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ger_ms2015-01_geol_map_lake_roesiger_24k

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Joseph Schilter

The document contains information about two lithologic cross sections (A and B) that show subsurface geology in the area. It includes data from 931 wells, 54 borings, and 214 test pits that were incorporated into the cross sections. It also references figures and an appendix that provide additional context. Key geologic units depicted on the cross sections include various Quaternary sediments and deposits (Qgav, Qgic, etc.), Tertiary sedimentary rocks (KJigbw, KJmsw), and pre-Tertiary bedrock (Ec). Faults such as the Sultan River thrust fault are also indicated.

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syncline anticline …Ec Qgog …Ec …Ec KJmw KJmw KJmw KJmw tz tz tz tz tz tz tz Qcph Qcph KJigbw Qcphl Qcphl Qgtv Qgtv Qgtv QgtvQgtv Qgav Qgav Qgav Qgic Qa Qaf Qgnpf W572 W625 W639 W469 W19 W498 W503,W813 W569 W823 W508 W807 W701 W600 W803 W487 W752,W622, W560,W597 W708,W799 W726 W865 W95 W722 W721 W138,W909 W341 W752 W377 W752 W848 W158 W830 Qgtv Qcphl Qgic QgtvQgtv Qaf Qaf Qgos Qglr Qgic Qglr Qaf Qp NORTHWEST -2,000 -400 -800 -1,200 -1,600 400 W832,W752 0 800 -2,400 SorgenfreiCreek creek EXPLORER FALLS BASIN CarpenterCreek CARPENTER CREEK FAULT B B′ SOUTHEAST THREE LAKES HILL FAULT SULTAN RIVER THRUST FAULT Elevation(feet) -2,000 -400 -800 -1,200 -1,600 400 0 800 -2,400 ? 2.5x vertical exaggeration syncline …Ec …Ec …Ec …Ec …Ec KJmswKJmsw KJmsw KJmsw tz tz tz tz tz tz tz tz tz tz tz tz tz tz Qgnpf KJigbw KJigbwQgnpf Qgnpf Qgnpf Qcws Qcws Qcws Qgtv Qgtv Qgtv Qgtv QcoQgog Qglr Qglr Qgos Qgos Qgos Qa Qgic Qgos Qgod KJmw KJmw KJmw Qglv W256 W854 W279 W410 W157 W14 W780 W155,W421, W415 W96 W322 W717 W318 W866,W867 W918,W347 W326 W227 W881 W340 W839 BH6,BH7 W380 W830 W72,W75 W74 W303 W709 W695 Qglr Qglv Qgav Qglv Qgtv Qgtd Qglv QgtvQgav Qgav Qgav Qgav Qgav Qgav Qgos Qgod Qglv Qgav Qa Qgs Qgs Qgtv -2,000 -1,600 -1,200 -800 -400 400 0 -2,400 -2,000 -1,600 -1,200 -800 -400 400 800 800 -2,400 Elevation(feet) 2.5x vertical exaggeration NORTHEASTSOUTHWEST RichardsonCreek WestForkWoodsCreek WoodsCreek WagnerRoad WOODSCREEKFAULTNO.3 WOODSCREEKFAULTNO.2 JOHNSONSSWAMPFAULTZONE S ULTAN RIVER THRUST FAULT WOODS CREEK FLUVIAL – DELTAIC COMPLEXRICHARDSON CREEK ICE– CONTACT COMPLEX MONROESYNCLINE Elevation(feet) Elevation(feet) A A′ 0 ? Lithologic Cross Sections A and B. For analyses of subsurface conditions, 931 wells, 54 geotechnical borings, and 214 test-pit stratigraphic logs were obtained from various public and private institutions. We show only the highest quality well and boring data near the cross sections. 234 wells were incorporated into the subsurface analyses for the diagrammatic cross section (Fig. 4, in pamphlet) and Cross Sections A and B. We show composite information where wells and borings are closely spaced and (or) where subsurface geologic conditions are stratigraphically consistent over a short distance. Figures M1 and M2 provide geophysical models of these lithologic cross sections. Appendix B provides information on earthquake hypocenters near the cross sections. The relationship between the Sultan River thrust, shown at depth on both cross sections, and the Lake Chaplain nappe is illustrated on Figure 6 in the pamphlet. CROSS SECTION EXPLANATION W146 BH6 Qls Surficial geologic units too thin to show as polygons at the scale of the cross sections. Black ticks mark separate units. Arrows show relative fault movement in the plane of the cross section. Arrow point shows fault movement toward the viewer; arrow feathers show fault movement away from the viewer. Water well or boring; water well labels begin with W; boring labels begin with B. D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ?? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 35A 33A 39S 33C 33E 31S 35B 33B 33D 83 25 13 36 10 12 32 7 60 9 4 8 7 50 14 55 14 24 44 6 11 48 9 21 30 28 8 35 75 23 80 78 4 25 10 75 35 10 10 82 10 33 5 70 49 24 5 27 20 19 65 23 65 10 12 13 75 33 35 20 2 6 81 19 16 25 5 47 85 10 15 41 16 4 15 13 4 10 7 20 13 8 2 22 70 29 10 16 36 26 15 40 13 51 86 17 31 56 85 25 13 20 27 23 3 19 2 21 65 25 46 5 4 15 8 6 85 60 11 12 37 16 70 55 20 14 76 67 2 12 12 25 13 8 5 36 25 25 21 90 12 20 21 25 55 7 58 29 14 15 85 20 46 24 11 37 7 13 5 35 42 17 6 85 10 25 52 15 14 32 64 13 80 7 7 4 20 2 20 47 29 50 25 6 14 13 4 31 11 15 9 14 W176 W780 W503 Quake 6 W322 W662 W722 W157 W813 SUBGLACIAL TUNNEL W495 W865 W279 W498 28M W600 W726 W854 W469 11P W19 W799 W918 W695 W770 23N W639 W708 W709 W415 W832 37N W752 W597 W326 W303 W572 39A W881 W560 W14 W74 W830 44D 120D W380 W487 W410 W75 W848 44E W227 W803 W72 W256 W377 BH-7 25H W318 W701 BH-13 W839 W341 BH-6 26T W96 W807 41AF W340 W909 2A 302C W347 W508 Quake 16 W867 W138 W158 W421 W823 W866 W721 W689 W155 W569 Quake 17 W717 W95 36N 5Q W644 W863 W527 W585 W646 W538 W589 W334 W625 W739 W616 W616 W536 W885 W544 W496 KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJmsw KJmsw KJmsw KJmsw KJmsw KJmsw KJmsw KJmsw KJmvw KJmvw „vr „vr …Ec …Ec …Ec …Ec …Ec …Ec Qa Qa Qa Qa Qa Qa Qa Qa Qa Qa Qa Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qco Qco Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav QgavQgav Qgav Qgav Qgav Qgav Qgav Qgav QgavQgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav QgavQgav Qgav Qgav Qgav Qgtv Qgtv Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic? Qgik Qgik Qgik Qgik Qgik Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv QglvQglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qgod Qgod Qgod Qgod Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qls Qls Qls Qls QlsQls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qtz tz tz Qgav tz tz tz tz tz tz tz tz Qls Qglr Qgic Qgav Qgav Qgod Qgtv Qgav Qgav Qgtv Qcws Qgtv tz Qglv Qa A′ A B′ B CARPENTER CREEK FAULT W O O D S C R EEK FAULT NO.4 W O O DS CREEK FAULT NO .5 W OO DS LAKE FAULT W OODS CREEK FAULT NO.2 DUBUQUE ROAD FAULT W OODS CREEK FAULT N O .1 WOODS CREEK FAULT NO .3 THREE LAKES HILL FAULT LAKE COCHRAN ICE-CONTACT COMPLEX W O O D S CR EEK FLU V IA L–D ELTA IC CO M PLEX RICHARDSON CREEK ICE – CONTACT COM PLEX JOHNSONS SWAMP ZO N E SULTAN RIVER THRUSTFAULT FAULT MONROE SYNCLINE FRENC H CREEK KAME CO M PLEX THREE LAKES HILL FAULT 121°52′30″ 48°00′00″ 122°00′00″ 48°00′00″ R 6 E R 7 E T 29 N T 28 N 55′00″ 55′00″ 55′00″ 55′00″ 57′30″ 121°52′30″ 47°52′30″ 122°00′00″ 47°52′30″ 57′30″ 57′30″ 57′30″R 6 E R 7 E T 29 N T 28 N Disclaimer: This product is provided ‘as is’ without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular use. The Washington Department of Natural Resources and the authors of this product will not be liable to the user of this