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The Central Basin of the Iran Plateau is between the geologically better-known regions of the Zagros and Alborz Mountains. Hydrocarbon exploration in the Central Basin has revealed the details of the late Eocene-Holocene evolution of the basin based on seismic refl ection data, geological fi eld work, basin modeling, and satellite interpretation. The multistage basin history commenced with broad sag-type subsidence and isolated normal faults during Oligocene-early Miocene time. It evolved to an extensional or transtensional basin in the early-middle Miocene, with as much as 4-5 km of Upper Red Formation section being deposited in some parts of the basin during this stage. The upper part of the Upper Red Formation is associated with a change to transpressional deformation, with the development of thrusts and folds. This latest (probably middle and/or late MioceneHolocene) deformation is transpressional, and includes a mixture of basementinvolved strike-slip and thrust faults and thin-skinned folding and thrusting detached on Oligocene evaporites. Local detachment levels higher in the stratigraphy also exist. Subsidence in mini-foredeep basins and strike-slip fault bounded basins occurred during this stage, and several kilometers of Upper Red Formation were deposited in the main depocenters. Northwest-southeast-to north-northwest-south-southeaststriking dextral strike-slip to compressional faults dominate the area, with subordinate east-west and north-south fault orientations also present. These different fault sets combine in places to form major strike-slip duplex geometries. The Eocene volcanic belt (Urumieh-Dokhtar zone) along the southern margin of the basin forms a chain of massifs as much as 3 km high, the outcrops of which were exhumed by movement along major thrusts from 5-6 km depth between the middle Miocene and present day. The Central Basin-Urumieh-Dokhtar zone forms a

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[1] The western branch of the East African Rift is composed of an arcuate succession of elongate asymmetric basins, which differ in terms of interaction geometry, fault architecture and kinematics, and patterns of uplift/subsidence and erosion/sedimentation. The basins are located within Proterozoic mobile belts at the edge of the strong Tanzanian craton; surface geology suggests that the geometry of these weak zones is an important parameter in controlling rift development and architecture, although other processes have been proposed. In this study, we use lithosphere-scale numerical models and crustal-scale analogue experiments to shed light on the relations between preexisting structures and rift architecture. Results illustrate that on a regional scale, rift localization within the mobile belts at the curved craton's western border results in an arcuate rift system, which implies that under a constant extensional stress field, part of the western branch experienced orthogonal extension and part oblique extension. Largest depocenters are predicted to form mostly orthogonal to the extension direction, and smaller depocenters will form along the oblique parts of the rift. The varying extension direction along the rift zone furthermore results in lengthwise varying rift asymmetry, segmentation characteristics, and border fault architecture (trend, length, and kinematics). Analogue models predict that discrete upper crustal fabrics may influence the location of accommodation zones and control the architecture of extension-related faults at a local scale. Models support that fabric reactivation is responsible for the oblique-slip kinematics on faults and for the development of Zshaped or arcuate normal faults typically documented in nature. Citation: Corti, G., J. van Wijk, S. Cloetingh, and C. K.Morley (2007), Tectonic inheritance and continental rift architecture: Numerical and analogue models of the East African Rift system, Tectonics, 26, TC6006,

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Structures produced by salt and mobile shales are commonly similar; however, the material behavior of the two is different. Salt mobility is a fundamental material property, shale mobility only occurs if overpressured fluids are present. Dewatering of shales will stop their mobility, while renewed burial or the onset of an internal overpressuring process (e.g., diagenetic release of water or hydrocarbon generation) may renew mobility. Consequently, structures in mobile salt will envolve continuously until salt withdrawal produces touchdowns sufficient to stop salt mobility. Shale mobility may follow a deformation sequence similar to salt, or it may display a more episodic evolution reflecting critical overpressuring events. While salt mobility is confined to specific lithological units, the same is not the case for shale. The overpressuring of shales is strongly dependent on depth, so that mobile shale zones may cut across time/bedding boundaries. The differences in mechanical behavior lead to differences in structural style although many basic aspects of gravity tectonics remain the same. (1) Prekinematic structures and synkinematic deformation occur in both salt and shale tectonics. However, much of the prekinematic deformation in mobile shale‐dominated deltas may be lost by burial and conversion of the prekinematic sequence into mobile shales. (2) Fault‐dominated depocenters occur in salt and shale tectonics. In the Niger delta, overpressured shales vary in thickness from thin decollement zones to massive chaotic zones some 4–6 km thick. Fault‐controlled basins develop over mobile shales. Maximum basin depth is approximately the thickness of the mobile shale plus the thickness of the overlying pregrowth fault strata (i.e., some 4–8 km). (3) Diapirs are common to both salt and shale tectonics. Normal faults associated with reactive diapirism are common in both. Salt has the potential to almost completely evacuate a particular volume, resulting in local touchdowns or welds. Shale may also create touchdown areas, but complete collapse is uncommon because a large volume of immobile dewatered shale is usually left behind. (4) Salt nappes can cover extensive areas in the Gulf of Mexico. Some limited shale tongues occur in the Niger delta. They form imbricate thrusts that pass down dip into gravity flows and slumped blocks of shale derived from the exposed mobile shale.