{"id":2465,"date":"2019-10-02T19:53:42","date_gmt":"2019-10-02T19:53:42","guid":{"rendered":"https:\/\/www.gsnv.org\/shop\/the-upper-crust-on-its-side-steeply-tilted-slabs-in-the-basin-and-range\/"},"modified":"2020-02-24T18:17:44","modified_gmt":"2020-02-24T18:17:44","slug":"the-upper-crust-on-its-side-steeply-tilted-slabs-in-the-basin-and-range","status":"publish","type":"product","link":"https:\/\/www.gsnv.org\/shop\/the-upper-crust-on-its-side-steeply-tilted-slabs-in-the-basin-and-range\/","title":{"rendered":"The upper crust on its side\u2014steeply tilted slabs in the Basin and Range"},"content":{"rendered":"","protected":false},"excerpt":{"rendered":"<p>Tilted slabs that expose as much as 8\u201315 km of the upper crust in the Basin and<br \/>\nRange province allowanalysis of pre-tilt depth variations in igneous systems and thermal<br \/>\nstructure. Before tilting the slabs were panels between moderately to steeply dipping<br \/>\nTertiary normal faults. The slabs and their bounding normal faults were tilted to<br \/>\npiggyback positions on deeper footwalls that warped up isostatically beneath them<br \/>\nduring crustal stretching and tectonic unloading. Stratal dips within some slabs are<br \/>\nnow vertical or even slightly overturned, especially in the southern Basin and Range,<br \/>\nwhere thick sections of basement granite and gneiss are tilted homoclinally as determined<br \/>\nfrom both stratified cover and intrusive-sheet proxies of original horizontality.<br \/>\nSome tilted slabs of basement rock display faults that splay upwards into overlying<br \/>\ncover sequences, folding them to shallower dips, so stratified rocks are not always the<br \/>\nbest indicators of slab tilt. The 12\u201315-km maximum exposed paleodepth for the slabs<br \/>\nmatches the depth of the modern base of the seismogenic zone of normal-fault earthquakes<br \/>\nin the Basin and Range, and so this depth is inferred to represent the pre-tilt<br \/>\nbase of the brittle part of the extending crust. Many highly tilted slabs are upper-<br \/>\nplates to metamorphic core complexes, but not all core complexes expose thick recumbent<br \/>\nupper-plate slabs. Paleozoic stratal sequences in thin upper-plate fault slices<br \/>\ncommonly are dragged or sheared subparallel to the faults, thereby obscuring the<br \/>\noriginal fault-bedding cutoff angles and maximum block tilt. The Ruby Mountains<br \/>\ncore complex, for example, preserves only scraps of upper-plate rocks as domed-up<br \/>\nextensional klippen uneven in stratal dips, and most of the thick crustal section that<br \/>\noriginally overlay the uplifted metamorphic core nowmust reside at depth to the west.<br \/>\nIn contrast, large intact tilted fault-bounded slabs of plutonic and metamorphic basement<br \/>\nrock near core complexes in the Colorado River extensional corridor and the<br \/>\nSan Pedro Trough expose 8\u201315 km paleodepths that originally roofed the<br \/>\nmetamorphic cores; the exposed paleodepths imply that deeper core-complex<br \/>\nfootwalls rolled up beneath such slabs.<\/p>\n","protected":false},"featured_media":4503,"comment_status":"closed","ping_status":"closed","template":"","meta":{"pmpro_default_level":""},"product_cat":[154],"product_tag":[],"_links":{"self":[{"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/product\/2465"}],"collection":[{"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/comments?post=2465"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/media\/4503"}],"wp:attachment":[{"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/media?parent=2465"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/product_cat?post=2465"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.gsnv.org\/wp-json\/wp\/v2\/product_tag?post=2465"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}