The recognition of remnants of large cauldron subsidence complexes along the trend of the Skeena Arch first occurred in the Tahtsa Lake area (MacIntyre, 1985). In subsequent years, evidence for other large subsidence complexes was documented in the Rocher DeBoule, Babine Mountains, Buck Creek and Babine Lake areas (MacIntyre, 2001; Church and Barakso, 1990). Originally all of these structures w...

A unique structure in the Earth's lowermost mantle, the Perm Anomaly, was recently identified beneath Eurasia. It seismologically resembles the large low-shear velocity provinces (LLSVPs) under Africa and the Pacific, but is much smaller. This challenges the current understanding of the evolution of the plate-mantle system in which plumes rise from the edges of the two LLSVPs, spatially fixed i...

Agate gemstones occurring in the Mesoproterozoic volcanic rocks of Priozersk Formation (PrF) within Pasha–Ladoga Basin (Fennoscandian Shield, NW Russia) were investigated to characterize mineral and geochemical composition agates provide new information concerning their origin. Optical scanning electron microscopy, EDS microanalysis, X-ray powder diffraction, fluorescence spectrometry, Raman sp...