WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES OPEN FILE REPORT 2003-4

Division of Geology and Earth Resources Ron Teissere - State Geologist

R. 4 W. R. 3 W. 123°00¢ 124°00¢ R. 10 W. R. 9 W. R. 8 W. R. 7 W. R. 6 W. R. 5 W. 48°00¢ 48°00¢ E†m Em1 Qa Evcf Evcf …Em …Emst Qao E†m Qgo Qgt DESCRIPTION OF MAP UNITS MEm(r) Marine rhythmites and other thin-bedded marine sedimentary rocks (Mio- REFERENCES st Qao Qa E†m Qgd Ev Qgo Qlss …Emr E†m Em1 Em1 cf „Emr Evcp Evcp E†m cene–Eocene)—Lithofeldspathic and feldspatholithic micaceous sandstone with Qlss E†m Ev Em2a Qls Quaternary Sediments Addicott, W. O., 1976, Neogene molluscan stages of Oregon and Washington. In Fritsche, A. E.; …Evb …Evb cp Qgd Qgt E†mstc Qgt less-abundant siltstone and slate, grading eastward to or tectonically intercalated Qlss …Em Qatm Ev Qgo Ter Best, Harry, Jr.; Wornardt, W. W., editors, The Neogene symposium—Selected technical Qa r Qls Ev(cp) Evcp cf Qgd NONGLACIAL DEPOSITS with semischist with slate and phyllite; rare granule conglomerate and thick-layered …Evb E†m Qgo papers on paleontology, sedimentology, petrology, tectonics and geologic history of the …Em E†m Em Em2a semischist; thicker sandstone and semischist contain platy shale or slate clasts Qgd Ev 2a Qls Qaf Alluvial fan deposits (Holocene)—Sorted to unsorted, angular to rounded cobble Pacific coast of North America: Society of Economic Paleontologists and Mineralogists Qao E†m E†m cp Ev r Qgt locally grading to platy-clast breccia; generally laminated and (or) thin-bedded T. 29 N. …Em cf Qaf and finer gravel deposited by migrating distributary channels of tributary streams at Pacific Section, 51st Annual Meeting, p. 95-115. …Em Evcp Qgo E†m T. 29 N. E†mstc EPAmstc Qgt Em2c (1–20 cm) with common rhythmites; rarely thick-bedded (>60 cm); moderate to E†m Evcp E†m Evcf the transition between slopes and valley floor; also includes debris-flow deposits at …Emr Qgd Em2c poor sorting; subangular where not thoroughly recrystallized; mostly metamor- Ansfield, V. J., 1972, The stratigraphy and sedimentology of the Lyre Formation, northwestern Qgl Qgt the mouths of tributary channels. …Emr Qgl Evcp …Em Evcp EPAmstc Qls phosed to zeolite facies; multiple cleavages and tectonic lenses common; interbed- Olympic Peninsula, Washington: University of Washington Doctor of Philosophy thesis, st Ev Em2a Em2c cp Qa Alluvium (Holocene–late Pleistocene)—Well-sorted, generally rounded to sub- ded with thick sandstones yielding unreset Miocene to Eocene detrital zircon fis- Qa E†mstc Qgt 131 p., 1 plate. …Em Qgd E†m Qa …Evb …Evb …Em Em rounded sand and gravel within active stream channels, including the approximate sion-track ages in the western part of the quadrangle and possible unreset Miocene st Ev Evcp 2a Qao cp Qgd E†m Evcf Babcock, R. S.; Suczek, C. A.; Engebretson, D. C., 1994, The Crescent "terrane", Olympic EPAmstc E†m area of the active flood plain; derived primarily from Olympic Mountains rock to Eocene fission-track ages in the east-central part of the quadrangle (Brandon and …Emr Qgd Peninsula and southern Vancouver Island. In Lasmanis, Raymond; Cheney, E. S., convenors, …Emst types; in river valleys of the northern portion of the quadrangle, includes igneous Vance, 1992; R. J. Stewart, Univ. of Wash., written commun., 1999); includes part …Evb Regional geology of Washington State: Washington Division of Geology and Earth Resour-- Qat …Em Qls and metamorphic material transported from the north by the Juan de Fuca lobe of of the Western Olympic and Grand Valley lithic assemblages of Tabor and Cady Qgl Ev E†m E†m cp the continental ice sheet. A large component of the sediment input is from valley- (1978a). ces Bulletin 80, p. 141-157. Qa Qgo Qlsr Ev wall landslides and debris flows and from fluvial reworking of alpine outwash cp MEmst Boyer, S. E.; Lingley, W. S., Jr., 1994, A model for the structural evolution of parts of the …Emst Evcf Em2c Marine thick-bedded sandstone and semischist (Miocene–Eocene)—Thick Qls Evcp deposits. „Emst Olympic subduction complex and associated piggyback basins [abstract]: Geological Qgt sequences of feldspatholithic to lithofeldspathic micaceous sandstone or semischist; Qad Society of America Abstracts with Programs, v. 26, no. 7, p. A-188. …Em …Evb Qatm Qgl Qls Landslide deposits, undifferentiated (Holocene–late Pleistocene)—Chaotic and minor granule and pebble conglomerate; medium to very coarse grained with silt- …Emst Qls …Em Qls Qls poorly sorted mixtures of soil, talus, colluvium, bedrock, and fluvial and glacial stone or slate clasts grading to platy siltstone- or slate-clast breccia; generally bed- Brandon, M. T.; Calderwood, A. R., 1990, High-pressure metamorphism and uplift of the …Emst st „Emr Qls sediments; landslide age is inferred from stratigraphic position, age of parent mate- ded thicker than 1 m; sequences separated by thin-bedded (1–20 cm) sandstone, …Evb Olympic subduction complex: Geology, v. 18, no. 12, p. 1252-1255. semischist, siltstone, slate, and (or) phyllite similar to unit „Em ; laterally discontin- Qa Qgt Eva rials, and geomorphic expression; may include any number of landslide types (for r …Em …Emst OLYMPIC NATIONAL PARK E†m Brandon, M. T.; Vance, J. A., 1992, Tectonic evolution of the Cenozoic Olympic subduction Qls example, rockfall, debris flow, deep-seated, slump-earthflow [Varnes, 1978]), map- uous; tectonic lenses common; mostly metamorphosed to zeolite facies; yields unre- Qgo complex, Washington State, as deduced from fission track ages for detrital zircons: T. 28 N. …Evb ped only where landslides exceed 160 acres in area. Includes both landslide deposits set Miocene to Eocene detrital zircon fission-track ages in the western part of the T. 28 N. Evcp Qatm American Journal of Science, v. 292, no. 8, p. 565-636. …Em Qls …Evb and associated headscarps. Locally divided into: quadrangle and possible unreset Miocene to Eocene fission track ages in the east- central part of the quadrangle (Brandon and Vance, 1992; R. J. Stewart, Univ. of Brown, R. D., Jr.; Gower, H. D.; Snavely, P. D., Jr., 1960, Geology of the Port Angeles– … Qgo Qgt Qls(r) Landslide deposits, rockfall—Poorly sorted, commonly angular cobbles and Qao Em … Qls Wash., written commun., 1999); includes part of the Western Olympic and Grand Evb r boulders; clast supported or in a matrix of sand, silt, and clay; locally includes Lake Crescent area, Clallam County, Washington: U.S. Geological Survey Oil and Gas Qls …Emr Em1 Valley lithic assemblages of Tabor and Cady (1978a). Qgo talus; commonly hummocky; usually occupies transition area between valley Investigations Map OM-203, 1 sheet, scale 1:62,500. …Em …Evb walls and valley floor; generally results from large-scale and catastrophic MEbx Tectonic breccia (Miocene–Eocene)—In the eastern part of the quadrangle near Qls …Em r „Ebx Cady, W. M.; Sorensen, M. L.; MacLeod, N. S., 1972a, Geologic map of the Brothers Qls landsliding. Because of its steep topography, Crescent Formation basalt (unit Mount Stone, consists of breccia of slate and phyllite with abundant small tectonic Qa „Emst …Evb quadrangle, Jefferson, Mason and Kitsap Counties, Washington: U.S. Geological Survey …Em „Emst Evcp) is a common source for these deposits, particularly in the Hamma lenses of sheared sandstone, semischist, quartz veins, and ptygmatically folded Geologic Quadrangle Map GQ-969, 1 sheet, scale 1:62,500. …Em Qat Qgo „Emst Qls Hamma, Duckabush, and Dosewallips River valleys. Sackung features are schist; in the western part of the quadrangle, consists of thick sequences of intensely Qatm „Em Qao Em1 Qat common along bedrock ridges in the Olympic Mountains (Tabor, 1971). sheared marine sedimentary and minor basaltic volcanogenic rocks; volcanogenic Cady, W. M.; Tabor, R. W.; MacLeod, N. S.; Sorensen, M. L., 1972b, Geologic map of the Tyler „Em …Em E†m Qao Qls …Evb Qlss rocks are tectonic blocks, range from granules to boulders, and have abundant