some taxonomic problems. A whole host of other microfossil groups are represented by specific parts of larger organic structures. Paramount amongst these are Conodonts, that are particularly good for dating Palaeozoic marine horizons. It is also likely that the conodont animals represented the first Vertebrates. Then there are some microfossil groups that have been regarded as having dubious biological affinities, such as Chitinozoa, which as there name implies are animal-like and chitinous in composition. However, since they have much the same stratigraphic range as Trilobites, many think that they may be something to do with the trilobite reproductive cycle.

The first half of the 20th century belonged to Foraminifera as far as industrial geology was concerned. There are usually considered to be seven different foraminiferal groups based upon test (shell) composition and structure and of these only the most recent and progressive group (Hyaline) have been of general use to the oil companies. These tests are composed of needle-shaped crystals of calcite arranged normal to the shell surface. Seen from the exterior, any view must therefore look down the c axis of each crystal, rendering the shell transparent. Most Foraminifera were fairly unusual in secreting original calcite, and as such are useful for isotope studies of marine temperature etc. since they have suffered none of the re-crystallisation associated with aragonite. Most species are benthonic, and as a result their detailed composition also reflects slight variations in sea-bed chemistry in the form of a long list of possible trace elements incorporated into the calcite. Whilst extensively used by oil companies, there were nevertheless two major problems concerning these microfossils. Hyaline calcite forms did not evolve until the Triassic and are therefore unavailable for Palaeozoic horizons. Also Foraminifera were in general prone to homeomorphic structural evolution, which is common in simple structures like these. This means that superficially similar forms were produced by different lines of evolution, often at different times, and until this was recognised many mis-correlations were perpetuated.

By way of mitigation, at an early stage Foraminifera were recognised as being supremely good at determining the depth of deposition of the sediments containing them, as well as indicating the general geochemical conditions of the sea-bed. Such information was very useful in predicting drilling depth, particularly if the seal was represented by a marine transgressive wedge. Extensive studies were therefore completed to determine the relationship between water depth and the distribution of modern Foraminifera on the floor of the Gulf of Mexico. Whilst species were often different, many genera occurring in the Cenozoic oil-producing horizons of the southern United States still exist in the Gulf, and could be directly applied to oil company interpretations. So developed the use of standard sample size, the number of specimens present per unit sample, faunal variability (V value), faunal dominance (D value), and species size, as parameters for on-site depth interpretations. Furthermore this information could also be applied to structural interpretations where information was required on the amount and direction of vertical movement that had occurred within a basin.

In view of the stratigraphic limitations of Foraminifera, it was no surprise that palynology, or more specifically spore studies, took over and soon dominated industrial palaeontology. Spores are windblown and can therefore occur within all sedimentary rocks, plus tuffs, salt-deposits etc. Even red beds, that are normally considered barren of fossils, can contain sufficient spores for statistical analysis, as witnessed by the stratigraphic zoning of both the Devonian and Triassic sequences. Spores are also incredibly abundant. The relationship between flowering plants and insects reduced the need for astronomical numbers of pollen grains (spores) to be produced, but such plants did not evolve until the early Cretaceous and they did not become the dominant group that they are today until well into the Cenozoic. Concentrations of one million spores per 100 litres of water and 5 million per gram of sediment are not rare. In addition the sporopollenin that forms the spore case is virtually indestructible in sedimentary environments. This does of course mean that derived spores are not uncommon, but providing that laboratory practice is beyond reproach and their presence within a sample is known to be a true reflection of the spore assemblage, such information can be very useful in reconstructing geological history. For example, Carboniferous rocks were being eroded during the deposition of the Jurassic strata in parts of Scotland, as indicated by the presence of Carboniferous spores mixed with the Jurassic spore assemblages.

Other research has demonstrated that a relationship exists between spore distribution in sediments and the distribution of the plants on the hinterland that released them. Similarly the petrographic type of coal shows a strong relationship to spore phases that occurred during the history of a given coal swamp / peat producing episode. One of the most recent developments however has been the use of spore colour in the interpretation of the oil generating potential of a given horizon. Individual spores undergo much the same changes in chemistry as a result of the increased pressure and temperate that are seen in the metamorphism of peat into coal, i.e. they become carbonised. This study developed into the Batten Scale of Colour vs. Hydrocarbon Potential, with spores ranging from colourless to black, with the greatest potential for hydrocarbon development occurring where the spores are light to dark brown. Such observations are highly valuable to the companies, since they represent a rapid, cheap, easy (comparison with a colour chart) and ‘dirty‘ method of determining the initial petroleum potential of rocks in a given field.

