Growth and linkage of a segmented normal fault zone; the Late Jurassic Murchison±Statfjord North Fault, northern North Sea Mike J. Young a,b, * , Rob L. Gawthorpe a , Stuart Hardy a a Basin and Stratigraphic Studies Group, Department of Earth Sciences, The University of Manchester, Manchester M13 9PL, UK b Present address: Norsk Hydro Produksjon, PO Box 7190, N-5020 Bergen, Norway Received 14 August 2000; revised 16 January 2001; accepted 13 February 2001 Abstract The structure of the 25 km long northeastern portion of the Murchison±Statfjord North Fault Zone and adjacent syn-rift stratigraphy are integrated to reconstruct the temporal and spatial evolution during c. 30.5 myr of Late Jurassic, North Sea rifting. Based on a structural analysisD± d data)alone,approximately14precursorfaultstrandsareidenti®ed.Incorporationofstratigraphicdatashowsthatonlysixof these strands were important in controlling stratal architecture and distribution. Three main stages in the evolution of the fault zone are recorded in the syn-rift stratigraphy and are biostratigraphically constrained. These are: 1) following initiation of rifting, six isolated fault strands developed each ,4kmlong)andcontrolledthestratigraphyforc.13myr;2)theisolatedstrandslinkedalong-strikeformingtwo .9kmlongfaultsegmentsseparatedbya2kmwiderelayramp,thatcontrolledthestratigraphyforatleastthefollowingc.10.5myr;and 3) the two fault segments hard-linked forming a single, continuous fault trace during the ®nal c. 7 myr of rifting. The results of this study revealthenecessitytoadoptanintegratedstructuralandstratigraphicapproachwhenreconstructingtheevolutionofnormalfaultzones.The results may also help to further constrain models of fault evolution. q 2001 Elsevier Science Ltd. All rights reserved. Keywords: Normal faulting; Segmentation; Fault growth and linkage 1. Introduction In regions of the Earth that have undergone prolonged crustal stretching, extension is usually accommodated on long-lived seismogenic, planar normal faults which bound half-grabensedimentarybasinsJacksonetal.,1988).Typi- cally, these fault zones can have lengths in excess of 100 km, but commonly comprise fault traces that are discontinuous along-strike, being composed of individual echelon stepping fault segments that are separated by areas of relatively low displacement i.e. segment bound- aries) or connected by distinct bends in the fault trace. Numerous outcrop and subsurface-based studies have used the structural geometry of the fault trace together with quantitative data sets of fault displacement D) and length L) or distance d), to investigate how fault segments grow and link. In particular, displacement±distance relationships and fault trace geometries have been used to suggest that normalfaultsdevelopthroughtheinteractionandlinkageof individual segments and that evolving faults follow a distinct growth path, as segments progressively link and transfer zones e.g. relay ramps) break down Peacock and Sanderson, 1991; Cartwright et al., 1995). Consequently, a number of transient geological structures are believed to characterise speci®c conceptual stages in the evolution of faults Table 1). However, because many studies of normal faults have only used the ®nal disposition of total displacement e.g. D± L characteristics and structural geometry), the temporal growth history cannot be quanti®ed or determined unequi- vocally.AlthoughthereareanumberofexceptionsAnders and Schlische, 1994; Schlische, 1995; Gawthorpe et al., 1997; Nicol et al., 1997; Rowan et al., 1998; Contreras et al., 2000; Dawers and Underhill, 2000), the stratigraphy deposited during fault growth has often not been fully utilised, either because it is not present or has not been studied in suf®cient detail. ThisstudyintegratesstructuraldatafromtheMurchison± Statfjord North Fault Zone Fig. 1) with stratigraphic infor- mation from the adjacent footwall and hanging wall, to reconstruct the temporal and spatial evolution of this fault zone during c. 30.5 myr of Late Jurassic rifting. This is Journal of Structural Geology 23 2001) 1933±1952 0191-8141/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved. PII:S0191-814101)00038-4 www.elsevier.com/locate/jstrugeo * Corresponding author. Tel.: 147-5599-6922; fax: 147-5599-5525. E-mail address: mike.young@hydro.com M.J. Young).