The Hudson Bay Basin is the largest intracratonic basin in North America, but remains a frontier area for our knowledge of its stratigraphy and sedimentology and its hydrocarbon potential. Large domal reefs (up to 10 m thick and 500 m wide) in the Upper Ordovician Red Head Rapids Formation on Southampton Island developed on the margin of this shallow-marine evaporitic basin in which physical and chemical seawater parameters were distinct from the open ocean and in which a diverse community of reef-building and dwelling metazoans was unable to flourish. The main reef facies comprise boundstone and cementstone composed of various proportions of early-calcified sponge tissues, microbial encrusters, synsedimentary cement and small colonial metazoans. The accretionary mechanisms of the Red Head Rapids reefs were mainly the result of framebuilding by early-calcified sponges and small colonial corals and binding by calcimicrobial elements for the boundstone facies, and of massive aragonitic cement precipitation near the seafloor for the cementstone facies. These Upper Ordovician reefs, in which microbialites dominate but coexist with metazoans, were more widespread in the Early Ordovician immediately prior to the Middle to Late Ordovician expansion of skeletal-dominant reefs. The Upper Ordovician reefs on Southampton Island, porous and locally bitumen impregnated, underwent early marine, near-surface and progressive burial diagenesis; reducing its primary porosity but significantly increasing its secondary porosity. They represent one of the major untested petroleum play types identified in the Hudson Bay Basin.

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The caribou (Rangifer tarandus groenlandicus) on Southampton Island, Nunavut, Canada for the years 1998-2000 and 2004, 2005, were investigated using stable isotope analysis (SIA) of carbon (d 13C) and nitrogen (d 15N). Spring signatures of rumen contents and muscle samples were correlated with standard biological measures of back fat and Riney kidney fat index. Caribou d 13C and d 15N ratios, together with detailed rumen content analysis, show that SIA data yields a time-integrated signal reflective of spatial and temporal variation in feeding ecology and as such is capable of detecting trophic interactions. Rumen content signatures provide current indication of forage selection, while muscle tissue signatures reflect bulk summer seasonal diet and in combination with rumen signatures, can help identify potential shifts in winter diet and the potential for short-term changes in caribou condition. <br /><br /> d 13C and d 15N signatures for major forage species categories were also compared to variations in rumen content and muscle signatures to investigate possible changes in forage preference. The results indicate that SIA is capable of assessing the importance of seasonal habitat use with regard to seasonal food intake. Stable isotopes analysis (SIA) was also used to investigate the effects of winter snow thickness and temperature on caribou (Rangifer tarandus), on Southampton Island. Variations found in isotope signatures of rumen content and muscle indicated that differences in winter climate conditions may affect forage selection, and impact on animal condition.

The caribou (Rangifer tarandus groenlandicus) on Southampton Island, Nunavut, Canada for the years 1998-2000 and 2004, 2005, were investigated using stable isotope analysis (SIA) of carbon (d 13C) and nitrogen (d 15N). Spring signatures of rumen contents and muscle samples were correlated with standard biological measures of back fat and Riney kidney fat index. Caribou d 13C and d 15N ratios, together with detailed rumen content analysis, show that SIA data yields a time-integrated signal reflective of spatial and temporal variation in feeding ecology and as such is capable of detecting trophic interactions. Rumen content signatures provide current indication of forage selection, while muscle tissue signatures reflect bulk summer seasonal diet and in combination with rumen signatures, can help identify potential shifts in winter diet and the potential for short-term changes in caribou condition. <br /><br /> d 13C and d 15N signatures for major forage species categories were also compared to variations in rumen content and muscle signatures to investigate possible changes in forage preference. The results indicate that SIA is capable of assessing the importance of seasonal habitat use with regard to seasonal food intake. Stable isotopes analysis (SIA) was also used to investigate the effects of winter snow thickness and temperature on caribou (Rangifer tarandus), on Southampton Island. Variations found in isotope signatures of rumen content and muscle indicated that differences in winter climate conditions may affect forage selection, and impact on animal condition.