796 INDEX Udotea 2:432 Ukraine 4:190, 4:197, 4:199 Ukraine Craton 5:39 Ukrainian Shield 2:35f, 2:36, 2:42f Ulawan volcano, Papua New Guinea 5:575 ulexite (NaCaB O -8H O) Argentine borate deposits 3:S13t commercial production 3:511-512, 3:512t composition 3:512t geochemical cycle 3:512f geology 3:511 mineralogy 3:511 mineral processing 3:519 Turkish borate deposits 3:513t uses 3:514 Ulianovsk-Saratov Basin 4:456 ultisols5:;/96* ultracataclasite 3:388t ultrahigh-pressure metamorphic rocks 5:533-540 background information 5:533 coesite 5:533, 5:533f, 5:534f exsolution effects 5:535f, 5:535-536 formation mechanisms 5:538, 5:539f global distribution Alps 5:536f, 5:537 Bohemian Massif 5:535-536, 5:536f, 5:538,5:539 continent-continent collisions 5:539 Dabie Shan, China 5:533, 5:535-536, 5:536/j 5:537 general discussion 5:536 Himalayan Mountains 5:536f, 5:538, 5:539 Kokchetav Massif, Kazakhstan 5:533, 5:535-536, 5:536/", 5:537, 5:539 Norwegian Caledonides 5:536/", 5:537 occurrences 5:536f polyphase aggregates 5:538f Variscides Orogeny 5:538 identification process 5:533 metamorphic facies 3:405, 3:406f mineral assemblages 5:533 Mohorovicic discontinuity 3:646-647 pressure-temperature diagram 5:533f, 5:539f ultramafic rocks See metamorphic rocks; olivine ultramylonite 3:388t ulvospinel (Fe2TiO4) 4:149f Umba granulite domain 2:44f Umbriel 5:290-291, 5:291t umohoite (UO2MoO4-4H2O) 3:552* uncomprahgrites 5:569-571 unconformities 5:541-547 angular unconformity 5:541/", 5:544t definitions 5:541, 5:546-547 diastem 5:541 disconformity 5:541f eustatic cycles 5:546f, S:547f heterolithic unconformity 5:541f, 5:542-543, 5:544* historical background 5:542 Hutton, James 2:203, 2:203f, 3:175, 3:175f, 5:542, 5:543f Isle of Arran 5:542, 5:543f lateral variations 5:543 marine-flooding surfaces 5:546, 5:546f nomenclature 5:544* nonconformity 5:542-543, 5:544* non-sequence 5:541 North American continental interior 4:30 offlap 5:542 onlap 5:541f, 5:542 overlap 5:541f, 5:542 overstep 5:541f, 5:541-542 seismic reflection 5:156f seismic stratigraphy 5:545 sequence stratigraphy 5:545, 5:545, 5:545*, 5:546/i 5:547f stratigraphic record 5:544 type unconformity 5:546, 5:546f type unconformity 5:546, 5:547f ungemachite (K Na Fe(N03) (S0 )6-6H 0) 3:556* ungulates 2:539, 5:485 unidirectional aqueous flow 5:548-556 background information 5:548 bedform type 5:554, 5:554f boundary layer structure 5:549, 5:550f boundary shear stress estimation 5:550 coherent flow structure 5:548, 5:551 flow separation 5:552, 5:552/", 5:554f free shear layers 5:553 Kelvin-Helmholtz instabilities 5:552/", 5:552-553 laminar flows 5:548, 5:549 particle roughness 5:553f, 5:554 porous beds 5:556, 5:556f stress-strain relationships 5:549, 5:549f subcritical flows 5:548-549, 5:549f suspended sediment characteristics 5:554, 5:554f, 5:555f turbulent flows boundary layer structure 5:549 clay concentrations 5:555f laminar-turbulent transition 5:552f processes 5:548 turbulent boundary layers 5:551, 5:551f vortices 5:551, 5:552f velocity profiles 5:549, 5:549f, 5:554f, 5:555f viscous sublayer 5:550, 5:550f uniformitarianism Hutton, James 1:430, 2:205, 5:296-297 Lyell, Charles 2:207, 3:177, 5:297-298 Union Fran^ais des Geologues 3:75 United Kingdom batholiths 3:238f beer brewing process 3:78-81 Carboniferous 4:202f Cornwall, United Kingdom 3:238f Devonshire, United Kingdom 4:194 East Kirkton, Scotland, United Kingdom 4:210-211 Faroe-Shetland Basin, United Kingdom l:103f, 1:103-104, l:104f geological surveys 3:173, 3:476, 3:69 Granton Shrimp Bed, Scotland, United Kingdom 2:455-456, 3:308, 3:441, 3:442f Isle of Wight, United Kingdom 5:468f Oxford Clay, United Kingdom 3:310-311 petroleum reserves 4:335f Pleistocene 5:493 Shropshire, United Kingdom 4:176, 4:177-178,4:185,4:188-189 Tertiary Igneous Province, United Kingdom 3:237*, 3:239 Thames Valley, England, United Kingdom 5:495 Yorkshire, United Kingdom 4:201 See also Australia; Canada; England; Europe; Ireland; New Zealand; Scotland; Wales United States 3:7*, 3:363*, 4:219f See also specific states United States Geological Survey (USGS) 3:67,3:69,4:332 Unzen, Japan 5:575, 5:575* upwelling zones 4:495, 4:496f Uralide orogeny 2:86-95 aeromagnetic map 2:87f, 2:93f Bouguer gravity anomaly 2:92-94, 2:93/ Central Uralian zone 2:86, 2:87f cross-sections 3:653f crustal structure 2:90, 2:91f East European Craton 2:34-35, 3:648 East Uralian zone 2:86, 2:87f, 2:88f, 2:91f, 2:92f geological map 2:88f heat flow density 2:91-92, 2:93f Magnitogorsk-Tagil zone 2:86, 2:87f, 2:90-91, 4:467 Mohorovicic discontinuity 3:652, 3:653f Pre-Uralian zone 2:86, 2:87f seismic profile 2:91f, 2:92f tectonic evolution foreland thrust-and-fold belt 2:90 general discussion 2:86 island arcs 2:88 strike-slip fault systems 2:90 subduction zones 2:89 tectonic processes 2:89f topography 2:94, 2:94f Trans-Uralian zone 2:86, 2:87f, 2:88f, 2:91f, 2:92f, 4:468 velocity profiles 2:91, 2:92f West Uralian zone 2:86, 2:87f zone classifications 2:86, 2:87f Ural Mountains Carboniferous 4:201 cross-sections 3:653f East European Craton 2:41 f gemstones 3:12 geological map 2:88f Global Standard Stratotype Sections and Points (GSSPs) 5:511f Kazakhstan-Khingan domain 4:467, 4:467f