chlor- Peak quadrangle, Clallam and Jefferson Counties, Washington: U.S. Geological Survey Qat Qlss „Em „Emst Qls(s) Landslide deposits, slump-earthflow—Weathered local bedrock and (or) Geologic Quadrangle Map GQ-970, 1 sheet, scale 1:62,500. st …Evb Qat Qlss ite and epidote; interpreted as unusually wide fault gouge zones; in the eastern part „Emst …Evb valley-fill sediments; ranges from preserved original stratigraphy to chaoti- …Evb Em1 Evcp Qgt of the quadrangle, structural relations near Mount Stone suggest that the eastern part …Em Qa Carson, R. J., 1976, Geologic map of north-central Mason County, Washington: Washington Qa st Qgo cally mixed; generally occurs in deeply weathered bedrock, along weak inter- of the unit is younger than middle Eocene; in the western part of the quadrangle, Qao „Emr Evcf Division of Geology and Earth Resources Open File Report 76-2, 1 sheet, scale 1:62,500. Qao beds, or within granular or fine-grained cohesive sediments (typically glacial unit is contiguous with rocks to the west containing foraminiferal assemblages refer- deposits); generally slow-moving and episodic; occurs along a surface (or sur- Qa Em1 able to the Narizian to Saucesian Stages (Rau, 1975, 1979). Clark, K. P., 1989, The stratigraphy and geochemistry of the Crescent Formation basalts and the „Em Qa „Emst „Emst Qlss faces) below the rooting depth of forest vegetation; has low shear strengths, is Qa a Qat bedrock geology of associated igneous rocks near Bremerton, Washington: Western Qls …Emr r Qa commonly unsorted and unstratified, and is easily remobilized. OEm Marine sedimentary rocks (Oligocene–Eocene)—Semischist and phyllite with …Emr …Em Washington University Master of Science thesis, 171 p., 1 plate. Evcp minor finely crystalline schist in the central Olympic Mountains; grades radially …Emstc Qao Em Qc Continental sediments (Pleistocene)—Stratified clay, silt, sand, gravel, and local Qatm 1 Qc away to sandstone, siltstone, and slate; mostly recrystallized, but includes fine- to Crandell, D. R., 1964, Pleistocene glaciations of the southwestern Olympic Peninsula, peat; greenish gray to brown and orange brown; moderately sorted; well rounded; very coarse-grained, moderately to poorly sorted, subangular, lithofeldspathic and Washington: U.S. Geological Survey Professional Paper 501-B, p. B135-B139. …Em Qa commonly hard, cemented, and iron-oxide stained; poorly bedded to massive; gen- „Em …Evb „Em feldspatholithic sandstone; minor granule conglomerate; common muscovite and …Emst st Crandell, D. R., 1965, The glacial history of western Washington and Oregon. In Wright, H. E., Qatm erally stratified deposits of wind, rivers, or lakes laid down during nonglacial peri- epidote; intensely sheared with multiple penetrative cleavages in the central Olym- Jr.; Frey, D. G., editors, The Quaternary of the United States: Princeton University Press, T. 27 N. Qatm …Evb ods, now exposed in coastal bluffs. …Em Qa Em1 pic Mountains; contains sequences of laminated and (or) thin-bedded (1–20 cm) Qao The upper age limit of this unit is inferred from stratigraphic position beneath p. 341-353. …Emstc Qls units and thick-bedded (>60 cm) units; thicker sandstone and semischist contain Qat Qat glacial deposits. The base is assumed to be no older than Quaternary. 14C ages are Qatm „Emr T. 27 N. abundant platy slate clasts grading to platy-clast breccia; thin-bedded units com- Dragovich, J. D.; Logan, R. L.; Schasse, H. W.; Walsh, T. J.; Lingley, W. S., Jr.; Norman, D. K.; Qa …Em Qao generally infinite; interlayered with glacial deposits. r Qao monly rhythmic where bedding is preserved; metamorphosed to zeolite facies; tec- Gerstel, W. J.; Lapen, T. J.; Schuster, J. E.; Meyers, K. D., 2002, Geologic map of Qat „Emst Qat …Evb Qls m ALPINE GLACIAL DEPOSITS tonic lenses common; in the western part of the quadrangle, contiguous with rocks Washington—Northwest quadrant: Washington Division of Geology and Earth Resources „Em Qa Qls to the west containing foraminiferal assemblages referable to the Narizian to Geologic Map GM-50, 3 sheets, scale 1:250,000, with 72 p. text. Qat m Qao Qat Qao Alpine outwash, Fraser age (late Wisconsinan?)—Cobbles and gravel in a tan to Zemorrian Stages (Rau, 1979) and yielding zircon fission-track ages ranging from …Emr Qao Duncan, R. A., 1982, A captured island chain in the coast range of Oregon and Washington: Qao …Emst Qatm buff sandy matrix; generally unconsolidated to weakly consolidated; stratified to Eocene to Oligocene; yields unreset Oligocene to Eocene detrital zircon fission- Qat …Emstc Journal of Geophysical Research, v. 87, no. B13, p. 10,827-10,837. m …Emst weakly stratified where deposition was ice-proximal; variable clast size, dominated track ages (Brandon and Vance, 1992; R. J. Stewart, Univ. of Wash., written com- …Emst …Evb Em1 by cobbles with rare boulders greater than 1 m in diameter; derived solely from mun., 1999; Gerstel and Lingley, 2000); includes part of the Western Olympic, „Em E†m Einarsen, J. M., 1987, The petrography and tectonic significance of the Blue Mountain unit, Evcf Olympic Peninsula rock types, distinguishing the unit from continental glacial out- Elwha, and Needles–Gray Wolf lithic assemblages of Tabor and Cady (1978a). Olympic Peninsula, Washington: Western Washington University Master of Science thesis, „Emr Qls Evcp Qat …Emst Em m …Evb Qatm 1 wash; upvalley extent of mapped deposits is commonly defined by moraines of sim- 175 p. …Em OEm(r) Marine rhythmites and other thin-bedded sedimentary rocks (Oligocene– Qaptm Qao Qao r Qao ilar age. …Em Qao r Eocene)—In the central Olympic Mountains, consists of semischist, slate, and phyl- …Emr „Emst Em1 Qlss Qlss Unit Qao in the western part of the quadrangle includes deposits of at least two Frisken, J. G., 1965, Pleistocene glaciation of the Brinnon area, east-central Olympic Peninsula, Qa …Emst Qatm Qatm advances of the Hoh Oxbow glaciation of Thackray (1996), ranging in age from lite; along the Elwha River and south to Mount Duckabush (T25N R5W), contains Washington: University of Washington Master of Science thesis, 75 p., 3 plates. Qao Qls …Evb s about 39,000 to 19,500 yr B.P., and of the Twin Creeks drift of Thackray (1996) thick monotonous sections of massive black slate; north of the Sol Duc River, con- Qao Qat Gerstel, W. J., 1997, Progress report on the geologic mapping and landslide inventory of the „Em Qa …Em (~19,000–17,000 yr B.P.), best exposed at the confluence of the Hoh and South Fork sists of argillite; on the margins of the Olympic Mountains, consists of laminated Dodwell and (or) thin-bedded (1–20 cm), lithofeldspathic and feldspatholithic, micaceous west-central portion of the Olympic Peninsula, Washington: Washington Geology, v. 25, Rixon Pass Hoh Rivers just west of the boundary of this quadrangle (sec. 29, T27N R10W). no. 4, p. 30-32. Qao Qa …Emst sandstone, siltstone, slate, and argillite; rare thick-bedded sandstone, granule con- Qatm …Evb …Evb These correlate to oxygen isotope stage 2. Unit Qao on the north and east sides of the quadrangle are also loosely corre- glomerate, and thick-layered (>60 cm) semischist, all containing platy slate clasts Gerstel, W. J., 1999, Deep-seated landslide inventory of the west-central Olympic Peninsula: …Emst Qls OLYMPIC … grading to platy-clast breccia; metamorphosed to zeolite facies; tectonic lenses com- Em Qao lated to oxygen isotope stage 2. On the east side of the peninsula, unit Qao underlies Washington Division of Geology and Earth Resources Open File Report 99-2, 36 p., Evcp mon; in the western part of the quadrangle, contiguous with rocks to the west con- …Emr deposits of the Vashon-age Puget lobe of the continental ice, and are therefore older 2 plates. …Emr Qa … Emr than about 14,000 yr B.P. (Porter and Swanson, 1998). taining foraminiferal assemblages referable to the Narizian to Zemorrian Stages Gerstel, W. J.; Lingley, W. S., Jr., compilers, 2000, Geologic