Atlantic Geology 69 Atlantic Geoscience Society ABSTRACTS 2006 Colloquium & Annual General Meeting GREENWICH, NOVA SCOTIA The 32nd Colloquium and Annual General Meeting was held at the Old Orchard Inn, Greenwich, Nova Scotia on February 2 and 4, 2006. On behalf of the society we thank the organizing committee, Liz Kosters, Rob Raeside and Ian Spooner, as well as their supporting staff. We also acknowledge sponsorship from the following companies and organizations: Acadia Gold Corporation, Corridor Resources, Falconbridge, Potash Company of Saskatchewan and the Nova Scotia Department of Natural Resources, Mines and Energy Branch. In the following pages we are pleased to publish the abstracts of oral presentations and posters from the Colloquium. THE EDITORS Atlantic Geology 42, 69–125 (2006) 0843-5561|06|010069–57$9.55|o 70 AGS Abstracts – 2006 Annual General Meeting Integrating analogue experiments and seismic 3D structures similar to those observed along the Scotian interpretation for improved understanding of Margin, including crestal grabens, landward-and seaward- sedimentation and salt dynamics in Mesozoic sub-basins dipping roller structures, triangular-shaped reactive and and their deepwater extensions, offshore Nova Scotia active diapirs, turtle structures, canopies, and allochthonous salt detachments. The tectonic evolution is strongly controled Juergen Adam1, John Shimeld2, Csaba Krezsek1, by sedimentation. Individual sub-basins and their deep-water Steve King1, Sheila Ballantyne1, and compressional belts are coupled spatially and temporally and Djordje Grujic1 are characterized by lateral and temporal migration and highly 1. Salt Dynamics Group, Department of Earth Sciences variable and localized subsidence patterns. Our results show Dalhousie University, Life Sciences Centre, Halifax, NS, B3H 4J1 that a strong relation exists between sedimentation, rate of <[email protected]> ¶ 2. Geological Survey of Canada (Atlantic), extension and dominant structural styles. Bedford Institute of Oceanography, P.O. Box 1006, Integration of 4D physical simulations with 2D/3D struc- Dartmouth, NS, B2Y 4A2 <[email protected]> tural modelling and seismic interpretation will lead to a new generation of improved interpretation templates for salt-re- Salt-deformation features beneath the shelf and slope of lated structures and basins of offshore Atlantic Canada. The the Scotian Margin manifest complex tectono-stratigraphic project will signifi cantly improve our understanding of the relationships with high rates of sedimentation and prograda- interaction of dynamic salt systems with sedimentation and tion during the Jurassic and Early Cretaceous. Exploration erosion processes and will aid interpretation of complex struc- and seismic interpretation concepts developed in other salt tures beneath the Scotian Margin. basins (e.g., Gulf of Mexico and South Atlantic basins) are not directly transferable to the Scotian Margin due to differences in palaeographic setting, sediment supply, and primary salt- An ornithischian dinosaur from the Sustut Basin, basin geometry. northern British Columbia, Canada We have begun an integrated geoscience study with innova- tive 4D physical simulations using scaled analogue models and Victoria Megan Arbour and Milton Graves 2D/3D seismic interpretation. Our objective is to investigate Dalhousie University, Halifax, NS, B3H 4R2 the complex interplay between sedimentation and salt defor- <[email protected]> <[email protected]> mation in different sub-basins and their deepwater extensions that are characterized by contrasting salt deformation styles In 1971, dinosaur bones were discovered during uranium ranging from major extension and roho-style detachment to exploration in the Sustut Basin in northern British Columbia, minor extension and vertical salt movement. Canada, and were donated to Dalhousie University in Nova Public domain seismic data provide the boundary condi- Scotia in 2004. Although dinosaur bones have been reported tions for the experiments including tectonic setting, geometry from British Columbia previously, this specimen is the earliest of salt basins, and sedimentation pattern and rates. The evolu- recorded discovery of dinosaur bones from the province. The tion of the sedimentary basins and the dynamic salt system specimen also represents one of the westernmost discoveries is simulated in physical experiments that consist of scaled of dinosaur bones in Canada. The bones were collected from granular-viscous models with syntectonic sedimentation. loose blocks in a talus slope, near the intersection of Birdfl at Model deformation is analysed by time-series of images and Creek and Sustut River. 