Withrow Moraine and Jameson Lake Drumlin Field
Encyclopedia
National Park Service
The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...
designated privately-owned National Natural Landmark
National Natural Landmark
The National Natural Landmark program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only natural areas program of national scope that identifies and recognizes the best examples of biological and geological features in...
located in Douglas County, Washington state, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Withrow Moraine is the only Ice Age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
terminal moraine
Terminal moraine
A terminal moraine, also called end moraine, is a moraine that forms at the end of the glacier called the snout.Terminal moraines mark the maximum advance of the glacier. An end moraine is at the present boundary of the glacier....
on the Waterville Plateau section of the Columbia Plateau. The drumlin
Drumlin
A drumlin, from the Irish word droimnín , first recorded in 1833, is an elongated whale-shaped hill formed by glacial ice acting on underlying unconsolidated till or ground moraine.-Drumlin formation:...
field includes excellent examples of glacially
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
-formed elongated hill
Hill
A hill is a landform that extends above the surrounding terrain. Hills often have a distinct summit, although in areas with scarp/dip topography a hill may refer to a particular section of flat terrain without a massive summit A hill is a landform that extends above the surrounding terrain. Hills...
s. (Coordinates: Withrow Moraine intersects Jameson Lake - 47°41′15"N 119°37′29"W ).
Geologic History
The plateau
The Withrow Moraine and Jameson Lake Drumlin Field National Natural Landmark is located on the Waterville Plateau, which lies in the northwest corner of the Columbia River PlateauColumbia River Plateau
The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River...
. The plateau is formed on top of the Columbia River Basalt Group
Columbia River Basalt Group
The Columbia River Basalt Group is a large igneous province that lies across parts of the Western United States. It is found in the U.S. states of Washington, Oregon, Idaho, Nevada, and California...
a large igneous province
Large igneous province
A Large Igneous Province is an extremely large accumulation of igneous rocks—intrusive, extrusive, or both—in the earth's crust...
that lies across parts of the states of Washington, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
, and Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
in the United States of America
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. During late Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
and early Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
times, one of the largest flood basalt
Flood basalt
A flood basalt or trap basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava. Flood basalts have occurred on continental scales in prehistory, creating great plateaus and mountain ranges...
s ever to appear on the earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's surface engulfed about 163,700 km² (63,000 mile²) of the Pacific Northwest, forming a large igneous province
Large igneous province
A Large Igneous Province is an extremely large accumulation of igneous rocks—intrusive, extrusive, or both—in the earth's crust...
with an estimated volume of 174,300 km³. Eruptions were most vigorous from 17—14 million years ago, when over 99% of the basalt was released. Less extensive eruptions continued from 14—6 million years ago.
These lava flows have been extensively exposed by the erosion resulting from the Missoula Floods
Missoula Floods
The Missoula Floods refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. The glacial flood events have been researched since the 1920s...
, which laid bare many layers of the basalt flows on the edges of the plateau at Grand Coulee
Grand Coulee
The Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about sixty miles southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower Grand Coulee....
and Moses Coulee
Moses Coulee
Moses Coulee cuts into the Waterville plateau in Douglas County, Washington. It is to the west of and roughly parallel to the more famous Grand Coulee...
.
The glacial history
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
epoch began and Ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
glaciers invaded the area. They scoured the Columbia River Plateau, reaching as far south as the middle of the Waterville Plateau highlands above the Grand Coulee and south to the head of Moses Coulee
Moses Coulee
Moses Coulee cuts into the Waterville plateau in Douglas County, Washington. It is to the west of and roughly parallel to the more famous Grand Coulee...
. In some areas north of the Grand Coulee
Grand Coulee
The Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about sixty miles southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower Grand Coulee....
they were as much as 3 km (10000 feet) thick. Grooves in the exposed granite bedrock are still visible in the area from the movement of glaciers and numerous glacial erratic
Glacial erratic
A glacial erratic is a piece of rock that differs from the size and type of rock native to the area in which it rests. "Erratics" take their name from the Latin word errare, and are carried by glacial ice, often over distances of hundreds of kilometres...
s in the elevated to the Northwest of the coulee.
Progress of the Okanogan Lobe of the Cordilleran Glacier
Cordilleran Ice Sheet
The Cordilleran ice sheet was a major ice sheet that covered, during glacial periods of the Quaternary, a large area of North America. This included the following areas:*Western Montana*The Idaho Panhandle...
moved down the Okanogan River
Okanogan River
The Okanogan River is a tributary of the Columbia River, approximately 115 mi long, in southern British Columbia and north central Washington...
valley, covering 500 mi² of the Waterville Plateau and blocked the ancient route of the Columbia River, backing up water to create Glacial Lake Columbia
Glacial Lake Columbia
Glacial Lake Columbia was the lake formed on the ice-dammed Columbia River behind the Okanogan lobe of the Cordilleran Ice Sheet when the lobe covered of the Waterville Plateau west of Grand Coulee in central Washington state during the Wisconsin glaciation. Lake Columbia was a substantially...
and Lake Spokane. Initially water discharged from Lake Columbia by running up through the head of Grand Coulee and down through Foster Coulee to rejoin the Columbia River. As the glacier moved further south, Foster Coulee was cut off and the Columbia River then discharged through Moses Coulee
Moses Coulee
Moses Coulee cuts into the Waterville plateau in Douglas County, Washington. It is to the west of and roughly parallel to the more famous Grand Coulee...
, which runs southward slightly to the east of the ancient and current course of the Columbia. As the Okanogan lobe grew, it blocked Moses Coulee as well; the Columbia found the next lowest route through the region which was eroded to become the modern Grand Coulee
Grand Coulee
The Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about sixty miles southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower Grand Coulee....
.
After the glacier
As the Okanogan lobe melted, the northern half of the Waterville Plateau, including the upper portions of Moses Coulee, were littered with clear evidence of its passing. The glacier left behind a blanket of glacial till, up to 50 feet thick in places. This glacial till, composed of clay, silt, sand, gravel, cobblestones, and erraticErratic
Erratic can refer to:* Erratic, a project of music artist Jan Robbe* Glacial erratic, is a piece of rock that differs from the size and type of rock native to the area in which it rests* Erratic ant, a species...
boulders, covers most of the upper Moses Coulee. The melting glacier discharged both down Moses Coulee and into the Grand Coulee as is evident in the Sims Corner eskers and kames
Sims Corner Eskers and Kames
The Sims Corner Eskers and Kames National Natural Landmark includes excellent examples of Pleistocene ice stagnation landforms including numerous glacial erratics, terminal moraines, eskers, and kames...
.