https://ewalexander.com/teaching/https://ewalexander.com/wp-content/uploads/2018/08/img_20170211_150149335.jpgIMG_20170211_1501493352022-12-12T22:52:42+00:00weekly0.6https://ewalexander.com/research/https://ewalexander.com/wp-content/uploads/2018/08/screen-shot-2018-08-09-at-4-23-06-pm.pngScreen Shot 2018-08-09 at 4.23.06 PMThe importance of barometry (depth) in reconstructing the history of an orogen. We can only directly reconstruct crustal thickness if we can identify the pressure (depth) of magmatism.https://ewalexander.com/wp-content/uploads/2018/08/ucla-15-1-1_postlicl.pngUCLA-15-1-1_PostLiCLCathodoluminesence (CL) image of a 4219±5 Ma zircon from Jack Hills, Western Australia. Changes in color and brightness are reflective of chemical changes as the zircon grew. Note the "unconformity" between the dark core with vertical zoning and the surrounding brighter layer: this grain likely underwent multiple magmatic and/or metamorphic recycling events.https://ewalexander.com/wp-content/uploads/2018/08/epshf-in-zircon-rafc-v3.pngepsHf in zircon RAFC v3Schematic representation of the effect of crustal thickness and magma recharge on the chemistry of zircon growth zones. A zircon grown in a magma body in a thin crust (left) will have a homogeneous, juvenile magmatic signal, as the country rock is too cold to assimilate appreciably with the magma. Periodic magma recharge will extend the time during which zircon can grow and enable more assimilation, leading to a heterogeneous and overall more crust-like chemical signature. Zircon grown in a deep magma body will have the opportunity for greater assimilation, leading to monotonic chemical zoning, from juvenile to crust-like from core to rim. Recharge further enables assimilation, with long residence times and frequent recharge leading to almost 100% isotopic assimilation of the country rock.https://ewalexander.com/wp-content/uploads/2018/08/ucla-15-2-3_postlicl.pngUCLA-15-2-3_PostLiCL3624±12 Ma zircon grain from Jack Hills, Western Australiahttps://ewalexander.com/wp-content/uploads/2018/08/creation-of-adam.jpgcreation of adam2022-12-12T22:51:57+00:00weekly0.6https://ewalexander.com/bio/https://ewalexander.com/wp-content/uploads/2021/06/img_2929.pngIMG_2929https://ewalexander.com/wp-content/uploads/2020/10/a6d1c65c-f856-43f6-933b-1c8e1d4a8b86.jpegA6D1C65C-F856-43F6-933B-1C8E1D4A8B86https://ewalexander.com/wp-content/uploads/2018/08/3591_1533495106019.jpeg3591_1533495106019Lumi (right) and her daughter Nova (left) were rescued from Carson L.A. Animal Care and Control by Carson Cats Rescue.https://ewalexander.com/wp-content/uploads/2018/08/patrol-candidates.jpgpatrol candidatesBig Bear Ski Patrol candidate class, 2016https://ewalexander.com/wp-content/uploads/2018/08/img_20180303_125234802.jpgIMG_20180303_1252348022021-06-17T23:47:48+00:00weekly0.6https://ewalexander.com/publications/2020-10-02T16:31:40+00:00weekly0.6https://ewalexander.com/contact/https://ewalexander.com/wp-content/uploads/2018/08/insta-e1533159810162.pnginstahttps://ewalexander.com/wp-content/uploads/2018/08/email.pngemailhttps://ewalexander.com/wp-content/uploads/2018/08/gmail-e1533159287186.pnggmailhttps://ewalexander.com/wp-content/uploads/2018/08/person-smartphone-office-table.jpegPlaceholder Image2019-11-15T23:21:38+00:00weekly0.6https://ewalexander.com/blog/2018-08-01T20:42:11+00:00weekly0.6https://ewalexander.comdaily1.02022-12-12T22:52:42+00:00