product for any activity involving the product with respect to the following: (a) lost profits, lost savings, or any other consequential damages; (b) fitness of the product for a particular purpose; or (c) use of the product or results obtained from use of the product. This product is considered to be exempt from the Geologist Licensing Act [RCW 18.220.190 (4)] because it is geological research conducted by or for the State of Washington, Department of Natural Resources, Division of Geology and Earth Resources. © 2015 Washington Division of Geology and Earth Resources Lambert conformal conic projection North American Datum of 1927; to place on North American Datum of 1983, move the projection lines approximately 17 meters north and 92 meters east as shown by crosshair corner ticks Base map from scanned and rectified U.S. Geological Survey Lake Roesiger 7.5-minute quadrangle, 1997 Shaded relief generated from a lidar bare-earth digital elevation model (available from Puget Sound Lidar Consortium, http://pugetsoundlidar.ess.washington.edu/); sun azimuth 315°; sun angle 45°; vertical exaggeration 0.03 GIS by Joseph F. Schilter and Christina L. Frattali Digital cartography by by Anne C. Olson, J. Eric Schuster, and Ian J. Hubert Editing and production by Alexander N. Steely This geologic map was funded in part by the U.S. Geological Survey National Cooperative Geologic Mapping Program. 7000 FEET1000 10000 2000 3000 4000 5000 6000 0.5 1 KILOMETER1 0 0.51 0 1 MILE SCALE 1:24,000 contour interval 20 feet Geologic Map of the Lake Roesiger 7.5-minute Quadrangle, Snohomish County, Washington Joe D. Dragovich, Shannon A. Mahan, Megan L. Anderson, James H. MacDonald Jr., Joseph F. Schilter, Christina L. Frattali, Curtis J. Koger, Daniel T. Smith, Bruce A. Stoker, S. Andrew DuFrane, Michael P. Eddy, Recep Cakir, and Kirsten B. Sauer October 2015 APPROXIMATE MEAN DECLINATION, 2015 MAGNETIC NORTH TRUENORTH 16.1° WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES MAP SERIES 2015-01 Lake Roesiger 7.5-minute Quadrangle Pamphlet accompanies map http://www.dnr.wa.gov/geology/ LAKECHAPLAIN SNOHOMISH VERLOT SULTAN LAKESTEVENS MALTBY LAKE ROESIGER GRANITEFALLS MONROE Verlot Maltby Monroe Lake Stevens GraniteFalls Sultan 2 2 9 9 203 522 92 Research supported by the U.S. Geological Survey, National Cooperative Geologic Mapping Program, under USGS award number G14AC00212. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. MAJOR FINDINGS • Deposits of the Olympia nonglacial interval and Whidbey Formation contain a record of the ancient Skykomish River in the southern half of the map area. These deposits are generally tilted south toward the broad axis of the Monroe syncline, a fold which is part of a family of neotectonic structures that control the lower Skykomish River valley. • The Monroe synclinal basin continues from the Skykomish Valley across the southwest corner of the map area. Geophysical data, mapping, and geochronology indicate that this fold is cored by latest Pleistocene deposits of the Olympia nonglacial interval. • The Explorer Falls basin preserves a thick sequence of weathered Pleistocene Pilchuck River alluvium. These deposits originally formed in a small graben which has been locally inverted. • The northwest-trending Woods Creek fault zone is right-lateral to oblique and forms the eastern edge of the Everett basin. DESCRIPTION OF MAP UNITS (See the pamphlet for detailed map unit descriptions and Table 1 for a summary of sediment provenance) Quaternary Sedimentary Deposits HOLOCENE NONGLACIAL DEPOSITS Peat—Peat, muck, and organic silt and clay, locally with diatomite and thin beds of Mazama ash; loose or soft. Alluvium—Sand, silt, gravelly sand, and sandy pebble gravel; unit locally includes peat and organic sediments and (or) cobble gravel; clasts subrounded to rounded; some subangular to angular clasts in alluvium near Woods Creek; loose; well stratified and sorted; sand is planar bedded. LP, SP, or PP provenance, depending on nearest major river system. Landslide deposits (Holocene to latest Pleistocene)—Unsorted mixture of clay, silt, sand, gravel, and wood debris (diamicton) or boulder gravel, and local minor sand or gravel; loose. The absence of a mapped landslide does not imply the absence of hazard. Alluvial fan deposits (Holocene to latest Pleistocene)—Diamicton, alluvial gravel, boulder gravel, and sand; loose, poorly to moderately sorted; moderately stratified to massive; locally contains significant amounts of debris flow deposits. PLEISTOCENE GLACIAL AND NONGLACIAL DEPOSITS Deposits of the Vashon Stade of the Fraser Glaciation Recessional Deposits Recessional glaciolacustrine (glacial lake) deposits—Silt and clayey or sandy silt to silty sand, typically with scattered dropstones; local lenses of sand or gravel; soft; deposited in proglacial lakes. Outwash sand deposits—Sand and pebbly sand with some interbeds of silty sand, silt, or gravel; loose or soft; unstratified, weakly stratified, planar bedded, laminated, or rarely crossbedded. Deltaic outwash and kame-delta deposits—Sandy cobble gravel, gravel, pebbly sand; loose; moderately to well sorted; thin to very thickly bedded; well stratified with conspicuous high-amplitude foreset beds. Fluvial outwash deposits—Cobble and boulder gravel, gravel, pebbly sand, and interbeds of sand and rare silt; loose; moderately to well stratified; beds subhorizontal; locally crossbedded with many rip-up clasts. Ice-contact deposits—Cobble to boulder gravel and gravel, locally containing diamicton, silty pebbly gravel, sand, pebbly sand, or silt; loose; moderately stratified and medium to very thickly bedded; abrupt grain-size changes common. Locally divided into: Ice-contact kames—Cobble and boulder gravel, gravel, sand, and pebbly sand, with rare lenses of diamicton; loose; crossbedded, with localized oversteepened or slumped strata; cut-and-fill structures and common rip-up clasts of till or silt. Outwash gravel deposits, undivided—Poorly exposed boulder–pebble gravel to pebbly sand; loose; massive to crudely bedded; largely ice-contact deposits; may include any of the gravelly Vashon recessional facies. Advance Proglacial and Subglacial Deposits Lodgment till—Diamicton (unsorted mixture of clay, silt, sand, and gravel); dense; matrix-supported; accreted at the base of the Vashon-age ice; typically has a friable shear fabric. Advance outwash deposits—Sand and pebble gravel, sand and cobble gravel, and local silt; dense; well sorted and stratified; thinly to thickly bedded; deltaic and channel bar foresets, cut-and-fill structures, and common silt rip-up clasts. Advance glaciolacustrine deposits—Silt, clayey silt, pebbly silt, and diamicton; locally contains very thin to thick beds of