Jeffrey G. Ryan, Petrologist/Geochemist (“Hard rock” geologist)

Time Scavengers is collaborating with the International Ocean Discovery Program Expedition 390/393 to showcase the scientists recovering sediment and rock cores, and conducting science at sea! Click here to learn more about IODP, and visit the Research Vessel JOIDES Resolution website here to read more about the drillship. To learn more about IODP Expeditions 390 and 393, click here!

You can follow the JOIDES Resolution on Twitter @TheJR, on Facebook @joidesresolution, and on Instagram @joides_resolution!


I’m Jeff Ryan, a Professor of Geology in the University of South Florida’s School of Geoscience.  On IODP Expedition 393, I’ll be sailing as an Inorganic Geochemist.  It’s my third IODP research drilling cruise, all sailing this role.

Dr. Jeff Ryan on the JOIDES Resolution during Expedition 366, which drilled rocks and sediments from the northwest Pacific Ocean.

In terms of geology subspecialty I’m a “hard-rock” geologist, as I mostly work on igneous and metamorphic rocks.  My research primarily focuses on subduction zones, where Earth’s tectonic plates head down deep-sea trenches and cycle back deep into the Earth’s mantle. I study subduction chemically, using key trace elements and isotopic ratios to understand how the old, cold, wet ocean crust reaching deep sea trenches changes as it subducts, and how fluids and melts driven off subducting plates change nearby mantle rocks and lead to volcanism at island arcs, and even at oceanic hotspots like Hawaii or Iceland.  My interest in Expeditions 390-393, which will drill sites in the south Atlantic, nowhere near a subduction zone (!!), is to better understand how the composition of ocean crust changes as it ages, and so what the differences are between the young seafloor subducting beneath the Cascades, and the very old crust going down beneath the Lesser Antilles, or the Mariana Islands in the Pacific.

In my courses at USF I use the ocean drilling research I’m doing directly in teaching our Geology students. My Junior-level Mineralogy/Petrology course has for the past six years examined unusual volcanic rocks from the Izu-Bonin subduction zone that I helped recover as a Shipboard Scientist on IODP Expedition 352.  The students made some very cool discoveries about the minerals and textures in those samples, which led to a recent student-authored scientific paper in the journal American Mineralogist (Scholpp et al 2022).   I hope to do something similar for my future students with Expedition 390-393 basaltic samples.

People come to geology a bunch of different ways, I’ve found.  In my case it was a childhood interest in rocks and minerals, combined with a penchant for creative writing.  Geology is at its core a storytelling science: we divine and tell the “stories” behind the places in the Earth that we examine.  When I encountered the science fully for the first time, as a Freshman in my first undergraduate college course at Western Carolina University, it was a perfect fit.  I’m looking forward to helping tell the story of how the south Atlantic Ocean crust formed and evolved as part of IODP Expedition 393.

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