ABSTRACT
Quantitative geological data collected from the first operational use of a long coring system is presented. This coring system was used on three scientific cruises in 1987 covering a geographic area extending from Baffin Bay to the Scotian Shelf on the Canadian continental margin. Forty cores were recovered during these cruises. Physical properties, which include index, geotechnical and acoustic data, were obtained on all core samples. In addition, cores were analyzed for sedimentology, biostratigraphy, and magnetic susceptibility. The large diameter of this corer allows multiple tests to be completed at important subseabed horizons. The scientific results are presented by illustrating core samples collected from the scotian shelf in Emerald Basin.
INTRODUCTION
A long coring facility' (LCF) was used onboard the CSS Hudson during scientific research cruises to the eastern Canadian continental margin. Core locations cover a large geographic region (Table 1) from the scotian Shelf in the south to Baffin Bay. Each of the three research cruises had different scientific objectives related to regional geological history of the Quaternary sediments. Results from cores collected in Emerald Basin are presented as representative of the quality of data collected with this coring system.
Emerald Basin (Fig. 1), located on the central scotian Shelf is a relatively deep basin of up to 250 meters water depth. The basin is formed in Tertiary bedrock and is infilled with glacial till at the base which is overlain by Quaternary finegrained sediment (Fig. 2). Piston cores collected in this basin served two purposes:calibration of high resolution seismic reflection data with sediment geotechnical and physicalproperties2 anddetermination of age and history of the sediment for input to glacial history models on the eastern Canadian margin(3,4).
In Emerald Basin, standard piston cores had previously been collected using conventional oceanographic equipment. At each site, longer core penetration and sample recovery was achieved (Fig. 3). This improvement allowed for a complete study of the Quaternary sediment sequences which had previously not been achieved with standard equipment.
METHODS
All core samples collected during these research cruises were processed onboard. After piston core recovery, core liners were removed from the barrels and cut into 1.5 meter sections (nominal). These sections were capped and stored vertically in a refrigerated container until processing. Handling of the core samples was minimized by location of the refrigerated core container immediately aft of the pipe storage rack1 and within 2 metres of the bulkhead entrance into the core processing laboratory.
Core processing included measurement of magnetic susceptibility, acoustic compressional wave velocity and undrained shear strength. In addition, the cores were split longitudinally into archive and working halves, photographed and described for color, sediment structure and lithology. Subsamples were taken for grain size; Atterberg limits; biostratigraphy; radiocarbon age-dating; paleomagnetics; and bulk density, water content, and pore water salinity.