sand, scattered dropstones, and iceberg melt-out or flow till; stiff or dense; stratification and sorting vary; massive to thinly bedded, laminated, or varved. Pre-Fraser Glacial and Nonglacial Deposits Deposits of the Olympia nonglacial interval—Sand, sandy silt, silty sand, and silt, with some clay and (or) organic silty clay in the southwest corner of the map area; minor peat, charcoal, disseminated detrital organic matter, and gravel beds; sand typically yellow, gray-brown, or brown-gray with distinctive dark gray-orange oxidation; dense; well stratified; laminated to very thickly bedded; liquefaction features common; SP provenance. Whidbey Formation—Sand, silt, and silty sand with lesser pebbly sand, clay, gravel, organic sediment including peat; lenses of (cobble) gravel observed regionally; sand is a light yellowish brown and weathers to a distinctive orange-gray; dense or hard; well sorted and stratified; SP provenance. Double Bluff till (cross section only)—Diamicton; very dense and massive bedded; laterally extensive in the subsurface beneath the Whidbey Formation in the southern part of the map area. Pre-Hamm Creek nonglacial deposits—Pebble gravel, gravelly sand, pebbly sand, sand, silty sand, silt with local cobble gravel and clay; sand is typically yellowish brown to pale brown, weathers orange; oxidized and strongly weathered with conspicuous mica; thin to very thickly bedded; well stratified; cross bedding, graded beds, charcoal, logs, or disseminated organic matter are common. PP provenance in the northern parts of the quadrangle, and SP provenance at one site (33D) along the south-central border of the map area. Pre-Hamm Creek nonglacial deposits, locally derived—Sand, pebbly sand, sandy pebble gravel, with less gravel, cobble–boulder gravel, or rare silt; locally contains peat, logs, or organic sediments; distinct local Western mélange belt (LP) provenance. Pre-Fraser glacial and nonglacial deposits, undivided (Pleistocene to Pliocene?)(cross section only)—Dense to very dense gravel, boulder gravel, sand, silt, clay, and diamicton; may locally contain peat or organic sediments. Tertiary Volcanic, Intrusive, and Sedimentary Rocks Rhyolite of Hughes Lake (Miocene)—Poorly exposed, high-K, calc-alkaline rhyolite flow and crystal-vitric to vitric-crystal (lapilli) tuff; white to pinkish white, weathers light yellowish brown; U-Pb zircon age of 23.300 ±0.032 Ma at site 31S. Rocks of Bulson Creek (Oligocene to Eocene)—Lithic to lithofeldspathic sandstone with less conglomerate, pebbly sandstone, siltstone, or coal with minor claystone; mostly preserved in the Explorer Falls and (or) Everett basins. Mesozoic Low- to Medium-Grade Metamorphic Rocks Western mélange belt of Tabor and others (1993), undivided (Cretaceous to Jurassic)(cross section only)—Meta-argillite, metasandstone, greenstone, metachert, with less metadiabase, metatonalite, slate, amphibolite, hornblendite, phyllite, minor marble with meta-quartz-diorite; ultramafic rocks rare regionally. Metavolcanic rocks—Low-grade greenstone derived from metamorphosed basaltic to andesitic tuff and volcanic flows of basaltic andesite to dacite. Metasedimentary rocks—Low-grade marine feldspathic to feldspatholithic subquartzose metasandstone, silty metasandstone, meta-argillite, metatuff, and chert-pebble metaconglomerate; minor metachert and rare marble; well to moderately sorted. Metagabbro—Medium-grade metagabbro, quartz metagabbro, feldspathic hornblendite and amphibolite; less metatrondhjemite or metatonalite; metadiabase and rare meta-quartz-diorite are reported regionally; medium to coarse grained; generally slightly foliated to schistose or gneissose. Holocene to Tertiary Tectonic Zones Tectonic zone—Cataclasite, fault breccia, clay-rich fault gouge, protomylonite, and (or) moderately to strongly slickenlined, fractured, and veined rocks in and near fault zones; variously colored and mottled; commonly altered. Unit Qtz is mapped where deformation is demonstrably Quaternary in age, such as along the Dubuque Road fault in the western part of the quadrangle. GEOLOGIC SYMBOLS Contact—Solid where location accurate; long-dashed where approximately located; queried where identity or existence questionable Fault, unknown offset—Solid where location accurate; short-dashed where inferred; dotted where concealed; queried where identity or existence questionable Thrust fault—Solid where location accurate; dotted where concealed; triangles on upper (structurally higher) plate Reverse fault—Solid where location accurate; long-dashed where approximately located; dotted where concealed; queried where identity or existence questionable; rectangles on upthrown block. High-angle dip-slip fault—Dotted where concealed; queried where identity or existence questionable; U, upthrown block; D, downthrown block Right-lateral strike-slip fault—Solid where location accurate; long-dashed where approximately located; dotted where concealed; queried where identity or existence questionable; arrows show relative motion High-angle right-lateral, oblique-slip fault—Solid where location accurate; short-dashed where inferred; dotted where concealed; queried where identity or existence questionable; arrows show relative horizontal motion; U, upthrown block; D, downthrown block High-angle left-lateral, oblique-slip fault—Short-dashed where inferred; dotted where concealed; queried where identity or existence questionable; arrows show relative horizontal motion; U, upthrown block; D, downthrown block Anticline—Short-dashed where inferred; dotted where concealed; queried where identity or existence questionable Syncline—Short dashed where inferred; dotted where concealed; queried where identity or existence questionable Fluvial terrace scarp—Identity and existence certain; location accurate; hachures point downslope Landslide scarp—Identity and existence certain; location accurate; hachures point downslope Cross section line Location of Figure 4 cross section in accompanying pamphlet Direction of downslope movement of landslide Inclined bedding—showing strike and dip Horizontal bedding Inclined bedding in unconsolidated sedimentary deposits—showing strike and dip Inclined foreset bedding in unconsolidated sedimentary deposits—showing strike and dip Inclined cleavage—showing strike and dip Vertical cleavage—showing strike Inclined metamorphic or tectonic foliation—showing strike and dip Vertical metamorphic or tectonic foliation—showing strike Small, minor inclined fault—showing strike and dip Small, minor vertical or near-vertical fault—showing strike Inclined slickenline, groove, or striation on fault surface—showing bearing and plunge Slickenside—showing strike and dip Inclined mylonitic foliation—showing strike