Summary: At Dykes End, Bridlington Bay, [National Grid Reference TA 216 692], a 200 m section of Chalk cliffs exposes folds with NW–SE-trending axes and north-eastward thrusting, accompanied by dome and basin structures in the foreshore, structures that are not exposed elsewhere in this region. The folding and thrusting resulted from transpression emanating from sinistral strike-slip reactivations of a right-hand bend, giving a local ESE–WNW trend, in the major E–W Langtoft Fault within the pre-Chalk basement just to the south. The northern side of the fault displaced westwards, underthrusting the Chalk cover which developed bedding-parallel shears, detachments, NW–SE axis folding, and thrusting north-eastwards. The underthrusting effects were localized and transient, ceasing as the strike-slip fault incised upwards through the Chalk. Subsequent flexuring, on ENE–WSW axes, curved foreshore bedding and enhanced closures of the earlier non-cylindroidal folding, producing domes and basins, sporadically exposed in the foreshore. Here, they have been downfaulted in a graben that is tilted, with downthrow increasing southward (seaward) towards the Langtoft Fault. Folding and faulting at Selwicks Bay, 4 km ENE, has been related to four deformation phases (‘D1–D4’). D1 produced gentle NNW–SSE folds and north-eastward shearing on bedding planes, comparable with the Dykes End cliff structures, and sinistral strike-slip movement on ESE–WNW faults, parallel to the Langtoft Fault. D2 was a tensional period. D3 produced E–W folds, comparable with the Dykes End cross-flexures, and D4 comprised extensional phases, comparable with the Dykes End faulting and graben development.

Folding (DSP implementation)

10.1144/pygs2013-319

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Citations (8)

The concentration of folding and faulting in the Chalk at Staple Newk (Scale Nab), near Flamborough, East Yorkshire

Proceedings of the Yorkshire Geological Society (2008)

I. C. Starmer

Summary At Staple Newk [TA 205 737], intensive folding and thrusting of the Chalk were restricted to a 200 m long section. The ENE-WSW folding and NNW-SSE thrusting resulted from dextral transpressive reactivation of the underlying ENE-WSW Bempton Fault. Detachment folding in the Welton Chalk Formation produced a monocline with a vertical limb that locked and was then cut by a thrust. This parallel style of folding contrasted with that in the overlying, more thinly bedded Burnham Chalk Formation, where tight and disharmonic, angular folding developed between the vertical limb and the north-north-west propagating thrust. When the tight, angular folding locked, south-south-eastward back-thrusts combined with the main thrust, but both diminished and died out upwards. Later, low-angle extensional faulting was followed by steep normal faulting. Folding and thrusting also developed in the Chalk at Selwicks Bay, 6 km to the south-east. Here, four deformation phases (‘D1–D4’) can be separated and the later phases can be correlated with those that affected Staple Newk. At both localities, folding and thrusting were produced by a ‘D3’ N–S contraction which was more than cancelled later by ‘D4’ N–S extension, causing low-angle extensional faulting and subsequent steep normal faulting. Within the Howardian Hills-Flamborough Fault Belt, contractional features (folds and thrusts) and subsequent low-angle extensional faults were local developments and were replaced en echelon by similar structures. The later, steep normal faults produced the more-continuous E–W fault pattern.

Folding (DSP implementation)

10.1144/pygs.57.2.95

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Citations (9)

Contortions in the Chalk at Staple Nook, Flamborough Head

Proceedings of the Yorkshire Geological Society (1995)

I. C. Starmer

The Victorian photographs reproduced in this account depict the most spectacular exposure of a localized zone of intense deformation within the generally gently dipping Chalk of the Yorkshire coast. They were published originally over a century ago to accompany the Proceedings of the Yorkshire Geological Society for 1885, with a description by James Davis. The photographs are views south-westwards of ‘Staple Nook’, a small embayment at the south end of (the NW-SE orientated) Bempton Cliffs, about 6 km north-west along the coast from Flamborough Head. This zone of intense deformation was recorded by the early workers in this area and was described by the local names: Davis (1885) called it ‘Staple Nook’ (also written as ‘Newk’), whereas Phillips (1829) and Lamplugh (1895) referred to it as ‘Old Dor’ (also written as ‘Door’ and ‘Dore’), although this is strictly the broad arch of rocks at its south-eastern end. The Ordnance Survey use the formal name ‘Scale Nab’ for the promontory at its north-eastern end. The section is only accessible from the sea (and then only with great difficulty and skilled, local help), but its general features can be viewed from the ships providing short tourist cruises from Bridlington. It is particularly spectacular because of its exposure in 80 m high cliffs and because of the restriction of intense east – west folding to a section 200 m long, bounded to the north-west and south-east by beds dipping constantly at around 10–15° S. The rocks belong to the Welton Chalk Formation (Upper ...

