sign in sign up
<<
Home , Fraser Lowland, Hood Canal, Lake Nisqually, Port Susan, Skagit Bay, Vashon Glaciation

Geology of Blaine-Birch Bay Area Blaine Middle Whatcom County, WA School / PAC

l, ul G ant, G rmor Wings Over Water 2020 C o n Nest s ero Birch Bay Field Trip Eagles! H March 21, 2020 Eagle "Trees"

Beach Erosion Dakota Creek

Eagle Nest , ics l at w G rr rfo la cial E te Ab a u ant W Eagle Nest n d California Heron Rookery Creek Wave Cut Terraces Kingfisher G Nests Roger's Slough, Log Jam Birch Bay Eagle Nest G Beach Erosion Sea Links Ponds Periglacial G Field Trip Stops G Features Birch Bay Route Birch Bay Berm Ice Thickness, 2,200 M G Surficial Geology Alluvium Beach deposits Owl Nest Glacial outwash, Fraser-age in Barn k Glaciomarine drift, Fraser-age e e Marine glacial outwash, Fraser-age r Heron Center ll C re Peat deposits G Ter Artificial fill Terrell Marsh Water T G err Trailhead ell M a r k sh Terrell Cr ee

0 0.25 0.5 1 1.5 2 ± Miles 2200 M Blaine Middle Glacial outwash, School / PAC Geology of Blaine-Birch Bay Area marine, Everson ll, G Gu Glaciomarine Interstade Whatcom County, WA morant, C or t s drift, Everson ron Nes Wings Over Water 2020 Semiahmoo He Interstade Resort G Blaine Semiahmoo Field Trip March 21, 2020 Eagle "Trees"

Semiahmoo Park G

Glaciomarine drift, Everson Beach Erosion Interstade Dakota Creek

Eagle Nest

Glac ial Abun E da rra s, Blaine nt ti c l W ow Eagle Nest a terf California Creek Heron Glacial outwash, Rookery Glaciomarine drift, G Field Trip Stops marine, Everson Everson Interstade Semiahmoo Route Interstade Ice Thickness, 2,200 M Kingfisher Surficial GNeeoslotsgy Wave Cut Alluvium Glacial Terraces Beach deposits outwash, Roger's Glacial outwash, Fraser-age Slough, SuGmlaacsio mSataridnee drift, Fraser-age Log Jam Marine glacial outwash, Fraser-age Peat deposits Beach Eagle Nest Artificial fill deposits Water

Beach Erosion 0 0.25 0.5 1 1.5 2 Miles ± Chronology of Glacial Events

Sources: Animation; Ralph Haugerud; Milepost Thirty-One, State Dept. of Transportation, Research Center, Waterlines; Brian Atwater, Britta Johnson, & Amir Sheikh; 2017, Retrieved June 15, 2017 Years Before Present Event

18,800 The weight of the ice begins to depress the earth crust. The Puget Sound troughs and basin had been created previously.

Corderillian Ice Sheet has filled the southward out into the , where it floats on the ocean. The glacial front is north of the junction of the to and fills the Whidbey Basin. The outwash plains fill the entrance of the Hood Canal, Admiralty Inlet and from north of Everett to the southern end of . The ice continued to move southward at an average rate of 450 feet (140 m) per year. 18,300 Three freshwater lakes filled the basin. Nearly the entire length of the Hood Canal was open water. To the east the largest body of water filled the East Passage, the Dalco Passage (Tacoma) with a river like basin along the west of Vashon Island. A separate lake flowed from the and west of Tacoma through the narrows into the river running north through the Colvos Passage. The ice sheet continues it’s southward progression, separating the Hood Canal from the other basins in Puget Sound. The ice front is just north of and the covers all of , from just north of West Point south to . 18,100 Three freshwater lakes that had been created early continued to exist, growing small as the ice front moved south.

