UTAH GEOLOGICAL SURVEY Plate 1 a division of Utah Geological Survey Miscellaneous Publication 96-1 UTAH DEPARTMENT OF NATURAL RESOURCES Geologic Map 01' the Logan Quadrangle 'It,"" ..,. rSA1!THFIFf DJ 28 2E ""''; 30 I - all I r---- :::'''::'1 II ' , --- - Qlps 31 -, 32 I '. I '. ,.:r: IIII I, 1= • I all , , Olpd ' \; II: .~ , .. , , "(+ I alps • • • i .. ____ JJ __ ~-- •. ,-- ------------- I .r '«s",( , • " : .:-: ..: ..... : dal, .......... ..,'.. ' aalu ,, ............ , " , 3 ~If .­ \ Rin'r H('i)!hL'l \ \ .'. \ , - \ ~ alpd \ , :. : .: ..... ' aalu •" Qlps .' " .... I t I r aalu ,, I i I all I Qlf I ",', - E --:+. :;4: " . ' . alps :. ,: , all ,' aalu "",,,,,,,,>t-~""''''\ " - ~ - " ('n'I!.' .' I \ , I " , + I ! ' , I 7 , . 18'. ,', " I all I \ I \ alps \ I, , , . \ . r " aalu .. ; ':'I1ill, ill" ... .. ~. ..\ .. .- , '. \ , I , \ ,I I' , , 19 ?O 2 .'- -- r --- - -.-;~ I I ,~i"lc,\.. .' I " . '. ... I ·"~ .c;, :I : -.' alps .. ;(. ,.. I alf ,.. : ,. , , ',". I . I : ~ I I 29 30 , I I " I • \ • • (, • ~ '" - . '\,' all -1- ..;:- I '1 32 alps /1 '/ I / I --J ~,~-~------------ ! t ~ I '. X 1 • " I "- '. i ::'S'::~':~I','" •• .1 ,.o . •." . ; I ,.. ~: ,~': - I ,...-~ .- ' , , : •••• 57 .1 ~ ..... , .. I "\ ", • '" • ~ : , . '"" ' "Jot •• ,.., ......"- " . .;.8'? '. ....... .............. '---L----------- ----. ..- .. ", -t::-~ ...::".;" ,,","'--. ..' , . ... FeET "' I 'AI !. '; (PARADISE.' ) 3667 !II SF J37,~r'n [ Base map from the U. S. Geological Survey SCAL E 1 21000 Geology mapped by J. P. Evans, J. P. McCalipin and D. C. Holmes Logan 7.5' Quadrangle. 1986 i:=='--:EL===r--,==it:""-F=='--==3"'--i0F=====================iJ '-1 IL[ bettween 1986 and 1991 , 1000 C lOoe 2OUO 3000 4000 5000 6000 /000 r LET ~1-L1~I~fJE6======~======~======~~====~======~~~~=~~--~ revisions by J. P. Evans and * a 1 KILO MFTFR Jon K. King (UGS) in 1993 and 1994. Lori J. Douglas, Cartographer CONTOUR INTERVA L 40 FEET DOTTED LI NES RFP RESEN T lO-FOOT CONTOlJ RS ~4 ' 18 ' E 254.2 MILS GEOLOGIC MAP OF THE LOGAN QUADRANGLE, OJADRAN GL ::: LOC Af ION 1996 MAGNETIC DECLINATION AT CENTER OF SHEET CACHE COUNTY, UTAH by The Miscellaneous Publication Maps provide an oullel for aulhors who are nol Utah Geological Survey staff Not all James P. Evans aspects of thiS publicalion have been reviewed by Ihe UGS. James P. McCalpin David C. Holmes 1996 UTAH GEOLOGICAL SURVEY Plate 2 a division of Utah Geological Survey Miscellaneous Publication 96-1 UTAH DEPARTMENT OF NATURAL RESOURCES Geologic Map of the Logan Quadrangle EXPLANATION OF MAP UNITS MAP SYMBOLS LITHOLOGIC COLUMN Thicknesses in feet and in meters (in parentheses) Holocene and Pleistocene (?) slides and slumps - Fine-grained sediment Contact between units - dashed where approximately located, dolted with few clasts, derived from the base of the Wells Formation. where concealed Undivided alluvium and colluvium - Holocene and Pleistocene (?) __ A__ • Thrust fault - teeth on upthrown plate, dashed where approximately pebble, cobble, and boulder gravets mixed with sand, silt, and ctay; located Wells Formaiton deposited as hills lope colluvium and fan alluvium, with small areas 600+ (183) of landslide deposits and stream alluvium, Normal