Delta-slope-turbidite deposition and synsedimentary deformation - County Clare, Ireland
Using seismic scale cliff exposures of Namurian strata, the course will demonstrate depositional complexities and syndepositional deformation structures that characterise delta-slope-turbidite successions
Exposures include 200m high cliffs of Carboniferous strata of County Clare currently undergoing intensive research and recently highlighted in an article in the AAPG Explorer magazine. They comprise some of the most spectacular sedimentary geology in Western Europe, displaying a wide range of delta, slope and turbidite facies and sequences enabling reconstruction of the infilling a major northern Europe basin. Cyclicity of the deltaic succession is thought to have been driven eustatic sea-level changes resulting in extensive flooding surfaces overlain by fossiliferous marine bands and in major palaeovalley fill sandbodies. The deltaic intervals show abundant soft-sediment deformation, egs. growth faults, mud diapirs, sand volcanoes. The course will include at least one boat trip to view key cliff exposures.
Course base: Kilkee, County Clare
- George’s Point, east side of Kilkee Bay to introduce the local stratigraphy and setting.
- Mouth bar sands, upper part of the Kilkee cyclothem;
- Penetrative mud diapir; flooding surfaces and marine bands.
- Loop Head; general basinal context; Ross Formation turbidites.
- Kilbaha Bay; Kilcloher Head. Turbidite facies including channels and mega-flutes.
- Bridges of Ross and east of Ross; major slump sheets, turbidite channels and sand volcanoes
- Ross Formation at Kilcredaun;
- Boat trip from Carrigaholt: Ross Formation in sea cliffs between Carrigaholt and Loop Head.
- Possible boat trip to south side of Shannon: basinal Clare Shales and base of Ross Formation.
- South of Tullig Point: Gull Island Formation (major basin-filling slope and slope ramp), lower part of Tullig cyclothem (oldest deltaic progradation). Tullig Sandstone (palaeovalley).
- Killard: upper part of Tullig slope succession; minor mouth bar, abandonment/flooding events, Tullig Sandstone with soft-sediment deformation.
- Truklieve. Tullig progradation, flooding surfaces, minor parasequences, palaeovalley erosion and stacking; wave-influenced mouth-bars; marine bands.
- Foohagh Point: Growth faulting in Doonlickey cyclothem.
- West End, Kilkee: Minor mouth bars in Tullig cyclothem; non-penetrative mud diaper; Kilkee cyclothem and sandstone.
- Carrowmore Point: Upper part of Tullig cyclothem; channel sandstone; flooding surfaces.
- Spanish Point: extensional faulting of mouth bar sands over diaper; Doonlickey cyclothem.
- Doolin; basinal mudstone facies at northern margin of basin.
- Fisherstreet: basal turbidites of northern margin and major slump sheet.
- Cliffs of Moher: northern equivalent of Gull Island and Tullig cyclothem.
- Drive to Shannon and depart.
John Collinson is an independent consultant, specializing in clastic sedimentology and reservoir geology.
He has worked as a consultant for over 20 years, dealing with projects from field to basin scale around the world. Before becoming established as a consultant, he was Professor of Sedimentology at Bergen University, Norway, Senior Exploration Geologist at Britoil, Glasgow, Scotland, and Senior Lecturer in Geology at Keele University, England. Throughout that time, he has been involved in classroom and field training for both academic and industry classes, in particular as a partner in Sedimentary Research Associates, a company that pioneered field courses for the oil industry from the mid-1970’s. Whilst at Bergen, he initiated research into the sedimentology of the Namurian succession of County Clare Ireland, an interest that persists to the present day.
Before his post at Keele University, he held a two year of post-doctoral research fellowship in Uppsala, Sweden. He has M.A. and D.Phil. degrees from Oxford University. He is co-author of "Sedimentary Structures" and of "Sedimentary Environments and Facies" and is an author and editor of many other publications.
He currently presents field courses in Ireland (in the NExT program), in Kenya, in the Spanish Pyrenees and in UK, as well as a lecture course within the NExT programme.
Petroleum geologists, general geologists, sedimentologists, reservoir modellers, reservoir engineers.