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Expedition Log

04.13.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 11

Wrapping up the Volcanoes and Seamounts leg Dave Clague writes: This has been a great cruise with almost all of our initial goals met and some new discoveries added on top. As Rob Zierenberg noted yesterday, numbers sometimes tell a story and here are some more from this cruise. We collected 191 lava samples, 14 samples …

Expedition Log

04.12.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 10

Collecting hydrothermal fluid Rob Zierenberg writes: The number for today seems to be 33—the current wind speed in knots. Waves are pounding into the ship and we cannot launch the ROV in this weather. Everyone was really looking forward to today’s dive, which was in Pescadero Basin, the next spreading segment north of the Alarcón Rise. …

Expedition Log

04.11.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 9

Understanding the evolution of Alarcón Rise Dave Clague writes: As previously mentioned, the Alarcón Rise is the northernmost segment of the East Pacific Rise spreading center. The Alarcón Rise is roughly 50 kilometers long. It is the axis along which new ocean crust is forming as a rocky ridge, compared to the short spreading segments …

Expedition Log

04.10.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 8

Traveling back in time Julie Bowles writes: Today was like traveling back in time! Our goal was to establish an approximate eruptive history at this location, so we started our dive about three kilometers to the west of the active Alarcón Rise axis. Flows out here are generally tens of thousands of years older than what is …

Expedition Log

04.09.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 7

Hydrothermal chimneys, basaltic pillows, and lava flows Jenny Paduan writes: Today’s dive was, as the Wisconsinites on board (Julie Bowles, Knute Brekke, and Patrick Mitts) would say, a smorgasbord! There were new and very impressive hydrothermal chimneys, mounds of lovely elongate basaltic pillows, and a vast flood of a relatively young, jumbled sheet-like lava flow, which …

Expedition Log

04.08.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 6

Tamayo transform fault Julie Bowles writes:Today’s dive targeted the southernmost end of the Alarcón Rise, where it transitions from oceanic spreading center to what is called a transform fault. Whereas the volcanically-active spreading center is where new oceanic crust is formed and two tectonic plates move away from one another, a transform fault is not …

Expedition Log

04.07.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 5

Meyibó hydrothermal vent field Ronald Spelz writes: Today’s dive on the Alarcón Rise started in a newly discovered active hydrothermal field, a vent through which hot fluids emerge from the seafloor. The tall chimney edifices, along with their peculiar deep-sea inhabitants, and their jetting hot fluids, literally gave us a “very warm” welcome. We decided …

Expedition Log

04.06.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 4

High-silica lava flows at Alarcón Rise Brian Dreyer writes: A primary goal of today’s dive was to explore the extent of high-silica lava flows at Alarcón Rise. These flows are common on land volcanoes but rare at oceanic spreading centers—sites where two tectonic plates move away from one another. Most spreading centers erupt low-silica lava …

Expedition Log

04.05.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 3

Pillow lavas Chrissy Maschmeyer writes: The purpose of our expedition today was to determine if volcanic rocks containing silica occurred along the spreading ridge south of the previously identified rhyolitic lava dome. Oceanic ridges typically erupt basalt, which is denser and contains less silica than continental crust, and is considered to be more directly derived from …

Expedition Log

04.04.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 2

Exploring a mid-ocean-ridge rhyolite dome Ryan Portner writes: Today we dove on the Alarcón Rise mid-ocean ridge. With few exceptions, mid-ocean ridges typically lie very deep beneath the sea surface. They are a locus of active volcanoes, hydrothermal vents and chimneys, and an abundance of life. Mid-ocean ridges occur where two tectonic plates move away …

Expedition Log

04.03.15

Gulf of California 2015, Leg 5 – Volcanoes and Seamounts – Log 1

A full day’s dive in volcano of Alarcón Seamounts Jenny Paduan writes: The R/V Western Flyer departed last evening from Pichilingue Harbor near La Paz, Mexico. The weather was clear and warm and the sea was smooth as glass. We steamed through the night and arrived in time to do a full day’s ROV dive on the …