fault - bar and ball on down thrown side, dashed where approximately located, dolted where concealed Holocene to latest Pleistocene slope-failure deposits - Unsorted and unstratified matrix-supported sparse gravels with abundant sand u Steeply dipping normal fault - U on upthrown side, D on downthrown Monroe Canyon and silt matrix; located at the base of steep hillsides of Lake D side (dip more steeply than faults with bar and ball) Limestone equivalent Bonneville deltaic and sandy deposits, where the hillsides have 750-1.150 (228-350) failed by slide, slump and/or flow, Strike-slip fault - arrows indicate relative motion Undivided fine-grained Lake Bonneville depoSits - Lacustrine clay, silt, Reverse fault reactivated in a normal Slip sense (on cross sections) and fine sand deposits in deep and/or quiet water in Lake c Bonneville, and not related to any specific shorelines; typically 40 EC'1 ''"5. Little Flat Formation 1----11 Locations of trenches dug acros the East Cache fault c. to 50 feet (- 12 to 15 m) thick. ~ 'iii 1,206 (367) Lacustrine sand and silt related to Provo and younger shorelines - Strike and dip of beds - numbers indicate dip in degrees ~'" Nearshore deposits of coarse to fine sand, silt, and minor clay; typically rhythmically bedded; exposed thickness less than 16 feet 6')3 Strike and dip of overturned beds .: «5 mi. Anticline axis t Lodgepole Limestone Lacustrine sand and gravel related to Provo and younger shorelines - Syncline axis Clast-supported pebble and cobble gravel in a sparse matrix of 690 (210) Leatham Formation sand and silt with interbedded thin sands; deposited in beaches, ,/ Prospect -=====,~= 0-80 (0-24) bars, and spits, typically south of Provo deltas; exposed thickness less than 16 feet «5 mi. Beirdneau Formation A A' Location of cross sections 524-1 ,087 (160-331) Deltaic deposits related to the Provo and younger shorelines - Clast­ supported pebble and cobble gra vel in a matrix of sand and minor Silt, with thin, sand beds; mostly deposited at the time of the Bonneville flood; exposed thickness less than 82 feet «25 mi. CORRELATION OF MAP UNITS c Hyrum Dolomite '00 '"o 932-1,101 (284-308) > Lacustrine sand and silt related to the Bonneville shoreline - Coarse to Mass-wasting 8 fine sand, silt, and minor clay with typically rhythmical bedding; Lacustrine deposits Alluvial deposits deposits deposited in a nearshore environment and as lagoon fill; up to 170 feet (52 m) thick in subsurface below Provo deltas. Qal, Qaf, Water Canyon Formation Qalu Qmsf 586 (178) :< :r : Holocene Lacustrine gravel and sand related to the Bonneville shoreline - Clast­ Qal, : ~~ ~: ' Qac Qms Quaternary ' .. supported pebble and cobble beds in a matrix of sand and silt, with Pleistocene Qlpd ~ '" Qlps interbedded sand; deposited in beaches, bars, spits, and small . ~: Qlf . deltas; exposed thickness less than 33 feet (<10 mi . Qlbd Qlbs Laketown Dolomite ·pl~ : ? - '---? - 1,150-1 ,610 (350- 490) Deltaic deposits related to the Bonneville shoreline - Clast-supported :. ~~t; i pebble and cobble gravel in a matrix of sand and minor silt, with ~ thin sand interbeds; deposited in deltas; exposed thickness less ~ / Fish Haven Dolomite than 33 feet (<10 mi. Unconformity ----7-7-- - 130-145 (40-44) Tertiary Late Holocene fan alluvium - Clast-supported pebble and cobble gravel, ~ , ':: Swan Peak Formation locally bouldery, in a matrix of sand, silt, and clay; has sharper c 134-283 (41-86) debris-flow levees and channels than the middle Holocene and Unconformity 1 ''"0 Prernian '> o Garden City Formation older fans ; exposed thickness less than 16 feet «5 mi. 