Continental Tectonics and Mountain Building

A combined research conference and field meeting to celebrate the centenary of the 'Peach and Horne' 1907 memoir on The Geological Structure of the North-West Highlands of Scotland.

Download final programme (talks and posters), instructions for presenters (talks and posters) and registration form.

Venue: The Macphail Centre, Ullapool, Wester Ross, NW Scotland

Convenors

• Rob Butler (University of Leeds)
• Bob Holdsworth (University of Durham) 
• Maarten Krabbendam (BGS)
• Rick Law (Virginia Polytechnic Institute and State University) 
• Rob Strachan (University of Portsmouth)

Conference Themes

• Deformation systems in the continental lithosphere
• The role of localised vs distributed strain during mountain building
• Kinematic studies of mountain belts
• Experimentation, modelling and field approaches to understanding orogenesis
• Structural inheritance and reactivation
• Rheology of continental lithosphere
• Fault zone processes
• Highlands controversies: historical perspectives for on going debates.

Field excursions

There will be a single field excursion through Assynt for participants on Sunday to establish a “common experience” to facilitate discussions during the rest of the meeting. Thereafter we will offer a choice of two excursions from the list below that will run during the two days (Tuesday/Thursday), operating out of Ullapool (transport and lunch provided). If demand warrants it we will run some of these trips more than once (and may drop some if there is insufficient demand). Full guidance as to the physical demands of these excursions will be available in September 2006 (including hazard assessments). We will do our best to match participants with their preferred trips but cannot guarantee spaces on all. Please give your rank order for the trips on your registration form – and add any comments that might influence your preference (e.g. limited mobility).


Note that all excursions involve harsh environments and participants should be well-equipped with sturdy footwear (boots), full rain gear and warm clothes (e.g. hats, fleeces). We recommend bringing a small rucksack to carry extra field kit and lunch etc.

All conference participants will receive the amalgamated field guide to all sites so that, should they choose, individuals could stay in the area after the conference to make further (unguided) field excursions.

The optional trips are:

• Trip A: Loch Eriboll and Durness (leader – Rob Butler)

A trip to see the Arnaboll thrust and related structures, together with the tectonic outlier of the Moine Thrust at Durness. Arnaboll is Lapworth’s type section for mylonites and is where Geikie first coined the term “thrust”. It is a great place to study fault rocks and to debate strain softening mechanisms in basement thrust zones. These contrast well with the younger faults at Durness that have dropped down the Moine Thrust Zone. The Arnaboll transect also crosses classic imbricate systems and their folds.

It involves a long coach journey from Ullapool. Walking to the Arnaboll Thrust involves about 1500m each way (with an ascent of about 200m total) on at times rough and steep ground. If the fitness of the party permits we will also follow Lapworh’s transect (Kempie) that he used to demonstrate tectonic repetition of rock units – and walk over the hill to Arnaboll (about 5 km in total, 300m ascent). The Duness outcrops are coastal and very easy of access.

• Trip B. Scourie-Laxford. (leaders: Rod Graham, Alastair Beach, Graham Park and John Wheeler)

This excursion provides an introduction to the tectonics of the Lewisian complex, by contrasting the geological history of the “Central Block”, including Scourian granulites, and their relationship to the younger “Laxfordian” crustal reworking. Recently the Laxford Front has been reassessed in terms of a major Proterozoic terrane boundary – so we expect lively discussions on the outcrop that contrast this interpretation with the earlier deformation gradient model approaches. This trip will include a visit to Teall’s shear zone at Scourie.

The outcrops include road cuttings and coastal/cliff-top sections. The longest walk is about 1 km but is over rough ground.

• Trip C. Stack of Glencoul (Leader Rick Law)

The excursion will examine the mylonitic Moine schists and Cambrian quartzites in the hangingwall and footwall to the Moine thrust in spectacular scenery at the Stack of Glencoul in the northern part of the Assynt area. This is a classic locality that has resulted in a considerable body of influential research into processes of fabric development in mylonites. Ongoing research into strain analysis, crystal fabrics (optical, X-ray texture goniometry and EBSD) and vorticity analyses will be summarized at outcrop.

This excursion will involve a combination of a boat trip and rough hike to the famous mylonites at the Stack of Glencoul. This is one of the most famous sections through the Moine Thrust and the site of early kinematic studies by Peach and co-workers. We will also study the Glencoul Thrust – scene of Callaway’s (1883) description of basement thrust tectonics. An additional surcharge to cover boat charter (a 40—passenger tourist craft) is levied on this trip.

The excursion involves a rough landing from the boat (requiring a ladder descent, followed by a walk of 3km each way and 400m ascent on paths and rough and steep ground, and fording of a small river (potential for wet feet here).