map of the Forks 1:100,000 …Emr …Emst (Rau, 1979) and yielding zircon fission-track ages ranging from Eocene to Oligo- „Em r …Emst …Evb Qat Alpine till, Fraser age (and younger?) (late Wisconsinan)—Most commonly cene (Brandon and Vance, 1992; R. J. Stewart, Univ. of Wash., written commun., quadrangle, Washington: Washington Division of Geology and Earth Resources Open File …Evb Qat NATIONAL OEm compact deposit of poorly sorted, rounded to subangular clasts in a gray to tan 1999); in the eastern part of the quadrangle, contains megafossil assemblages refera- Report 2000-4, 36 p., 2 plates. Qa Qls …Evb matrix of clay and silt (lodgment till); clasts derived solely from Olympic Peninsula T. 26 N. ble to the Tejon Stage (Squires and Geodert, 1997); includes part of the Western Gillespie, Alan; Molnar, Peter, 1995, Asynchronous maximum advances of mountain and PARK „Emst Qad rock types, mostly sandstone and basalt; stratified to unstratified; locally weakly Olympic, Elwha, and Needles–Gray Wolf lithic assemblages of Tabor and Cady „Emst ANTIFORM Qao continental glaciers: Reviews of Geophysics, v. 33, no. 3, p. 311-364. „Em Qa oxidized to depths of less than 1 m. Low permeability commonly causes saturation (1978a). OLYMPIC Qls Qa T. 26 N. Qa and landsliding of the overlying sediments. Glassley, W. E., 1974, Geochemistry and tectonics of the Crescent volcanic rocks, Olympic …Evb Qa Qgl …Em …Ev OEmst Marine thick-bedded sandstone (Oligocene–Eocene)—Thick sequences of feld- Qatm Qa …Evb In the west-side drainages of the quadrangle, unit Qat includes deposits of at …Em Peninsula, Washington: Geological Society of America Bulletin, v. 85, no. 5, p. 785-794. Qls Qat st spatholithic to lithofeldspathic semischist and micaceous sandstone; common phyl- … Qao least two advances of the Hoh Oxbow glaciation of Thackray (1996), ranging in age „Emr Evb Qls Evcf Gutscher, Marc-Andre; Klaeschen, Dirk; Flueh, E. R.; Malavieille, Jacques, 2001, Non- Qls Qls r from about 39,000 to 19,500 yr B.P. It also includes deposits of the Twin Creeks lite and granule conglomerate; medium to very coarse grained; contains common Ev Qat Coulomb wedges, wrong-way thrusting, and natural hazards in Cascadia: Geology, v. 29, …Ev cp advance of Thackray (1996) (19,000–14,000 yr B.P.), best exposed at the confluence slate clasts grading to breccia; generally bedded thicker than 1 m; sequences sepa- „Em Qgt no. 5, p. 379-382. Qao …Emr Qat of the Hoh and South Fork Hoh Rivers about 1 mile west of the boundary of this rated by medium- to thin-bedded semischist, sandstone, siltstone, or slate; laterally „Em Qls „Em …Emr r quadrangle. discontinuous; metamorphosed to zeolite facies with local Al-pumpellyite; contigu- Heusser, C. J., 1964, Palynology of four bog sections from the western Olympic Peninsula, Deposits in north- and east-side drainages are similar in age to unit Qao in ous with rocks to the west containing foraminiferal assemblages referable to the Washington: Ecology, v. 45, no. 1, p. 23-40. „Em …Evb „Emst those locations. Narizian to Zemorrian Stages (Rau, 1979; Gerstel and Lingley, 2000) and yielding Qa …Em Ev(cp) Locally divided into: Eocene to Oligocene zircon fission-track ages (Brandon and Vance, 1992; R. J. Heusser, C. J., 1973, Age and environment of allochthonous peat clasts from the Bogachiel …Emr Stewart, Univ. of Wash., written commun., 1999); includes part of the Western River valley, Washington: Geological Society of America Bulletin, v. 84, no. 3, p. 797-804. Qaf Qls …Evb E†m Qaf …Evb Qat(m) Alpine till moraines, Fraser age (and younger?)—Where unconsolidated Qat Olympic, Elwha, and Needles–Gray Wolf lithic assemblages of Tabor and Cady „ „Em m Heusser, C. J., 1974, Quaternary vegetation, climate, and glaciation of the Hoh River valley, Ebx Qao …Evb …Em st alpine till occurs as distinct landforms within the upper reaches of valley bot- (1978a). Qaf st …Evb Qao Washington: Geological Society of America Bulletin, v. 85, no. 10, p. 1547-1560. Qao toms, it is mapped as a moraine. These deposits may include lenses of strati- Qat …Evb OEmst(c) Marine pebble conglomerate (Oligocene–Eocene)—Micaceous, feldspatholithic m Ev fied sand, gravel, and silt or clay, and may include some deposits of Holocene Qao Qa cf …Emstc Heusser, C. J., 1978, Palynology of Quaternary deposits of the lower Bogachiel River area, Qaf Qlsr age in cirques of the Olympic Mountains. to lithofeldspathic conglomerate; medium to very coarse grained; generally massive Qls Qa Qao Olympic Peninsula, Washington: Canadian Journal of Earth Sciences, v. 15, no. 10, p. 1568- …Evb Qao Qgo or thick bedded (>1 m); laterally discontinuous; sheared; common sandstone, meta- …Evb Evcf 1578. Qa Qad Alpine drift, undifferentiated, Fraser age (late Wisconsinan)—May include out- sedimentary, metavolcanic, chert, and conglomerate clasts; metamorphosed to zeo- Qad …Evb Qat wash (unit Qao), till (unit Qat), and lacustrine sediments; mapped where deposits Qaf lite facies; interbedded with Eocene to Oligocene rocks (units …Em and …Emr); Heusser, C. J.; Heusser, L. E.; Peteet, D. M., 1999, Humptulips revisited—A revised Qa E†m cannot confidently be assigned to any particular depositional environment, or where includes part of the Western Olympic and Elwha lithic assemblages of Tabor and interpretation of Quaternary vegetation and climate of western Washington, USA: …Em …Evb Qgo …Emr Qao Evb several depositional environments are represented by deposits in a small area such Cady (1978a). Palaeogeography, Palaeoclimatology, Palaeoecology, v. 150, no. 3-4, p. 191-221. …Emst as along stream banks, or over short horizontal distances. Qao T. 25 N. „Emst Em(2c) Marine conglomerate (Eocene)—Pebble to cobble conglomerate; clasts mostly Lingley, W. S., Jr., 1995, Preliminary observations on marine stratigraphic sequences, central Em Qapo Alpine outwash, pre-Fraser age (pre–late Wisconsinan)—Cobbles and gravel in 2c argillite, quartzite, chert, metavolcanic rock, and metasandstone; thick bedded (>60 and western Olympic Peninsula, Washington: Washington Geology, v. 23, no. 2, p. 9-20. „Emst Qapo a sandy matrix; weakly consolidated; clast supported; stratified to weakly stratified „Em Qatm cm) to massive; matrix contains phyllite; contains foraminiferal assemblages refera- …Em where deposition was ice-proximal; variable clast size, dominated by cobbles with Lingley, W. S., Jr.; Logan, R. L.; Walsh, T. J.; Gerstel, W. J.; Schasse, H. W., 1996, Evcp T. 25 N. ble to the Narizian Stage (Ansfield, 1972); consists of the Lyre Formation. rare boulders greater than 1 m in diameter; derived solely from Olympic Peninsula Reconnaissance geology of the Matheny Ridge–Higley Peak areas, Olympic Peninsula, rock types; occurs as isolated terrace deposits along the Sams River. Similar to unit Em(2a) Marine siltstone and sandstone (Eocene)—Olive-gray to black siltstone and Washington: Washington Division of Geology and Earth Resources [under contract to] U.S. Qatm Evb Em2a …Em greenish gray lithofeldspathic sandstone, siltstone, and sandy siltstone; thin to Minerals Management Service, 31 p., 1 plate. Qa r Ev Qao deposits in grain-size distribution, clast lithology, and bedding characteristics, Qao …Evb cp medium bedded and interbedded with thin- to medium-bedded, fine- to very fine- Qao but weathered to depths of 1 to 2 m. Logan, R. L., in press, Geologic map of the Copalis Beach 1:100,000 quadrangle, Washington: „Emst These deposits represent a broad age range that might correlate to the Lyman grained feldspatholithic sandstone; siltstone commonly contains thin sandy lamina- Qa „Em NAL PARK Washington Division of Geology and Earth Resources Open File Report, 1 sheet. Qatm Qa O Rapids drift of Thackray (1996) (early or middle Wisconsinan) in the Hoh and tions; local thin to medium beds of fine-grained limestone or limey, very fine- …Emr Queets River valleys, and to oxygen isotope stage 4 or 3, although they could be as grained