- © 2000. AAPG/DEG
The geochemistry of Recent sediments from Pigeon Lake, Alberta was studied using Rock-Eval-6 in conjunction with Instrumental Neutron Activation Analyses137Cs isotope. The results of this study indicate that the variations in Rock-Eval parameters within the sedimentary column are correlated with the concentration of lithophile elements. These variations appear to be controlled by a balance between a number of interrelated processes concerned with both the nature of the deposited biomass and the depositional conditions. Two marker horizons were identified showing an abrupt decrease in Rock-Eval parameters (TOC, S2, and HI) and an increase in concentration of lithophile elements, indicating the clastic nature of the sediments with low autochthonous organic contents. This is attributed to significant natural events such as a storm or flood, which result in a rapid increase in the rate of erosion and subsequently in a high clastic input to the lake. Two cycles showing high organic content were also identified. The first cycle (productivity cycle) corresponds to the increase in algal productivity of the lake due to agricultural activities in the lake’s catchment. In the second cycle (diagenetic cycle), the downward decrease of organic matter is interpreted as the result of selective degradation of organic matter during early diagenesis. The estimated sedimentation rates based on the established marker horizons and 137Cs isotope indicate higher sedimentation in the deeper part of the lake prior to the productivity cycle. However, the sedimentation rates increased towards the littoral zone coinciding with an increase in productivity and subsequently the rise in growth of macrophytes in the nearshore area.
Lloyd R. Snowdon completed a Bachelor’s degree in chemistry at the University of Calgary in 1969 and then joined the Geological Survey of Canada with the responsibility for setting up the organic geochemistry lab. He completed his Doctorate in geology at Rice University, Houston in 1978. His research interests extend to many of the sedimentary basins of Canada and he has published over 130 papers and reports covering exploration and environmental geochemistry as well as various theoretical and analytical aspects of organic geochemistry. Dr. Snowdon is currently a research scientist at the Institute of Sedimentary and Petroleum Geology, a division of the GSC.
Lavern D. Stasiuk is an organic petrologist with the Geological Survey of Canada, Calgary. After completing his Ph.D. at the University of Regina in 1991, Vern joined the GSC as a postdoctoral fellow and then as a research scientist in 1994 where he is head of the Organic Petrology Laboratory. Vern has extensive international experience in optical microscopy of dispersed organic matter (DOM) in hydrocarbon source rocks, carrier beds, and reservoir rocks. His work has included defining organic facies and microfacies of macerals in Proterozoic and Paleozoic source rocks as related to local and regional paleoenvironments, the origin of solid bitumens and pyrobitumens in oil and sweet and sour gas reservoirs, thermal history of DOM in diamondiferous kimberlites, fluorescence microspectrometry of hydrocarbon fluid inclusions, regional mapping of thermal maturity in Canadian basins, and organic petrology of Holocene sediments.
Eileen Van der Flier-Keller is an Associate Professor in the School of Earth and Ocean Sciences at the University of Victoria, British Columbia, Canada. She was born and educated in Ireland and received a Ph.D. in Geology from the University of Western Ontario in Canada. Her research areas are in sedimentary and environmental geochemistry, and she has a strong interest in education and public awareness of geoscience.
Hamed Sanei completed his B.Sc. degree at the Shiraz University, Iran in 1996. He joined the Environmental Study Group of Geological Survey of Canada in Calgary in 1998 and since then has been involved with various environmental geochemical studies. At present, the main focus of his research is in environmental aspects of lake sediments as related to natural and anthropogenic activities, which forms part of his graduate study with the School of Earth and Ocean Sciences at the University of Victoria, British Columbia, Canada.
Fariborz Goodarzi completed his Ph.D. at the University of Newcastle-Upon-Tyne, United Kingdom in 1975. He joined the Geological Survey of Canada–Calgary in 1982, where he is principal research scientist and coordinator of environmental studies. His interests range from the impact of geogenic activities on the environment associated with the heavy metal and organic matter and impact of in situ coal beds on water quality in geological settings, lakes, and the emission and deposition of pollutants from stationary sources such as coal-fired power plant and metal smelters. He has been an expert in the United Nations Development Program since 1981, an editor of Fuel, International Journal Coal Geology and Energy Sources, and has served as president of the Canadian Society for Coal Science and Organic Petrology.