WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES OPEN FILE REPORT 2003-9 Division of Geology and Earth Resources 18 16 Ron Teissere - State Geologist VARIATIONS O/ O 2.0 2 16 6 12 20 1.5 18 10 4 8 1.0 14 8 ft Qgof Qgt 0.5 10 ft Qga 3 Qgas Beta No. 143971 122°52¢30² R 2 W R 1 W 122°45¢ 0 47°07¢30² 47°07¢30² >45,700 yr B.P. 14 Qgof Qgt Qga C age in wood 5b 5d Qga Sandy NISQUALLY REACH -0.5 peat PPPP 21 63rd Ave NE O VARIATIONS Qga Point 17 19 Qgt Qpg 18 Woodard Big Slough Beta No. 143031 d -1.0 47 ft Qps 5a 5c Woodard Bay Rd Bay Qb >46,970 yr B.P. 13 15 Qps 14C age in peat HENDERSON INLET Qp -1.5 Qmw 1 7 Qgof 11 Puget Beach Road Qgas Butterball 9 19 Tolmie Qb tephra XXXX -2.0 24 Qgof Cove (in standard deviation units about a zero mean) Qa 20 State Park 5e Qgof 22 23 Qmw 21 10 ft Qpg -2.5 Qp Qp Qp base of bluff Qps 0 100 200 300 400 500 600 700 800 Qga TIME (K years ago) Puget Road Qgic Qp Qgof Qmw Qmw Figure 2. Outcrop of tephra interbedded with unit Qps at Butterball Cove. Chemical analysis Figure 1. Marine oxygen-isotope stages (from Morrison, 1991). The numbers within the graph are stage numbers; the even- Qgt 24 at three different laboratories identified this tephra as probably from Mount St. Helens, numbered peaks (at top) are glacial maxima and the odd-numbered troughs (at bottom) are interglacial minima. The blue areas Qmw Qgt Qgo although a specific match could not be positively identified. indicate interglacial episodes, based on a cutoff at -0.5 δ18O oxygen-isotope values (equivalent to Holocene interglacial values). 56th Ave NE Qb Woodard Qp Qp Qa Qgo Qga Qa Qgt Qmw Beachcrest 37 Qps Qgof Johnson Point Road Qgof Qp 25 30 28 27 Qgic Qgo Geologic Map of the Lacey 7.5-minute Quadrangle, 26 25 Qgt Qgof Lemon Road Qgos Qgt Schinke Road Qgt Thurston County, Washington Qp Marvin Road Qp 29 Qp by Robert L. Logan, Timothy J. Walsh, Henry W. Schasse, and Michael Polenz Qgo 46th Ave NE Qgof Qgof 2003 Sleater- Kinney Road Sleater- Qgt Qp Bay 37 Qgof Qa Qgt INTRODUCTION ACKNOWLEDGMENTS PLEISTOCENE DEPOSITS OLDER THAN VASHON DRIFT Qgof Qp Qp 31 32 34 33 35 36 The Lacey quadrangle is located at the south end of Puget Sound in Thurston Support for identification of tephra was provided by Franklin F. Foit, Jr. Qps Pre-Vashon sand-size or finer deposits—Massive to cross-bedded Qp 36 County and includes most of the city of Lacey and part of the city of Olympia. (Wash. State Univ.) and Andrei M. Sarna-Wojcicki and Thomas W. Sisson Qps Qgt Qgt sand interbedded with laminated silt and minor peat, diatomite, and Land use is primarily urban, industrial, or low-density residential. (U.S. Geological Survey). We have also benefited greatly from discussions with gravel; immediately subjacent to Vashon Drift and generally Qp Qp Derek Booth and Kathy Troost (Univ. of Wash.) and Ray Wells and Brian overlying unit Qpg. This unit is thought to be of nonglacial origin, Qp Woodar Hawks Prairie Road GEOLOGIC HISTORY Sherrod (U.S. Geological Survey). This map is supported by the National Qgt and is dominated by varied Cascade-source volcanic lithic rock types. Qp Qgt Geologic Mapping Program under Cooperative Agreement No. 02HQAG0047 Libby Road Qa Late Wisconsinan–age Vashon Drift covers most of the quadrangle. Pre-Vashon These sediments have previously been referred to the Kitsap d with the U.S. Geological Survey. units are generally exposed only along coastal bluffs, where mass wasting is Formation and were inferred to be of Olympia age, although all known deposits in the south Puget Lowland are older than the type T 19 N 36th Ave NE common. Landslides and colluvium disrupt and obscure the continuity of Qgt T 19 N DESCRIPTION OF UNITS T 18 N exposures so that pre-Vashon geologic history is not easily deciphered. In the section of the Olympia nonglacial interval (Armstrong and others, 1 T 18 N Qgof south Puget Lowland (south of Tacoma), all finite radiocarbon ages reported Quaternary Unconsolidated Deposits 1965) and most are radiocarbon-infinite or suspect. Two radiocarbon South Carpenter Road Qgo samples were obtained from the cliff exposure that is detailed in the Qgos Bay before 1966 are suspect due to laboratory contamination (Fairhall and others, Qp HOLOCENE NONGLACIAL DEPOSITS stratigraphic column next to Figure 2. Deeter (1979) has shown that 37 Trail 1966, p. 501). Stratigraphic assignments based on these invalid radiocarbon ages Qp are now questionable and need to be re-evaluated. We have systematically the type locality of the Kitsap Formation includes radiocarbon- Qp Qgt Qf Fill—Clay, silt, sand, gravel, organic matter, rip-rap, and debris; infinite sediments of both glacial and nonglacial origin, and we Qgos 31st Ave NE sampled all datable