sandstone; limey beds are light tan on weathered surfaces; locally interfin- Long, W. A., 1975, Glacial studies on the Olympic Peninsula: U.S. Forest Service, 1 v., 9 plates. …Evb …Emr …Evb Qgo gers with volcanic rocks of the Crescent Formation; contains foraminifera of middle Qao old as stage 5b. Minimum-age radiocarbon dating and stratigraphic correlations of Long, W. A., 1976, Glacial geology of the Olympic Peninsula, Washington: U.S. Forest Service, „Ebx Evcf deposits in the Hoh and Queets River valleys suggest an age range of approximately to late Eocene age (Brown and others, 1960); consists of the Aldwell Formation. OLYMPIC NATI 135 p. …Evb 55,000 to 110,000 yr B.P. or greater. In some drainages, unit Qapo may represent or 1 …Emr Em(1) Marine sedimentary rocks (Eocene–Paleocene )—Breccia, conglomerate, volca- Em1 McCrory, P. A., 1997, Evidence for Quaternary tectonism along the Washington coast: Qa „Em Qapo be reworked from pre-Wisconsinan drift; because source rock types for both depos- nolithic sandstone, argillite, limestone, and chert; green, red, or black; chiefly basalt „Em Qls Qaptm „Em st its are the same, and radiocarbon dates for both would be infinite, it is impossible to and diabase clasts; micaceous, carbonaceous, lithic, calcareous, and fossiliferous; Washington Geology, v. 25, no. 4, p. 14-20. …Emst make the distinction between the two. interfingers with basaltic rocks; includes part of the Crescent Formation. Qao Qap Moore, J. L., 1965, Surficial geology of the southwestern Olympic Peninsula: University of Qls Qapt Alpine till, pre-Fraser age (pre–late Wisconsinan)—Most commonly compact Washington Master of Science thesis, 63 p., 1 plate. Qao Qapt EPAm Marine sedimentary rocks (Eocene–Paleocene)—Gray to black lithic sandstone, Qa E†m Qad deposit of poorly sorted, rounded to subangular clasts in a gray to tan matrix of clay E†m Qao Qlsr semischist, siltstone, slate, granule or pebble conglomerate, and siltstone- or slate- Palmer, S. P.; Lingley, W. S., Jr., 1989, An assessment of the oil and gas potential of the „Emst Qa and silt (lodgment till); generally unstratified; limited exposures in the upper Prairie Qapo Qatm Qad Qaf Evcp clast breccia; commonly laminated and rhythmically bedded; local very thick sand- Washington outer continental shelf: University of Washington, Washington Sea Grant PARK Qa Qgt Creek drainage (T23N R10W) and at the confluence of the Hoh and South Fork Hoh Qgt stone beds; abundant muscovite and basalt detritus; metamorphosed to zeolite Program, Washington State and Offshore Oil and Gas, 83 p., 12 plates. Qat …Em Qao Qad Qlsr Rivers suggest clasts are derived solely from Olympic Peninsula rock types. Similar facies; foraminiferal assemblages referable to the Ulatisian or older stages (Rau, Qls Evb r in age to unit Qapo. 40 39 Phillips, W. M.; Walsh, T. J.; Hagen, R. A., 1989, Eocene transition from oceanic to arc …Em Evcf 2000); Babcock and others (1994) reported Ar/ Ar ages from overlying Crescent … Qa Locally divided into: volcanism, southwest Washington. In Muffler, L. J. P.; Weaver, C. S.; Blackwell, D. D., Evb Qaf Formation volcanic rocks of 56.0 to 45.6 Ma; consists of the Blue Mountain unit of editors, Proceedings of workshop XLIV—Geological, geophysical, and tectonic setting of …Emr „Em Qao Evcf Qls Tabor and Cady (1978a). „Emst r Qa Qad Qapt(m) Alpine till moraines, pre-Fraser age—Where unconsolidated alpine till „Ebx …Emr Qao Qls Qaptm the Cascade Range: U.S. Geological Survey Open-File Report 89-178, p. 199-256. Qao Evb Qat Evcf occurs as distinct landforms, it is mapped as a moraine. Deposits are com- E†mst(c) Conglomerate and pebbly sandstone (Eocene–Paleocene)—Thick-bedded to NATIONAL …Em Ev Qls monly weakly bedded and may include lenses of stratified sand, gravel, and E†mstc Porter, S. C.; Swanson, T. W., 1998, Radiocarbon age constraints on rates of advance and retreat T. 24 N. Qa „Ebx Qgt cf Evcf massive conglomerate and pebbly sandstone or semischist with minor interbedded Qa …Evb Qgo Qa Evcf silt or clay. Moraines are mapped in the lower reaches of the Sams River near of the Puget lobe of the Cordilleran ice sheet during the last glaciation: Quaternary Qap Qlsr slate or argillite; subrounded pebbles and minor cobbles of dark gray chert and vol- Qlsr Qgo Em Qao Qao 1 its confluence with the Queets River. canic rocks with less-abundant light-gray sandstone; commonly contains very dark Research, v. 50, no. 3, p. 205-213. SA Qap Qao Qgt T. 24 N. LMON …Em Evcf gray to grayish black angular siltstone rip-up clasts, locally forming slate-chip brec- Qls Evcf Qap Alpine drift, undifferentiated (pre–late Wisconsinan)—May include outwash Rau, W. W., 1964, Foraminifera from the northern Olympic Peninsula, Washington: U.S. Qls Qls Em1 Qap Qga (unit Qapo), till (unit Qapt), and lacustrine sediments; mapped where deposits can- cia; interbedded with rocks of Eocene to Paleocene age (unit E†m); consists of part Geological Survey Professional Paper 374-G, 33 p., 7 plates. „Em …Emr Qgt Qga not confidently be assigned to any particular depositional environment, or where of the Blue Mountain unit of Tabor and Cady (1978a). Qao Evcp Rau, W. W., 1973, Geology of the Washington coast between Point Grenville and the Hoh River: „Ebx „Emst Qa several depositional environments are represented in a small area such as at the con- OLYMPIC Evb RIVER EPAmst Marine thick-bedded sandstone (Eocene–Paleocene)—Thick-bedded to massive, Washington Division of Geology and Earth Resources Bulletin 66, 58 p. Qat E†mst E†m Evcf fluence of the Sams and Queets Rivers on the adjacent Forks 1:100,000-scale quad- volcanolithic to feldspatholithic sandstone, with less-abundant thin-bedded, fine- …Emr Evb Qat 101 …Em Qao rangle to the west. grained silty sandstone; slate, rare limestone, coal laminations, and pebble conglom- Rau, W. W., 1975, Geologic map of the Destruction Island and Taholah quadrangles, „Emr …Em Ev Qa Qgt cf erate; fine to very coarse grained; angular; gray, black, and olive-black, weathering Washington: Washington Division of Geology and Earth Resources Geologic Map GM-13, „Emr Evcf CONTINENTAL GLACIAL DEPOSITS NATIONAL Evb Qgo to red or brown; moderately to poorly sorted; commonly basaltic; contains locally 1 sheet, scale 1:63,360. Qlss THRUST Evb Qao …Evb Qgo Continental recessional outwash, Fraser (Vashon) age (late Wisconsinan)— abundant muscovite and rounded clinopyroxene; interbedded with rocks of Eocene Rau, W. W., 1979, Geologic map in the vicinity of the lower Bogachiel and Hoh River valleys, Qa Qgo „Em Cobbles and gravel in loose gravelly sand matrix; moderately well-sorted; well- to Paleocene age (unit E†m); consists of part of the Blue Mountain unit of Tabor Qc and the Washington coast: Washington Division of Geology and Earth Resources Geologic … …Evb „Emst PARK Evb Qgo stratified; unconsolidated; highly permeable; contains abundant granitic and meta- and Cady (1978a). Evb …Emr Qa Map GM-24, 1 sheet, scale 1:62,500. Qao Qls morphic clasts from the North Cascades and Canada, distinguishing it from alpine Qls OLYMPIC Qgo Qgo Qga glacial deposits dominated by locally derived sandstone and basalt clasts; may con- Rau, W. W., 1981, Pacific Northwest Tertiary benthic foraminiferal biostratigraphic FAULT …Evb Tertiary Igneous Rocks „Em „Em Evb r Evcp Evcf Qgt Qc tain reworked alpine outwash in the lower reaches of river valleys of the Olympic framework—An overview. In Armentrout, J. M., editor, Pacific Northwest Cenozoic Qapt E†mst …Emr OEv Volcanic rocks, undifferentiated (Oligocene–Eocene)—Undifferentiated inter- Qao …Em …Evb Evcp Ev Evcf Qls T. 23 N. Mountains; may exceed 30 m in thickness. The deposits cover much of the upland …Ev biostratigraphy: Geological Society of America Special Paper 184, p. 67-84. Evcp E†m cp Qgt T. 23 N. Qa …Evb surface between elevations of about 500 and 1500 ft and extend upstream into river mediate volcanic rocks including flows, breccia, and other volcaniclastic rocks; „Ebx Ev Qgo Qls „Ebx „Em Ev cp E†m Ev Ev Qad Qa interbedded with rocks of Oligocene to Eocene age (unit …Emr); includes part of the Rau, W. W., 2000, Appendix 4—Foraminifera from the Carlsborg 7.5-minute quadrangle, „Em cp cp cp Qga valleys, with foreset beds dipping upstream. r Qa Qgt 47°30¢ Washington. In Schasse, H. W.; Wegmann, K. W., Geologic map of the Carlsborg 7.5- Evb Evcp Evcp The base of unit Qgo, exposed in a bank of the Sol Duc River in the Forks Elwha lithic assemblage of Tabor and Cady (1978a). 