Reflections South Sawyer Glacier
The Sea Bird turned eastward into Holkham Bay and then entered Tracy Arm early on July 31. We awoke to a calm but misty day as we traveled east along the sinuous fjord. The ship threaded between icebergs to about half a mile from South Sawyer Glacier. Near the glacier, we were treated to views of harbor seals resting on icebergs, Arctic terns, and calving of ice into the calm green water. Freshly exposed rock below lush vegetation and glacial sediment (or till) perched along the valley walls indicated the recent retreat of the ice. The exposed bedrock formed a black, white, and gray swirl in front of the icy wall of the glacier. This mixture of formerly molten igneous and solid metamorphic rock is known as migmatite. These rocks flowed like plastic as they were metamorphosed, deformed, and melted far beneath the Earth’s surface. After passing Sawyer Glacier on our return westward, we spotted two mountain goats high on the cliffs. We went below deck to enjoy breakfast while the Sea Bird headed west toward Holkham Bay. During the scenic trip out of Tracy Arm we examined numerous glacial and other geological features, including the spectacular waterfall known as hole in the wall. As we departed Tracy Arm, we marveled at shear cliffs of the great tonalite sill, an igneous intrusion which is so resistant to erosion that it underlies mountains that extend upward over 5,000 feet above the narrow fjord. After lunch, we anchored in Williams Cove, along the north side of Holkham Bay, where we spent the afternoon kayaking and hiking in the rain forest. The Sea Bird crossed the submerged end moraine in Holkham Bay and turned south along Stephens Passage just before dinner. During our passage south toward Petersburg we paused to see numerous humpback whales.
The Sea Bird turned eastward into Holkham Bay and then entered Tracy Arm early on July 31. We awoke to a calm but misty day as we traveled east along the sinuous fjord. The ship threaded between icebergs to about half a mile from South Sawyer Glacier. Near the glacier, we were treated to views of harbor seals resting on icebergs, Arctic terns, and calving of ice into the calm green water. Freshly exposed rock below lush vegetation and glacial sediment (or till) perched along the valley walls indicated the recent retreat of the ice. The exposed bedrock formed a black, white, and gray swirl in front of the icy wall of the glacier. This mixture of formerly molten igneous and solid metamorphic rock is known as migmatite. These rocks flowed like plastic as they were metamorphosed, deformed, and melted far beneath the Earth’s surface. After passing Sawyer Glacier on our return westward, we spotted two mountain goats high on the cliffs. We went below deck to enjoy breakfast while the Sea Bird headed west toward Holkham Bay. During the scenic trip out of Tracy Arm we examined numerous glacial and other geological features, including the spectacular waterfall known as hole in the wall. As we departed Tracy Arm, we marveled at shear cliffs of the great tonalite sill, an igneous intrusion which is so resistant to erosion that it underlies mountains that extend upward over 5,000 feet above the narrow fjord. After lunch, we anchored in Williams Cove, along the north side of Holkham Bay, where we spent the afternoon kayaking and hiking in the rain forest. The Sea Bird crossed the submerged end moraine in Holkham Bay and turned south along Stephens Passage just before dinner. During our passage south toward Petersburg we paused to see numerous humpback whales.
