Allan Cox

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<div class="img-caption">Figure 1. Allan Cox</div>
<div class="img-credit"><em>(Krauskopf 1997)</em></div>
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<p><span style="font-size:12px;">Allan Cox was born on December 17, 1926 in Santa Ana, California. After taking a rigorously paced chemistry course during his high school education, Allan became interested in the subject and chose to pursue it as his college major at the University of California Berkeley. After a brief stint at Berkeley, Allan joined the merchant marine and worked for three years. Afterwards, he returned to Berkeley and landed a summer position in Alaska with Clyde Wahrhaftig studying glacial motion mechanics. It was here that Cox’s interest in geology began. Unfortunately, his interest in chemistry simultaneously dwindled and poor grades resulted in his drafting into the U.S. Army. After two years of service, he returned to Berkeley where he was able to continue academic research with Wahrhaftig in Alaska and graduated with a degree in geology.</span></p>
<p><span style="font-size:12px;">In 1954, Allan’s graduate work at Berkeley shifted away from glaciology and towards rock magnetism when he began working with John Verhoogen. This partnership left a lasting impression on Cox and formed the backbone of his professional career as Verhoogen was one of the few faculty members that supported continental drift.</span></p>
<p><span style="font-size:12px;">After receiving his doctorate in 1959, Cox went on to work for the U.S. Geological Survey at Menlo Park which began the period of time in which his major contributions to plate tectonics and our current view of the solid Earth began. His academic success during this time period led to a teaching position at Stanford in 1967 and ultimately his promotion to the Dean of the School of Earth Sciences in 1979. Cox received many accolades in this position and showed a particular knack for academic leadership. He continued working in this position until his untimely death on January 27, 1987 from a bicycle accident.</span></p>
<p><span style="font-size:12px;">Days after his death, reports of Cox’s involvement in the sexual abuse of an adolescent began to circulate. Evidently, Cox was made aware of the allegations by the boy’s parents and was put under investigation by local police. Ultimately, some evidence points to Cox’s bicycle accident actually being suicide. No matter what the case, it is a socially saddening end to what was an otherwise successful academic career.</span></p>
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<p><span style="font-size:12px;">Allan Cox is best known for his work in the field of paleomagnetism. His greatest contribution to the theory of plate tectonics and our current view of the solid Earth came in the 1960s as a joint effort with colleagues Richard Doell and Brett Dalrymple. As previously mentioned, Cox’s interest in rock magnetism was sparked during his graduate studies with Berkeley professor John Verhoogen. His thesis was titled “The Remanent Magnetization of Some Cenozoic Volcanic Rocks.” Generally, volcanic rocks tend to contain one or more magnetic minerals (iron-containing magnetite, for example). In simplistic terms, as a volcanic rock cools those magnetic minerals may preserve the direction of the Earth’s magnetic field at the time of cooling or at least its orientation. Allan was an expert at reading the magnetic clues locked in this variety of rock.    </span></p>
<p><span style="font-size:12px;">During this time period, many volcanic rocks were shown to have unexplained “flipped” magnetic orientations. The nature of these magnetic reversals were poorly understood at the time but there were essentially two schools of thought: one that said the minerals were able to self-reverse after formation such as when heated or exposed to different magnetic fields while the other said that global geomagnetic reversals were responsible. Self-reversal would imply a random distribution of magnetic alignments of rocks with the same age while global geomagnetic reversals would imply synchronization of magnetic alignments in volcanic rocks of a certain age. Cox and his colleagues ultimately showed the latter to be correct.</span></p>
<p><span style="font-size:12px;">When Cox began working at the U.S. Geological Survey at Menlo Park, he was reunited with Berkeley peer Richard Doell and the two teamed up for nearly an entire decade. Much of their initial work dealt with learning about the nature of Earth’s magnetic field and the remanent magnetization recorded in volcanic rocks. During this time, they planned and built their own paleomagnetism laboratory in attempt to study the magnetic properties of volcanic rocks from around the world. While Cox and Doell were able to determine the magnetic properties of their specimens, it was also necessary for them to determine accurate ages of those specimens. Enter Brett Dalrymple.</span></p>
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<div class="img-caption">Figure 2. Allan Cox (seated) with Richard Doell (left) and Brent Dalrymple (right) working at a mass spectrometer in the early 1960s.</div>
<div class="img-credit">Image retrieved from http://quake06.stanford.edu/centennial/gallery/people/cox.html</div>
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<p><span style="font-size:12px;">At the time, dating rock specimens that were only a few million years old was a difficult task. Fortunately, a method using K-Ar radioactive dating became available and Brett Dalrymple was one of the few experts on the technique. The three collected samples from lava flows around the world and determined their age and magnetic polarity. What they found was perhaps the crowning achievement of all three men: the magnetic reversals recorded in rocks were synchronized for rocks of the same age over the past four million years. In other words, the vast majority of volcanic rocks of a certain age recorded the same magnetic polarity. While the time between each reversal was irregular, this still showed that self-reversals were uncommon and that the Earth’s magnetic field had reversed a number of times in the past.</span></p>
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<div class="img-caption">Figure 3. Example of the magnetic polarity and age data that today is known as the "Rosetta Stone" of paleomagnetic reversals.</div>
