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The Tooth of Time: the North American Cordillera from Tanya Atwater to Karin Sigloch

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The Tooth of Time: the North American Cordillera from Tanya Atwater to Karin Sigloch See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/270679894 The Tooth of Time: The North American Cordillera from Tanya Atwater to Karin Sigloch Article · September 2013 DOI: 10.12789/geocanj.2013.40.009 CITATION READS 1 527 1 author: Paul F. Hoffman University of Victoria 108 PUBLICATIONS 12,001 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Snowball Earth View project All content following this page was uploaded by Paul F. Hoffman on 04 April 2015. The user has requested enhancement of the downloaded file. GEOSCIENCE CANADA Volume 40 2013 71 COLUMN The Tooth of Time: batholith; R.V. Fisher and Bill Wise, Not long after, he became legendary the Cenozoic volcanic fields; and Pres for a different reason. As a Richfield The North American Cloud, the Death Valley area. Yet all Oil Corporation geologist, Natland Cordillera from Tanya the trips had one thing in common: proposed that detonating up to 100 Atwater to Karin Sigloch sooner or later, at every stop, the talk underground nuclear devices (atomic would turn to Tanya. Tanya says this bombs) might allow Athabasca Tar and Tanya says that. The trip leaders Sands oil to be extracted by conven- Paul F. Hoffman would get in a tizzy, like actors handed tional means. A pilot project outside 1216 Montrose Ave., Victoria, BC a new script at show time. If anyone Fort McMurray (Project Cauldron, V8T 2K4 was upset because Tanya was a woman later renamed Project Oilsand), backed in a man’s game, they didn’t say so, but by the government of Alberta, I remember the first time I met Tanya Atwater. She was still a graduate stu- a marine geophysicist interpreting the received federal government approval dent at Scripps Institution of complexities of onshore California following the Conservative landslide Oceanography, but over a year had geology was something else. For my under John Diefenbaker in 1958. passed since her paper came out on the part, I hadn’t the foggiest notion who When Lester Pearson’s Liberals were San Andreas Fault, arguably the best this Tanya person was, but I inferred elected in 1963, the project was quietly paper ever written on continental geol- that she must be a pretty formidable cancelled in line with Canada’s policy ogy (Atwater 1970). I was reminded of character. of nuclear non-proliferation. Four our meeting a few months ago, during Returning from one of the decades later, tar sands oil production a talk I heard at the Pacific Geoscience last trips of the year, we pulled off the would become a reality, not through Centre in Sidney, BC. coastal highway west of Ventura to nuclear technology but through $80-a- The plate tectonic revolution examine an upturned section of Upper barrel oil. was a great leveller: everyone found Pliocene turbidites. In the 1930’s, an Given what had followed— themselves in the same boat, regardless enterprising young micropaleontologist Kennedy’s assassination, Civil Rights, of age or experience. Yet, having come had compared Plio-Pleistocene Viet Nam, Richard Nixon—our from one dead orogenic belt, the cen- foraminifera in the subsurface of the thoughts were not about tar sand when tral Appalachians, to study another Ventura Basin with species living today we ran into another group of geolo- one, six times older, prudence urged off the California coast. He found that gists as we left the outcrop. Even then, me to see a living orogen first-hand. So the graded sandstone beds carry a Berkeley hippy with beads, long curly I eagerly accepted an offer—GSC reworked and indigenous shallow- hair and a flower-print dress, stood out granting leave-without-pay—to teach water, even lagoonal forms, while the in a group of geologists. She was about classes for 9 months at UCSB (Univer- shales have exclusively indigenous a year younger than I and was at least 7 sity of California – Santa Barbara), forams similar to those found today at months pregnant. When she talked, then a hotbed of igneous and Califor- water depths of 300–600 m (Natland effervesced would be a more apt nia geology. The geology department 1963). He had been ridiculed for sug- description, she giggled and flapped had been built up by Aaron Waters, gesting that the sandstones and associ- her hands. Before we parted, John who brought from Johns Hopkins the ated gravels were physically transported Crowell turned, beaming, and said, tradition of regular weekend field trips to deeper water, then thought to be the “Paul, meet Tanya Atwater”. for incoming graduate students. John reserve of strictly fine-grained Tanya grew up in Los Angeles, Crowell and Art Sylvester led trips to deposits, but after the turbidite revolu- where her mother was a