NEWS

Spring 2015: Starting September 2015, I'll be an Assistant Professor in the Department of Geological Sciences at Cal State-San Bernardino. Until then, I'm a professional mover and a Visiting Investigator in petrology and geochemistry at Geophysical Lab, where I'm working on some new projects: inter-mineral fractionation of Ni and Fe isotopes in the Josephine Peridotite, cryptic Au-Fe catalysis during experimental hydrothermal alkanogenesis, and Fischer-Tropsch-type organic synthesis on natural awaruite. Publication news: our high-pressure methane paper just came out in Geochimica et Cosmochimica Acta and our work on Ca-C-O-H equilibria was recently published as a notable paper in American Mineralogist.



MY RESEARCH: the professional/geek version

A kinetic pressure effect on methanogenesis
Aqueous abiotic methane concentrations in a range of geologic settings are below levels expected for equilibrium with coexisting CO2 and H2, indicating that kinetics can control the speciation of reduced carbon-bearing fluids. Previous studies have suggested that mineral catalysts or gas phase reaction may increase the rate of methanogenesis. Here, we report experiments that indicate pressure can also accelerate hydrothermal aqueous reduction of CO2 to methane. The pressure effect was interpreted to be mediated by one of the following three processes: reduction of metastable methanol, formation of Fe-carbonyl complexes in the fluid, and/or heterogeneous catalysis by Fe. Pressure-enhanced methanogenesis may lead to CH4-rich fluids in the forearc regions of subduction zones. A kinetic pressure effect may be particularly important on the deep ocean floors of planetary bodies where pressure may compensate for the otherwise sluggish reaction kinetics expected at low temperatures. [Lazar et al. 2015, Geochimica et Cosmochimica Acta, PDF]
Calcite reduction in subduction zones
Calcite is an important carrier of inorganic carbon in subduction zones. We show that calcite solubility increases with decreasing ƒO2 until a critical point below which portlandite is stable relative to calcite (LEFT). As depth increases, the enhancement of carbon mobility above oxidized values requires lower and lower ƒO2 values. For example, at the seafloor, QFM is sufficient to enhance carbon mobility, but at blueschist conditions only serpentinization and other very low ƒO2 processes can increase calcite solubility above oxidized conditions. Notably, we report a fascinating phenomenon wherein calcite melts at low ƒO2 in the presence of H2O at 700 °C and 10 kbar because the reduction of calcite to portlandite causes a freezing point depression. [Lazar et al. 2014, notable paper, American Mineralogist, PDF]
Experimental Ni isotope equilibrium
Recent advances in mass spectrometry have led to exciting advances in nontraditional stable isotope geochemistry. Measurements in natural materials require high quality experimental calibrations of relevant fractionation factors. Combining the three-isotope method with classical experimental petrology, we measured the equilibrium Ni isotope fractionation factor between Ni-metal and Ni-talc (LEFT) as a model for metal-silicate fractionation in general. [Lazar et al. 2012, Geochimica et Cosmochimica Acta, PDF]
Greenhouse methane from komatiite alteration
Greenhouse methane that formed during serpentinization of a komatiitic seafloor may have warmed the early Earth, possibly enough to prevent glaciation and solve the so-called Faint Young Sun paradox. To test this hypothesis, we measured methane yields during experimental hydrothermal alteration of komatiites. Ni-sulfides ("N", LEFT) were inferred to catalyze methanogenesis. Chromite, previously proposed as an alkane catalyst, was not catalytic. Modeling suggests that komatiite alteration alone could not have warmed the early Earth above freezing, although it may have had secondary climatic effects [Lazar et al. 2012, Chemical Geology, PDF]
Novel moderately-reducing experimental buffers
A persistent problem in experimental petrology is the availability of buffering assemblages between QFM and IM or IW. We discovered an easy-to-use buffering assemblage that falls in the ƒO2 "blind spot": quartz-metal-willemseite, where willemseite is nickel talc (light blue-green at LEFT). Such a buffer should also exist in the cobalt system. Calibration of these buffers requires measurement of the standard state Gibbs free energy of the relevant talc phases. We performed this for willemseite with UCLA undergrad Mike Huh. [manuscript in prep.]
Tc-Mo-Ru partitioning in metal-sulfide melt
Several authors reported molybdenum and ruthenium isotope anomalies in iron meteorites, suggesting that short-lived parent isotopes of technetium were active during core formation. Evaluation of whether such a process is feasible requires knowledge of the partitioning behavior of Tc, which was unknown until we measured it during my master's thesis work. The experiments (LEFT) showed that Tc partitioning between metal and sulfide melt was too modest to result in substantial fractionation during core formation. [Lazar et al. 2004, Geochimica et Cosmochimica Acta, PDF]

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Labs I've worked in

UCLA PTX Lab
Cold seal lab, Carnegie
Mysen's lab, Carnegie
McCollom's flex cell, CU/NASA
Walker's multianvil, Lamont
Gas mixing furnaces, Caltech for a day


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MY RESEARCH: the simple version for musicians and laypeople


Sample collecting in Kamchatka,
Russia, 1997

If asked at a cocktail party, I just call myself a geologist because it's easier than differentiating the subdisciplines of earth science to some attorney buzzed on Chardonnay. But in the halls of the ivory tower, a "geologist" is someone who hangs out in the field for weeks on end, usually mapping rock formations and getting very dirty. Technically, I consider myself more of a hybrid geologist/geochemist; although I love to work outside, I also love hanging out in laboratories and making arcane graphs about the chemistry of rocks. When I first got into rocks, I of course imagined myself as more of a classical geologist: my prospecting silhouette perched high upon a remote mountaintop, pick in hand. These days, however, I do most of my science within a reasonable walking distance from ice cream. That's not to say I can't map or lead field trips or haven't seen—oh—a gajillion outcrops and rocks, just that the research I've been interested lately relies more on experimental simulations than fieldwork. (Editor's note: when I run field trips and field camp, I will find a way to include ice cream.)