<div class="img-credit">Image retrieved from (Doell, Dalrymple, & Cox, 1966).</div>
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<div class="img-caption">Figure 4. Magnetic polarities and potassium-argon ages of volcanic rocks as determined by Cox, Doell, and Dalrymple.</div>
<div class="img-credit">Image retrieved from (Cox & Dalrymple, 1967).</div>
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<p><span style="font-size:12px;">Through the 1960s, the three men continued to refine what became known as the Cox-Doell-Dalrymple calendar or the “Rosetta Stone” of paleomagnetic reversals. The calendar comprised a record of the magnetic polarities recorded in volcanic rocks over the most recent 4 million years and helped confirm the hypothesis that Earth's magnetic field undergoes reversals. Soon thereafter, ships bearing magnetometers were able to establish a map of the magnetic properties of rocks on the seafloor. It was the first time that the now familiar symmetrical pattern of magnetic reversals on the seafloor was visualized. When Cox saw this discovery side by side the Cox-Doell-Dalrymple calendar he stated, “I felt cold chills. This was the most exciting moment of my scientific career.” Indeed, their work played a major role in providing physical evidence to support the concept of seafloor spreading and in developing the theory of plate tectonics. Cox continued his work on rock magnetism and paleomagnetic reversals for twenty more years until his untimely death.</span></p>
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<div class="img-caption">Figure 5. Conceptual picture of the magnetic properties of rocks on the seafloor. Actual data recovered by ship-based magnetometers matched well with the Cox-Doell-Dalrymple calendar. The comparison was enough for Cox to have "cold chills" the first time he saw the data matched up.</div>
<div class="img-credit">Image retrieved from http://pubs.usgs.gov/gip/dynamic/developing.html#anchor10912731</div>
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<p><span style="font-size:12px;">During his undergraduate years, Cox spent his summers working with glaciologist Clyde Wahrhaftig studying glacial motion mechanics. In 1959 they wrote a paper titled “Rock glaciers in the Alaska Range” that outlined their classification and mechanical processes. The quantity and quality of the data they generated made the paper so well received that in 2011 it was quoted as being “the single most influential paper on rock glaciers” ever.</span></p>
<p><span style="font-size:12px;">After linking their data to the growing theory of plate tectonics, Cox continued working on geologic topics for two more decades. During this time he more directly studied Earth’s geomagnetic field and began working on an explanation as to why the length of time between magnetic reversals varied.</span></p>
<p><span style="font-size:12px;">Lastly, Cox was also an environmentalist. He focused specifically on the effects of timber harvesting on local ecosystems. In addition to providing local politicians and environmental groups with counsel on logging in the area, he also drafted a short book titled <em>Logging in Urban Counties</em>. The book outlined the effect of unrestricted logging on soil, streams, watersheds, fires, and landslides. His work resulted in additional logging regulations being put in place in the areas surrounding his home.</span></p>
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<p><span style="font-size:12px;">1. Allan received a large number of awards and honors for the work completed with colleagues Doell and Dalrymple. He was elected to the National Academy of Sciences, the American Academy of Arts and Sciences, and the American Philosophical Society. Among a number of other awards, he received the Vetlesen Prize in 1970 for his work in paleomagnetism. Lastly, he served as President of the American Geophysical Union from 1978 to 1980.</span></p>
<p><span style="font-size:12px;">2. Outside of work, Allan enjoyed ballet, theater, music, and art. He often spoke with Wahrhaftig about these interests while working on glacial mechanics and the two remained life-long friends.</span></p>
<p><span style="font-size:12px;">3. Allan and fellow graduate students at Berkeley formed a geology club at school to discuss continental drift. This “radical” idea was not being adequately covered in their classes. The club had two rules: all meetings had to occur where beer was served and faculty was not allowed. A secret vote by the club determined that continental drift was probably real. As scientists themselves, the group found it humorous that they had unscientifically voted to accept a concept despite a lack of supporting evidence. It turns out their vote got it right. </span></p>
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<p><span style="font-size:12px;">Coe, R., & Dalrymple, B. (1987). Allan Cox 1926-1987. <em>Eos, 68</em>. Retrieved from <a href="http://onlinelibrary.wiley.com.ezaccess.libraries.psu.edu/doi/10.1029/EO...
<p><span style="font-size:12px;">Cox, A., & Dalrymple, B. (1967). Statistical analysis of geomagnetic reversal data and the precision of potassium-argon dating. <em>Journal of Geophysical Research, 72</em>. Retrieved from <a href="http://onlinelibrary.wiley.com.ezaccess.libraries.psu.edu/doi/10.1029/JZ...
<p><span style="font-size:12px;">Doell, R., Dalrymple, B., & Cox, A. (1966). Geomagnetic polarity epochs: Sierra nevada data, 3. <em>Journal of Geophysical Research, 71</em>(2)<em>.</em> doi: 10.1029/JZ071i002p00531</span></p>
<p><span style="font-size:12px;">Krauskopf, K. (1997). Allan V. Cox 1926-1987. <em>Biographical Memoirs, 71</em>. Retrieved from <a href="http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/c...
<p><span style="font-size:12px;">Netzer, B. (1987, January 30). Officials say cox’s death was suicide. <em>The Stanford Daily</em>. Retrieved from <a href="http://stanforddailyarchive.com/cgi-bin/stanford?a=d&d=stanford1...
<p><span style="font-size:12px;">Stine, M. (2013). Clyde wahrhaftig and allan cox (1959) rock glaciers in the alaska range. <em>Bulletin of the Geological Society of America, 70</em>(4). doi: 10.1177/0309133313475693</span></p>
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