Geology About Farmington Hills, MI

Farmington Hills is a city in southeastern Michigan, located in western Oakland County. With a population of over 80,000, it is one of the largest suburbs of Detroit.

The geology of Farmington Hills provides insights into the natural history and land formation processes that have shaped this area over millions of years. In this local guide, we will explore the basic geology, rock formations, soils, minerals, and other geological features that characterize the landscape of Farmington Hills.

Basic Geology

Regional Setting

Farmington Hills is situated on the Interior Plains physiographic province of North America. This stable region has been shaped over long periods of time by glaciation, erosion, and deposition. The topography is characterized by relatively flat plains, gentle hills, and ancient glacial landforms.

The bedrock underneath Farmington Hills consists of sedimentary rocks dating back to the Mississippian and Pennsylvanian subperiods of the Carboniferous period, between 358 and 298 million years ago.

During this time, shallow seas covered the region, accumulating layers of marine sediments like sandstone, shale, limestone and dolostone. These bedrock units tilt downward toward the Michigan Basin, a circular depression filled with younger sedimentary rocks.

Surficial Geology

The bedrock surface is overlain by unconsolidated glacial deposits left behind by the retreat of massive ice sheets during the last ice age. These deposits include ground moraine, end moraine, outwash plains, ice-contact stratified drift, lacustrine deposits, and loess.

The composition ranges from clay, silt, sand, gravel, and boulders. In some areas, the glacial drift can reach hundreds of feet in thickness. The landscape has also been reshaped by streams and rivers cutting into the relatively soft sediments.

Rock Formations

The uppermost bedrock units found in Farmington Hills belong to the Mississippian Marshall Formation and Michigan Formation, and the Pennsylvanian Saginaw Formation.

Marshall Formation

This consists of marine sandstone, shale, and limestone. The sandstones are fine-grained and gray, yellowish, or brown. The shales are gray, green, and reddish. The limestones are usually gray to brown. Fossils include brachiopods, bryozoans, crinoids, blastoids, and corals.

Michigan Formation

This is composed of dolomite and dolomitic limestone. Dolostone makes up the bulk of this formation, and it varies from tan, brown, and gray depending on clay content. It contains stromatolites, brachiopods, corals, and other marine fossils.

Saginaw Formation

The lower portion of this group contains sandstone, shale, and limestone deposited in a coastal environment. The upper portion is composed of sandstone, shale, and coal formed in a terrestrial swamp setting. Tracks, trails, and plant fossils are found in this formation.

Glacial Landforms

Farmington Hills contains many classic glacial features that were molded into the landscape by the advance and retreat of massive ice sheets during the Pleistocene epoch.

Moraines

Moraines are accumulations of unsorted, unstratified sediments called till that were bulldozed and pushed forward by the leading glacial ice margin. The hilly terrain of Farmington Hills marks the former presence of end moraines created when the glacier temporarily halted, piling up debris along its edge. Later melting formed pitted outwash plains and kettle lakes.

Eskers

These winding ridges represent the remains of old glacial river channels that flowed within or under the ice. They can be found crossing parts of Farmington Hills, rising above the flat outwash plains. Eskers consist of stratified sand and gravel deposited by glacial streams.

Kettle Lakes

These water bodies were formed when large blocks of ice calved off the glacier, became buried in sediment, and melted to leave behind depressions that later filled with water. Dozens of scenic kettle lakes dot the landscape across Farmington Hills.

Drumlins

Drumlins are elongated teardrop shaped hills made of till that were molded into shape beneath the ice sheet as it advanced over the land. They have a gently sloping side that aligned to the glacier flow direction. Several drumlins have been mapped within the hilly moraine belts.

Soils

The soils across Farmington Hills reflect the glacial parent materials, topography, climate, and natural vegetation. They are mostly well drained loamy soils formed in glacial till and outwash.

Some of the main soil series include:

• Miami soils – loamy, mixed soils found on till plains and moraines. Well drained and moderately permeable.
• Conover soils – sandy, coarse-loamy soils on outwash plains. Excessively drained and rapid permeability.
• Brookston soils – fine loamy soils in lowlands and drainageways on glacial outwash. Poorly drained.
• Houghton mucks – very poorly drained organic soils in depressions and kettle holes. High organic content.

Economic Geology

Crushed Stone

Sand, gravel, and crushed limestone quarries operate in Farmington Hills and the surrounding region to produce construction aggregate for roads, concrete, asphalt, and other uses. These resources originate from glacial deposits.

Oil and Gas

Northern and western portions of Oakland County have a history of oil and gas production dating back to the 1920s. The Antrim Shale provides a source rock, and reservoirs occur in the Thumb Formation sandstone member. Small oil and gas fields have been developed in Farmington Hills and adjacent townships.

Groundwater

The unconsolidated glacial deposits form a significant groundwater reservoir that is tapped by municipal and household water wells across the area. However, overpumping has caused water levels to decline in some locations. Rivers, lakes, and wetlands are hydrologically connected to this aquifer system.

Geologic Sites of Interest

There are several parks and nature areas in Farmington Hills that showcase the local glacial landscape and geology:

• Riley Park – Features rolling moraine topography, kettle lakes, wetlands, hiking trails.
• Power Park/Farmington Hills Golf Club – Glacial terrain with kames, eskers, kettle lakes. Part of Huron River watershed.
• Heritage Park – Panoramic views from steep end moraine slopes and ravines. Also archaeological sites.
• Brecon Park – Scenic drumlins, eskers, and moraines.
• Chatham Hills Park – Hilly end moraine with ravines.

Conclusion

In summary, the landscape of Farmington Hills reveals a complex glacial history shaped by the advance and retreat of massive ice sheets during the last ice age. The rolling topography and scenic kettle lakes provide clues to the erosional and depositional processes during glaciation.

The soils and surficial geology influence land usage, ecology, water resources, and development in the region. As one of Michigan’s larger suburbs, understanding the geology provides insights into how the natural setting and resources of the area have influenced human settlement and activities.