Unravelling the Geologic History of Mosquito Lake State Park, Ohio

SCHUSTER, Kelsey M., kschust2@kent.edu, TIMKO, Samuel B. C., stimko3@kent.edu and HACKER, David B., Kent, OH 44242 Department of Geology

Kent State University, Kent, OH 44242

AcknowledgmentsOhio Department of Natural Resources Geology Division

Ohio Geological SurveyKent State University Map Library

Special Thanks to Stacee Stinedurf for all her hard work and dedication

AbstractTo the residents of Trumbull County, Mosquito

Lake, one of the largest lakes in Ohio, is a premier location for family camping and various water recreation activities. However, many are unaware of the geologic and glacial activities that shaped the area into what it is today. The objective of this project was to conduct a detailed investigation to better understand the geologic history of Mosquito Lake State Park.

Detailed investigation of the park was conducted through field work and published geologic data. From this data, bedrock and glacial geologic maps were derived using ArcGIS and MicroDEM mapping programs. Water well data was also used to determine the thickness of glacial material as well as subsurface bedrock formations. An east-west cross section was constructed to show the park’s geology in the subsurface.

The geology of the park shows a history of glacial advances during the Pleistocene that deposited drift material over older bedrock. Bedrock geology consists of Mississippian shales and sandstones that were deposited along ancient shorelines in delta and offshore marine environments. The area was later covered by several ice advances of the Wisconsinan Glacier during the late Pleistocene. The park contains three distinct glacial features: portion of the Defiance End Moraine, 40 to 70 feet thick, located in the southeastern sections of the park; ground moraine, 10 to 20 feet thick, forming the relatively flat surface of the western section of the park; and lacustrine deposits of former Rock Creek Lake located in the northern part of the park.

History and FeaturesMosquito Lake State Park was originally established to prevent flooding along the Mahoning River, in

addition to providing fresh water to the city of Warren. Many citizens of Trumbull County drive across the Route 305 dam each day. Mosquito Lake exhibits multiple glacial depositional areas. These deposits can be traced back to the Wisconsinan glacier, which advanced into Ice Age Ohio 22,000 years ago, and had retreated by 14,000 years ago. The bedrock deposited in the park beneath the glacial till is Devonian (~416 million years ago) in age. Any other rocks that were deposited after this time period were eroded away by rivers and the glacial advancement and retreat.

Glacial TillTill is a general term used for unsorted glacial sediment that is

deposited directly from the melting glacial ice during the glaciers retreat. Mosquito Lake’s glacial till consists of ground moraines, end moraines, as well as lacustrine plains, and outwash.

Ground moraines are areas of topography that are relatively flat to hilly caused by ice retreating rapidly. An end moraine is a ridge of till that forms at the front boundary of a glacier during times when the glacier is stationary. These contain more ridges and sharp topography.Lacustrine plains are sediments that have been left behind from the draining of a lake. Outwash is comprised of sandy and silty sediments that have been deposited by running water from glacial melting.

The Hiram Till is located north, west, and southwest of the park, and is a ground moraine consisting of clayey particles. The Lavery ground moraine is located east and southeast of the park, and consists of silty particles. A ridge of the Hiram end moraine, known as the Defience End Moraine, traverses the east side of the lake, then cuts across just south of the lake, and continues west. An outwash plain lies to the south of the park, just beneath the Hiram end moraine. A lacustrine plain at the immediate north of the lake, the source originating northwest of the park.

Bedrock GeologyThe bedrock geology in Mosquito Lake State Park and

the surrounding areas was laid down during the Devonian Age of the Paleozoic Era. The sedimentary layers consist of beds of primarily sandstones and shales, topped with glacial till. However, there are no bedrock exposures in the vicinity of the park. Bedrock units beneath the till include the Cuyahoga Shale, Berea Sandstone, Bedford Shale, Cussewago Sandstone, and the Chagrin Shale. These five rock layers were deposited in a primarily shallow marine environment.

Shale and sandstones are both sedimentary rocks, but exhibit differences in grain size and composition. Shale is fine grained and composed of mud, clay particles, and silt particles. Sandstone can be fine to coarse grained, and is made up of sand sized particles and minerals such as quartz and feldspars.

Bedrock GeologyThe bedrock geology in Mosquito Lake State Park and

the surrounding areas was laid down during the Devonian Age of the Paleozoic Era. The sedimentary layers consist of beds of primarily sandstones and shales, topped with glacial till. However, there are no bedrock exposures in the vicinity of the park. Bedrock units beneath the till include the Cuyahoga Shale, Berea Sandstone, Bedford Shale, Cussewago Sandstone, and the Chagrin Shale. These five rock layers were deposited in a primarily shallow marine environment.

Shale and sandstones are both sedimentary rocks, but exhibit differences in grain size and composition. Shale is fine grained and composed of mud, clay particles, and silt particles. Sandstone can be fine to coarse grained, and is made up of sand sized particles and minerals such as quartz and feldspars.

Ancient Lake Drainage Rock Creek Lake was originally present to the northwest

of Mosquito Creek during the Pleistocene Epoch. The deposits that were left behind from the draining of the lake was made up of fine sand and silt. When the lake began to drain, the waters traveled east to the Mosquito Creek, which then ultimately drained to the Mahoning River. The lacustrine plain present in the area today are the remains of the silty sediments that were once prevalent in Rock Creek Lake.

Geologic Time Scale(right) courtesy of paleo.cortland.edu

The relatively gentle topography formed by glacial sediments present around Mosquito Lake State Park.