47°30¢ 123°00¢ minute quadrangle, Clallam County, Washington: Washington Division of Geology and 124°00¢ R. 4 W. R. 3 W. 1:100,000-scale quadrangle to the west, yielded a radiocarbon date of about 12,500 R. 10 W. R. 9 W. R. 8 W. R. 7 W. R. 6 W. R. 5 W. OEvb Basalt (Oligocene–Eocene)—Dark green-gray basalt, basaltic tuffs, basalt breccia, Earth Resources Open File Report 2000-7, p. 24-26. yr B.P. (sample Beta-117686, Gerstel and Lingley, 2000). This suggests that reces- …Evb basaltic sandstone, and greenstone with rare pillow or amygdaloidal basalt; includes sion of the Juan de Fuca lobe had not been long in progress. These dates also gener- rare gabbro, diabase, greenstone, and interbedded gray or brick-red limestone; meta- Schasse, H. W., in press, Geologic map of the Cape Flattery 1:100,000 quadrangle, Washington: ally correlate with the timing of advance and retreat of the Puget lobe in Puget SCALE 1:100,000 morphosed to zeolite facies; similar to parts of units Evb and „Ebx; interbedded Washington Division of Geology and Earth Resources Open File Report, 1 sheet. Sound (Porter and Swanson, 1998). 1 0 1 2 3 4 5 6 7 8 MILES with rocks containing foraminiferal assemblages referable to the Ulatisian Stage at Snavely, P. D., Jr., 1987, Tertiary geologic framework, neotectonics, and petroleum potential of Lambert Conformal Conic Projection Mount Claywood (T27N R5W) (W. W. Rau, Wash. Division of Geology and Earth 1927 North American Datum Qgt Continental till, Fraser (Vashon) age (late Wisconsinan)—Poorly sorted cobbles, the Oregon–Washington continental margin. In Scholl, D. W.; Grantz, Arthur; Vedder, J. G., 1 0 1 2 3 4 5 6 7 8 9 1 0 KILOMETERS Qgt Resources, oral commun., 1999; Tabor and Cady, 1978a) and interbedded with rocks Washington Coordinate System, South Zone gravel, and scattered boulders in a clay and silt matrix; compact to very compact; compilers and editors, Geology and resources potential of the continental margin of western of Oligocene to Eocene age elsewhere (units …Em and …Emr); includes part of the Base map information from the Washington Department of gray to brown; contains abundant granitic and metamorphic clasts transported from North America and adjacent ocean basins—Beaufort Sea to Baja California: Circum-Pacific the North Cascades and Canada as well as locally derived, angular to subangular Needles–Gray Wolf and Elwha lithic assemblages of Tabor and Cady (1978a). Council for Energy and Mineral Resources, Earth Science Series, v. 6, p. 305-335. Natural Resources, Geographic Information System, 1997 contour interval 500 feet Washington Division of Geology and Earth Resources basalt and sandstone clasts; commonly weakly oxidized to a depth of less than 1 m Eva Andesite (Eocene)—Altered thick-bedded hornblende andesite and thin-bedded Eva Snavely, P. D., Jr.; Wells, R. E., 1996, Cenozoic evolution of the continental margin of Oregon Digital cartography by Anne C. Heinitz and Chuck Caruthers where not overlain by younger deposits; ranges in thickness from less than 1 m to hornblende andesite tuff; locally includes porphyritic pyroxene andesite; local col- about 4 m. and Washington. In Rogers, A. M.; Walsh, T. J.; Kockelman, W. J.; Priest, G. R., editors, umnar jointing; probable Narizian age (Cady and others, 1972b); includes part of Assessing earthquake hazards and reducing risk in the Pacific Northwest: U.S. Geological The Juan de Fuca lobe of the continental ice sheet occupied the Strait of Juan the Lyre Formation. Survey Professional Paper 1560, v. 1, p. 161-182. de Fuca and covered the northern Olympic Peninsula from about 14,000 yr B.P. (Schasse, in press) to about 13,000 yr B.P. (Gerstel, 1997; Gerstel and Lingley, Evb Basalt (Eocene)—Basalt, pillow basalt, greenstone, and basaltic volcaniclastic Geologic Map of the Mount Olympus 1:100,000 Quadrangle, Washington Evb Spicer, R. C., 1986, Glaciers in the Olympic Mountains, Washington—Present distribution and 2000). A radiocarbon date on wood from till in the Dickey River drainage on the rocks with minor gabbro, diabase, tuff, basaltic sandstone, siltstone, and red argil- recent variations: University of Washington Master of Science thesis, 158 p., 1 plate. Cape Flattery 1:100,000-scale quadrangle to the northwest yielded an age of about lite; locally metamorphosed to upper zeolite facies; commonly fault-bounded; con- 13,200 yr B.P. (Schasse, in press). The age of unit Qgt is therefore constrained to tiguous with rocks yielding Eocene to Miocene zircon fission-track ages (see unit Squires, R. L.; Goedert, J. L., 1997, Eocene megafossils from the Needles–Gray Wolf lithic by Wendy J. Gerstel and William S. Lingley, Jr. between about 14,000 and 13,000 yr B.P. „Emr of Brandon and Vance, 1992; R. J. Stewart, Univ. of Wash., written commun., assemblage of the eastern "core rocks", Olympic Peninsula, Washington: Washington 1999); has basalt chemistry correlative with the Crescent Formation in the south- Geology, v. 25, no. 4, p. 25-29. Qga Continental advance outwash, Fraser (Vashon) age (late Wisconsinan)—Mod-- western corner of the quadrangle (Lingley and others, 1996); includes part of the Qga Stewart, R. J., 1970, Petrology, metamorphism and structural relations of graywackes in the erately well-sorted, commonly cross-bedded, compact, well-rounded sandy cobble Western Olympic and Grand Valley lithic assemblages of Tabor and Cady (1978a). 2003 gravel; oxidized where groundwater movement occurs; includes granitic and meta- western Olympic Peninsula, Washington: Stanford University Doctor of Philosophy thesis, Ev(cf) Marine basaltic rocks, flow dominated (lower–middle Eocene)—Tholeiitic 123 p., 5 plates. morphic clasts originating from the North Cascades and Canada and incorporates Ev cf basalt, basalt breccia, volcaniclastic conglomerate, and tuff; minor diabase and gab- GEOLOGIC SYMBOLS local rock types; commonly exposed in road cuts and river banks underlying unit Stewart, R. J., 1974, Zeolite facies metamorphism of sandstone in the western Olympic Qgt; stratigraphically overlies pre-Fraser nonglacial sediments (unit Qc) or bedrock. bro; subordinate pillow basalt; minor interbeds of marine siltstone, feldspatholithic INTRODUCTION 2. Middle Eocene sedimentary and volcanic rocks northeast of and stratigraphically over- Heusser (1973, 1974) suggested evidence for at least two major glacial advances in the glacial. Differentiation of the time-stratigraphic unit groupings is based primarily on rela- Most workers have interpreted the faults within the Mount Olympus quadrangle and Contact—dashed where inferred, dotted where concealed, hachured Peninsula, Washington: Geological Society of America Bulletin, v. 85, no. 7, p. 1139-1142. Radiocarbon dates from unit Qgt provide a minimum age of about 14,000 yr B.P. and basaltic sandstone, chert, and gray foraminiferal limestone; mostly aphyric; lying the Crescent Formation. These include deep-marine rocks of the Aldwell Forma- Hoh and Bogachiel River drainages of the Forks 1:100,000-scale quadrangle area, one tive dating techniques. Where they exist, numerical ages are expressed in radiocarbon adjacent areas primarily as a series of east-dipping, westward-younging decollement where gradational This map of the Mount Olympus 1:100,000-scale quadrangle covers the central and eastern for the advance of the Puget and Juan de Fuca lobes in the map area (Porter and sparsely jointed; dark gray and dark