Kansas Geological Survey Public Information Circular 28 • April 2009 Revised November 2020 Glaciers in Kansas Shane A. Lyle, Kansas Geological Survey Revised by Anthony L. Layzell, Kansas Geological Survey Introduction Yellowstone National Park area were During each stage, many smaller, Melting glaciers in Earth’s polar and deposited throughout the state. regional lobes of ice locally advanced alpine regions are beacons of climate During the Pleistocene, continent- and retreated (fig. 2). The Pre-Illinoian change. To better understand what sized ice sheets formed in different parts Stage included many glacial and is happening today, it is helpful to of the world: North America, Greenland, interglacial stages, with 11 distinct consider past glaciation and climate- Eurasia, Tibet, the Himalayas, and glacial stages currently recognized. The change examples. Glaciers seemingly Antarctica. Ice sheets in the polar regions Sangamonian was a warm interglacial couldn’t be further removed from the and Greenland were fairly stable, but stage of ice retreat. hot summers and windswept plains of other areas, including North America, At its peak, Pre-Illinoian ice covered Kansas. However, in the not-so-distant saw repeated expansion and contraction more than one-third of North America geologic past, glaciers repeatedly in response to fluctuating climates (fig. and extended into northeastern advanced across the Midwest and at 1). These successive glacial advances Kansas. In Kansas, at least two separate least twice reached northeast Kansas. As and retreats are known as glacial stages glacial advances took place, first from the ice progressed across the continent, and interglacial stages, respectively. Minnesota and later from the Dakota the landscape, climate, plants, and In North America, geologists regions. Ice lobes dammed the ancestral animals all changed. recognize four stages. They are the Pre- Kansas River in several places and The purpose of this public Illinoian (2.6 million–191,000 years ago), crept over the locations of present-day information circular is to show how Illinoian (191,000–130,000 years ago), Topeka, Lawrence, and downtown Kansas was literally on the forefront of Sangamonian (130,000–71,000 years Kansas City (fig. 2). climate change when a continental ice ago), and Wisconsinan (71,000–11,700 At its maximum, Illinoian ice covered sheet last extended into the northeast years ago). most of Illinois and did not enter corner of the state about 700,000 years ago. The geologic sciences are uniquely capable of describing these events, in that geologists nearly always look back in time to understand our current climate and environment. This publication provides insight into how the Midwest was affected by repeated continent-sized glacial advances during the Pleistocene Epoch. It explains glaciation in Kansas and the ecological and climate response since the last ice sheet retreat. The Pleistocene provides an important analog, or past example, to better understand some of the concepts associated with climate change. The Pleistocene The Pleistocene Epoch lasted from about 2.6 million to 11,700 years ago. Although commonly referred to as the Ice Age, the Pleistocene encompassed many glacial and interglacial events and warm and cool climates. It was also a period of volcanic activity in North America and along the North and South American Pacific coasts. In Kansas, at Figure 1. Extent of glaciation in North America. Solid white areas represent Late Wisconsinan ice least three large ash falls from volcanoes sheets and glaciers. Dotted white line indicates maximum extent of older Quaternary glaciations. in California, New Mexico, or the © 2013 Colorado Plateau Geosystems Inc. past Tarkio and Chillicothe, Missouri, Last glacial maximum ice limit into the present-day Missouri River Pre-Illinoian ice limit (fig. 2). The Big and Little Blue rivers in Unglaciated area Marshall and Pottawatomie counties probably developed as ice-margin streams or spillways to a proglacial lake, a lake formed just beyond the frontal margin of a glacier, near Atchison. Advancing ice also buried ancestral rivers that once flowed east through Marshall, Nemaha, Jackson, Brown, Atchison, and Doniphan counties in northeastern Kansas. Some of these valleys were more than 3 miles (4.8 km) wide, 400 feet (122 m) deep, and 75 miles (121 km) long. These buried valleys are now important groundwater sources for agriculture and industry in an area that otherwise does not have much groundwater. When the ice flow reached a depression such as the Kansas River, it spilled over the side, slowly filled the valley, then flowed over the opposite side. The ice was perhaps 300 feet (91 m) thick north of the river near Wamego and 500 feet (153 m) thick over the Kansas River valley. An ice lobe covering what is now the Kansas City area was Figure 2. Maximum extent of pre-Illinoian and late Pleistocene ice sheets (after “Glacial probably hundreds of feet thick (fig. 2). stratigraphy and paleomagnetism of late Cenozoic deposits of the north-central United States,” by Glacial