Robert G. Marvinney State Geologist

Maine Geological Survey Dept Agriculture, Conservation and Forestry

Maine’s Geology and

Mineral Potential

November 9, 2012 Geological Society of Maine

Presentation Overview

Maine Geological Survey – who we are

Our place in the Northern Appalachians

Overview of Maine Geology

Important Mineral Discoveries

Types and Associations

Assistance from the Maine Geological Survey

Within the Department of Agriculture, Conservation and

Forestry, one of several Natural Resources departments in

Maine government

Programs in

Bedrock mapping

Surficial mapping

Groundwater resources characterization

Coastal/marine geology.

Hazards

Maine Geological Survey

Bedrock

and

Surficial

mapping

projects

Northern Appalachians

Northern Appalachian Terranes

Hibbard and others, 2006, Lithotectonic map of the Appalachian orogen

A Brief Word on Plate Tectonics

Geology of Maine and New Brunswick

Hibbard and others, 2006, Lithotectonic map of the Appalachian orogen

Significant

Mineral Deposits

Bald Mountain: 30 MT

Cu, Zn, Au, Ag

Alder Pond: 3 MT Zn,

Cu, Pb, Ag

Warren Nickel

Harborside and Second

Lake: Mined in the

1970s

Tectonic Settings of Metal Deposits

From Skinner and Porter, 1987

Tectonic Settings of Metal Deposits

Hydrothermal Vents

Porphyry Cu/Mo

Late stage of

granite intrusion

with extensive

fracture system

above cooling

magma.

Significant

Mineral Deposits

Commodity:

Base Metals

Cu, Pb, Zn, Fe, Ni,

(Mn)

Significant

Mineral Deposits

Commodity:

Precious Metals

(Au, Ag)

Significant

Mineral Deposits

Maine’s geology hosts

a variety of genetic

mineral deposit

types.

Maine Minerals Information on the Web

Significant Mineral Deposits

Google: Maine

Geological Survey

Significant Mineral Deposits

Google: Maine

Geological Survey Scanned Core Records

in Google Earth

Resources:

Geologists knowledgeable about Maine’s mineral

resources.

Geologic maps and reports.

Core facility – hundreds of core and logs from past

exploration.

Assistance:

Guidance on land ownership.

Listing of consulting geologists in Maine.

Contact information for regulatory agencies.

Maine Geological Survey

Current Activities:

Geologic mapping – bedrock and surficial.

Groundwater investigations.

Geologic hazards.

Future Activities:

Web-accessible core logs.

Statewide airborne geophysical survey.

Maine Geological Survey

Exploration

History

Basic geologic

mapping 1837-1950

identified coastal

base metal deposits.

1950s-1960s:

Government-funded

airborne geophysical

surveys identified

prospective areas.

1970s-1980s: Privately

funded exploration

in northern volcanic

belts.

Geology

Many diverse geologic environments.

Igneous and Volcanic terranes that may host a

variety of deposits.

Metal deposits

Numerous mineral occurrences.

Several well-characterized deposits.

Opportunities for undiscovered resources.

Summary

Prospecting in Maine