greenish gray, weathering to brown and dark Tabor, R. W., 1971, Origin of ridge-top depressions by large-scale creep in the Olympic tion, marine rocks of the Lyre Formation (Ansfield, 1972), and small exposures of occurring at around 18,000 years ago and the other at least 30,000 years ago. He correlated years. thrusts (Stewart, 1970; Rau, 1973, 1979; Tabor and Cady, 1978b; Palmer and Lingley, Olympic Peninsula and was compiled to support construction of the northwest quadrant of Contact, scratch boundary Swanson, 1998; Schasse, in press). Therefore, unit Qga deposits must be older than brown; breccia consists of angular clasts of basalt, typically 4 to 10 cm in diameter; Mountains, Washington: Geological Society of America Bulletin, v. 82, no. 7, p. 1811-1822. basalt and andesite. the earlier advance to the Salmon Springs Glaciation. Recently, Heusser and others (1999), Deposits left by the Juan de Fuca lobe of the continental ice sheet have yielded only a 1989; Brandon and Calderwood, 1990; Brandon and Vance, 1992; Snavely and Wells, the 1:250,000-scale geologic map of Washington (Dragovich and others, 2002). Until about 14,000 yr B.P. A date of about 38,000 yr B.P. (this study, sample Beta-123941) partially nonmarine near top with local columnar jointing; altered to greenstone in 3. Middle Miocene to middle Eocene minor sedimentary and volcanic rocks tectonically in a paper on the stratigraphy and vegetation of the Humptulips River drainage, located limited number of radiocarbon dates on the Olympic Peninsula. Based on these dates, we 1996). Zircon fission-track ages (R. J. Stewart, Univ. of Wash., written communs., 1999, Fa ult, unknown offset—long dashed where approximately located, Tabor, R. W., 1972, Age of the Olympic metamorphism, Washington—K-Ar dating of low-grade recently, most geologic maps of the peninsula featured bedrock stratigraphy and structure. from a sandy fluvial deposit underlying till a few miles from the northeast corner of part with coarsely crystalline epidote on fracture surfaces; contains foraminiferal underlying the Crescent Formation including the Needles–Gray Wolf, Grand Valley, within the Copalis Beach 1:100,000-scale quadrangle to the southwest (Logan, in press), correlate the deposits to the Vashon Stade (~14,000–12,000 yr B.P.) of the Fraser Glaciation 2001; Brandon and Vance, 1992), cleavage development, and map patterns suggest that short dashed where inferred, dotted where concealed metamorphic rocks: Geological Society of America Bulletin, v. 83, no. 6, p. 1805-1816 Quaternary deposits were shown primarily where they obscured the bedrock, and then only the quadrangle provides a maximum age for the advance outwash. assemblages referable to the Ulatisian Stage (Rau, 1979, 1981); Babcock and others Elwha, and Western Olympic lithic assemblages of Tabor and Cady (1978a). This suggested glacial advances occurring during oxygen isotope stage 5a (about 60,000 yr B.P.), (Schasse, in press; and this study). The continental glacial deposits are represented by other major thrust systems may extend from the vicinity of Mount Tom (T26N R8W) 40 39 as two or three units defined by broad-scope chronological assignment and origin. In Thrust fault—sawteeth on upper plate; dashed where inferred, (1994) give a Ar/ Ar plateau age of 56.0 Ma and indicate correlative units adja- Tabor, R. W., 1975, Guide to the geology of Olympic National Park: University of Washington sequence of deep-marine sedimentary and minor marine volcanogenic rocks represents and several times each during stages 4 (infinite radiocarbon age), 3 (~40,000–30,000 yr extensive compact lodgment till and some areas of unconsolidated ablation till. Most east- through the North Fork Quinault River and in the vicinity of Finley Creek (T24N R9W). Qgd Continental drift, undifferentiated, Fraser (Vashon) age (late Wisconsinan)— cent to the Mount Olympus quadrangle of 57.8 to 55.3 Ma; consists of the upper compiling the mapping for the Mount Olympus quadrangle, we have attempted to give dotted where concealed Qgd Press, 144 p., 2 plates. an exhumed section of the Cascadia accretionary prism (Tabor, 1975). B.P.), and 2 (between 24,600 and 18,440 yr B.P.). and north-flowing rivers were, at various times, dammed by continental ice filling the low- The Salmon River thrust fault (Stewart, 1970; Gerstel and Lingley, 2000), which is exposed May include outwash, till, and lacustrine sediments; mapped where a combination equal attention to the Tertiary bedrock and Quaternary sediments, contributing new infor- part of the Crescent Formation. Rau (1973, 1979) broke out two Quaternary units, undivided alpine glacial deposits land Puget Sound and Strait of Juan de Fuca, forming lakes and resulting in thick sequen- in the southwestern part of the Mount Olympus quadrangle, is the easternmost (and there- Right-lateral strike-slip fault—concealed of depositional environments is represented or no characteristic sediment type is Tabor, R. W.; Cady, W. M., 1978a, Geologic map of the Olympic Peninsula, Washington: U.S. mation on age correlations for the geologic materials and climatic events on the peninsula. Three dominant deep-marine lithofacies are interpreted within these stratigraphic 1 and alluvium. ces of glaciolacustrine deposits. North- and east-flowing river valleys are generally shorter, fore oldest) thrust system that is not folded by the Olympic antiform. Although west-dip- dominant. Ev(cp) Marine basaltic rocks, pillow dominated (middle Eocene–Paleocene )— Geological Survey Miscellaneous Investigations Series Map I-994, 2 sheets, scale Our bedrock geology is largely modified from Tabor and Cady (1978a) using addi- sequences (Lingley, 1995): (1) thick-bedded, coarse channel deposits that commonly grade Anticline—dashed where inferred, dotted where concealed Evcp Long (1975, 1976) compiled his field observations of the Quaternary deposits of the steeper, and more commonly incised into bedrock than west-flowing river valleys, and ping thrusts have been identified offshore (Snavely, 1987; Lingley, 1995; Gutscher and oth- Tho-leiitic pillow basalt, basaltic breccia, and volcaniclastic sandstone and conglom- 1:125,000. tional age dates and mapping of Stewart (1970; Univ. of Wash., written commun., 1999), laterally to (2) medium-bedded sandy levee deposits, and, in turn, to (3) rhythmically bed- entire Olympic Peninsula applying stratigraphic correlations developed in the Cascade therefore did not preserve much of the glacial depositional record. ers, 2001), none have been identified in the Mount Olympus quadrangle, except overturned Syncline—dotted where concealed GLACIAL DEPOSITS, UNDIFFERENTIATED erate; minor aphyric basalt flows, gabbroic dikes and sills, and flow basalts; locally Cady and others (1972a, 1972b), Tabor (1972), Addicott (1976), Brandon and Vance ded sandy interdistributary deposits. (Also see Tabor and Cady, 1978a; Stewart, 1970; Rau, contains thin interbeds of basaltic tuff, chert, red argillite, limestone, and siltstone; Tabor, R. W.; Cady, W. M., 1978b The structure of the Olympic Mountains, Washington— Range, perpetuating confusion of age assignment. Interglacial periods were characterized by erosion in the upper areas of the drainage segments of larger east-dipping features. Thrust faulting probably commenced prior to the Qgl Alpine and continental glaciolacustrine deposits, Fraser age or older (late Wis- (1992), Squires and Goedert (1997), Gerstel and Lingley (2000), and W. W. Rau (Wash. 1979.) A fourth lithofacies consisting of tectonic breccia and (or) sheared sedimentary Minor anticline—showing bearing and plunge altered to greenstone in part; common chlorite, zeolites, and epidote; typical Analysis of a subduction zone: U.S. Geological Survey Professional Paper 1033, 38 p. Carson (1976) mapped glacial deposits adjacent to the Mount Olympus quadrangle to basins, and relatively low rates of sedimentation in the lowland