• Trip D. Ductile deformation in the Moine: Loch Shin – Strath Oykell (leaders: Rob Strachan and Graham Leslie)

This excursion will examine aspects of the geology of the Caledonian hinterland to the Moine Thrust Zone. A traverse along the shore of Loch Shin across a major Caledonian isocline demonstrates interfolding of medium-grade metasedimentary rocks of the Neoproterozoic Moine Supergroup with intensely reworked basement gneisses that are broadly correlative with the Lewisian Complex of the Caledonian foreland. The excursion will also visit the classic outcrops of mullions in Strath Oykell, first discussed in detail by Gilbert Wilson, and outline current thinking on the origin of these structures in the light of recent BGS mapping.

Logistics: The Loch Shin part of the excursion will involve ~7 km of walking, some across rough ground, but no significant ascent. Outcrops in Strath Oykell will be close to the road.

• Trip E. Loch Borralan: the Alkali igneous rocks of Assynt (leader: Kathryn Goodenough)

This excursion will examine the Loch Borralan Pluton, one of the major syenite plutons within the Moine Thrust Zone. The pluton is considered to cut thrusts within the thrust zone, and has been dated at 430 ± 4 Ma; it thus provides a constraint on the age of the thrust zone, although this age is increasingly in conflict with other data. The excursion will start at the Cam Loch Thrust, and then will visit key localities to study the relationship between the Loch Borralan pluton and thrust structures in the area, as well as the deformation state of the pluton.

Logistics: This day will include roadside stops and relatively short walks of no more than 2 km, mostly on good paths, with short distances over rough ground.

• Trip F. Thrust systems of Central Assynt. (leaders: Maarten Krabbendam and Graham Leslie)

The excursion will examine a variety of thrust structures in the core of the classic Assynt culmination in spectacular landscape, including: major thrust structures, such as the Breabag Dome and the klippe of the Ben More thrust, frontal and oblique ramps, and the Bealach Traligill cross-fault. Discussion will include the linkages of thrust structures from north to south Assynt, problems that were addressed by Ben Peach, John Horne, Edward Bailey and Mike Coward; the character of the Ben More Thrust and the related recumbent Sgonnan Mor folds and the role of steep basement structures in the development of lateral changes in architecture of the thrust belt.

Logistics: This day will involve a fairly long walk (~ 14 km), with ~400 m of ascent, on paths and rough ground. There will be plenty of stops along the way. In poor visibility the itinerary may be shortened, but this still offers a worthwhile excursion.

• Trip G: Achmelvich-Clachtoll (leaders Robert Wilson & Ruth Wightman)

The high-grade Lewisian basement rocks of the Caledonian foreland consist of lower, middle and upper crustal shear zones and faults that preserve a complex history of deformation and reactivation during progressive exhumation, spanning from the Archaean to the Cenozoic. The excursion will traverse the transpressional Canisp Shear Zone, examining deep crustal Badcallian (Archaean) basement structures at Achmelvich, followed by detailed examination of exposures showing Inverian, Laxfordian and late-Laxfordian (Palaeoproterozoic) structures and ending with the deposition of the sedimentary rocks of the Mesoprotoerozoic Stoer Group at Clachtoll.

Logistics: this excursion will involve a 4 km walk over moderate, generally low-lying coastal terrain. You will be able to select your options of field excursions at the payment stage.

Participation

Accommodation and the size of the conference venue means that participation in the conference is strictly limited to 200. Details on the application process (with call for papers), costs and timetable of deadlines will appear in due course. The intention is that all participants stay for the full meeting.

Individuals notified as to status of registration (whether application to participate is accepted). This decision will not be based solely on a first-come, first-served basis as we wish to maximise the diversity of participants to cover a broad range of interests/disciplines at the meeting, to ensure a good mix of students, established scientists, local experts, specialists of other orogenic systems, to promote participation from different countries and different institutes.

On this basis we will draw a list of participants together with a reserve list. All applicants will be informed directly by the Geological Society in late September 2006 for their participation status (accepted or on reserve list), together with instructions for making payments. Note that all payment must be made in full at this time. Information on cancellation fees etc will be available then too. We will include information on field excursions at this time.

Registration

Full payment must be received by the Conference Office at the Geological Society to secure your place at the meeting. On receipt of this participants will be sent accommodation and further information to allow them to make travel and housing arrangements. Don't finalise your booking for these until your place at the meeting is confirmed by us. If payment is not received by the deadline you will lose your place and it will be offered to people on the reserve list (pending receipt of their payment). The deadline for payments for the reserve list will be 15 th December. Thereafter we will allow further registrations on a first-come, first-served basis, based on receipt of payment, filling cancellations as appropriate.

Abstract

We will publish extended abstracts at the meeting – and make these available as a pdf via the meeting website.

Accommodation

A range of expensive to cheap accommodation is available in Ullapool, including a series of mid-priced hotels, bed and breakfasts, bunkhouse, youth hostel and campsite. All are walking distance from the MacPhail Centre. We plan to use an agency to stream-line hotel bookings (with appropriately discounted rates). Information on the accommodation booking options will be available in the first circular.

Costs

A single registration fee will be set to cover conference facilities, field trips and social events. This fee will not include accommodation.

There will be a discount for fellows of the Geological Society and members of the Geological Society of America.

For further information, please visit www.see.leeds.ac.uk/peachandhorne/