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For sheer complexity, braincases are generally considered anatomically conservative. However, recent research on the braincases of tyrannosaurids have revealed extensive morphological variations. This line of inquiry has its root in Dale Russell's review of tyrannosaurids in which he established Daspletosaurus torosus — a large tyrannosaurine from the Campanian of southern Alberta. In the wake of systematic revisions to tyrannosaurines previously assigned to Daspletosaurus, one potentially distinct species remains undescribed. This paper describes and compares a braincase referable to this species with that of the holotype for Daspletosaurustorosus using computerized-tomography-based reconstructions. The two braincases have numerous differences externally and internally. The specimen of Daspletosaurus sp. has a bottlenecked olfactory tract, short and vertical lagena, and a developed ascending column of the anterior tympanic recess. The holotype of Daspletosaurus torosus has many unusual traits, including an anteriorly positioned trochlear root, elongate common carotid canal, distinct chamber of the basisphenoid recess, asymmetry in the internal basipterygoid aperture, and laterally reduced but medially expanded subcondylar recess. This comparison also identified characters that potentially unite the two species of Daspletosaurus, including deep midbrain flexures in the endocasts. However, many character variations in the braincases are known in other tyrannosaurids to correlate with body size and maturity, or represent individual variations. Therefore, taxonomic and phylogenetic signals can be isolated from background variations in a more comprehensive approach by using additional specimens. New information on the two braincases of Daspletosaurus is consistent with the emerging view of tyrannosaurid braincases as highly variable, ontogenetically dynamic character complexes. [ABSTRACT FROM AUTHOR]

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This paper focusses on obtaining a better understanding of the subsurface geology of the Chibougamau area, in the northeast of the Abitibi greenstone belt (Superior craton), using geophysical data collected along a 128 km long traverse with a rough southwest–northeast orientation. We have constructed two-dimensional (2D) models of the study area that are consistent with newly collected gravity data and high-resolution magnetic data sets. The initial models were constrained at depth by an interpretation of a new seismic section and at surface by the bedrock geology and known geometry of lithological units. The attributes of the model were constrained using petrophysical measurements so that the final model is compatible with all available geological and geophysical data. The potential-field data modelling resolved the geometry of plutons and magnetic bodies that are transparent on seismic sections. The new model is consistent with the known structural geology, such as open folding, and provides an improvement in estimating the size, shape, and depth of the Barlow and Chibougamau plutons. The Chibougamau pluton is known to be associated with Cu–Au magmatic-hydrothermal mineralisation and, as the volume and geometry of intrusive bodies is paramount to the exploration of such mineralisation, the modelling presented here provides a scientific foundation to exploration models focused on such mineralisation. [ABSTRACT FROM AUTHOR]

Published estimates on the paleoclimate of the Florissant fossil beds site of Colorado (34.1 Ma) have led to extremely different estimates of paleoelevation. The purpose of this paper is to review the paleoclimate methods used and to add the coexistence approach (CA) method to estimate paleotemperature for the Florissant site. The basis of the CA method is the dependence on overlapping climatic requirements for different taxa in the flora and their nearest living relatives. These relationships tie the fossil identities to the actual plant habitats and climatic requirements of close relatives. Based on the CA method, we conclude that the mean annual temperature ranged between 14.3 and 18.2 °C. These results support the conclusions offered by several other studies that the Florissant was a warm temperate to subtropical flora, and they are consistent with recent conclusions by structural geologists as well as other studies, indicating that the Florissant site was deposited at a relatively low elevation, probably between 1 and 1.5 km. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although the performance of surface, piled, and caisson foundations has been investigated against a large tectonic dislocation from a dip-slip fault, to date, the embedment depth has not been clearly considered on the behavior of shallow foundations subjected to dip-slip faulting. This paper presents a series of centrifuge model tests to investigate the effects of foundation embedment depth and contact pressure on the interaction of reverse faults and shallow foundations embedded at a depth of D. The effect of embedment depth on the behavior of a foundation was observed by comparing the results of the embedded foundation tests with those of surface foundation tests. The depth of the embedment, acting as a kinematic constraint, prevents the occurrence of sliding at the foundation-soil interface and consequently leads to significant foundation rotation and translation. Moreover, embedding the foundation causes the mechanism of the fault rupture - foundation interaction to change. The effect of contact pressure on the interaction of the fault rupture and the embedded foundations depends on the foundation position relative to the fault. In addition to the propagation of fault ruptures through the soil layer, passive failure wedges primarily occurred on both sides of the embedded foundations because of their translation and rotation, thereby imposing unfavorable effects on the adjacent structures. [ABSTRACT FROM AUTHOR]

Large-scale lateral mobility of the Earth's lithosphere (mobilism) was a hotly debated issue in Earth Sciences during some two decades following publication of Wegener's (1912) theory of continental displacement. The final acceptance of lithospheric mobility was brought about with the plate tectonics revolution during the late 1960s. Support for mobilism was rather popular in certain European countries during the 1920s, whereas the reactions in North America were mostly hostile. One of the very few influential mobilists in the New World was Reginald Aldworth Daly of Harvard University. The present paper discusses his model of continental displacement which is very remarkable in many aspects. We focus on the hitherto neglected fact that Daly proposed in the mid-1920s a mechanism to create oceanic crust which would have been totally consistent with the Vine-Matthews hypothesis of seafloor generation published in 1963. It is furthermore suggested that Daly's geotectonic proposals were inspired by small-scale analogues of lava flows and multiple dike swarms he observed on Atlantic islands such as St. Helena and Ascension. His model to account for the construction of new oceanic crust is reminiscent of the models of Vine and Moores (1972) and Cann (1970) which eventually led to the 'Penrose-definition' of ophiolites in 1972. As these scientists arrived at their conclusions absolutely independently of Daly, this episode is an instructive example of a multiple or repeated discovery in the Earth Sciences which renders it difficult to believe certain theories of science which assume scientific models to depend mostly on social factors. [ABSTRACT FROM AUTHOR]