Endicott Arm, Alaska
The National Geographic Sea Lion plied the calm waters of Stephens Passage early on the morning of June 6th and arrived at Holkham Bay before 5 am. Sun light sparkled on snow-capped mountains as the ship turned southeast down the glacially carved valley, or fjord, of Endicott Arm. After breakfast, we boarded Zodiacs to wind through the icebergs in front of Dawes glacier.
As we approached the wall of ice, we saw numerous harbor seals and arctic terns on the ice bergs. The fjord walls on either side of the bergs provided exceptional views of exhumed metamorphic and igneous rocks of the Coast Mountains. These hard rocks display spectacular examples of glacial striations and ‘scalloped’ surfaces formed when the glacier dragged rocks along the wall of the fjord. We gazed at the cliffs and pondered the black and white migmatite or mixed igneous and metamorphic rock, formed as these rocks were heated to cause partial melting deep in the Earth’s crust. Adjacent to this we saw pale grey trondhjemite, an igneous rock named for Trondheim, Norway. Beyond the rocky walls of the fjord, the glacier shone brilliantly in the sun showing the dark blue color, characteristic of clean coarsely crystalline glacial ice near the water, and white less smooth surfaces elsewhere. Although we only saw minor calving while we watched, the bare rock surfaces in front of the glacier provided testimony for the recent retreat of the glacier.
We re-boarded the National Geographic Sea Lion for lunch and then continued our journey northwest, up the long fjord of Endicott Arm. The afternoon was packed with great views of glacially carved rock forms (U-shaped valleys, glacial horns, and striations) and geologic evidence for the tectonic forces that formed the Coast Mountains between 90 and 60 million years ago. As the ship entered the mouth of Tracy Arm, dozens of bald eagles were perched on grounded ice on the end moraine. Misty rain enveloped Holkham Bay as we turned north into Williams Cove. We anchored and divided into groups for hikes along a coastal forest beach or kayaking in the cove. Holkham Bay was bathed in showers, as we ate dinner in the quiet waters of Williams Cove. The National Geographic Sea Lion turned north into Stephens Passage after dinner and we sailed north toward Juneau.
The National Geographic Sea Lion plied the calm waters of Stephens Passage early on the morning of June 6th and arrived at Holkham Bay before 5 am. Sun light sparkled on snow-capped mountains as the ship turned southeast down the glacially carved valley, or fjord, of Endicott Arm. After breakfast, we boarded Zodiacs to wind through the icebergs in front of Dawes glacier.
As we approached the wall of ice, we saw numerous harbor seals and arctic terns on the ice bergs. The fjord walls on either side of the bergs provided exceptional views of exhumed metamorphic and igneous rocks of the Coast Mountains. These hard rocks display spectacular examples of glacial striations and ‘scalloped’ surfaces formed when the glacier dragged rocks along the wall of the fjord. We gazed at the cliffs and pondered the black and white migmatite or mixed igneous and metamorphic rock, formed as these rocks were heated to cause partial melting deep in the Earth’s crust. Adjacent to this we saw pale grey trondhjemite, an igneous rock named for Trondheim, Norway. Beyond the rocky walls of the fjord, the glacier shone brilliantly in the sun showing the dark blue color, characteristic of clean coarsely crystalline glacial ice near the water, and white less smooth surfaces elsewhere. Although we only saw minor calving while we watched, the bare rock surfaces in front of the glacier provided testimony for the recent retreat of the glacier.
We re-boarded the National Geographic Sea Lion for lunch and then continued our journey northwest, up the long fjord of Endicott Arm. The afternoon was packed with great views of glacially carved rock forms (U-shaped valleys, glacial horns, and striations) and geologic evidence for the tectonic forces that formed the Coast Mountains between 90 and 60 million years ago. As the ship entered the mouth of Tracy Arm, dozens of bald eagles were perched on grounded ice on the end moraine. Misty rain enveloped Holkham Bay as we turned north into Williams Cove. We anchored and divided into groups for hikes along a coastal forest beach or kayaking in the cove. Holkham Bay was bathed in showers, as we ate dinner in the quiet waters of Williams Cove. The National Geographic Sea Lion turned north into Stephens Passage after dinner and we sailed north toward Juneau.