The ice sheet has created a uniform arched front running from mouth, southeast across the , through Bremerton , arcing across the southern tip of Vashon Island , ending in the Green River valley in the area of Kent . Outwash plains fill the mid reaches of the Hood Canal, the Clifton Channel and 3 to 5 miles (4.8 to 8.0 km) in the Carr Inlet, Colvos Channel, Quartermaster Harbor, and the East Passage of Puget Sound and a similar plain in the valley 17,800 of the Green River from Kent to Auburn . A single freshwater lake extends across the glacial front cover the lower Hood Canal and the lower hills north of the Black Hills north of Olympia . A smaller body of water filled the valleys of the Puyallup and White Rivers .

The ice front reached to just north of Olympia. The entire basin of the Puget Sound was filled with ice. A small outwash plain covered 2 to 3 miles (3.2 to 4.8 km) in an arch from the heights south of the Hood Canal south and eastward to the 17,500 Eastern bluffs of the mouth. A narrow band of water lay to the south of this plain and covered the area where Olympia now stands. The ice front reached its southernmost most point. It road along the east face of the , south to the plains north of the Black Hills, skirting their northern hills, reaching southward into the Black River Valley to its junction with 16,900 the Chehalis River . The front rested on the flanks of Mount Rainier, turning northward, joined by numerous small glaciers in the valleys of the eastern front of the Cascade Mountains . There was 3,000 feet (910 m) of ice over Seattle and the land was depressed 275 feet (84 m) near Pioneer Square.

The ice began to retreat after 16,900 ya. By 16,600, it had returned to north of Olympia, as it was 1000 years earlier. 16,600 The ice continued to retreat. Still standing south of Tacoma, substantial freshwater bodies had formed. Lake Skokomish stood in the southern bend of the Hood Canal and the lower reaches of the . Early Lake Russell or a late version of .

16,400 Continuing to recede to the north, the ice front reaches from the south side of Tacoma in a northwest arc across the Kitsap Peninsula, exposing the southern hook of Hood Canal, reaching the Olympic Mountains near Quilcene Bay.

16,400 A large freshwater body formed.

The ice front became anchored on the west among the Olympic Mountains near Quilcene Bay. Lake Russell spread across the southern basins of Puget Sound. Lake Hood drained across its southern outlets into Lake Russell. From Tacoma, the ice lay ice front lay 7 to 10 miles (11 to 16 km) to the north and lay across the Green River at Kent. 16,300 Within a very short period, the glacier retreated up to 15 miles (24 km) in a few decades. Bremerton and Renton are now ice free.

16,200 Continuing the advanced rate of retreat, Seattle becomes the southern tip of the ice sheet. The Hood Canal has fully joined with Lake Russell, leaving only the highest points the Kitsap Peninsula standing above the shore.

The retreat appears to have slowed or halted with evidence that the ice sheet was thinning, rather than receding. The water levels of Lake Russell have dropped correspondingly. 16,100 The upper end of the has formed a freshwater lake. and Lake Sammamish appear as water bodies along the southern margin of the lake.

The ice front has receded north opening the mouth of Hood Canal and lies just south of the southern end of Whidbey Island . 16,000 The length of the Stillaguamish River is a freshwater lake. Lake Sammamish has linked to Lake Washington along its present watercourse with Lake Washington draining across Lake Union and then only through the at its south end.

15,900 The ice front has receded north into the Strait of Juan de Fuca, linking the Puget Sound Basin to the ocean. The Duwamish-Green River Valley was salt-water reach of the sound. The Stillaguamish River is also a salt-water branch of the sound.

Except for the Duwamish-Green River saltwater embayment, the modern waterways have formed into the waterways known today. The Whidbey basin has taken a rudimentary form, with the Stillaguamish River flowing into Passage 7,500 and has appeared.

5,500 Mt. Rainier's northern crest collapsed sending a down the White River . This creates the Auburn delta in the Duwamish Embayment, separating the valley from the Green River valley.

2,100 An eruption of Mt Rainier send sand down White River to its junction with he Duwamish at Tukwila.

