An approximately 0.4 km diameter elliptical structure formed in Devonian granite in Southwestern Nova Scotia, herein named the Bloody Creek structure (BCS), is identified as a possible impact crater. Evidence for all impact origin is based oil integrated geomorphic, geophysical, and petrographic data. A near-continuous geomorphic rim and a 10 m deep crater that is infilled with lacustrine sediments and peat define the BCS. Ground penetrating radar shows that the crater has a depressed inner floor that is sharply ringed by a 1 m high buried scarp. Heterogeneous material under the floor, interpreted as deposits from collapse of the transient cavity wails, is overlain by stratified and faulted lacustrine and wetland sediments.Alteration features found only in Hill rocks Include common grain comminution, polymict lithic microbreccias, kink-banded feldspar and biotite, single and Multiple sets of closely spaced planar microstructures (PMs) in quartz and feldspar, and quartz mosaicism, rare reduced mineral birefringence, and chlorite showing plastic deformation and flow microtextures. Based on their form and crystallographic orientations, the quartz PMs consist of planar deformation features that document shock-metamorphic pressures <= 25 GPa.The age of the BCS is not determined. The low depth to diameter ratio of the crater, Coupled with anomalously high shock-metamorphic pressures recorded at its exposed rim, may be a result of significant post-impact erosion. Alternatively, impact onto glacier Ice during the waning stages of Wisconsinian deglaciation (about 12 ka BP) may have resulted in dissipation of much impact energy into the ice, resulting in the present morphology of the BCS.

Field studies recently conducted on the west coast of Ungava Bay, in the southern part of the continuous permafrost zone, have permitted the establishment of the pattern of active-layer development for six different geomorphological and vegetational terrain types. All study sites were situated on horizontal surfaces free from local topographic influences, to permit the explanation of thaw progression, in terms of the earth materials, moisture content, and vegetation cover characterizing each terrain type. Thermal properties for organic and mineral soil, and for bedrock, were calculated from field data on texture, bulk density, and moisture content of the earth materials at the sites, and were used to explain thaw-layer development for each terrain type. A linear regression was established for each group of sites between the logarithmic transformation of thaw penetration and an atmospheric thawing index obtained through interpolations of air temperature data from the two closest meteorological stations—Kuujjuaq (Fort Chimo) and Koartaq (Cape Hope's Advance). This regression was then used to estimate the total thickness of the active layer at the end of the thaw season for each terrain type, and to assess probable variations in active-layer depths in the region over a 20 year time period. Probable spatial variations of active layers for extreme climatic variations in the Ungava Peninsula are also briefly presented. Key words: active layer, permafrost, thermal, thaw penetration, terrain analyses, Ungava.