Strain and scaling of faults in the chalk at Flamborough Head, U.K

• Published in: Journal of structural geology Vol. 16; no. 1; pp. 97 - 107
• Main Authors: Peacock, D.C.P., Sanderson, D.J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.1994; Elsevier Science
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Tectonics. Structural geology. Plate tectonics; England; United Kingdom; Europe; models; orientation; carbonate rocks; finite strain analysis; extension faults; normal faults; lineation; sedimentary rocks; structural analysis; limestone; brecciation; polyphase processes; chalk; fault displacements; marl; clastic rocks
• DOI: 10.1016/0191-8141(94)90021-3
• ISSN: 0191-8141

Analysis has been made of the orientations, displacements and spacings of 1340 extensional faults, with displacements of up to 6 m, along an almost completely exposed 6 km length of cliff. This data set has been used to study how fault populations account for strain in a region and to study relationships between different scales of fault. Strains have been estimated; the maximum and intermediate extensions are sub-horizontal, with approximately equal extension (e ≈ 0.01) in all horizontal directions. It can be inferred that the minimum extension (maximum compression) was sub-vertical, but that the wide variety of fault orientations and cross-cutting relationships resulted from variable horizontal extensions. Some faults have oblique-slip slickenside lineations, which imply a period of later, dominantly NNW-SSE extension, which possibly developed as the exposure-scale faults linked up E-W-striking larger-scale normal faults, effectively forming a single wide fault zone. Graphs of displacement per unit distance are used to illustrate variations in displacement. The scaling of fault displacement appears to follow a power-law relationship. The differences in orientation between the small-scale and large-scale faults precludes a simple estimation of the total strain over all scales.