1,100 Duwamish valley earthquake lifts the Duwamish valley by 20 feet (6.1 m) draining what was left of the salt-water embayment, creating the Duwamish delta and what has become the Port of Seattle. Chronology of the Fraser Glaciation in the Northern Puget Lowland/Southern Fraser Lowlands From Booth, D. B, et. al. The , 2003

The Cordilleran ice sheet most recently advanced out of the mountains of about 25,000 years ago. It flowed west onto the continental shelf, east into the intermontaine valleys of British Columbia where it probably merged with the western edge of the , and south into the lowlands of Washington State.

In southern British Columbia and , the Puget lobe filled the Fraser Lowland and the Puget Lowland between the Olympic Mountains and . The Juan de Fuca lobe extended east along the Strait of Juan de Fuca ending some 100 km west of Washington’s present coast. Several ice lobes east of the Cascade Range expanded south down the Okanogan Valley and down other valleys farther east. The Fraser-age ice-sheet maximum on both sides of the Cascade Range was broadly synchronous (Waitt & Thorson, 1983). It approximately coincided with the maximum advance of some parts of the Laurentide ice sheet in central at about 14,000 years ago but lagged several thousand years behind the culminating advance of the most of the Laurentide ice sheet (Lowell et al. , 1999; Mickelson et al. , 1983; Prest, 1969).

The Fraser glaciation began about 25,000 years ago , with an expansion of alpine glaciers in the of British Columbia, the Olympic Mountains, and the Cascade Range of Washington. Glaciers in the Coast Mountains coalesced to form piedmont ice lobes that reached the Fraser Lowland of British Columbia about 21,000 years ago during the Coquitlam Stade (Hicock & Armstrong, 1981).

The Coquitlam Stade was followed by a period of climatic warming that lasted from about 19,000 to 18,000 years ago, called the Port Moody Interstade (Hicock & Armstrong, 1985). The Port Moody Interstade was in turn followed by the late Wisconsin advance of the Cordilleran ice sheet during the Vashon Stade (Armstrong et al. , 1965). The Puget lobe advanced into northern Washington about 17,000 years ago and retreated rapidly from its maximum position around 14,000 years ago . (Clague, 1981; Easterbrook, 1986; Porter & Swanson, 1998).

The Vashon Stade was followed by a period of rapid and extensive glacier retreat (Everson Interstade) that ended with a resurgence of the southwestern margin of the Cordilleran ice sheet in the Fraser Lowland about 12,000 years ago (Sumas Stade) (Clague et al. , 1997; Kovanen, 2002; Kovanen & Easterbrook, 2001). Several advances separated by brief periods of retreat apparently marked the Sumas Stade . The final advance(s) occurred 11,000 years ago or shortly thereafter. Soon after 10,500 years ago, the Cordilleran ice sheet rapidly disappeared from the lowlands.

Comparison of the marine oxygen-isotope curve stages (MIS) using the deep-sea oxygen-isotope data for ODP677 from Shackelton et al. (1990), global magnetic polarity curve (Barendregt, 1995; Cande & Kent, 1995; Mankinnen & Dalrymple, 1979), and ages of climatic intervals in the Puget and Fraser lowlands. Glossary of Glacier Terms Extracted from U.S. Geological Survey Open-File Report 2004–1216 and other sources

Glacial Chronology (Timing)

Holocene - The current part of geologic time. The Holocene epoch began ~12,000 years ago, at the end of the epoch.

Interstade - A short period of time (less than 10,000 years) characterized by climatic conditions associated with minimum glacial extent.

Little (Neoglaciation) - The most recent interval of temperate glacier expansion and advance on Earth. It began ~650 years ago and continued into the 20th century in many locations. Temperate glaciers form in North and South America, Africa, Europe, and Asia.