areas. Thick, often exten- onset of transitional andesitic volcanism of the Cascade arc (Phillips and others, 1989) at Qgl consinan)—Well-sorted, fine-grained, laminated sand, silt, and clay; bluish gray, Division of Geology and Earth Resources, oral communs., 1987–2001). Quaternary geol- rocks reflects deformation within wide fault zones (Stewart, 1970; Tabor and Cady, 40 39 the east. He recognized Vashon-age and several pre-Vashon-age deposits of the Puget lobe sive, deposits of peat, some of which are now exposed in coastal bluffs were laid down dur- about 42 Ma. Ar/ Ar plateau ages of 56.0 ±1.0 to 55.3 Ma; contains foraminiferal assemblages Thackray, G. D., 1996, Glaciation and neotectonic deformation on the western Olympic ogy is refined from the previous mapping based on correlations to the chronology and strat- 1978a,b; Lingley, 1995; Lingley and others, 1996). Inclined bedding—showing strike and dip gray, and tan. The most extensive deposits are located in the Elwha River valley of the continental glacier, and described these as including and interbedded with older ing these times (Heusser, 1964; Thackray, 1996). These non-glacial deposits, variable in The Olympic antiform, a regional, east-plunging fold, dominates the study area. (See referable to the Penutian to Ulatisian Stages (Rau, 1964); consists of the lower part Peninsula, Washington: University of Washington Doctor of Philosophy thesis, 139 p., igraphy developed primarily by Thackray (1996). Igneous rocks in the study area are dominated by the Crescent Formation basaltic where the Juan de Fuca lobe formed lakes by damming rivers draining the Olympic alpine glacial deposits from the Olympic Mountains. thickness, generally represent much longer time intervals than the coarser, rapidly depos- Tabor, 1975.) It covers an area of about 120 by 70 mi and is defined by the strike of litho- Inclined bedding—showing strike and dip; top direction of beds of the Crescent Formation. 2 plates. This map displays geologic units chiefly by age and lithology. Age–lithology symbols rocks, interpreted as marine, marginal rift-basin deposits (Wells and others, 1984; Babcock Mountains. Similar but smaller deposits also occur in the lower reaches of east- Correlations to Cascade stratigraphy perpetuated the concept of synchronous alpine ited glacial deposits. They have been mildly folded along the western margin of the Olym- logic layering and S1 (first-generation) cleavage, folding of faults, and alignment of lentic- known from local features for geologic units consist of capital letters signifying the age of the unit and lowercase let- and others, 1994). Younger basaltic rocks and rare intermediate volcanic rocks were flowing drainages; because they are smaller and generally older than and underlying Thackray, G. D., 1999, Pacific moisture delivery and the variability of alpine glacier glaciation throughout North America. However, recent work on the peninsula by Thackray pic Peninsula and help document the timing of tectonic deformation (Thackray, 1996; ular lithologic units, especially in the eastern part of the quadrangle. The outer limbs of the ACKNOWLEDGMENTS ters indicating the general lithology. Some also include subscripted letters indicating for- extruded on or adjacent to the Juan de Fuca plate, but not as mid-oceanic ridge basalts. Vertical bedding—showing strike the latest Fraser (Vashon) continental till (unit Qgt) and outwash (unit Qgo), they are chronologies in western North America [abstract]: Geological Society of America Abstracts (1996) and a global review by Gillespie and Molnar (1995) suggest that alpine glaciation in Thackray and Pazzaglia, 1994; McCrory, 1997; Thackray, 1999). Much less extensive peat antiform are composed of the Crescent Formation and overlying middle Eocene sedimen- mation name or additional lithologic information, and (or) subscripted numbers indicating Some of the volcaniclastic rocks are channel-fill sequences. not mapped on this quadrangle. with Programs, v. 31, no. 4, p. A-58. the Olympic Mountains may have been asynchronous, and particularly responsive to cli- deposits formed during the waning stages of glaciations, both up-valley and down-valley of tary and volcanic rocks, which are mostly older than the middle Miocene to middle Eocene Ve rtical bedding—showing strike; ball shows top direction of beds Rowland Tabor (USGS, retired), Glenn Thackray (Idaho State U.), Scott Babcock (Western whether a unit is in the lower (1) or upper (2) part of a chronostratigraphic interval. Unit Most of the rocks in the central and western parts of the study area are metamorphosed matic change, with respect to glaciations in other North American mountain ranges. moraines. rocks in the core of the fold; earlier imbricate thrusting had brought the older rocks over where known from local features Wash. U.), Steve Boyer (Charles Wright Academy), Mark Brandon (Yale University), Dave Thackray, G. D.; Pazzaglia, F. J., 1994, Quaternary stratigraphy, tectonic geomorphology, and symbols for Quaternary units indicate relative ages and separate deposits of Olympic to zeolite facies (Stewart, 1974; Tabor and Cady, 1978a). Tertiary Sedimentary Rocks Thackray (1996), working in the Hoh and Queets River valleys on the west side of the Landslides are abundant in the Olympic Peninsula landscape, but we map them only the younger rocks. The antiform formed during the early to middle Miocene, and deforma- Engebretson (Western Wash. U.), Leslie Lingley (Leslie Geological Services), Josh Logan fluvial evolution of the western Olympic Peninsula, Washington. In Swanson, D. A.; Mountains alpine glaciers from those of continental glaciers originating in Canada and the Sedimentary structures are well preserved throughout most of the study area including Ove rturned bedding—showing strike and dip Olympic Mountains, developed a chronology of glacial advances and retreats unique to the where they exceed approximately 160 acres in area. They occur throughout the map area in tion ceased before 14.7 Ma, the age of the oldest strata that are not folded. MEm Marine sedimentary rocks (Miocene–Eocene)—Lithofeldspathic and feldspatho- (DGER), Bill Phillips (Univ. of Edinburgh), Weldon Rau (DGER, retired), Hank Schasse Haugerud, R. A., editors, Geologic field trips in the Pacific Northwest: University of North Cascades. much of the deformed core of the Olympic Mountains. However, in the central part of the „Em Olympic Peninsula. He defined at least four major glacial advances, some including several drainage headwalls, on mid- and lower slopes, and along terrace edges in valley bottoms. Other mesoscopic folds in the study area mostly trend northwest, but west- or south- Inclined bedding in phacoids in shear zone—showing strike and dip lithic sandstone, siltstone, and slate grading eastward to or tectonically intercalated (DGER), and Kevin Kelly (Western Wash. U.) provided assistance in the field, insight into Washington Department of Geological Sciences, v. 2, p. 2A 1 - 2A 29. This map is available electronically as a series of digital geographic information sys- quadrangle where phyllite and semischist predominate, bedding is entirely obliterated by minor readvances. Thackray's nomenclature for the Hoh and Queets drainages, based in They are generally deep-seated and are mapped as either rockfall or slump-earthflow west-trending folds are present (Tabor and Cady, 1978b; Lingley and others, 1996). The with semischist, slate, and phyllite; minor sheared granule conglomerate; semis- various aspects of Olympic geology, map reviews, and (or) contributions of geological or tem (GIS) coverages, which can be obtained by contacting the Washington Division of shearing. Inclined crenulated or warped bedding—showing approximate Todd, M. R., 1939, The glacial geology of the Hamma Hamma Valley and its relation to the part on mapping by Moore (1965), included, from older to younger: the Wolf Creek deposits. Debris