3D displacement data obtained with high-resolution optical The fossils are encased in a hard siltstone that shares char- image correlation techniques (2D/3D PIV – Particle Imaging acteristics with both the Early Albian to Late Cenomanian Velocimetry). Tango Creek Formation and the Late Campanian to late Early Structural 3D models are built from model sections with Maastrichtian Brothers Peak Formation, making a more pre- commercial seismic interpretation software to provide insights cise age estimate for this specimen diffi cult. Bones collected in the architecture of the linked salt-controled basins and fault include the right humerus, a radius, the distal portion of the structures. The integration of structural interpretation with right tibia and fi bula, several pedal phalanges including two time-series of fault strain data allows the reliable 3D fault cor- unguals, and several unidentifi able fragments. A small block of relation and the mechanical analysis of complex fault systems. matrix removed from the tibia contains additional small bones, For the fi rst time, this new modelling approach allows us to but further preparation is not possible at this time. quantitatively assess: 1) the timing and mechanisms of faulting, Comparison of the material with specimens at the Royal folding and salt migration, 2) the role of variable sedimentation Ontario Museum and descriptions in the scientifi c litera- patterns and rates, and 3) the coupling between extensional, ture indicates that a relatively small (less than fi ve metres in translational and compressional regimes. length), bipedal ornithischian is represented. General features In this experiment series we have investigated the role of of the tibia and phalanges are consistent with the ornithopod basin fl oor dip, sedimentation pattern and rates on the basin Thescelosaurus, but a low deltopectoral crest on the humerus evolution at regional scale. The experiment results show that matches closely with Stegoceras and other pachycephalo- gravitational collapse and salt mobilization generate complex saurs. Atlantic Geology 71 Distinguishing primary versus hydrothermal The high economic risk in hydrocarbon exploration on alteration assemblages at the Chuquicamata the Scotian Slope, offshore Nova Scotia, is caused by the porphyry copper system, Chile complex salt structures, which developed from the Triassic to Cretaceous periods. This study applies physical experiments Alexandra M. Arnott and Marcos Zentilli with optical strain monitoring to develop new concepts for the Dalhousie University, Halifax, NS, B3H 4J1, interpretation of geological and geophysical data, and provides <[email protected]>, <[email protected]> information for the hydrocarbon exploration in this area. The scaled analogue models, which use silica sand and silicone as One of the major problems facing a new geologist at a mine sediments and salt analogues, simulate gravity-driven syn-sedi- is learning how to distinguish in the workings and in drillcore mentary deformation in passive margin sedimentary wedges the various fresh, generally unmineralized rock units, their overlying a mobile substratum. High-resolution optical strain hydrothermally altered equivalents, and those altered by monitoring techniques (2D/3D Particle Imaging Velocimetry, weathering, which are often intermingled due to complex PIV) enable one to quantify the complete 3D deformation and structural deformation. It is also tricky to distinguish between surface fl ow in the experiments. magmatic biotite and K-feldspar from that formed by potassic A series of experiments have been conducted to study the alteration. Previous review of previous work is essential, and effects of varying sedimentation rates and the dip variation classical mineralogy and petrographic techniques, such as slab- of the experimental base on the spatiotemporal deformation bing and staining of feldspars can help, but often thin section pattern. Results show that complex relationships exist be- microscopy, x-ray diffraction and other modern mineralogical tween sedimentation pattern, basal dips, salt structures, and tools (e.g., electron microprobe) are necessary to unravel the fault formation in the overburden. Time-series strain data alteration record. At the Chuquicamata porphyry copper de- and structural interpretation of these experiments provides posit, Chile, mineralogical and geochemical evidence suggest insights in the dynamic evolution of sedimentary basins over a multiphase history of intrusion and alteration/mineralization a mobile substratum. Our results have the potential to improve complicated due to structural complexity. A strike-slip struc- the structural and seismic interpretation of the Scotian Slope ture, the West Fault, truncates the Chuquicamata Intrusive salt province. Complex (CIC), which consists of the calcalkaline granodioritic Este,