One final trend has resulted in a blurring of the distinction made earlier between microfossils and macrofossils on the basis of use / application, since microfossils, particularly spores and conodonts, are being increasingly used to define internationally agreed stratigraphic boundaries. This is to be expected in view of their (often) superior distribution and taxonomic characteristics, but it does create a problem for the field geologist where fossils used to define a particular boundary cannot be seen in the field.

The answer to the rhetorical question of the title is therefore that they have become indispensable to our modern industrialised society.

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Miocene vegetation and climate: from the Brassington Formation of Derbyshire to global distributions
Matthew Pound

A “Tortonian Earth rise over the Moon”
Credit: Matthew Pound

Introduction
As a result of anthropogenic emissions of greenhouse gases it has been predicted that by the end of the 21st Century average global surface temperatures will have increased by 1.8 to 4°C. In order to fully understand the consequences of global warming, climate modelling is a widely used approach when assessing the future impacts of climate change. A good way of testing these models is by studying a geological interval with good palaeoclimate information available and then modelling this interval to see if the models can replicate the data. The Miocene Epoch is an ideal time period to study.

Why the Miocene?
The Miocene has been described as “the making of the modern world” (Potter and Szatmari, 2009). The main characteristics include:

• Major uplift of the modern mountain chains
• Initiation of bipolar glaciation
• The origin of modern ocean currents
• The aridification of the continental interiors
• The continuation of Cenozoic global cooling
• The reduction of atmospheric carbon dioxide levels

This interplay of elements has created a complex story of evolving climate. This makes the Miocene interesting for palaeoclimate studies. My research focuses on the Late Miocene Tortonian Stage (11.61-7.25 Ma) which is an interval generally considered to have been warmer than today with modest changes in continental position and orography. Modern biome (a large naturally occurring community of flora and fauna occupying a major habitat) distribution is mainly controlled by temperature and precipitation and is well understood. Understanding ancient biome distributions not only provides an excellent view of global climate, but also provides a means by which climate models can be assessed. State–of–the–art climate models can produce hypothesised biome distributions based upon simulated climate, thus allowing direct comparisons between the reality of the fossil record and the climate model predictions.

Miocene in the UK
Onshore Miocene rocks in the UK are extremely rare. Four localities are have been identified in which useful data can be obtained: 1. Pollen from the solution pipes at Trwyn Y Parc on Anglesey; 2. Pollen from a small outcrop in the St Agnes Outlier, Cornwall; 3. Pollen of Neogene age from a borehole at Mochras Farm, Snowdonia National Park, and finally the focal point of my study; 4. Pollen, wood, leaves retrieved from large (2 km2) karstic fills in the Brassington Formation in Derbyshire. This Formation is a relatively thick sequence of sands and clays preserved in around 60 karstic hollows. Originally studied in the 1970’s a palynoflora was recovered from the lignite and clay beds of the Kenslow Member - the uppermost member of the Brassington Formation (Boulter, 1971). Based on the state of the art at the time, the formation was assigned to the Late Miocene or Early Pliocene. The erosional surface that these sediments rest upon has been used to date the uplift of the Pennines mountain chain of central England. The uncertainties in the dating of the palynoflora has led to uncertainties in the rate of uplift.

A new field campaign at Kenslow Top Pit, Derbyshire has produced a new palynoflora from the coloured clays of the Kenslow Member. This new palynoflora contains many taxa recorded in the original work but also some previously not reported. The palynoflora represents a warm - temperate mixed forest, which was the dominant biome in Europe during this time period. By comparing the climate tolerances of the palynomorphs nearest living relatives the Kenslow Member forest would have lived in a climate with a mean annual temperature of 15.7 to 16.5°C. This is double the present day mean annual temperature! By comparison of the new palynoflora, and the original palynoflora, with floras from continental Europe, the age of the Kenslow Member can confidently be placed in the Tortonian Stage of the Miocene. This means that the uplift rate of the Pennines has been more modest than previously reported.