and dip Geochronology sample location, uranium-lead (U-Pb) Geochronology sample location, infrared stimulated luminescence (IRSL) Significant site Earthquake hypocenter; number corresponds to focal mechanisms in Appendix B Water well Drill hole for hydrocarbon exploration Drill hole or test pit ? ? ? D U ? ? D U ? D U ?? ?? ?? A′A 31S W487 BH-13 BH-6 48 67 55 5 32 60 86 36 30 33A 23N Quake 6 KJigbw KJmsw KJmvw KJmw „vr …Ec Qa Qaf Qco Qcph Qgtd Qcphl Qgnpf Qcws Qgav Qgic Qgik Qglv Qglr Qgod Qgof Qgog Qgos Qgtv Qls Qp Qtz tz ? ? ?? Qcph Qgnpf Qcphl KJigbw KJmw KJmswKJmvw …Ec „vr Qglr Qgos Qgod Qgtv Qgav Qglv Qgof Qgic Qgik Qgog Qls QafQp Qa Qco Qcws Qgtd The pamphlet provides direct or indirect age constraints for many of the geologic units, including new IRSL ages for glacial and nonglacial deposits (Appendix A). See Morrison (1991) for Pleistocene age constraints on the glacial and nonglacial intervals. Tabor and others (1993) indicate that the Western mélange belt meta-intrusive rocks (unit KJigbw) are ~150–170 Ma and are about the same age or older than the Kimmeridgian to Valanginian (157–134 Ma) metasedimentary rocks of the belt. However, detrital zircon U-Pb ages for unit KJmsw (Dragovich and others, 2014) indicate that the metasandstone in this unit is locally as young as 74 Ma. FRASER GLACIATION POSSESSION GLACIATION DOUBLE BLUFF GLACIATION 2.588 Ma Holocene QUATERNARY Pleistocene TERTIARY Jurassic Paleogene Neogene Cretaceous 66 Ma 145 Ma 200 Ma HAMM CREEK INTERGLACIAL INTERVAL DEPOSITS OF THE OLYMPIA NONGLACIAL INTERVAL DEPOSITS OF THE WHIDBEY INTERGLACIAL INTERVAL DEPOSITS OLDER THAN HAMM CREEK INTERGLACIAL INTERVAL (~60–80 ka) (~130–190 ka) (>300–550 ka) (~190–245 ka) (~80–130 ka) (~20–60 ka) CORRELATION OF MAP UNITS Glacial Geologic Units Bedrock Geologic Units Nonglacial Geologic Units TH R EE LA K ES H ILL FAU LT Explorer Falls basin Sh-4 Sh-8 Sh-3 33F 47A 33A 33B 35A 35B 33C 33D 33E 28M SUBGLACIAL TUNNEL 5Q 302C 26T 25H 44E 44D 39S120D 31S 2A 11P 41AF 23N37N 39A 36N 10M C A R PENTER CR E E K FAU LT Snohomish Lake Roesiger quadrangle Lake Chaplain Lake Roesiger Flowing Lake Storm Lake Chain Lake Lake Hughes Lake Cochran 0 2 4 miles 47A 33F 10M Sh-8 significant site IRSL age site U-Pb age site oil and gas exploration well Figure M3. Map of oil and gas exploration wells, age sites, and significant sites in and near the Lake Roesiger quadrangle. The Three Lakes Hill and Carpenter Creek faults are shown schematically. gravity station Gravity(mGals)Magnetics(nT)Depth(ft) A A′ Modeled Cross Sections observed calculated -55 -50 -45 -40 -35 -300 -200 -100 6 9 12 3,000 2,000 1,000 0 -1,000 gravity station Distance (km) B′B observed calculated -50 -45 -40 -35 9 12 15 3,000 2,000 1,000 0 -1,000 Gravity(mGals)Depth(ft) Tertiary rocks Western mélange belt Tectonic zones Δρ = -650 Δρ = 30 to 50 Δρ = 10 to 30 Δρ = 170 Δρ = -400 Δρ = 10 χ = 1 to 2 χ = 0 χ = 50 χ = 0.4 χ = 2 χ = 2 metagabbro, unit KJigbw unit …Ec metasedimentary, unit KJmsw unit KJmw, excluding metagabbro cataclasite of unit KJmw undifferentiated Quaternary deposits Δρ = -650 χ = 4 unit Qco Quaternary deposits Geologic unitsSusceptibility Density contrast (kg/m3 ) Δρ = -650 χ = 4 unit Qcws Δρ = -650 χ = 2 to 5 unit Qgnpf Δρ = -70 to 0 χ = 0 cataclasite of unit KJmsw χ = 40 to 50 cataclasite of unit KJigbw Δρ = -490 to -470 χ = 0 cataclasite of unit …Ec Δρ = 80 to 110 Figure M2. Geophysical models A and B correspond to lithologic Cross Sections A–A′ and B–B′ (both at 2.5x vertical exaggeration) and show the match between modeled density and magnetic susceptibility from the cross sections and the observed gravity and aeromagnetic values. Here we use the total field magnetic anomaly to interpret both the shallow and deep-seated structures that contribute to the magnetic anomalies of the region, unlike in Figure M1, which focuses on near-surface structures. Although we modeled the gravity data, we did not model the aeromagnetic data for B–B′ because most or all of the aeromagnetic anomalies along this transect are either to the east or west of the cross section line (see Fig. M1) and do not reflect the subsurface structure along the transect. Aeromagnetic data sampling distance along A–A′ is approximately twice the flightline spacing. Gravity data points are shown where good data control exists within 1.5 km of the line. The models extend to infinity in both directions perpendicular to the profiles, and data is tied to the model off to the right of both models, coinciding with locations where the model lines project across models developed in previous studies (Lake Chaplain quadrangle for A–A′ and Sultan quadrangle for B–B′). Δρ is the density contrast relative to normal crust (2,670 kg/m3) used for the model; χ is magnetic susceptibility in SI units x 1,000. Note that the higher susceptibilities for deformed units correspond to deformed metagabbro and lower densities correspond to deformed metasedimentary rocks. Though a wide range of densities for cataclasite of unit KJmsw are included in the model, most of these rocks have Δρ of -10 kg/m3. Solid lines show fault locations that are well constrained by the geophysical data; dashed lines are faults constrained by surficial geologic mapping, but are less certain at depth. Figure M1. Aeromagnetic anomaly and isostatic gravity map of the Lake Roesiger quadrangle. Base map is reduced-to-pole aeromagnetic anomaly, filtered (upward continued and differenced with original grid) to bring out magnetic anomalies originating from near-surface sources. GB1 through GB4 are four distinct magnetic highs associated with Western mélange belt metagabbro (unit KJigbw). The anomaly at GB1 starts at the label and continues northwest; this whole trend is considered the same anomaly. MS is a gravity low associated with Monroe syncline; NE1 and NE2 are northeast-trending gravity highs; OL is a strong gravity gradient associated with the eastern edge of a thick deposit of Oligocene sediment; SP1 to SP4 are weak aeromagnetic highs that correlate with areas of moderately magnetically susceptible Skykomish River provenance Pleistocene sediment along the northern limb of the Monroe syncline; UL is a small gravity low associated with a small unnamed basin. GEOPHYSICAL DATA AND INTERPRETATIONS 47°52′30″ 122°00′00″ 48°00′00″ 121°52′30″ -50 -50 -40 -40 - 4 0 -40 -30 -30 -30 A A′ B′ B OL GB1 GB2 GB3 GB4 SP1 SP2 SP3 SP4 MS UL NE1 NE2 - 2 0 A A′ Gravity measurement locations used to control interpolation of gravity data Fault—solid where certain; dashed where inferred; dotted where uncertain Gravity contours—hachures point in the direction of decreasing gravity values; contour interval 1 milligal Gravity and magnetic profile line 0 0 0.5 1 1 mi 2 km Aeromagnetic anomaly in nanoTeslas (nT) 0 2-2-5 5 10-10 20-20

