Kauaʽi: jungle, beaches, and very steep cliffs
This past February I visited the island of Kauaʽi, Hawaiʽi, for the first time. My initial, and quite frankly continued, reaction was “wow!” What a place. KauaʽI, Hawaiʽi’s northernmost island, has a landscape unlike any other I have ever seen on Earth: on an island approximately 50 km in diameter you can float at sea-level, hike up a 5000 ft. mountain, walk through dense rain-forest, bake in a semi-arid desert, fly through valleys almost a kilometer deep, or peer down sheer cliffs that plunge straight into the sea. At 5 million years old, Kauaʽi is Hawaiʽi’s oldest island, and since its formation Mother Nature has called the shots, carving deep canyons into the volcanic rock to create the pre-historic looking landscape that dominates today (don’t believe me? Just take a look at the scene in Jurassic Park where the helicopter flies to the island and lands next to Manawaiopuna Falls).
Kauaʽi, like the other Hawaiian Islands, is the result of intraplate hotspot volcanism, meaning that it formed in the center of a tectonic plate that is moving over a stationary body of hot, buoyant, material that has risen from deep within the Earth. This hot material is called a ‘mantle plume’, and the Hawaiian mantle plume in particular has been responsible, over the past 85 million years, for the formation of about 107 individual volcanic islands and seamounts spanning a distance of roughly 5 800 km. If you look at a map of the Pacific Ocean, you can see that the seamounts and islands form a chain from the island of Hawai’i all the way to the Kuril-Kamchatka Trench in the northwest, near Russia.
I visited Kauaʽi in the context of my Ph.D. project, which will be a volcanological and geochemical study of the lavas on the island. I will spend time on Kauaʽi searching for, and collecting, samples that I can then take back to a lab and analyze (http://pcigr.eos.ubc.ca/). The results of these analyses will help us better understand how the island was formed, and what kind of magma contributed to its formation. This, in turn, will add to our ever-growing knowledge of the Hawaiian mantle plume. Hawaiʽi is unique in that it offers geologists the best natural laboratory in the world for studying hotspot volcanism because A) the products of this volcanism are relatively well-preserved, and B) they record plume activity over a long period of time and are still doing so today with the eruptions of Kilauea on the big island of Hawaiʽi, and Loʽihi seamount off its south coast.
Over the course of four days on Kauaʽi we visited as many places as possible in order to identify sampling locations that are accessible and safe (called a ‘reconnaissance’). Our reconnaissance included hikes along the northern Napali Coast and in the Waimea Canyon, driving coast-to-coast, and a very informative chat with Chuck Blay, resident Kauaʽi rock expert. We managed to see a lot in four days: all of the 5 million years’ worth of tropical weathering, all of the inaccessible mountains, all of the steep cliffs, and all of the 3000 ft. drops (that’s a bit melodramatic because there’s actually only one, into Mount Waiʽaleʽale Canyon). The river-incised valleys of Waimea Canyon are spectacular close-up, and render even the chattiest geologists completely speechless. What we observed during our four day reconnaissance might not sound ideal from a sampling perspective, but I believe that with careful preparation, many backup plans, a good amount of patience, and some time on a ‘Stairmaster,’ it will be a very good adventure and a wonderful project.
Photo:View along the northern Napali Coast, looking east. Photo by Dominique Weis.
Nicole Williamson is a new PhD student in the Department of Earth, Ocean and Atmospheric Sciences at the University of British Columbia, under the supervision of Dr. James Scoates and Dr. Dominique Weis.
Views expressed in blog posts reflect those of the author, and not necessarily those of the CFES.