ice transports all sizes of M. Roy, P. U. Clark, R. W. Barendregt, J. R. Glasmann, and R. J. Enkin, 2004, Geological Society sediment and rocks, often for hundreds of America Bulletin, v. 116, no. 1–2, https://doi.org/10.1130/B25325.1). of miles. Deposits of debris, ranging in size from boulders to clay particles, Kansas. Wisconsinan ice reached as Many geologists believe we haven’t left are collectively called glacial drift. Drift far south as Nebraska and Iowa, and the last ice age and simply consider the deposits are found in Washington, glacial deposits from this period provide Holocene as a short warm period before Marshall, Nemaha, Brown, Doniphan, important clues to the Pleistocene the next glacial onset. Riley, Pottawatomie, Jackson, Atchison, ecology and climate. Jefferson, Leavenworth, Wyandotte, The Wisconsinan Stage at the end Kansas Glacial Features Johnson, Douglas, Shawnee, and of the Pleistocene Epoch was followed The initial Kansas ice front was Wabaunsee counties. by the Holocene Epoch (11,700 years probably only tens of feet thick and Most glacial landforms, such as ago to the present). Although the slid irregularly forward under pressure moraines (mounds or ridges of drift Holocene has been a warm period from thicker ice to the north. Buried deposited by direct action of glacier without active glaciation, fluctuations wood in Atchison and Doniphan ice), are largely absent in Kansas due in the climate still have occurred. A counties indicates that the ice likely to long periods of erosion since pre- time of significant climatic variability overrode a spruce forest there. If a time- Illinoian time. Some glacial features and from about 900 to 1300 AD known as lapse picture could have recorded the deposits, however, are still visible on the the Medieval Warm Period (MWP) Pleistocene Epoch, it would have shown surface. Directional grooves carved into was first identified in northern Europe a lurching, amoeba-like ice movement limestone bedrock have been mapped in and later also documented elsewhere, along with ecological waves of tundra, Nemaha, Brown, Doniphan, Atchison, including parts of the western United forests, and grasslands progressing Jefferson, Leavenworth, Wyandotte, States. A shift to droughts of shorter across the Great Plains as glaciers Johnson, and Shawnee counties. A thick duration around 1500 coincided with advanced and retreated. blanket of mixed soil and rocks, called the onset of cooler climatic conditions Advancing ice reshaped the land, till, covers large portions of northeastern during a period known as the Little Ice forcing new stream channels and burying Kansas. “Till” is Scottish for a drift Age, which contributed to widespread others. Before glaciation, the ancestral deposit that formed underneath glacial social unrest in Europe. In France, crop Missouri River was a lesser tributary to ice and was not reworked by meltwater failure due to climatic changes helped a larger ancestral Kansas River. Then (water from melting snow or ice that spark the French Revolution that led advancing ice pushed the drainage from flows out in streams and carries rocks to the beheading of Marie Antoinette. a now-buried river valley that flowed and sediment away from a glacier). 2 Figure 3. Sea of Sioux Quartzite erratics on ridge crest 5 miles (8 km) south of Wamego. Glacial ice carried and dropped Monument in southern Minnesota, was previously weathered rocks from carried almost 345 miles (552 km) into hundreds of miles away into Kansas. Kansas. Collectively called erratics, these Because glacial retreat exposed lake rock fragments range from the size beds and meltwater left river valleys of pebbles to house-sized blocks. The covered with silt-sized sediment, large most common is Sioux Quartzite, tracts of land were susceptible to wind a pink metamorphosed sandstone erosion. Strong prevailing winds picked more than a billion years old. Sioux up lightweight debris and whipped up Indiana Quartzite boulders in Kansas came from immense sand and sediment storms southern Minnesota, South Dakota, that far exceeded the storms of the Dust and northwestern Iowa. Sometimes Bowl era. These storms blanketed the these rocks occur in such density Midwest with sand dunes and thick that geologists describe the resulting layers of fine-grained silt called loess, block field or masses of rock rubble on which is still found at or near the surface summits as a felsenmeer, German for throughout much of Kansas (fig. 5). Figure 4. Sources of identifiable glacial erratics “sea of rocks” (fig. 3). Before disappearing from northeast found in northeastern Kansas. Fragments of More exotic erratics, such as granitic Kansas, pre-Illinoian ice thinned, Sioux Quartzite are common throughout the rocks, Lake Superior agate, Duluth-area leaving hilltops exposed like islands terminal zone and eastward into Missouri. iron ore, Keweenawan volcanics, and in a sea of ice. In valleys, stagnant and Specimens of ore from the Iron Ranges are native copper, are occasionally found in isolated ice persisted for centuries before scarce.