Faults basin margin

Table 1. Examples of major carbonate-cemented zones as identified from sonic and bulk density logs and lithological descriptions of cuttings for a variety of structures in dilferent parts of the Eromanga basin (Fig. lA). Note that the carbonate-cemented zones in Jurassic sandstones vary in cumulative thickness, from a few metres (e.g. Strzelecki-10) to about 110 m (Spencer West-1), including over short distances (e.g. Strzelecki). All wells occur near the Cooper basin margin, or along major fault-bounded structural trends where the regional Nappamerri Group seal (Triassic) underlying the Jurassic sandstones is incompetent or missing...

With the exception of well 7125/1-1, group GUI fractures are restricted to the master fault complexes which are known to be characterised by inversion. Well 7125/1-1 is situated in the foot-wall of the Nys-leppen Fault Complex, and it may be speculated as to whether the abundance of low-angle fractures in this well implies that inversion also took place at the northwestern margin of the Nordkapp Basin. 

The structure of the deposit, with homoclinal northeast dip, is uncomplicated, although faulting occurs. This appears to be limited to a set of strike-normal faults, dipping to the northwest. The western margin of the basin is faulted the displacement is probably of considerable magnitude. The Tertiary beds are masked by up to 30m of alluvial gravels and sands. 

Internally complex, ferroan dolomite-cemented fractures are a prominent feature within a fluvial sand body at Ballycastle, on the margins of the Rathlin basin in northeast Ireland. The cemented fractures display a tight modal orientation that is coincident with the dominant local normal faulting trend, and are interpreted to have formed in the same tectonic regime. However, there is no clear trend in the spatial distribution or width of the fractures with respect to a fault plane situated at one end of the outcrop. 

Fig. 10.12 Beacon rocks of the Victoria Group within the Rennick basin in northern Victoria Land. All of the outcrops of Beacon rocks rest unconformably on the Kukri erosion surface which is not shown. The Rennick Fault defines the western edge of the Rennick basin. The outcrops of Beacon rocks along this margin are identified in Fig. 10.11 (Adapted from Gair et al. 1969)...

Mechanisms of Earthquakes in Aegean, Fig. 6 Development of WNW-ESE and E-W normal faulting In Thessaly, as deduced from focal mechanisms, mainly along the southern margins of the basins. 

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