Summary
My Tortonian reconstruction shows significant changes in the distribution of vegetation compared to modern natural vegetation. For example in contrast to the modern scenario in the Northern Hemisphere, boreal forests reached 80°N and temperate forests were present above 60°N. Warm-temperate forests covered much of coastal North America, South-East Asia and Europe, as preserved at Kenslow Top Pit, Derbyshire. This reconstruction shows a spread of temperate savanna in central USA, the Middle East and on the Tibetan Plateau. Evidence for arid deserts is sparse, with the exception of the Atacama region (South America). Areas that exhibit arid desert today in the Tortonian were instead covered by shrublands, grasslands, savannas and woodlands. The extent of tropical forests in South America was likely reduced but expanded in the Indian sub-continent and East Africa. This pattern of global vegetation in the Late Miocene suggests a warmer and wetter world, which is supported by the pattern of climate anomalies predicted by our best-fit palaeoclimate-vegetation model experiment. Global mean annual temperature may have been as much as 4.5°C higher than present day with many regions experiencing higher than modern amounts of precipitation over the annual cycle. The pattern of temperature and precipitation change reconstructed palaeobotanically, and predicted within our climate model experiment, requires a global forcing agent on Tortonian climate (e.g. such as elevated concentrations of greenhouse gases) to explain the observed and modelled climate anomalies. This is in contrast to current proxy records of Tortonian atmospheric carbon dioxide which range from Last Glacial Maximum to mid-20th Century levels.

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Life and death at high latitudes: marine biodiversity, environmental change and extinction in latest Cretaceous Antarctica
James Witts

Introduction
The Maastrichtian (70 to 65 Ma) was the final stage of the Cretaceous period, and was terminated by the Cretaceous – Paleogene (K/Pg) mass extinction event, one of the largest of the ‘Big 5’ Phanerozoic episodes of mass extinction which bought about a fundamental change in the nature and composition of global marine and terrestrial faunas. The current leading hypotheses for the cause of this event can be divided into two categories;

Asteroid impact – the discovery worldwide of a thin layer of rock enriched in the rare Earth element iridium, coincident with the mass extinction of marine plankton and invertebrates like ammonites, temporary devastation of plant communities globally, and major disruption to the global carbon cycle, led to the hypothesis that a large extraterrestrial object struck the Earth 65 Ma. This would have led to a prolonged impact ‘winter’ and a break down in the global food-chain leading to the extinction of larger animals such as the dinosaurs.

The discovery and subsequent dating of the Chicxulub crater in Mexico to 65 Ma appears to bolster this hypothesis, and it currently enjoys the support of many scientists.

Volcanism – the Deccan Traps volcanic province in India is one of the largest flood basalt provinces in the world. The latest evidence indicates the bulk of the huge eruptions from this province occurred around 65 Ma, potentially releasing large amounts of volatiles such as carbon and sulphur dioxide into the atmosphere, which would have caused global warming and associated environmental deterioration. Proponents of this hypothesis claim that the K/Pg event may have been more protracted – and not caused solely by a single devastating event such as the Chicxulub impact.

Global Maastrichtian climate appears to have been dynamic – with overall cooler temperatures than during the mid Cretaceous, punctuated by several short-term global warming events. It is still unclear to what extent these climatic and environmental changes affected the extinction patterns of key fossil groups.
Whilst the northern hemisphere has a number of well-dated and fossiliferous outcrops of late Maastrichtian – earliest Paleogene age, there is a lack of published data from many parts of the southern hemisphere. My research aims to improve our knowledge of this key interval of Earth history at high southern latitudes.

Antarctica
The James Ross Basin, Antarctica contains one of the best sedimentary sequences in the world in which to investigate Maastrichtian environments and climate change prior to the K/Pg mass extinction event, as well as the immediate after – effects of the mass extinction in a high latitude setting. Plate reconstructions indicate that during the latest Cretaceous this region was located at roughly the same palaeolatitude as today - ~65°S, so the fossil animals and plants found there belonged to a truly high latitude ecosystem, having to cope with a polar light regime and high seasonality.


The shallow marine López de Bertodano Formation on Seymour Island (above photograph) is over 1000 m thick, and probably all late Maastrichtian in age representing ~3 million years of time prior to the K/Pg boundary. It is made up of fine-grained silt deposited in a back – arc marine basin, and contains a diverse invertebrate fauna (ammonites, bivalves and gastropods), along with abundant fossil wood and organic microfossils (marine algae).