Pleistocene - The epoch of geologic time, informally called the 'The Great Ice Age' or the 'Glacial Epoch', that began ~1.8 million years ago and ended ~8,000 years ago. During this interval continental glaciers repeatedly formed and covered significant parts of the Earth's surface. Together, the Holocene and Pleistocene epochs comprise the Quaternary Period.

Stade - A short period of time (less than 10,000 years) characterized by climatic conditions associated with maximum glacial extent.

Types of “Continental” Glaciers

Ice Cap - A dome-shaped accumulation of glacier ice and perennial snow that completely covers a mountainous area or island, so that no peaks or Nunataks (Inuit/Greenlandic - poke through) are exposed.

Ice Field - A continuous accumulation of snow and glacier ice that completely fills a mountain basin or covers a low-relief mountain plateau. When the thicknesses become great enough, tongues of ice overflow the basins or plateaus as Valley Glaciers.

Ice Sheet - A thick, subcontinental to continental-scale accumulation of glacier ice and perennial snow that spreads from a center of accumulation, typically in all directions. Also called a Continental Glacier.

Piedmont glacier - A fan or lobe-shaped glacier, located at the front of a mountain range. It forms when one or more valley glaciers flow from a confined valley onto a plain where it expands. The 30-mile wide Malaspina is the largest in .

Tidewater Glacier - A glacier with a terminus that ends in a body of water influenced by tides, such as the ocean or a large lake. Typically, tidewater glaciers calve ice to produce icebergs.

“Continental” Glacier Terms

Advance - An increase in the length of a glacier compared to a previous point in time. As ice in a glacier is always moving forward, a glacier's terminus advances when less ice is lost due to melting and/or calving than the amount of yearly advance.

Drift - A collective term used to describe all types of glacier sedimentary deposits, regardless of the size or amount of sorting. Includes all sediment transported by a glacier, whether it is deposited directly by a glacier or indirectly by running water originating from a glacier.

Drumlin - An elongated ridge of glacial sediment sculpted by ice moving over the bed of a glacier. Generally, the down-glacier end is oval or rounded and the up-glacier end tapers. The shape is often compared to an inverted, blunt-ended canoe. Although not common in Alaska, cover parts of the Eastern and Midwestern (Irish - littlest ridge).

Erratic - A rock of unspecified shape and size, transported a significant distance from its origin by a glacier or iceberg and deposited by melting of the ice. Erratics range from pebble-size to larger than a house and usually are of a different composition that the bedrock or sediment on which they are deposited.

Esker - A meandering, water-deposited, generally steep-sided sediment ridge that forms within a subglacial or englacial stream channel. Its floor can be bedrock, sediment, or ice. Subsequent melting of the glacier exposes the deposit. Generally composed of stratified sand and gravel, can range from feet to miles in length and may exceed 100 feet in height (Irish - ridge).

Eustacy - Fluctuations in the worldwide sea-level regime caused by changes in the quantity of seawater available. The greatest changes are caused by water being added to, or removed from, glaciers.

Glacial Groove/Glacial Furrow - A linear depression, inches to miles in length, produced by the removal of rock or sediment by the erosive action of a glacier.

Glacial Lake - An accumulation of standing liquid water on (supraglacial), in (englacial), or under (subglacial) a glacier.

Glacial Stream - A channelized accumulation of liquid water on (supraglacial), in (englacial), or under (subglacial) a glacier, moving under the influence of gravity.

Glacier - A large, perennial accumulation of ice, snow, rock, sediment and liquid water originating on land and moving down slope under the influence of its own weight and gravity; a dynamic river of ice. Classified by their size, location, and thermal regime.

Glacier Flow - The movement of ice in a glacier, typically in a downward and outward direction, caused by the force of gravity. 'Normal' flow rates are in feet per day. 'Rapid' flow rates (i.e. surge) are in 10s or 100s of feet per day.

Ice-Dammed Lake - A lake that exists because its water is restricted from flowing by an ice dam. Sometimes these lakes form because an advancing glacier had blocked a valley. See Jökulhlaup.

