Nonesuch Shale
Encyclopedia
The Nonesuch Shale is a Proterozoic
geologic formation that outcrops in Michigan
and Wisconsin
, United States
, but has been found by drill holes to extend in the subsurface as far southwest as Iowa
.
The Nonesuch is a lacustrine
sequence of shale
, siltstone
, and sandstone
, 150 to 210 m thick, that conformably overlies the alluvial Copper Harbor Conglomerate and is conformably overlain by the fluvial
Freda Sandstone. Together, the Copper Harbor, Nonesuch, and Freda make up the Oronto Group
. The Nonesuch is Middle Proterozoic, with an estimated age of approximately 1.1 billion years. It was deposited in the Midcontinent Rift. The Nonesuch beds contain common organic carbon and pyrite
.
, and is considered a prospective source of petroleum
.
in Ontonagon County, Michigan
, failed because of the difficulty of recovering the fine grains of native copper
.
The Copper Range Company
opened the White Pine mine in Ontonagon County, Michigan
, in 1955. The principal ore minerals were chalcocite
and native copper
. The underground mine produced copper from the Nonesuch Shale until it closed in 1995.
for petroleum. Oil identified as Precambrian
has been found seeping into the White Pine copper mine in Michigan. Exploration wells have been drilled to Nonesuch-equivalent sediments in the rift basin in Michigan, Wisconsin
, and Iowa
, but no petroleum deposits have been discovered.
Proterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
geologic formation that outcrops in Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
and Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, but has been found by drill holes to extend in the subsurface as far southwest as Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
.
The Nonesuch is a lacustrine
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
sequence of shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
, siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
, and sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
, 150 to 210 m thick, that conformably overlies the alluvial Copper Harbor Conglomerate and is conformably overlain by the fluvial
Fluvial
Fluvial is used in geography and Earth science to refer to the processes associated with rivers and streams and the deposits and landforms created by them...
Freda Sandstone. Together, the Copper Harbor, Nonesuch, and Freda make up the Oronto Group
Oronto Group
The Oronto group is a thick group of arkose sandstone and shale located beneath the Bayfield Group in northern Wisconsin, and believed to extend into Minnesota. Because it is almost entirely red in color and highly tilted, it is considered separate from the Bayfield Group. The Oronto group is...
. The Nonesuch is Middle Proterozoic, with an estimated age of approximately 1.1 billion years. It was deposited in the Midcontinent Rift. The Nonesuch beds contain common organic carbon and pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...
.
Natural resources
The Nonesuch Formation has been a major source of copperCopper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, and is considered a prospective source of petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
.
Copper
Copper was discovered in the Nonesuch in the 1800s, but early mining efforts, such as those at the Nonesuch MineNonesuch Mine
The Nonesuch Mine is an abandoned copper mine and small ghost town in the southeast corner of the Porcupine Mountains State Park in Carp Lake Township, Ontonagon County, near Silver City, Michigan, United States. The area was given its name soon after Ed Less discovered the Nonesuch vein of copper...
in Ontonagon County, Michigan
Ontonagon County, Michigan
-National protected areas:* Keweenaw National Historical Park * Ottawa National Forest -Demographics:As of the census of 2000, there were 7,818 people, 3,456 households, and 2,225 families residing in the county. The population density was 6 people per square mile . There were 5,404 housing units...
, failed because of the difficulty of recovering the fine grains of native copper
Native copper
Copper, as native copper, is one of the few metallic elements to occur in uncombined form as a natural mineral, although most commonly occurs in oxidized states and mixed with other elements...
.
The Copper Range Company
Copper Range Company
The Copper Range Company was a major copper-mining company in the Copper Country of Michigan, United States. It began as the Copper Range Company in the late 19th century as a holding company specializing in shares in the copper mines south of Houghton, Michigan...
opened the White Pine mine in Ontonagon County, Michigan
Ontonagon County, Michigan
-National protected areas:* Keweenaw National Historical Park * Ottawa National Forest -Demographics:As of the census of 2000, there were 7,818 people, 3,456 households, and 2,225 families residing in the county. The population density was 6 people per square mile . There were 5,404 housing units...
, in 1955. The principal ore minerals were chalcocite
Chalcocite
Chalcocite, copper sulfide , is an important copper ore mineral. It is opaque, being colored dark-gray to black with a metallic luster. It has a hardness of 2½ - 3. It is a sulfide with an orthorhombic crystal system....
and native copper
Native copper
Copper, as native copper, is one of the few metallic elements to occur in uncombined form as a natural mineral, although most commonly occurs in oxidized states and mixed with other elements...
. The underground mine produced copper from the Nonesuch Shale until it closed in 1995.
Petroleum
The Nonesuch Shale has sufficient organic carbon content (greater than 0.5%) to be considered a potential sourcebedSource rock
In petroleum geology, source rock refers to rocks from which hydrocarbons have been generated or are capable of being generated. They form one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments including...
for petroleum. Oil identified as Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
has been found seeping into the White Pine copper mine in Michigan. Exploration wells have been drilled to Nonesuch-equivalent sediments in the rift basin in Michigan, Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, and Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
, but no petroleum deposits have been discovered.