Abstract A synthesis of low-temperature thermochronologic results throughout the Laramide foreland illustrates that samples from wellbores in Laramide basins record either (1) detrital Laramide or older cooling ages in the upper ~1 km (0.62 mi) of the wellbore, with younger ages at greater depths as temperatures increase; or (2) Neogene cooling ages. Surface samples from Laramide ranges typically record either Laramide or older cooling ages. It is apparent that for any particular area the complexity of the cooling history, and hence the tectonic history interpreted from the cooling history, increases as the number of studies or the area covered by a study increases. Most Laramide ranges probably experienced a complex tectono-thermal evolution. Deriving a regional timing sequence for the evolution of the Laramide basins and ranges is still elusive, although a compilation of low-temperature thermochronology data from ranges in the Laramide foreland suggests a younging of the ranges to the south and southwest. Studies of subsurface samples from Laramide basins have, in some cases, been integrated with and used to constrain results from basin burial-history modeling. Current exploration for unconventional shale-oil or shale-gas plays in the Rocky Mountains has renewed interest in thermal and burial history modeling as an aid in evaluating thermal maturity and understanding petroleum systems.This paper suggests that low-temperature thermochronometers are underutilized tools that can provide additional constraints to burial-history modeling and source rock evaluation in the Rocky Mountain region.

Abstract We present a synthesis based on the interpretation of two pairs of deep seismic reflection crustal sections within the Southern Rift System (SRS) separating Australia and Antarctica. One pair of sections is from the conjugate margins between the Great Australian Bight (GAB) and Wilkes Land, in the central sector of the SRS, which broke up in the Campanian. The second pair of conjugate sections is located approximately 400 km further east, between the Otway Basin and Terre Adélie, which probably broke up in Maastrichtian time. Interpretations are based on an integrated synthesis of deep multi-channel seismic, gravity and magnetic data, together with sparse sonobuoy and dredging information, and the conjugate sections are presented with the oceanic crust removed beyond the continent–ocean boundary (COB). At first order, both conjugate pairs show a transition from thinned continental crust, through a wide and internally complex continent–ocean transition zone (COTZ), which shows features in common with magma-poor rifted margins worldwide, such as basement ridges interpreted as exhumed subcontinental mantle. In the central GAB sector, the COTZ is symmetric around the point of break-up and displays a pair of mantle ridges, one on each margin, outboard of which lies a deep-water rift basin. Break-up has occurred in the centre of this basin in this sector of the SRS. In contrast, the Terre Adélie margin is nearly 600 km wide and shows an abandoned crustal megaboudin, the Adélie Rift Block. This block is underlain by interpreted middle crust, and appears to have a mantle ridge structure inboard, as well as an outboard exhumed mantle complex from which mylonitized harzburgite has been dredged. The conjugate margin of the Beachport Sub-basin is relatively narrow ( c. 100 km wide) and does not appear to contain an exhumed mantle ridge, as observed along strike in the GAB. These observations from a single rift spreading compartment show that radically different break-up symmetries and margin architectures can result from an essentially symmetric rifting process involving multiple, paired detachment systems. This indicates the need for caution in interpreting causative mechanisms of rifting from limited conjugate sections in other rifts. We speculate that the underlying crustal composition, rheology and structural preconditioning play a significant role in partitioning strain during the transition to break-up.

Abstract The purpose of this Seals Atlas is to present the microstructural, petrophysical, and geomechanical properties of selected examples of cap rocks and fault seals for use as analogs in the prediction of seal capacity or containment potential. Similar atlases exist; however, this is the first such atlas to focus specifically on the characteristics of cap rocks. The atlas is primarily based on extensive mercury injection capillary pressure (MICP) analyses, but also includes thin section, XRD, grainsize distribution, SEM/EDS, and 'V shale' data. The samples included in this atlas are a result of APCRC and CO2CRC (Cooperative Research Centres) research programs focusing on top and intraformational seals and some fault seals (cataclasites) throughout Australia and New Zealand. The hydrocarbon/carbon dioxide seal examples are grouped by basin localities and further distinguished by formation, well, then depth. Where multiple examples are available, a range of lithologies and MICP data are included in the sample selection. This atlas also can be used in an evaluation of integrated seal potential for prospect risking and reservoir management.