Abstract A widespread and well-documented episode of Late Jurassic–Early Cretaceous rifting followed multiple events of mid- to late Mesozoic crustal contraction in NE China. This extensional deformation was closely associated with widespread Mesozoic magmatism, thought to be related to lithospheric delamination and destabilization of the previously stable North China craton. Early Cretaceous rift-related sedimentary basins in the western Liaoning region of NE China comprise numerous discrete, largely lacustrine half-graben basins bounded by NW-rooting low-angle normal faults that sole into older thrusts or mid-crustal shear zones. These basins characteristically lack post-rift thermal subsidence and significantly postdate most of the Mesozoic volcanism in the region. Instead, magmatism that has been attributed to lower crustal foundering, and hence lithospheric delamination (perhaps as old as 160 Ma) accompanied continuing crustal thickening in eastern North China. Thus, although widespread magmatism plausibly played a role in thermally weakening the crust prior to extension, there is little upper crustal evidence that wholesale removal of the lithosphere and lower crust occurred during Mesozoic time. The expansive Cenozoic rift basins of Eastern China, which do contain thick post-rift sequences, constitute a more viable response to lithospheric delamination.

Abstract The Tres Pasos Formation, Magallanes Basin, Chile, represents the deposit of a submarine slope depositional system. The formation is approximately 1500 m thick where exposed in the Ultima Esperanza district of southernmost Chile. It is characterized by a basal turbiditic sandstone unit up to 200 m thick that shows a north-to-south, proximal-to-distal facies evolution from turbidite channel-fill complexes to sheet-like sandstone units. This unit is interpreted as having been deposited at or near the base of slope. Overlying the basal sandstone unit is approximately 500 m of amalgamated mass transport complexes, fine-grained strata, and channelized and non-channelized turbidity current deposits, collectively comprising the middle part of the formation. Mass transport complexes exert a primary control on the character and grain size of turbidite sandstone bodies in the basal and middle part of the formation. In the southern part of the study area, a 300 m thick coarse-grained unit interpreted as a turbidite channel-fill complex partially replaces the middle part. The upper part of the formation is approximately 500 m thick and consists primarily of fine-grained strata. Failure scarps and thin turbidite channel-fill units are present in this upper part, interpreted as upper slope deposits.

Abstract The Miocene Temblor Formation is a prolific producer of heavy crude oil at Coalinga oil field in central California, having produced nearly 700 million barrels of 20° API oil from the lower part of the formation from 1900 through 1981. In Coalinga field and other nearby fields, the Temblor Formation often produces from multiple, discrete intervals. Primary lenticularity of reservoir stratigraphy suggested by this production history was further demonstrated by qualitative log-shape mapping of one Temblor interval published by Shell Oil geologists in the 1970s. These data indicate that optimum efficiency in production from steam soak and steam drive demands full knowledge of the fabric of the Temblor reservoir.Outcrop studies indicate that the lower Temblor Formation of the Coalinga area represents fluvial deposits left by southerly flowing braided streams, overlain by transgressive lagoonal and shallow-marine deposits. This record can also be recognized in the subsurface nearby, where depositional trends have been mapped using a “resistivity factor” that takes into account interval thickness and magnitude of resistivity response. The method works well for lower Temblor units where only porosity and oil-water saturation vary appreciably among petrophyscial factors. The maps produced show good correlation between depositional trends and concentrations of oil, within an individual depositional unit. Recognition of these units and their lateral anisotropy aids efficient recovery of heavy oil from the reservoir .