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ger_ms2015-01_geol_map_lake_roesiger_24k

  • 1. syncline anticline …Ec Qgog …Ec …Ec KJmw KJmw KJmw KJmw tz tz tz tz tz tz tz Qcph Qcph KJigbw Qcphl Qcphl Qgtv Qgtv Qgtv QgtvQgtv Qgav Qgav Qgav Qgic Qa Qaf Qgnpf W572 W625 W639 W469 W19 W498 W503,W813 W569 W823 W508 W807 W701 W600 W803 W487 W752,W622, W560,W597 W708,W799 W726 W865 W95 W722 W721 W138,W909 W341 W752 W377 W752 W848 W158 W830 Qgtv Qcphl Qgic QgtvQgtv Qaf Qaf Qgos Qglr Qgic Qglr Qaf Qp NORTHWEST -2,000 -400 -800 -1,200 -1,600 400 W832,W752 0 800 -2,400 SorgenfreiCreek creek EXPLORER FALLS BASIN CarpenterCreek CARPENTER CREEK FAULT B B′ SOUTHEAST THREE LAKES HILL FAULT SULTAN RIVER THRUST FAULT Elevation(feet) -2,000 -400 -800 -1,200 -1,600 400 0 800 -2,400 ? 2.5x vertical exaggeration syncline …Ec …Ec …Ec …Ec …Ec KJmswKJmsw KJmsw KJmsw tz tz tz tz tz tz tz tz tz tz tz tz tz tz Qgnpf KJigbw KJigbwQgnpf Qgnpf Qgnpf Qcws Qcws Qcws Qgtv Qgtv Qgtv Qgtv QcoQgog Qglr Qglr Qgos Qgos Qgos Qa Qgic Qgos Qgod KJmw KJmw KJmw Qglv W256 W854 W279 W410 W157 W14 W780 W155,W421, W415 W96 W322 W717 W318 W866,W867 W918,W347 W326 W227 W881 W340 W839 BH6,BH7 W380 W830 W72,W75 W74 W303 W709 W695 Qglr Qglv Qgav Qglv Qgtv Qgtd Qglv QgtvQgav Qgav Qgav Qgav Qgav Qgav Qgos Qgod Qglv Qgav Qa Qgs Qgs Qgtv -2,000 -1,600 -1,200 -800 -400 400 0 -2,400 -2,000 -1,600 -1,200 -800 -400 400 800 800 -2,400 Elevation(feet) 2.5x vertical exaggeration NORTHEASTSOUTHWEST RichardsonCreek WestForkWoodsCreek WoodsCreek WagnerRoad WOODSCREEKFAULTNO.3 WOODSCREEKFAULTNO.2 JOHNSONSSWAMPFAULTZONE S ULTAN RIVER THRUST FAULT WOODS CREEK FLUVIAL – DELTAIC COMPLEXRICHARDSON CREEK ICE– CONTACT COMPLEX MONROESYNCLINE Elevation(feet) Elevation(feet) A A′ 0 ? Lithologic Cross Sections A and B. For analyses of subsurface conditions, 931 wells, 54 geotechnical borings, and 214 test-pit stratigraphic logs were obtained from various public and private institutions. We show only the highest quality well and boring data near the cross sections. 234 wells were incorporated into the subsurface analyses for the diagrammatic cross section (Fig. 4, in pamphlet) and Cross Sections A and B. We show composite information where wells and borings are closely spaced and (or) where subsurface geologic conditions are stratigraphically consistent over a short distance. Figures M1 and M2 provide geophysical models of these lithologic cross sections. Appendix B provides information on earthquake hypocenters near the cross sections. The relationship between the Sultan River thrust, shown at depth on both cross sections, and the Lake Chaplain nappe is illustrated on Figure 6 in the pamphlet. CROSS SECTION EXPLANATION W146 BH6 Qls Surficial geologic units too thin to show as polygons at the scale of the cross sections. Black ticks mark separate units. Arrows show relative fault movement in the plane of the cross section. Arrow point shows fault movement toward the viewer; arrow feathers show fault movement away from the viewer. Water well or boring; water well labels begin with W; boring labels begin with B. D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U D U ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ?? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 35A 33A 39S 33C 33E 31S 35B 33B 33D 83 25 13 36 10 12 32 7 60 9 4 8 7 50 14 55 14 24 44 6 11 48 9 21 30 28 8 35 75 23 80 78 4 25 10 75 35 10 10 82 10 33 5 70 49 24 5 27 20 19 65 23 65 10 12 13 75 33 35 20 2 6 81 19 16 25 5 47 85 10 15 41 16 4 15 13 4 10 7 20 13 8 2 22 70 29 10 16 36 26 15 40 13 51 86 17 31 56 85 25 13 20 27 23 3 19 2 21 65 25 46 5 4 15 8 6 85 60 11 12 37 16 70 55 20 14 76 67 2 12 12 25 13 8 5 36 25 25 21 90 12 20 21 25 55 7 58 29 14 15 85 20 46 24 11 37 7 13 5 35 42 17 6 85 10 25 52 15 14 32 64 13 80 7 7 4 20 2 20 47 29 50 25 6 14 13 4 31 11 15 9 14 W176 W780 W503 Quake 6 W322 W662 W722 W157 W813 SUBGLACIAL TUNNEL W495 W865 W279 W498 28M W600 W726 W854 W469 11P W19 W799 W918 W695 W770 23N W639 W708 W709 W415 W832 37N W752 W597 W326 W303 W572 39A W881 W560 W14 W74 W830 44D 120D W380 W487 W410 W75 W848 44E W227 W803 W72 W256 W377 BH-7 25H W318 W701 BH-13 W839 W341 BH-6 26T W96 W807 41AF W340 W909 2A 302C W347 W508 Quake 16 W867 W138 W158 W421 W823 W866 W721 W689 W155 W569 Quake 17 W717 W95 36N 5Q W644 W863 W527 W585 W646 W538 W589 W334 W625 W739 W616 W616 W536 W885 W544 W496 KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJigbw KJmsw KJmsw KJmsw KJmsw KJmsw KJmsw KJmsw KJmsw KJmvw KJmvw „vr „vr …Ec …Ec …Ec …Ec …Ec …Ec Qa Qa Qa Qa Qa Qa Qa Qa Qa Qa Qa Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qaf Qco Qco Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcph Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcphl Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qcws Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav QgavQgav Qgav Qgav Qgav Qgav Qgav Qgav QgavQgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav QgavQgav Qgav Qgav Qgav Qgtv Qgtv Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgav Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic Qgic? Qgik Qgik Qgik Qgik Qgik Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv QglvQglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglv Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qglr Qgod Qgod Qgod Qgod Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgof Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgog Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgos Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qgtv Qls Qls Qls Qls QlsQls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qls Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qp Qtz tz tz Qgav tz tz tz tz tz tz tz tz Qls Qglr Qgic Qgav Qgav Qgod Qgtv Qgav Qgav Qgtv Qcws Qgtv tz Qglv Qa A′ A B′ B CARPENTER CREEK FAULT W O O D S C R EEK FAULT NO.4 W O O DS CREEK FAULT NO .5 W OO DS LAKE FAULT W OODS CREEK FAULT NO.2 DUBUQUE ROAD FAULT W OODS CREEK FAULT N O .1 WOODS CREEK FAULT NO .3 THREE LAKES HILL FAULT LAKE COCHRAN ICE-CONTACT COMPLEX W O O D S CR EEK FLU V IA L–D ELTA IC CO M PLEX RICHARDSON CREEK ICE – CONTACT COM PLEX JOHNSONS SWAMP ZO N E SULTAN RIVER THRUSTFAULT FAULT MONROE SYNCLINE FRENC H CREEK KAME CO M PLEX THREE LAKES HILL FAULT 121°52′30″ 48°00′00″ 122°00′00″ 48°00′00″ R 6 E R 7 E T 29 N T 28 N 55′00″ 55′00″ 55′00″ 55′00″ 57′30″ 121°52′30″ 47°52′30″ 122°00′00″ 47°52′30″ 57′30″ 57′30″ 57′30″R 6 E R 7 E T 29 N T 28 N Disclaimer: This product is provided ‘as is’ without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular use. The Washington Department of Natural Resources and the authors of this product will not be liable to the user of this product for any activity involving the product