10.1144/pygs.50.4.271

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Citations (6)

Oblique Terrane Assembly in the Late Paleoproterozoic during the Labradorian-Gothian Orogeny in Southern Scandinavia

The Journal of Geology (1996)

I. C. Starmer

The earliest deformation of the curved Kongsberg-Bamble Belt in Norway produced a northwestward-directed tectonic wedge, suggesting oblique NW-SE collision during the Labradorian-Gothian Orogeny in southern Scandinavia. Oblique terrane assembly, with the outboard (western) units colliding last, explains the trapping of the Ostfold-Marstrand island arc (formed at c. 1760 Ma) between younger (1700-1600 Ma) terranes, the apparent lack of Svecofennian crust west of the Trans-Scandinavian Igneous Belt, and the apparent lack of Labradorian-Gothian age crust in the British Isles. The Labradorian of North America may have also resulted from oblique terrane assembly.

Orogeny

10.1086/629829

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Citations (14)

The Evolution of the South Norwegian Proterozoic as Revealed by the Major and Mega-Tectonics of the Kongsberg and Bamble Sectors

Springer eBooks (1985)

I. C. Starmer

Orogeny

Greenschist

10.1007/978-94-009-5450-2_16

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Citations (84)

Accretion, rifting, rotation and collision in the North Atlantic supercontinent, 1700-950 Ma

Geological Society London Special Publications (1996)

I. C. Starmer

Abstract Events in the North Atlantic region, from c. 1700 to 950 Ma, are unified in a model compatible with palaeomagnetic results and Neoproterozoic supercontinent reconstructions. Following Labradorian-Gothian accretion, largely between 1700 and 1550 Ma, post-collisional effects continued until c. 1500 Ma. Continental extension from c. 1500 Ma onwards, related to ocean opening, developed granite-rhyolite provinces: the Central Metasedimentary Belt (Grenville Province) started to form at c. 1425 Ma, with arcs outboard at c. 1350–1300 Ma. Baltica started to separate from Laurentia and rotate at c. 1240 Ma, causing crustal delamination of its leading edge, in South Norway. Here, subduction-related gabbroids intruded at c. 1230–1225 Ma, as rotation proceeded. The Elzevirian Orogeny occurred at c. 1190 Ma in the Southwest Grenville Province, marking the start of convergence of Baltica, in which backarc extension was accompanied by granites and bimodal volcanics. Collision at c. 1080 Ma caused the Ottawan Orogeny which thrust accreted terranes northwestwards and closed the Mid-Continental Rift. In southern Baltica, complex deformation occurred. Post-collisional convergence and sinistral slip of Baltica against Laurentia (possibly related to convergence of Amazonia) caused thrusting, sinistral strike-slip faulting, folding and granitic intrusion until c. 950 Ma. Post-tectonic granites intruded until c. 900 Ma.

Supercontinent

10.1144/gsl.sp.1996.112.01.12

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Citations (31)

Deformation of the Upper Cretaceous Chalk at Selwicks Bay, Flamborough Head, Yorkshire: its significance in the structural evolution of north-east England and the North Sea Basin

Proceedings of the Yorkshire Geological Society (1995)

I. C. Starmer

SUMMARY Four deformation phases (D1–4) can be recognized in the Upper Cretaceous Chalk of Selwicks Bay. D1 ENE–WSW compression formed gentle NNW–SSE buckles in Selwicks Bay, with localized overturned folds and minor thrusts to the south. Regionally, D1 is correlated with Laramide sinistral slip on the Dowsing Fault, inversion of the Sole Pit Basin, and N–S to NNE–SSW folding in the Cleveland Basin. Subsequent D2 extensional fracturing developed during general post-Laramide tension, with a dominant E–W component at one stage. D3 N–S compression produced gentle E–W folds, later tightened in the south of Selwicks Bay as sinistral E–W strike-slip faults formed in the north: subsequent southward and northward thrusting resulted from NW–SE transpression across the whole area. North of Selwicks Bay, the Bempton Fault Zone underwent E–W folding and N–S thrusting, and the E–W Cleveland Anticline was enhanced, causing some inversion of the Cleveland Basin. The strike-slip faulting is interpreted as a derivative of Alpine dextral slip on the Dowsing Fault, which subsequently caused the NW–SE transpression. D4 deformation at Selwicks Bay produced N–S normal faults with later dextral shear, followed by northward spreading of faulting in a N–S extension complex. Regionally, this is correlated with E–W tension, caused by North Sea subsidence, becoming modified and eventually dominated by uplift (enhanced inversion) of the Cleveland Basin: this tilted the region south to Selwicks Bay, where hinging produced a classic N–S extension complex.

Transpression

Anticline

Pacific Plate

10.1144/pygs.50.3.213

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Citations (39)

Rb-Sr Systematics of a Gardar-Age Layered Alkaline Monzonite Suite in Southern Norway: A Discussion

The Journal of Geology (1990)

I. C. Starmer

Laurentia

Quartz monzonite

Baltica

10.1086/629380

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Citations (9)