In the UCLA experimental petrology lab, 2008, with
an undergrad assistant (they keep getting younger)
Even more technically speaking, I'm not just a geologist/geochemist: I'm a high-pressure aqueous computational and experimental petrologist. Translation: I use large machinery and those persistent laws of thermodynamics to simulate the high pressures and temperatures in the otherwise inaccessible interior of the Earth. Yes, I can make diamonds, rubies, sapphires, and other mineralized status symbols of love. Legend has it, a fellow in the Lamont petrology lab--where I did my master's work--once made diamonds from peanut butter. Yet alas, ladies, before you start sneaking out at night to tap on my window, you should know that our lab-grade diamonds are unglamourously powdery and dark, not the sort of hypnotic gems that you might imagine twinkling from your wildly gesticulating fingers in a frenzied pitch to summon the waiter for another order of foie gras on our honeymoon in Provence. Besides, I'm already happily married, so stop pressuring me.

Typical cocktail question (if I reveal that I am indeed a petrologist): "Hey, so you're a petrologist...does that mean you go hunt for oil?" No. "Petro" is merely a Latin root that means rock. "Petroleum" is roughly translated as "rock oil", or something like that. Ergo, "petrology" just means the study of rocks. For some of you, petrology may thus seem like a punishment for bad behavior at a hard labor camp, but I rather like it, thank you very much. Many petrologists go to every corner of Earth to collect and observe rocks in their natural habitat. Some whack their way through exotic malarial jungles to sample remote lava flows, sustained only by dried monkey meat and tree bark chips. Some go to sea in research submarines to study underwater rocks, active volcanoes, and an occasional hydrothermal vent ecosystem, home to those weird white crabs and tube worms you may have seen on the Discovery Channel between fistfuls of potato chips. So, please promise me that the next time you meet a petrologist at a cocktail party or AA meeting, please don't ask her if she can solve the world's oil crisis. Such an etmylogical misunderstanding would be akin to asking a proctologist if he ever catches cheaters while administering the SAT (that's a proctor). The person who looks for oil is called a "petroleum geologist" or, depending on your politics, a "planet destroyer".



Collecting serpentinite samples from the Josephine
Peridotite, Oregon, with josephinite enthusiast Robert
Nolan and my slightly pregnant wife, Wendy, in 2007
Lest you think I spend long winter nights in candlelit sub-museum basements cataloging grey chips of dusty stone, painstakingly labeling each specimen with a feather quill and occasionally removing my green visor to properly flip down my monocle ("Ah, yes, this xenolith is a fluoritic peraluminous haplogranite!"), I actually do real scientific research. Among other things, I'm interested in how a process called serpentinization produces methane. Serpentinization is a common geological process wherein nature adds water to a special type of rock called peridotite, which is unstable when it gets wet. In a manner less delicious but otherwise not too dissimilar to the soggification of a crouton in French onion soup, peridotite expands in the presence of water and transforms into a softer, greasier rock called serpentinite. During the bloating, most of the iron in the rock oxidizes (rusts) and gives its electrons up for adoption. Water, being a gracious host to many chemical guests, takes in the estranged electrons and, in a classy act of self-administered chemical plastic surgery, transforms itself to hydrogen gas. If there happens to be any carbon dioxide around, the hydrogen reacts with it to form methane.


Gas chromatograph of methane, not meth,
that I have made (right peak)

Most methane in modern times is produced in your digestive system or in hydrocarbon deposits. Both of these environments are essentially biological. But the methane made during serpentinization is "abiogenic" or "abiotic", meaning it's formed during a process that had nothing to do with living (or dead) organisms. The whole process is called something like serpentinization-induced abiotic methanogenesis, and may be responsible for supplying, not only enough syllables to impress your next date, but also enough methane to influence the bulk composition of a planetary atmosphere. That the process is common on Earth--and likely throughout the Solar System--should inspire images of flatulent, methane-oozing planets. This, of course, appeals to the 12-year-old in me: I study rock farts.



Dragging my family to unattractive
serpentine barrens near Baltimore
I also work on a bunch of other stuff, like non-traditional stable isotopes and thermodynamic measurements of redox-dependent minerals, but it's harder to distill those topics into something musicians can understand, such as farts. Anyways, I'm surprised you're even still reading, so the thought of tacking on about 100 more paragraphs seems unrealistic. If you're really interested, you can read my papers (see above).


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TEACHING


Dinosaur dig, Petersen Ranch, Wyoming, 2014


UCLA igneous petrology, Peninsular batholith
in San Diego County, 2007


Lava tube tour as a Park Ranger, 1997,
Craters of the Moon NM, Idaho



Teaching in a NYC public school L-R: Central Park glaciology field trip; 2nd period earth science; Mr. Kotter wannabe before moustaches came back

Here's some more images from my two years as an earth science teacher at Washington Irving High School.

Here's me on NPR in 2007 narrating the sounds of experimental petrology.

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IMAGES

Here's some artsy photo galleries of
the UCLA PTX Lab
Tom McCollom's flex cell lab at CU-Boulder and
a few other labs I've worked in.



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