Previous work has suggested that the K/Pg extinction record in Antarctica may be consistent with a gradual rather than sudden mass extinction, a hypothesis we can test with a new >3000 specimen fossil collection at British Antarctic Survey and the University of Leeds tied to sedimentary sections across the K/Pg boundary. The boundary itself can be identified on Seymour Island based on the presence of an iridium anomaly in the sediment, and by plotting the stratigraphic ranges of key micro and macrofossils against sedimentary logs.

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Meteorites, Stardust and the Early Solar System
Jamie Gilmour

Introduction
Astronomers understand that solar systems like ours form in molecular clouds such as those visible in the Eta Carinae nebula shown below. Our best understanding of how this happened in the particular case of our solar system is gained from analysis of meteorites.

Carina Nebula
Image Credit: NASA, ESA, N. Smith (U. California, Berkeley) et al.,
and The Hubble Heritage Team (STScI/AURA)
http://www.nasa.gov/multimedia/imagegallery/image_feature_1146.html

Meteorites
A meteorite’s arrival at the Earth is heralded by a fireball such as that which has attracted news coverage over the last week. If sufficiently detailed observations are available, the orbit that the meteorite followed before its arrival at the Earth can be reconstructed. When this has been possible the aphelion of the orbit has been in between the orbits of Mars and Jupiter, suggesting an origin in the asteroid belt.

Meteorites are classed as stones, stony-irons and irons. The stones are subdivided into achondrites, which are recognisable igneous rocks, and chondrites. Achondrites, stony-irons and stones can be seen as originating in the mantle, core-mantle boundary and core of asteroids that had differentiated. Chondrites (named for chondrules) on the other hand, can be recognised as accumulations of fragments that had a separate existence before lithification – they might be seen as a sort of preterrestrial sediment. They contain grains of metallic iron and silicate. Melting such a rock would produce two immiscible melts that would separate under gravity to produce the core and mantle of a differentiated body. We can thus understand a process that occurred on the first asteroids – material that was much the same as the chondrites got hot, melted, and separated out to produce differentiated bodies. At some later stage these were disrupted to produce the parent asteroids of the irons, stony-irons and achondrites.

Two questions remain – what happened before the formation of the chondrites, and what was the heat source that caused them to melt. (In fact, chondrites almost all show evidence of either thermal metamorphism or aqueous alteration, each of which requires some input of heat – heating appears to have been ubiquitous on the first asteroids.) Isotopic analysis helps to address both of these questions.

Calcium- Aluminium Rich Inclusions
Some clasts in carbonaceous chondrites are rich in the oxides of calcium and aluminium that would be the first condensates as a gas of solar composition cooled. For this reason they are identified as the first objects to have formed in our solar system. It is found that excesses of the isotope 26Mg in these inclusions correlate with the Al/Mg ratio – this demonstrates that they formed from in situ decay of the radioisotope 26Al, which has a half life of 720000 years. This is an example of an extinct radioisotope – a short-lived species that was present in the early solar system but decayed away rapidly. The 26Al/27Al ratio when the CAI formed was 5 x 10-5.

The presence of this short-lived isotope in our solar system demonstrates that the elements were being synthesised until no more than a few million years before our solar system formed. (The galaxy was around 8-9 billion years old at this point.) We can understand this to some extent – stars form over a short period of time in molecular clouds. Large stars form, evolve and die on timescales comparable to the duration of star formation. These are the stars that make 26Al and inject it into their surrounding through stellar winds and supernova events. Thus, the later stars to form might be expected to incorporate 26Al produced by their elder siblings as they died.

This process can be modelled- Gaidos et al. suggest that around 6% of planetary systems incorporate as much 26Al as ours. This is interesting because 26Al is implicated as the heat source that processed material in the first asteroids, and by implication processed the material that went on to form terrestrial planets like ours. We can speculate that a solar system that didn’t incorporate this heat source would produce planets more volatile rich than those in our solar system, a proposal that resonates with the recent identification of a hot, water rich planet around a nearby star.