with respect to the following: (a) lost profits, lost savings, or any other consequential damages; (b) fitness of the product for a particular purpose; or (c) use of the product or results obtained from use of the product. This product is considered to be exempt from the Geologist Licensing Act [RCW 18.220.190 (4)] because it is geological research conducted by or for the State of Washington, Department of Natural Resources, Division of Geology and Earth Resources. © 2015 Washington Division of Geology and Earth Resources Lambert conformal conic projection North American Datum of 1927; to place on North American Datum of 1983, move the projection lines approximately 17 meters north and 92 meters east as shown by crosshair corner ticks Base map from scanned and rectified U.S. Geological Survey Lake Roesiger 7.5-minute quadrangle, 1997 Shaded relief generated from a lidar bare-earth digital elevation model (available from Puget Sound Lidar Consortium, http://pugetsoundlidar.ess.washington.edu/); sun azimuth 315°; sun angle 45°; vertical exaggeration 0.03 GIS by Joseph F. Schilter and Christina L. Frattali Digital cartography by by Anne C. Olson, J. Eric Schuster, and Ian J. Hubert Editing and production by Alexander N. Steely This geologic map was funded in part by the U.S. Geological Survey National Cooperative Geologic Mapping Program. 7000 FEET1000 10000 2000 3000 4000 5000 6000 0.5 1 KILOMETER1 0 0.51 0 1 MILE SCALE 1:24,000 contour interval 20 feet Geologic Map of the Lake Roesiger 7.5-minute Quadrangle, Snohomish County, Washington Joe D. Dragovich, Shannon A. Mahan, Megan L. Anderson, James H. MacDonald Jr., Joseph F. Schilter, Christina L. Frattali, Curtis J. Koger, Daniel T. Smith, Bruce A. Stoker, S. Andrew DuFrane, Michael P. Eddy, Recep Cakir, and Kirsten B. Sauer October 2015 APPROXIMATE MEAN DECLINATION, 2015 MAGNETIC NORTH TRUENORTH 16.1° WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES MAP SERIES 2015-01 Lake Roesiger 7.5-minute Quadrangle Pamphlet accompanies map http://www.dnr.wa.gov/geology/ LAKECHAPLAIN SNOHOMISH VERLOT SULTAN LAKESTEVENS MALTBY LAKE ROESIGER GRANITEFALLS MONROE Verlot Maltby Monroe Lake Stevens GraniteFalls Sultan 2 2 9 9 203 522 92 Research supported by the U.S. Geological Survey, National Cooperative Geologic Mapping Program, under USGS award number G14AC00212. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. MAJOR FINDINGS • Deposits of the Olympia nonglacial interval and Whidbey Formation contain a record of the ancient Skykomish River in the southern half of the map area. These deposits are generally tilted south toward the broad axis of the Monroe syncline, a fold which is part of a family of neotectonic structures that control the lower Skykomish River valley. • The Monroe synclinal basin continues from the Skykomish Valley across the southwest corner of the map area. Geophysical data, mapping, and geochronology indicate that this fold is cored by latest Pleistocene deposits of the Olympia nonglacial interval. • The Explorer Falls basin preserves a thick sequence of weathered Pleistocene Pilchuck River alluvium. These deposits originally formed in a small graben which has been locally inverted. • The northwest-trending Woods Creek fault zone is right-lateral to oblique and forms the eastern edge of the Everett basin. DESCRIPTION OF MAP UNITS (See the pamphlet for detailed map unit descriptions and Table 1 for a summary of sediment provenance) Quaternary Sedimentary Deposits HOLOCENE NONGLACIAL DEPOSITS Peat—Peat, muck, and organic silt and clay, locally with diatomite and thin beds of Mazama ash; loose or soft. Alluvium—Sand, silt, gravelly sand, and sandy pebble gravel; unit locally includes peat and organic sediments and (or) cobble gravel; clasts subrounded to rounded; some subangular to angular clasts in alluvium near Woods Creek; loose; well stratified and sorted; sand is planar bedded. LP, SP, or PP provenance, depending on nearest major river system. Landslide deposits (Holocene to latest Pleistocene)—Unsorted mixture of clay, silt, sand, gravel, and wood debris (diamicton) or boulder gravel, and local minor sand or gravel; loose. The absence of a mapped landslide does not imply the absence of hazard. Alluvial fan deposits (Holocene to latest Pleistocene)—Diamicton, alluvial gravel, boulder gravel, and sand; loose, poorly to moderately sorted; moderately stratified to massive; locally contains significant amounts of debris flow deposits. PLEISTOCENE GLACIAL AND NONGLACIAL DEPOSITS Deposits of the Vashon Stade of the Fraser Glaciation Recessional Deposits Recessional glaciolacustrine (glacial lake) deposits—Silt and clayey or sandy silt to silty sand, typically with scattered dropstones; local lenses of sand or gravel; soft; deposited in proglacial lakes. Outwash sand deposits—Sand and pebbly sand with some interbeds of silty sand, silt, or gravel; loose or soft; unstratified, weakly stratified, planar bedded, laminated, or rarely crossbedded. Deltaic outwash and kame-delta deposits—Sandy cobble gravel, gravel, pebbly sand; loose; moderately to well sorted; thin to very thickly bedded; well stratified with conspicuous high-amplitude foreset beds. Fluvial outwash deposits—Cobble and boulder gravel, gravel, pebbly sand, and interbeds of sand and rare silt; loose; moderately to well stratified; beds subhorizontal; locally crossbedded with many rip-up clasts. Ice-contact deposits—Cobble to boulder gravel and gravel, locally containing diamicton, silty pebbly gravel, sand, pebbly sand, or silt; loose; moderately stratified and medium to very thickly bedded; abrupt grain-size changes common. Locally divided into: Ice-contact kames—Cobble and boulder gravel, gravel, sand, and pebbly sand, with rare lenses of diamicton; loose; crossbedded, with localized oversteepened or slumped strata; cut-and-fill structures and common rip-up clasts of till or silt. Outwash gravel deposits, undivided—Poorly exposed boulder–pebble gravel to pebbly sand; loose; massive to crudely bedded; largely ice-contact deposits; may include any of the gravelly Vashon recessional facies. Advance Proglacial and Subglacial Deposits Lodgment till—Diamicton (unsorted mixture of clay, silt, sand, and gravel); dense; matrix-supported; accreted at the base of the Vashon-age ice; typically has a friable shear fabric. Advance outwash deposits—Sand and pebble gravel, sand and cobble gravel, and local silt; dense; well sorted and stratified; thinly to thickly bedded; deltaic and channel bar foresets, cut-and-fill structures, and common silt rip-up clasts. Advance glaciolacustrine deposits—Silt, clayey silt, pebbly silt, and diamicton; locally contains very thin to thick beds of sand, scattered dropstones, and iceberg melt-out