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The Cockburn Substage readvance marks the last major late-glacial advance of the northeast sector of the Laurentide Ice Sheet on Baffin Island. The causes of this abrupt, late reversal of retreat are still unclear, but greater chronological control may provide some insight. To date, the literature has focused on the large terminal moraines in the region, providing a date of readvance (circa 9.5–8.5 ka cal BP). In Frobisher Bay, the Cockburn Substage readvance and recession onshore are marked by a series of moraines spread over ∼20 km along the inner bay. Acoustic marine mapping reveals five distinct transverse ridges, morphologically suggestive of grounding-zone wedges, and two later fields of DeGeer moraines on the floor of the inner bay. These indicate that the style of ice retreat (beginning no later than 8.5 ka cal BP) changed over time from punctuated recession of a floating ice front (20 km over >680 years, with four pauses) to more regular tidewater ice-front retreat, reaching the head of the bay 900 years or more after withdrawal from the outer Cockburn limit. The established chronology for final recession in the region is based largely on radiocarbon dating of bulk shell samples and single shells of deposit-feeding molluscs, notably Portlandia arctica, affected by old carbon from carbonate-rich sediments. Sedimentary analysis and judicious sampling for 14C dating of glaciomarine and marine facies in seabed sediment cores enables development of a late- and post-glacial lithostratigraphy that indicates final withdrawal of ice from the drainage basin by 7 ka cal BP.

Over the past decade, wood-energy use in Alaska has grown dramatically. Since 2000, several dozen new wood-energy installations have been established, with numerous others in the design or construction phase. This case study report compares two wood-pellet heating systems in Juneau, Alaska. The Tlingit-Haida Regional Housing Authority, a native housing authority that serves more than 27,000 tribal residents in 11 communities in the southeast, recently established a wood-pellet boiler to provide heating to their 10,000-square-foot warehouse. The Sealaska Corporation is an Alaska Native Corporation that recently installed a wood-pellet system to heat its 58,000-square-foot office building in downtown Juneau. In this case study, we consider the ongoing efforts of both organizations to advance wood energy in southeast Alaska. We review the wood energy conversion process—including the motivation for change, feasibility work, construction, system operation, and lessons learned.