Presolar Grains
Clearly the CAIs formed from material that got very hot in our solar system. Chondrules appear to have been produced by flash heating, and metal grains are predicted products of the same condensation sequence as the CAIs. It is tempting to assume that all the material of our solar system was heated and homogenised, erasing a lot of the record of what went before, but noble gas isotopic analysis has led to a discovery that shows this is not the case.

Noble gases are extremely depleted in the solid phase. For this reason, isotopic anomalies arising from nuclear processes show up dramatically when analyses are made of bulk material. In fact, the first extinct radioisotope identified, 129I was found because of the massive mono-isotopic 129Xe excesses presenting meteorites.

In the 1960s, two unusual isotopic signatures were identified in xenon released from stepwise heating of chondrites. They were identified as products of the two neutron capture processes responsible for producing most of the isotopes heavier than iron. Over subsequent decades painstaking experiments were carried out, progressively dissolving away the meteorites until the carriers of these anomalies could be isolated in pure form. These are the presolar grains, micron-sized (and smaller) grains of dust that condensed in the outflows from stars that contributed material to our suns parent molecular cloud. Their survival into the asteroids that act as the parent bodies of meteorites demonstrates that dust survived the formation of our solar system without being homogenised.

To learn more about our group’s work check our blog at . . . .
http://earthandsolarsystem.wordpress.com/

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Strange places, the dales - the shaping of the Lakes and Pennines by huge landslips and rockslides
David Jarman

Rock slope failure (RSF) is a significant erosional process in glacial times and during the unstable conditions following periods of glaciation. They are characterised by huge rockslides, vast landslips seaming valley-sides with furrows hundreds of metres long, and mountain crests deeply fissured or split in two. All these types of ‘rock slope failure’ abound in the mountains of Britain, and especially in the Scottish Highlands. They nearly all occurred soon after the retreat of the last glaciers, and so have become stabilised and blended back into the landscape.

The mountains of Britain are mostly cut in ‘old hard rocks’ which are highly resistant - hence the rugged glacial landscapes - but they can also be surprisingly vulnerable. Metamorphic rocks especially are riddled with intersecting faults, joints, and slaty cleavages, and where these ‘discontinuities’ are suitably inclined, the valley-sides become prone to large-scale slippage. Rockslides are the most visible but least common kind of failure - notably those slicing Beinn Alligin, and enclosing the Lost Valley of Glencoe (Coire Gabhail). More numerous and intriguing are slope deformations, where valley-sides have fractured or sagged but not collapsed.

Ingleborough

A classic rock slope failure on the west flank of Ingleborough
as viewed from Kingsdale. Photo: Dave Jarman

RSF recognition indicators include: cavities, slope bulges and lobes, contrast vegetation, trees, deranged drainage, fissures, grabens, basal springs, and antiscarps. In terms of when these phenomena occurred it has been suggested that:

1. Most RSFs occurred around deglaciation ~10,000 BP
2. Dated rockslides span Holocene, youngest Glencoe 1800 BP
3. Some could predate last glaciation
4. Almost no active RSF in mountain areas

And the culprit? Whereas in coastal cliffs it is the sea, and on sedimentary scarps and valley sides it is water lubricating weaker beds beneath harder, with mountain RSFs it is ice but indirectly, hence ‘paraglacial RSF’. Glaciers excavate deep troughs and then retreat, leaving steep slopes unsupported. Where it all gets too much, sections of slope can give way - aided by meltwaters, freeze-thaw, and maybe even earthquakes. After earlier glacial cycles, RSF was probably endemic. Today, RSFs are widespread - many hundreds in the Highlands, over 50 in the Lake District, a few in the Southern Uplands and North Wales - but their incidence is a bit of a mystery. They can be densely clustered, thinly spread, or absent regardless of terrain; in most rock types; on steep or gentle terrain; and at all levels from loch-shore to high summits. Quite a few are close to ‘breaches’ such as Loch Ericht or Glen Shiel, where glaciers have overspilled and cut deep notches through former watersheds. This suggests they are responding to rebound stresses after ‘concentrated erosion of bedrock’. They might even be pointers to ancient climate change, as icecaps shifted to and fro. Rockslides, antiscarp arrays, and ‘brokeback mountains’ are dramatic geomorphological features, offering great potential for interpretation to students, visitors, and hill-lovers.