flows, both natural and road-related, occur in abundance in mountain gul- axial planes of these folds are generally subparallel to bedding and S1 cleavage and the chist, sandstone, and granule conglomerate contain abundant platy shale, siltstone, geophysical data. We thank the Olympic National Park for providing accommodations during Geology and Earth Resources, PO Box 47007, Olympia, WA 98504-7007; phone (360) strike and dip glacial history of the Puget Sound basin: University of Washington Master of Science thesis, advance (inferred to be older than 780,000 years based on reversely magnetized glaciola- lies and on steep slopes, but are generally too small to be mapped at the scale of this map. fold axes plunge northwest or southeast at shallow to moderate angles. These relations sug- tuff, or slate clasts, grading to platy-clast breccia; moderately to poorly sorted; sub- the fieldwork. At DGER, Eric Schuster, Anne Heinitz, and Chuck Caruthers performed the 902-1450; fax (360) 902-1785; e-mail [email protected]. digital cartography, Karen Meyers did the editing and layout, and Jari Roloff provided editing 48 p., 1 plate. QUATERNARY DEPOSITS custrine sediments), the Whale Creek advance (~125,000–250,000 yr B.P.), the Lyman Rap- Deep-seated landslides with a high certainty level in Gerstel (1999) are included on this gest most of the folds are ramp and leading-edge anticlines, piggyback basins, and other Ve rtical crenulated or warped bedding—showing approximate strike angular where not thoroughly recrystallized and schistose; laminated and (or) thin- and cartographic support. Scott Babcock, Dick Stewart (Univ. of Wash.), Alan Niem (Oregon ids advance (~50,000-60,000 yr B.P.), the Hoh Oxbow advance (~29,000–39,000 yr B.P.), map. Landslides in bedrock commonly occur along bedding surfaces, within shear and thrust-related bends. bedded (1–20 cm) to thick-bedded (>60 cm); thin-bedded rocks commonly rhythmic Varnes, D. J., 1978, Slope movement types and processes. In Schuster, R. L.; Krizek, R. J., Todd (1939) and Frisken (1965) laid the foundation for mapping of glacial deposits in the Inclined cleavage—showing strike and dip State Univ., retired), Josh Logan, and Karl Wegmann (DGER) provided thoughtful reviews. BEDROCK and the Twin Creeks advance (~17,000–19,000 yr B.P., and possibly a late readvance of the mineralogically altered zones, and through structural weaknesses within rock units. Land- A prominent cleavage is well developed throughout the middle Miocene to middle and have sharp to gradational planar contacts; thick-bedded rocks discontinuous, editors, Landslides—Analysis and control: National Academy of Sciences Transportation east-side drainages of the Olympic Peninsula. Crandell (1964, 1965) and Heusser (1973, Hoh Oxbow glaciation). Only those alpine glacial deposits correlated to the Lyman Rapids, slides are also common where dense, fine-grained sediments (such as till or lacustrine Eocene rocks and in the Blue Mountain unit. This cleavage is nearly parallel to bedding in massive or banded (1–3 cm) with rare normal grading and sharp, planar to scoured Research Board Special Report 176, p. 11-33. Three major stratigraphic sequences occur within the Tertiary rocks of the Mount Olympus 1974, 1978) were among the earliest workers to establish a chronology with their observa- Ve rtical cleavage—showing strike Hoh Oxbow, and Twin Creeks advances are mapped on the Mount Olympus quadrangle. deposits) within valley-fill sequences create barriers to ground-water flow. thin-bedded lithofacies, but at higher angles to bedding in the thick-bedded lithofacies. In contacts; detrital muscovite common; mostly metamorphosed to zeolite facies; pen- quadrangle: tions based on relative age-dating methods and limited radiocarbon dating of peat deposits. Wells, R. E.; Engebretson, D. C.; Snavely, P. D., Jr.; Coe, R. S., 1984, Cenozoic plate motions However, glaciers still exist in the headwaters of many valleys (Spicer, 1986), forming several locations, cleavage is penetrative in hanging walls adjacent to major faults, but Inclined cleavage and bedding—showing strike and dip etratively cleaved; tectonic lenses common; yields unreset Miocene to Eocene detri- and the volcano-tectonic evolution of western Oregon and Washington: Tectonics, v. 3, 1. The Eocene to Paleocene Crescent Formation and Blue Mountain unit of Tabor and Crandell (1965) suggested correlations with Puget Sound and Cascade glacial stratigraphy, small moraines and depositing till and outwash. Some deposits mapped as Fraser age (late diminishes progressively at structurally higher levels, and thus is interpreted to result from tal zircon fission-track ages in the western part of the quadrangle and possible unre- no. 2, p. 275-294. n assigning major advances to Salmon Springs Glaciation at greater than 36,000 yr B.P. (and STRUCTURE Inclined deformed cleavage—showing approximate strike and dip Cady (1978a). (Also see Glassley, 1974, and Duncan, 1982.) The Crescent Formation Wisconsinan) may therefore be Holocene in age. strain transmitted from thrusting. Two additional cleavages that are locally developed in the set Miocene to Eocene fission track ages in the east-central part of the quadrangle probably correlating to the penultimate or pre-Wisconsinan glaciation), Evans Creek Stade is interpreted as a marginal rift-basin sequence, and the Blue Mountain unit consists of The Quaternary glacial stratigraphic record on the Mount Olympus quadrangle has Variation in the angle and rate of convergence of the Juan de Fuca plate under the North central part of the quadrangle may result from renewed mountain building during out-of- Ve rtical deformed cleavage—showing approximate strike (Brandon and Vance, 1992; R. J. Stewart, Univ. of Wash., written commun., 1999); 1 Although 40Ar/39Ar geochronometry (Babcock and others, 1994) indicates that lower parts of the of the Fraser Glaciation at greater than 25,000 to 20,000 yr B.P., and Vashon Stade of the Disclaimer: This product is provided ‘as is’ without warranty of any kind, either expressed or implied, including, but not limited to, the submarine fan deposits beneath and between the eruptive centers (Wells and others, been divided into four time-stratigraphic and origin-based unit groupings: pre-Fraser (pre- America plate is responsible for the distinct geology and structure of the Olympic Penin- sequence faulting (Boyer and Lingley, 1994) and (or) folding of the rocks into the Olympic includes part of the Western Olympic and Grand Valley lithic assemblages of Tabor Crescent Formation are of Paleocene and Eocene age, Eocene unit symbols (units Evcp and implied warranties of merchantability and fitness for a particular use. The Washington Department of Natural Resources will not be liable Fraser Glaciation at 20,000 to about 12,000 yr B.P. Dates from a limited number of samples Lineation—showing bearing and plunge 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 1984; Einarsen, 1987; Clark, 1989; Babcock and others, 1994; Snavely and Wells, late Wisconsinan) alpine glacial, pre-Fraser (pre-late Wisconsinan) continental glacial, sula (Babcock and others, 1994; Brandon and Calderwood, 1990; Brandon and Vance, antiform. In some areas such as Dodwell Rixon Pass and west of Mount Stone, considera- and Cady (1978a). Em1) are retained for consistency with earlier DGER products. were extrapolated throughout the drainages of the peninsula. consequential damages; (b) the fitness of the product for a particular purpose; or (c) use of the product or results obtained from use of the 1996). Fraser (late Wisconsinan) alpine glacial, and Fraser (Vashon, late Wisconsinan) continental 1992). ble ductile deformation is present. Limit of influence of the late Wisconsinan Cordilleran ice sheet 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 the State of Washington, Department of Natural Resources, Division of Geology and Earth Resources.