material from nonglacial sediments subjacent to the Vashon Qf Qp includes engineered and non-engineered fills; shown only where fill follow his suggestion that the name be abandoned. Because we Qgt Marvin Road Drift and found them to be older than previously reported. With a few Friendly Grove Road Qgof placement is extensive, sufficiently thick to be of geotechnical cannot establish that all pre-Vashon nonglacial sediments are 6 Woodland exceptions, these sediments have been beyond the range of radiocarbon dating. Qp significance, and readily verifiable. correlative, we have chosen not to assign them a stratigraphic name. 5 The antiquity of the pre-Vashon units causes radiocarbon dating to be of Qgo 3 2 1 67 4 little help for making correlations, and abrupt facies changes within glacial and Qp Qgt Qml Modified land—Soil, sediment, or other geologic material that has Qpg Pre-Vashon gravel—Gravel and sand, generally of mixed northern Qp Qml Qpg nonglacial units also render correlations tenuous. Despite these difficulties, we been locally reworked to modify the topography by excavation and and Cascade Range provenance; moderately to poorly sorted; Road have developed a conceptual model for the more recent pre-Vashon geologic 36 (or) redistribution. commonly cross bedded but may lack primary sedimentary Qgos Qgos Qgt Qp Creek history that is consistent with our observations but by no means compelling. structures; commonly tinted orange with iron-oxide staining; South Bay QpRoad The oxygen-isotope stage 4 glaciation, called the Possession Glaciation in Bay Qa Alluvium—Silt, sand, gravel, and peat deposited in stream beds and stratigraphically underlying the Vashon Drift; most commonly the northern Puget Lowland, was mild relative to stages 2 and 6 (Mix, 1987; Qa Qgt Qp estuaries; may include some lacustrine and beach deposits. exposed immediately beneath exposures of unit Qps; gravelly 26th Ave NE Creek Fig. 1), which are represented in the Puget Lowland by the Vashon and Double portions of unit Qpg are relatively resistant to erosion; inferred to be Bluff Drifts respectively. The Possession ice sheet probably did not extend far Qb Beach deposits—Mud and sand deposited in the intertidal zone or Hawks Prairie of glacial origin because interglacial conditions do not appear Qp Qgos Hogum south of Seattle (Lea, 1984; Troost, 1999). Because the ice sheet blocked Qb Qp Qgo Qml residual gravel on a wave-cut platform. conducive to streams with sufficient competency to deposit drainage out of Puget Sound to the Strait of Juan de Fuca, a proglacial lake was widespread gravels in most of the Puget Lowland and because the impounded in most of the southern Puget Lowland. Streams flowing into this Q mw Colluvium—Loose soil and glacial sand and gravel deposited by soil Setchfield Qf Qgt Qga Qmw majority of the exposures include northern-source metamorphic rock Lake lake, such as the Nisqually, Puyallup, and Skokomish Rivers, formed an alluvial creep and shallow ravelling on hillslopes, some of which occurred 40 clasts. Qp plain and deltas grading to lake level. These nonglacial sediments, deposited during the waning stages of the Vashon Stade of the Fraser 64 Qf Qgt during stage 4, are all radiocarbon-infinite and overlie and interfinger with Glaciation. Shown where colluvium is of sufficient thickness to mask 7 8 9 Qf REFERENCES CITED Qp Qga 10 11 Possession outwash deposits. Once Possession ice no longer impounded the lake underlying geologic strata. 12 Draham St (but sea level was still significantly below modern sea level), existing drainages, Armstrong, J. E.; Crandell, D. R.; Easterbrook, D. J.; Noble, J. B., 1965, Late 5 Qp Peat—Organic and organic-matter-rich mineral sediments deposited such as the Nisqually and Puyallup Rivers, deeply and rapidly incised into their Qp Pleistocene stratigraphy and chronology in southwestern British Columbia Bigelow in closed depressions; includes peat, muck, silt, and clay in and Lake former alluvial plains and became entrenched. At least initially, stage 3, called and northwestern Washington: Geological Society of America Bulletin, 15th Ave NE Thompson the Olympia Interglaciation locally (Armstrong and others, 1965), was adjacent to wetlands. Carpenter Road Place v. 76, no. 3, p. 321-330. Qgt characterized by downcutting and erosion. As sea level began to rise, most deposition was confined to the entrenched channels. Because stage 3 sea level Bodle, T. R., 1992, Microzoning the likelihood of strong spectral amplification Qp Qgt PLEISTOCENE GLACIAL DEPOSITS Qgo was probably about 100 ft lower than modern sea level (Ludwig and others, of earthquake motions using MMI surveys and surface geology: Earthquake Qp Spectra, v.