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Death in a cold climate: Permian extinctions in Svalbard, Norway
Paul Wignall

Expedition Health and Safety
Planning and preparation for a successful field visit to the Arctic Circle is essential. This typically includes making sure you have everything you need at base camp and familiarising yourself with the various modes of transport such as sailing dingy’s and helicopters. Additional safety measures are also required when dealing with the threat of Polar Bear visits to camp, hence special fences are erected around base camp to warn of impending visits by bears. Having left camp and gone into the field, and in the event that you come across a Polar Bear, each member of the party needs to be able to use a rifle! During the expedition there was evidence of what the Polar Bear is cable of doing if left unchecked. You may recall the recent news item on the 17 year old British adventurer who was mauled to death by a Polar Bear on expedition at Von Postbreen glacier here on Spitsbergen.

Spitsbergen
Spitsbergen is an archipelago in the Norwegian Sea about 565 km north of Norway. The study area offers much potential for revealing the secrets of the great Permian mass extinctions which are in themselves truly global phenomena. Although the name Spitsbergen is well known, the Norwegians prefer Svalbard which means ‘cold coast’. The area is 63000 km² (about the size of Ireland), and 60% is covered by glaciers. The research being conducted is a joint effort between the University of Leeds and the Norske Polar Institute. The part of Spitsbergen investigated in 2011 was the area to the south in and around Bellsunde fjiord.

Late Permian Kapp Starostin Formation
The uppermost Permian beds examined in this part of Spitsbergen belong the Kapp Starostin Formation which extends for about 400 m. The fossiliferous limestone beds in this formation are well known for their extensive brachiopod faunas exposed just below the extinction boundary. Other fossils spectacularly preserved in the limestones are bryozoans, commonly known as moss animals.

The photograph illustrates the nature of the landscape and the elevated position of the section where the main Permian extinction events are situated. The prominent beds are composed of limestones and sandstones whilst the finer-grained units are mudstones. Photo: Paul Wignall

Within this stage lies the Capitanian horizon where an extinction event took place prior to the major catastrophic end-Permian event. The name comes from the Capitan Reef in the Guadalupe Mountains (Texas, USA). This may be related to the main end-Permian-Triassic extinction event that followed about 10 million years later in the Changhsing stage (named after the Changhsing Limestone from Changxing County in China).

The Great Dying
The mass extinction at the end of the Permian Period (c. 252 million years ago) was the most severe event of its kind in the Phanerozoic (the current geologic eon in the geologic timescale, and the one during which abundant animal life has existed) affecting both marine and terrestrial organisms. Understanding the causes and consequences of the end-Permian extinction is important to understanding the evolution of the Earth’s biosphere.

Oceanographic changes during the end-Permian mass extinction have been the focus of much study in the past decade. In particular, the widespread development of oxygen-poor bottom waters in shallow-marine sections has been held as a likely cause of benthic-marine extinctions. The presence of organic-rich shales straddling the Permian-Triassic (P–Tr) boundary indicates that the anoxic event was an oceanic phenomenon. Besides ocean anoxia there are two other popular mechanisms for causing mass extinctions i.e., bolide impact, and the eruption of one of Earth’s largest continental flood basalt provinces, the Siberian Traps.

Things to Do
During this summer’s visit to Svalbad, our team hope to address the following:
1. What age is this first extinction?
2. What happened at this level?
3. What happened between the first and end-Permian extinction events? Radiation? 4. This happened in Bellsund area of Spitsbergen, what about elsewhere?

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FIELD MEETINGS

Penistone Hill Country Park (Haworth): rocks, quarrying, and landscapes
Guides: Steve Birch & Karen Ashworth

Time / Date: 10:30am, Sunday 27 May.

Meeting at: West End car park [SE 021 363]. As you leave Stanbury, turn right onto Reservoir Road past Lower Laithe Reservoir for about 1 km. Turn left up a track for 300 m where there is ample car parking space adjacent to West End Quarry. Carry packed lunch for the day.

Geological setting: The region lies to the south of the Askrigg Block, in the Huddersfield Sub-Basin of the Pennine Basin, an area of subsidence associated with the development of half grabens during Namurian times.The area around Haworth is underlain by rocks of the Millstone Grit Group, ranging in age from the Pendleton (Pendleian) to the Rossendale (Yeadonian) Formation, and Lower Coal Measures, of Langsettian (Westphalian A) age. Evidence of prograding deltas, lakes, and swamps are to be seen in the local quarries. Fossil plants, bivalves and trace fossils are common in these rocks.