botanist and the San Andreas Fault zone and the tion of 1950 (Kuenen and Migliorini her father an engineer. She loved Salton Sea; Cliff Hopson, the Coast 1950), Manley Natland became a leg- geometry in school and thought of Range ophiolites and the Sierra Nevada end in sedimentology (Walker 1973). becoming an artist until age 15, when Geoscience Canada, v. 40, http://dx.doi.org/10.12789/geocanj.2013.40.009 © 2013 GAC/AGC® 72 the launch of the Sputnik drew her during an upcoming cruise to the features had emerged. Tanya gravitated attention to science and engineering. Gorda Rift, north of the Mendocino to Menard’s group and soon found She went to MIT (Massachusetts Insti- Fracture Zone. He needed a capable that she and Menard shared a common tute of Technology), where women student to work up the data and he trait—the need to discuss geologic could enroll in those fields, and was in was willing to fight to have a woman structures with pencils on scraps of her fifth major in three years when she allowed on board the cruise. The high- paper (Atwater 2001). Menard was “accidentally took a physical geology course resolution survey showed that active troubled that the larger Pacific frac- [taught by petrologist W.H. Dennon] volcanism was limited to the axial rift tures zones have disturbed regions of and was hooked immediately” (Atwater valley and that the ridge crests were structural complexity, where their 2001). Field camp in Montana ban- not volcanic in origin but structural traces deviate from small circles in ished any doubts and, eager to return uplifts flanked by inward-dipping nor- seeming defiance of a cardinal rule of to California where “rocks don’t spend mal faults. The resulting report likely plate tectonics. However, the rule that most of their time covered by green or white satisfied her orals committee: it was transform faults follow small circles stuff”, she transferred to UC – Berkeley published as the lead article in Science with respect to the rotation pole in 1963, graduating two years later in (Atwater and Mudie 1968). between two plates is valid only if the geophysics. The hippy scene was in its The years 1967–68 were a rotation pole remains fixed. In a sys- early heyday. watershed. Tuzo Wilson’s concept of tem with multiple plates, competing in Back east again as a summer mobile rigid plates (Wilson 1965) had a struggle for existence, rotation poles intern in 1965, she saw Tuzo Wilson been given mathematical expression in must shift from time to time with con- demonstrate transform faults when it terms of Euler rotations on a sphere, sequent changes in sea-floor spreading was a new concept (Coode 1965; Wil- allowing the concept to be tested quan- direction. In a series of papers, the son 1965). The next year, working as a titatively (Bullard et al. 1965; McKenzie patriarch and the graduate student technician at the Geophysics Institute and Parker 1967; Morgan 1968; Le showed that the disturbed zones are in Santiago, Chile, she heard Jim Heirt- Pichon 1968; see also Le Pichon 1991; not random but are systematically relat- zler report on a new magnetic profile Frankel 2012a, b). Breaking ranks with ed to episodic changes in sea-floor obtained across the Pacific–Antarctic their elders, three young seismologists spreading direction (Menard and Atwa- Rise (Pitman and Heirtzler 1966). The assembled comprehensive independent ter 1968, 1969; Atwater and Menard Eltanin-19 profile remains the longest, support for plate tectonics (Isacks, 1970). They inferred that a particularly cleanest and most symmetrical of any Oliver and Sykes 1968)—rescuing seis- marked change in spreading direction spreading ridge in the world (Atwater mology from ignominy for had occurred ~55 Ma, according to the 2001), convincing even Lamont- stonewalling mantle convection and Heirtzler time scale (Heirtzler et al. Doherty’s Director Maurice Ewing and continental drift. Perhaps most impor- 1968), close to the age of the subse- other skeptics that sea-floor spreading tant, magnetic profiles covering large quently described bend in the Hawaii- was a reality (Glen 1982; Le Pichon parts of the Pacific, South Atlantic and Emperor seamount chain. From 1986). Like its continuation, the East Indian oceans, which Lamont-Doherty Menard, Tanya also learned that any Pacific Rise, it had been thought a vessels for years had been systematical- new concept, to gain attention, needs a poor candidate for sea-floor spreading ly acquiring for no apparent reason, name that clicks (Atwater 2001). Soon, because it lacked an axial rift valley. were compiled and interpreted in everyone was talking about “leaky” Historians mark 1967 as the terms of sea-floor spreading (Dickson transform faults (Menard and Atwater year the plate tectonics revolution et al. 1968; Le Pichon and Heirtzler 1969). ended, but for marine geophysicists it 1968; Pitman et al.
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