or flow till; stiff or dense; stratification and sorting vary; massive to thinly bedded, laminated, or varved. Pre-Fraser Glacial and Nonglacial Deposits Deposits of the Olympia nonglacial interval—Sand, sandy silt, silty sand, and silt, with some clay and (or) organic silty clay in the southwest corner of the map area; minor peat, charcoal, disseminated detrital organic matter, and gravel beds; sand typically yellow, gray-brown, or brown-gray with distinctive dark gray-orange oxidation; dense; well stratified; laminated to very thickly bedded; liquefaction features common; SP provenance. Whidbey Formation—Sand, silt, and silty sand with lesser pebbly sand, clay, gravel, organic sediment including peat; lenses of (cobble) gravel observed regionally; sand is a light yellowish brown and weathers to a distinctive orange-gray; dense or hard; well sorted and stratified; SP provenance. Double Bluff till (cross section only)—Diamicton; very dense and massive bedded; laterally extensive in the subsurface beneath the Whidbey Formation in the southern part of the map area. Pre-Hamm Creek nonglacial deposits—Pebble gravel, gravelly sand, pebbly sand, sand, silty sand, silt with local cobble gravel and clay; sand is typically yellowish brown to pale brown, weathers orange; oxidized and strongly weathered with conspicuous mica; thin to very thickly bedded; well stratified; cross bedding, graded beds, charcoal, logs, or disseminated organic matter are common. PP provenance in the northern parts of the quadrangle, and SP provenance at one site (33D) along the south-central border of the map area. Pre-Hamm Creek nonglacial deposits, locally derived—Sand, pebbly sand, sandy pebble gravel, with less gravel, cobble–boulder gravel, or rare silt; locally contains peat, logs, or organic sediments; distinct local Western mélange belt (LP) provenance. Pre-Fraser glacial and nonglacial deposits, undivided (Pleistocene to Pliocene?)(cross section only)—Dense to very dense gravel, boulder gravel, sand, silt, clay, and diamicton; may locally contain peat or organic sediments. Tertiary Volcanic, Intrusive, and Sedimentary Rocks Rhyolite of Hughes Lake (Miocene)—Poorly exposed, high-K, calc-alkaline rhyolite flow and crystal-vitric to vitric-crystal (lapilli) tuff; white to pinkish white, weathers light yellowish brown; U-Pb zircon age of 23.300 ±0.032 Ma at site 31S. Rocks of Bulson Creek (Oligocene to Eocene)—Lithic to lithofeldspathic sandstone with less conglomerate, pebbly sandstone, siltstone, or coal with minor claystone; mostly preserved in the Explorer Falls and (or) Everett basins. Mesozoic Low- to Medium-Grade Metamorphic Rocks Western mélange belt of Tabor and others (1993), undivided (Cretaceous to Jurassic)(cross section only)—Meta-argillite, metasandstone, greenstone, metachert, with less metadiabase, metatonalite, slate, amphibolite, hornblendite, phyllite, minor marble with meta-quartz-diorite; ultramafic rocks rare regionally. Metavolcanic rocks—Low-grade greenstone derived from metamorphosed basaltic to andesitic tuff and volcanic flows of basaltic andesite to dacite. Metasedimentary rocks—Low-grade marine feldspathic to feldspatholithic subquartzose metasandstone, silty metasandstone, meta-argillite, metatuff, and chert-pebble metaconglomerate; minor metachert and rare marble; well to moderately sorted. Metagabbro—Medium-grade metagabbro, quartz metagabbro, feldspathic hornblendite and amphibolite; less metatrondhjemite or metatonalite; metadiabase and rare meta-quartz-diorite are reported regionally; medium to coarse grained; generally slightly foliated to schistose or gneissose. Holocene to Tertiary Tectonic Zones Tectonic zone—Cataclasite, fault breccia, clay-rich fault gouge, protomylonite, and (or) moderately to strongly slickenlined, fractured, and veined rocks in and near fault zones; variously colored and mottled; commonly altered. Unit Qtz is mapped where deformation is demonstrably Quaternary in age, such as along the Dubuque Road fault in the western part of the quadrangle. GEOLOGIC SYMBOLS Contact—Solid where location accurate; long-dashed where approximately located; queried where identity or existence questionable Fault, unknown offset—Solid where location accurate; short-dashed where inferred; dotted where concealed; queried where identity or existence questionable Thrust fault—Solid where location accurate; dotted where concealed; triangles on upper (structurally higher) plate Reverse fault—Solid where location accurate; long-dashed where approximately located; dotted where concealed; queried where identity or existence questionable; rectangles on upthrown block. High-angle dip-slip fault—Dotted where concealed; queried where identity or existence questionable; U, upthrown block; D, downthrown block Right-lateral strike-slip fault—Solid where location accurate; long-dashed where approximately located; dotted where concealed; queried where identity or existence questionable; arrows show relative motion High-angle right-lateral, oblique-slip fault—Solid where location accurate; short-dashed where inferred; dotted where concealed; queried where identity or existence questionable; arrows show relative horizontal motion; U, upthrown block; D, downthrown block High-angle left-lateral, oblique-slip fault—Short-dashed where inferred; dotted where concealed; queried where identity or existence questionable; arrows show relative horizontal motion; U, upthrown block; D, downthrown block Anticline—Short-dashed where inferred; dotted where concealed; queried where identity or existence questionable Syncline—Short dashed where inferred; dotted where concealed; queried where identity or existence questionable Fluvial terrace scarp—Identity and existence certain; location accurate; hachures point downslope Landslide scarp—Identity and existence certain; location accurate; hachures point downslope Cross section line Location of Figure 4 cross section in accompanying pamphlet Direction of downslope movement of landslide Inclined bedding—showing strike and dip Horizontal bedding Inclined bedding in unconsolidated sedimentary deposits—showing strike and dip Inclined foreset bedding in unconsolidated sedimentary deposits—showing strike and dip Inclined cleavage—showing strike and dip Vertical cleavage—showing strike Inclined metamorphic or tectonic foliation—showing strike and dip Vertical metamorphic or tectonic foliation—showing strike Small, minor inclined fault—showing strike and dip Small, minor vertical or near-vertical fault—showing strike Inclined slickenline, groove, or striation on fault surface—showing bearing and plunge Slickenside—showing strike and dip Inclined mylonitic foliation—showing strike and dip Geochronology sample location, uranium-lead (U-Pb) Geochronology sample location, infrared stimulated luminescence (IRSL) Significant site Earthquake hypocenter; number corresponds to focal mechanisms in Appendix B Water well Drill hole for hydrocarbon exploration Drill hole or test pit ? ? ? D U ? ? D U ? D U ?? ?? ?? A′A 31S W487 BH-13 BH-6 48 67 55 5 32 60 86 36 30 33A 23N Quake 6 KJigbw KJmsw KJmvw KJmw „vr …Ec Qa Qaf Qco Qcph Qgtd Qcphl Qgnpf Qcws Qgav Qgic Qgik Qglv Qglr Qgod Qgof Qgog Qgos Qgtv Qls Qp Qtz tz ? ? ?? Qcph Qgnpf Qcphl KJigbw KJmw KJmswKJmvw …Ec „vr Qglr Qgos Qgod Qgtv Qgav Qglv Qgof Qgic Qgik Qgog Qls QafQp Qa Qco Qcws Qgtd The pamphlet provides direct or indirect age constraints for many of the geologic units, including new IRSL ages for glacial and nonglacial deposits (Appendix A). See Morrison (1991) for Pleistocene age constraints on the glacial and nonglacial intervals. Tabor and others (1993) indicate that the Western mélange belt meta-intrusive rocks (unit KJigbw) are ~150–170 Ma and are about the same age or older than the Kimmeridgian to Valanginian (157–134 Ma) metasedimentary rocks of the belt. However, detrital zircon U-Pb ages for unit KJmsw (Dragovich and others, 2014) indicate that the metasandstone in this unit is locally as young as 74 Ma. FRASER GLACIATION POSSESSION GLACIATION DOUBLE BLUFF GLACIATION 2.588 Ma Holocene QUATERNARY Pleistocene TERTIARY Jurassic Paleogene Neogene Cretaceous 66 Ma 145 Ma 200 Ma HAMM CREEK INTERGLACIAL INTERVAL DEPOSITS OF THE OLYMPIA NONGLACIAL INTERVAL DEPOSITS OF THE WHIDBEY INTERGLACIAL INTERVAL DEPOSITS OLDER THAN HAMM CREEK INTERGLACIAL INTERVAL (~60–80 ka) (~130–190 ka) (>300–550 ka) (~190–245 ka) (~80–130 ka) (~20–60 ka) CORRELATION OF MAP UNITS Glacial Geologic Units Bedrock Geologic Units Nonglacial Geologic Units TH R EE LA K ES H ILL FAU LT Explorer Falls basin Sh-4 Sh-8 Sh-3 33F 47A 33A 33B 35A 35B 33C 33D 33E 28M SUBGLACIAL TUNNEL 5Q 302C 26T 25H 44E 44D 39S120D 31S 2A 11P 41AF 23N37N 39A 36N 10M C A R PENTER CR E E K FAU LT Snohomish Lake Roesiger quadrangle Lake Chaplain Lake Roesiger Flowing Lake Storm Lake Chain Lake Lake Hughes Lake Cochran 0 2 4 miles 47A 33F 10M Sh-8 significant site IRSL age site U-Pb age site oil and gas exploration well Figure M3. Map of oil and gas exploration wells, age sites, and significant sites in and near the Lake Roesiger quadrangle. The Three Lakes Hill and Carpenter Creek faults are shown schematically. gravity station Gravity(mGals)Magnetics(nT)Depth(ft) A A′ Modeled Cross Sections observed calculated -55 -50 -45 -40 -35 -300 -200 -100 6 9 12 3,000 2,000 1,000 0 -1,000 gravity station Distance (km) B′B observed calculated -50 -45 -40 -35 9 12 15 3,000 2,000 1,000 0 -1,000 Gravity(mGals)Depth(ft) Tertiary rocks Western mélange belt Tectonic zones Δρ = -650 Δρ = 30 to 50 Δρ = 10 to 30 Δρ = 170 Δρ = -400 Δρ = 10 χ = 1 to 2 χ = 0 χ = 50 χ = 0.4 χ = 2 χ = 2 metagabbro, unit KJigbw unit …Ec metasedimentary, unit KJmsw unit KJmw, excluding metagabbro cataclasite of unit KJmw undifferentiated Quaternary deposits Δρ = -650 χ = 4 unit Qco Quaternary deposits Geologic unitsSusceptibility Density contrast (kg/m3 ) Δρ = -650 χ = 4 unit Qcws Δρ = -650 χ = 2 to 5 unit Qgnpf Δρ = -70 to 0 χ = 0 cataclasite of unit KJmsw χ = 40 to 50 cataclasite of unit KJigbw Δρ = -490 to -470 χ = 0 cataclasite of unit …Ec Δρ = 80 to 110 Figure M2. Geophysical models A and B correspond to lithologic Cross Sections A–A′ and B–B′ (both at 2.5x vertical exaggeration) and show the match between modeled density and magnetic susceptibility from the cross sections and the observed gravity and aeromagnetic values. Here we use the total field magnetic anomaly to interpret both the shallow and deep-seated structures that contribute to the magnetic anomalies of the region, unlike in Figure M1, which focuses on near-surface structures. Although we modeled the gravity data, we did not model the aeromagnetic data for B–B′ because most or all of the aeromagnetic anomalies along this transect are either to the east or west of the cross section line (see Fig. M1) and do not reflect the subsurface structure along the transect. Aeromagnetic data sampling distance along A–A′ is approximately twice the flightline spacing. Gravity data points are shown where good data control exists within 1.5 km of the line. The models extend to infinity in both directions perpendicular to the profiles, and data is tied to the model off to the right of both models, coinciding with locations where the model lines project across models developed in previous studies (Lake Chaplain quadrangle for A–A′ and Sultan quadrangle for B–B′). Δρ is the density contrast relative to normal crust (2,670 kg/m3) used for the model; χ is magnetic susceptibility in SI units x 1,000. Note that the higher susceptibilities for deformed units correspond to deformed metagabbro and lower densities correspond to deformed metasedimentary rocks. Though a wide range of densities for cataclasite of unit KJmsw are included in the model, most of these rocks have Δρ of -10 kg/m3. Solid lines show fault locations that are well constrained by the geophysical data; dashed lines are faults constrained by surficial geologic mapping, but are less certain at depth. Figure M1. Aeromagnetic anomaly and isostatic gravity map of the Lake Roesiger quadrangle. Base map is reduced-to-pole aeromagnetic anomaly, filtered (upward continued and differenced with original grid) to bring out magnetic anomalies originating from near-surface sources. GB1 through GB4 are four distinct magnetic highs associated with Western mélange belt metagabbro (unit KJigbw). The anomaly at GB1 starts at the label and continues northwest; this whole trend is considered the same anomaly. MS is a gravity low associated with Monroe syncline; NE1 and NE2 are northeast-trending gravity highs; OL is a strong gravity gradient associated with the eastern edge of a thick deposit of Oligocene sediment; SP1 to SP4 are weak aeromagnetic highs that correlate with areas of moderately magnetically susceptible Skykomish River provenance Pleistocene sediment along the northern limb of the Monroe syncline; UL is a small gravity low associated with a small unnamed basin. GEOPHYSICAL DATA AND INTERPRETATIONS 47°52′30″ 122°00′00″ 48°00′00″ 121°52′30″ -50 -50 -40 -40 - 4 0 -40 -30 -30 -30 A A′ B′ B OL GB1 GB2 GB3 GB4 SP1 SP2 SP3 SP4 MS UL NE1 NE2 - 2 0 A A′ Gravity measurement locations used to control interpolation of gravity data Fault—solid where certain; dashed where inferred; dotted where uncertain Gravity contours—hachures point in the direction of decreasing gravity values; contour interval 1 milligal Gravity and magnetic profile line 0 0 0.5 1 1 mi 2 km Aeromagnetic anomaly in nanoTeslas (nT) 0 2-2-5 5 10-10 20-20