Maps
O.S. Sheet: 1:25,000 OL 21 South Pennines
BGS Geological 1:50,000 Sheet 69 Bradford (Solid and Drift Edition)

References
Stephens, J. V., Mitchell, G. H. & Edwards, W. (1953): Geology of the Country between Bradford and Skipton. Geological Survey Memoir, England and Wales, Sheet 69.

Waters, C.N., Aitkenhead, N. & Jones, N.S. et al. (1996): Late Carboniferous stratigraphy and sedimentology of the Bradford area, and its implications for the regional geology of northern England. Proceedings of the Yorkshire Geological Society, Vol. 51, pp. 87 - 101

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Permian geology from South Shields to Seaham

Guide: Paul Wignall

FRIDAY

Locality 1. Middridge Quarry (disused) [NZ 252 252]
Meet at the village of Middridge on Friday for 1:30 pm From the PH about 1.7 km
The quarry exposes rocks from the basal unconformity and breccia with the overlying Marl Slate Formation up to the Ford Formation (formerly Middle Magnesian Limestone). The Marl Slate formation is the considered to be the most important locality in Britain for Upper Permian fossil reptiles and plants.

Locality 2. Trow Point (coastal section) [NZ 382 668]
Meet on the cliff top in the evening.
Trow Point is exposes the Raisby Formation (formerly Lower Magnesian Limestone) and the underlying Concretionary Limestone Formation. There are also stromatolites exposed here. Rocks from Trow Quarry were used in the construction of the Roman Fort at Arbeia.

SATURDAY

Locality 3. Marsden Bay [NZ 398 651]
Meet at the Grotto carp park for 9:30 am.
A variety of features in the Roker Dolomite Formation i.e., Concretionary Limestone including excellent collapse breccia pipes. Also noting classic examples of coastal erosion including stacks, arches and wave-cut platform.

Locality 4. Tunstall Hills [NZ 391 544]
Meet at the Nature Reserve off Tunstall Road [NZ 391 5445]
This locality exposes a Permian Reef in the Ford Formation. The reef is known for its diverse and superbly preserved shelly fauna, including colour-banded gastropods. There is also a vertebrate fauna here.

Locality 5 Claxheugh Rock [NZ 362 574]
Meet at the car park next to the River Wear (South Hylton) for Claxheugh Rock.
This outcrop exposes the Early Permian aeolian Yellow Sands Formation which is overlain by the Marl Slate formation and succeeding magnesian limestones of the Raisby and Ford Formations.

Locality 6. Seaham Harbour [NZ 430 499]
Meet on the promenade. Car park 750 m north of the outcrop.
This is one of the best sections to observe evaporite dissolution. Collapse zones expose brown-red mudstones of the Roxby Formation. The Seaham Formation is unusual here in its content of several thick units of calcite spherulites (small, usually spheroidal body consisting of radiating crystals).

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A seismological journey to the centre of the Earth

Speaker: Ed Garnero
Rupert Beckett Lecture Theatre
* Parking onsite is free after 6pm *

Ed Garnero will lead us on a journey deep into the Earth to discover the complex inner workings of our planet. We will see massive continental-sized structures sitting atop the molten fluid iron core. These deep mega-blobs appear to possess Earth's largest magma chambers, which may be the birthing place of plumes that result in large volcanoes at the surface. Our journey down will highlight a dynamic and complex planetary interior that has profound implications for shaping Earth's surface on which we live.

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Great Scar Limestone Group: Conistone Dib and the Cracoe reefs

Guide: Paul Kabrna

Time / Date: 10:30am, Saturday 14 July.

Meeting at: the bridge over the River Wharfe at Conistone. In the afternoon meet at [SD 966 611] on Thorpe Lane which is located off the main B6265 between Swinden Quarry and Cracoe. Carry packed lunch for the day.

Geological setting: The morning part of the excursion is in Conistone Dib [SD 983 675 to 992 682]. Here we will be able to view the succession from the Kilnsey Limestone Formation up through the Malham Formation (Cove Limestone and Gordale Limestone members) of Askrigg Block platform. These limestones belong to the Great Scar Limestone Group which marks a period of time when sea level rose sufficiently to flood the block.

