Passing of a Legend in Sierra Nevada Geology

[giantbrookie]

The geologic community lost one of its brightest stars last weekend when Jason Saleeby passed away at the age of 74. Jason was a professor at CalTech for the bulk of his academic career (1978-2015; he had a brief stint as assistant professor at UC Berkeley from 1975-1978). Whereas a brief memorial notice was posted on the CalTech website (https://www.caltech.edu/about/news/jaso ... y-19482023), I figured I'd post a little notice here, because the Sierra Nevada was a central component of his research, and in my opinion, he contributed more to geologic knowledge about the Sierra Nevada than anybody else during the period of time spanned by his career. This amounts to a personal tribute for Jason.

As many of you know, geologic research spans a wide range of subdisciplines and the vast majority of researchers tend to focus on various of them, so that someone might study the evolution of topography (geomorphology) but they would not study the generation of granites, or metamorphism and deeper fault movements associated with said metamorphism. Thus, in Sierra Nevada research there have been those who studied the older "basement" rocks, the granitic rocks and metamorphic rocks and these have not been the same group that studied the younger gravels and volcanic rocks (once called the "superjacent series") and those folks wouldn't be those studying the landscape evolution (geomorphology) and/or associated geologically recent tectonic processes. Jason Saleeby is the only geoscientist of his era who made seminal contributions to the research of the Sierra Nevada basement as well as to its more recent history.

Although a world-renowned scientist at a top echelon academic institution, Jason never struck an elitist attitude, he was a down-to-Earth good guy. I think you can see this reflected in the numerous photos of him you'll find if you Google search him. Jason was also unusual in being a leader in geochronology and high-temperature geochemistry, which are lab/instrumentally-based fields, but always going to the field. And whereas there are some "field-oriented" geochemists and petrologists, Jason's geologic field skills were absolutely top-of-the-line. There has been the tendency for geologic researchers to oversimplify interpretations and analysis in spite of the fact that we have orders of magnitude more data than we had five decades ago and we have technologic means of acquiring data that could not have been imagined before. Jason stands out among researchers in his willingness to tackle geologic complexity head on. It is my opinion that his drive to embrace and confront complexity derives from his field-oriented approach which included developing methods of mapping geologically complex field relationships.

It is for the latter that I owe the most to Jason. I was never one of his students, but his teaching at UC Berkeley--I arrived at UCB as a junior community college transfer in Fall 1978 after he had left for CalTech--left a legacy that would find its way to me. Part of this was his development of a 10-week, instead of the usual (in those days) 6-week geologic field camp. The great Clyde Wahrhaftig (one of the greatest figures in the study of Sierra Nevada geomorphology) took over instruction of field camp after Jason left, and my own class (1980) was Clyde's last (he retired shortly thereafter from UCB but continued at the USGS he held a joint appointment) and he taught it as a 10-week course (Clyde passed away in 1994 at the age of 74). A key component of the field camp I took was instruction in how to made block-in-matrix relationships of units known as mélanges. This requires a different mindset and methodology than mapping layered rocks. As far as I can tell from talking with students who took field camp from Jason, this methodology was passed on to Clyde who taught it well ('normal' mapping of contacts was also taught for areas for which it is appropriate). In any case the block-in-matrix mapping methods stood me in good stead as I went on to do research in the notoriously mélange-rich Franciscan Complex of western California. I have continued to build on and develop new sorts of pattern recognition in such rocks and use this to update teaching methods, because I teach geologic mapping in that type of geology (few if any in the USA teach that anymore). I told my students at the orientation meeting for their culminating field class last Friday that a bit of Jason would live on in them as a result of what they'd learn.

A testament to Jason's unique combination of Sierra Nevada research knowledge the challenges I faced in finding appropriate reviewers for a geologic field trip guide I'm writing (or have written, depending on perspective) for a 2-day northern Sierra Nevada field trip I'll be leading for the upcoming May 2023 Geological Society of America (GSA) Cordilleran Section meeting (hosted in Reno). The geology I'd like to highlight for participants includes some really neat new observations and interpretations in the basement metamorphic rocks as well as the interesting record of landscape evolution and recent faulting. Only Jason would have had the expertise to be review both aspects, but he had been in poor health for sometime so I did not want to burden him with a review request. Accordingly, I had to seek out a reviewer with expertise in the "younger" geology and another one with expertise in "older" geology. Years ago, his stellar expertise across geologic subdisciplines came through in his thorough and thoughtful review of my 2013 paper on uplift of the Sierra Nevada; his review led to huge improvements in that paper.

Finally, here are my personal recollections of Jason. I first read some of his early papers on Sierra Nevada and Klamath Mtns geology back around 1980-1981, but it wasn't until I went to grad school, starting in 1983 that I fully realized that he was one of the seminal figures in California geology. Although the research target of my PhD research was my beloved Franciscan Complex, my advisor Eldridge Moores' main research interest, outside of Cyprus, was the basement of the Sierra Nevada where he supervised many theses. During the time I was in grad school (1983-1989) there were three main 'powers' in research of the Sierra Nevada basement: Eldridge, Rich Schweickert (UN Reno), and Jason. They were rivals to some extent but there was a dependence of all on Jason because he was the one getting the most crucial information: the age dates obtained by U-Pb dating of zircons from various plutonic rocks (analyzed in Jason's lab at CalTech). During my early grad days one of my classmates went on a field trip led by Jason in the Sierra and told me afterwards that she had learned more in three days than in the rest of her educational experience combined; she said that Jason was the brightest person she had ever encountered. In the meantime my own first "near encounter" with Jason was not auspicious. I gave a talk at the American Geophysical Union (AGU) fall meeting in San Francisco in December 1987 on some metamorphic rocks in the northern Sierra Nevada. One of my classmates reported that Jason was saying I screwed up and got things horribly wrong. Whether or not my classmate actually heard this unknown, given that he had a penchant for exaggeration.

I don't think I met Jason personally until many years later and our meetings and correspondence became increasingly cordial and mutually respectful after I had published my paper with Tom Sawyer on evidence for uplift history of the Sierra Nevada in 2001. Jason himself had published (as 2nd author to his finishing PhD student) a key paper in Sierra Nevada uplift geodynamics (evidence for the sinking or peeling away of a dense "root" beneath the Sierra) in 1998 (Ducea and Saleeby, 1998). This led to me being a participant in a session and after-party in honor of Jason in 2012 when he received the Distinguish Career Award from one of the divisions of GSA. During those years I had a difficult personal tightrope to walk because Jason and my Jedi Master (Eldridge) had morphed into bitter enemies of each other. At any rate, I am very grateful for what Jason taught me, directly or indirectly and I will treasure the memories of moments we interacted. I also recall that he is the only geologist who has ever beaten me in bets over beer (that involve a something we're debating on geology). In fact I'd be undefeated were it not for two bets I had with him during debates on the geology of his bread-and-butter field area, the Kings ophiolite that crops out around Pine Flat Reservoir (this was his PhD dissertation area and he built on that work with many subsequent studies). I debated him on a field trip he led in 2007, cut a thin section (to be examined under a microscope) to find the answer and realized at my first glance that I owed Jason a six pack of IPA for which I paid up the next day. Later, sometime around 2014 or so we debated another geologic relationship and his final line was so elegantly framed I knew I had been trounced and conceded right away.

[rlown]

Sorry for the loss. Death keeps rearing its ugly head lately. Gotta think this is going to continue as we get older until we join the list.

[Fly Guy Dave]

Other than family and friends, it is some of the college professors that one had that make a lasting and positive impact on one's life. People like that are dearly treasured and are certainly missed when they pass on. My condolences.