Ice-Marginal Lake - A lake that is located adjacent to the terminus of a glacier. Typically, these lakes form in bedrock basins scoured by the glacier. They enlarge as the glacier retreats. Sometimes they are dammed by an End or Recessional .

Isostasy - The balance between changes within the Earth's crust and mantle, where material is displaced in response to an increase (isostatic depression) or decrease (isostatic rebound) in mass at any point on the Earth's surface above. Such changes are frequently caused by advances or retreats of glaciers.

Jökulhlaup - A glacier outburst flood resulting from the failure of a glacier-ice-dam, glacier-sediment-dam, or from the melting of glacier ice by a volcanic eruption (Icelandic – glacial run).

Kame - A sand and gravel deposit formed by running water on stagnant or moving-glacier ice. Crevasse fills or crevasse ridges form within crevasses. form on flat or inclined ice, in holes, or in cracks. A terrace forms between the glacier and the adjacent land surface. Shapes include hills, mounds, knobs, hummocks, or ridges (Scottish - comb).

Kettle - A depression formed in an outwash plain or other glacial deposit by the melting of an in-situ block of glacier ice that was separated from the retreating glacier-margin and buried by glacier sedimentation. As the buried ice melts, the depression enlarges.

Mass Balance - A measure of the change in mass of a glacier at a certain point for a specific period of time. The balance between accumulation and ablation. Also called Mass Budget.

Moraine - A general term for unstratified and unsorted deposits of sediment that form through the direct action of, or contact with, glacier ice. Many different varieties are recognized on the basis of their position with respect to a glacier (French – snout).

Moraine, Ablation - An irregular-shaped layer or pile of glacier sediment formed by the melting of a block of stagnant ice. Ultimately, ablation moraine is deposited on the former bed of the glacier. Also called Ablation Till.

Moraine, Ground - A blanket of glacier till deposited on all of the surfaces over which a glacier moves, typically by moving ice.

Moraine, Recessional - A ridge of glacial sediment that forms when the terminus of a retreating glacier remains at or near a single location for a period of time sufficient for a cross-valley accumulation to form.

Moraine, Terminal - A cross-valley, ridge-like accumulation of glacial sediment that forms at the farthest point reached by the terminus of an advancing glacier. Also called an End Moraine.

Outwash plain - A broad, low-slope angle alluvial plain composed of glacially eroded, sorted sediment (termed outwash), that has been transported by meltwater. The alluvial plain begins at the foot of a glacier and may extend for miles. Typically, the sediment becomes finer grained with increasing distance from the glacier terminus.

Pit Pond - A depression in an outwash plain by the melting of a block of ice floated to its depositional site by meltwater and subsequently buried by sediment. As it melts, a depression in the surface of the outwash plain develops. See .

Remnant - An isolated melting mass of glacier ice that has become detached from its source and the remainder of the glacier. Some remnants cover many square miles.

Retreat - A decrease in the length of a glacier compared to a previous point in time. As ice in a glacier is always moving forward, its terminus retreats when more ice is lost at the terminus to melting and/or calving than reaches the terminus. During retreat, ice in a glacier does not move back up the valley.

Roche Moutonnee - An elongated, rounded, asymmetrical, bedrock knob produced by glacier erosion. It has a gentle slope on its up- glacier side and a steep- to vertical-face on the down-glacier side (French – sheep rock).

Stagnation - The in-situ melting of glacier ice. Many glaciers have stagnant termini, covered by thick sediment debris. Some support vegetation, including mature forests.

Striations - Multiple, generally parallel, linear grooves, carved by rocks frozen in the bed of a glacier into the bedrock over which it flows.

Terminus - The lower-most margin, end, or extremity of a glacier. Also called Toe, End or Snout.

Till - An unsorted and unstratified accumulation of glacial sediment, deposited directly by glacier ice. Till is a heterogeneous mixture of different sized material deposited by moving ice (lodgement till) or by the melting in-place of stagnant ice (ablation till). After deposition, some tills are reworked by water.