Glacier ice has had a major influence in shaping the present day scenery. Within the last half a million years there has been at least three occasions where it has been cold enough for great ice sheets to have covered much of northern England. The influence on the landscape of the most recent Ice Age is well illustrated in Conistone Dib in the Upper Wharfedale valley.

The afternoon will be based on the Cracoean reefs which are a continuation of the Settle-Malham reef trend which follows the line of the Middle Craven Fault. These reefs are very fossiliferous and are quite unlike the Waulsortian mounds of the Craven Basin in that they were formed in relatively shallow water on the edge of the Askrigg Block.

Maps
O.S. 1:25 000 Outdoor Leisure 10, Yorkshire Dales, Southern Area

References
Arthurton, R. S., Johnson, E. W. & Mundy, D. J. C. (1988): Geology of the country around Settle. British Geological Survey Memoir, England and Wales, Sheet 60.

Mundy, D.J.C (2000): Craven Reef Belt: Settle & Cracoe. YGS field meeting guide reproduced by Talisman Energy Inc. Calgary

Wilson, A. (1992): Geology. Yorkshire Dales National Park/Topic Series

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Geology and mineralogy around Grassington Moor

Guides: Alan French & Paul Kabrna

Time / Date: 10:30am, Sunday 12 August.

Meeting at: at SE 015 658 on Moor Lane adjacent to Yarnbury Cottages. Please bring packed lunch and be prepared for inclement weather conditions. Walking terrain is relatively flat.

Geological setting: The area lies on the edge of the Askrigg Block, bounded to the south by the North and Mid Craven Faults. The shelly limestones of the block elong to the Craven Group and are overlain unconformably by the late Pendlton Grassington Grit.

The Yarnbury mineral field is divided structurally into two areas known as the High and Low Moors. Initial exploitation of lead ore began in the 1600’s but the area was most active in the late 1700’s. Declining lead prices resulted in the closure of the mines in 1882. Reworking of the old spoil heaps for baryte and fluorite has occurred sporadically this century up until relatively recently (1970’s).

The Yorkshire Dales National Park have established a Mineral Trail illustrating many of the historical remains. Spoil heaps can be examined for mineral specimens i.e, galena, baryte, and fluorite can be collected, and with luck rarer sphalerite and rosasite may also be found. Mineralisation on Grassington Moor is confined to two horizons, the Grassington Grit Formation and the Middle Limestone Formation. A lead - zinc suite of minerals was emplaced epithermally by reheating of the granite underlying the Askrigg Block. It is unclear when exactly this took place, though the Upper Permian is the most likely date.

The Grassington Grit Formation is typically 50 m thick and comprises cross bedded, pebbly feldspathic sandstone. There are up to five seat earths, some with coal seams. In the interbedded mudstones Lingula and fish remains have been found. Beds were laid down in a deltaic complex, with periodic marine incursions. On Grassington Moor the lower half of the formation is a thick coarse grained sandstone termed the Bearing Grit. This was the major ore bearing horizon in the area.

References
Wilson, A. (1992): Geology. Yorkshire Dales National Park/Topic Series

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Geology of lkley Moor

Guide: David Leather

Time and date: Saturday 8 September 2012. Meet at 10.30am.

Place of meeting: the Cow and Calf Rocks car park [SE 132 468] where there’s a small (new) cafe and a free car park. Take packed lunch for the day. We will make two loops onto the Moor to take in all the outcrops and features planned. Total distance will be about 7km. There are some short steep ups and downs, wet patches, rocky tracts and a bit of (optional) scrambling. Notes will be provided.

Geological features: The Addingham Edge Grit (about the middle of the Millstone Grit Group) forms the Cow and Calf rocks and much of the scarp overlooking Ilkley. It includes some wonderful cross-bedding, ripple marks, fossil plant remains, sand volcanoes and the more recent discovery of (globally rare) tidal laminites. There are some very fine slickensides, glacial striations, a 650m long moraine and a classic landslip. We will also see numerous examples of cup and ring marked rocks and even some rock-carved poetry.

Maps
BGS Bradford sheet 69
Explorer Map 297 Lower Wharfedale & Washburn Valley

References
The Pennines and Adjacent Areas
(BGS 4th Edition 2002, Aitkenhead et al.)

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