Foreword

Introduction

Acknowledgments

Overview

Water Use

Topography of the County

Geology of the County

Groundwater Availability

Exploration for Groundwater

Karst

Water Quality

Maps and Data

Additional Reading

References Cited

Definitions of Geologic Terms

Rock Descriptions

In Lincoln County, water is obtained from consolidated sedimentary rocks ranging in age from Ordovician to Mississippian, and from unconsolidated sediments of Quaternary age. The oldest rocks exposed on the surface in Lincoln County were deposited in shallow seas 450 million years ago during the Late Ordovician Period. Above the Ordovician rocks are rocks of the Devonian Period, which includes the New Albany Shale. The New Albany Shale, also called the black shale, was formed 400 million years ago when the deep sea floor became covered with an organic black muck. The muck is now hard, black shale (an oil shale) and is one of the most distinctive of all geologic formations in Kentucky. The Mississippian sandstones and siltstones are the result of a great influx of muds, silts, and sands brought in by rivers and streams from uplands many miles away and deposited as a great delta. The Mississippian limestones found in Lincoln County were deposited 350 million years ago in the bottom of a warm, shallow sea. Over the last million years, unconsolidated Quaternary sediments have been deposited along the larger streams and rivers.

Geologic Formations in the County
Unconsolidated deposits
Alluvium (Qa)

Limestones
St. Louis Limestone (Mgl)
Salem and Warsaw Formations (Msh)
Borden Formation (Mbf)
UPPER PART OF Lexington Limestone (Tanglewood Limestone, Millersburg, Strodes Creek, Devils Hollow, Sulfur Well, Brannon, and Perryville Members) (Ol)
LOWER PART OF Lexington Limestone (Grier, Logana, and Curdsville Members) (Ol)
HIGH BRIDGE GROUP ( Tyrone Limestone, Oregon Formation, Camp Nelson Limestone) (Ohb)

Dolomites
KNOX GROUP (Okx)

Interbedded clay shales, siltstones, and sandstones
Borden Formation (MDbb)
Garrard Siltstone (Okc)

Fractured shales
New Albany Shale (MDnb)
Boyle Dolomite (MDnb)

Clay shales
Crab Orchard Formation and Brassfield Dolomite (Scb)

Interbedded limestones and shales
ASHLOCK FORMATION and Calloway Creek Limestone (Oaf)
Drakes Formation (Od)
Clays Ferry Formation Okc)

Interbedded shales and limestones
KOPE FORMATION (Okc)

For more information, see the definitions of geologic terms and rock descriptions, a geologic map of Lincoln County, a summary of the geology of Kentucky, and a discussion of fossils and prehistoric life in Kentucky.

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