'Ie o 1,160-1 ,400 (354-426) Pennsylvanian Middle Holocene to latest Pleistocene fan alluvium - Clast-supported, Unconformity locally bouldery, pebble and cobble gravel in a matrix of sand, Silt, • • • thrust fault contact I Mmc I and clay; deposited in alluvial fans of post-Bonneville lake cycle; I exposed thickness less than 16 feet « 5 mi. Mississippian cI SI. Charles Formation ~ to .-::.:: ... :.: .. : Middle Pleistoeene (pre-Bonneville lake cycle) fan alluvium - Clast­ ~ E ::.' :Qaf,': '.' supported pebble, cobble, and boulder gravel in a matrix of sand, ~ to E§EJ"." : .. : ....... () silt,· and minor clay; only exposed at the mouth of Logan Canyon Unconforrnity KEY TO SYMBOLS ON LITHOLOGIC COLUMN where the Logan River has cut through younger deposits; maximum exposed thickness about 33 feet (-10 mi. ~ Unconformity IIIIIIII Thin-bedded limestone ~ Dolostone Undivided Holocene to latest Pleistocene stream alluvium - Sand, silt ~ Devonian and gravel on undifferentiated post-Provo-stand floodplains 1 and terraces; mapped where the age of the alluvium (Oal, ~ ~ Micritic limestone _ Sandy dolostone vs. Oal.) cannot be determined; probably less than 33 feet (<10 m) thick. lOwe I j Sandy limestone Late Holocene stream alluvium - Clast-supported pebble and cobble [~§&~ l::·; ~~:::~. ·: :' :i;~:::1 Quartzite Silurian gravel in a matrix of sand, silt, and minor clay, with thin sand o Unconformity tenses; located on modern floodplains and low terraces; exposed ~ Limestone thickness less than 16 feet «5 mi. ~ r~l=~=] Shale Middle Holocene to latest Pleistocene stream alluvium - Clast-supported Unconformity I pebble and cobble gravels, in a matrix of sand, silt, and minor clay, Ordovician Cherty limestone with thin sand tenses; present on terraces more than 16 feet above 10ep I Iti!t! t!l!J I f?/:/.)//j Sandstone modern stream levels; exposed thickness less than 16 feet «5 mi· lOge I ~ j ,tUt) Shaly limestone ~ Sandstone interbedded with shale Undifferentiated Pre-Bonneville-Iake-cycle deposits - Uncemented sand, ~ clay, and gravels of pre-Bonneville Ouaternary deposits; only Cambrian shown on cross sections, ~ Undifferentiated Tertiary depOSits - Tuffaceous siltstone and sandstone, conglomerate, and fresh-water limes/one of the Salt Lake Formation; basal deposits may be congtomerates of the Tertiary Wasatch Formation only shown on cross sections. Wells Formation - Incompletely exposed fine to medium-grained, brown A West A' East to gray, calcareous, quartz sandstone and interbedded, gray Temple Baldy limestone; thickness exposed in quadrangle is 600 feet (183 mi· 8,000 8,000 Monroe Canyon Limestone equivalent - Lower, gray to brown-gray, thick BEAR RIVER RANGE bedded, massive, cliff-forming limestone; middte, medium-bedded,