Nonesuch Shale

{{Short description|Geologic formation in Michigan and Wisconsin}}

{{Infobox rockunit

| name = Nonesuch Shale

| image = Native copper-replaced cross-bedded sedimentary rocks (Nonesuch Shale, Mesoproterozoic; White Pine Mine, Upper Peninsula of Michigan, USA) 1 (17110279879).jpg

| caption =Native copper replaces cross-bedded sedimentary rocks of the Nonesuch Shale, White Pine mine, Upper Peninsula of Michigan

| type = Formation

| age = Proterozoic

| period = Proterozoic

| prilithology =

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| region = {{Flag|Michigan}}

| country = {{Flag|United States}}

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| unitof = Oronto Group

| subunits =

| underlies = Freda Sandstone

| overlies = Copper Harbor Conglomerate

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File:Potholes (Presque Isle River, Porcupine Mountains State Park, Upper Peninsula of Michigan, USA) (21466113862).jpgs in Nonesuch shale, Presque Isle River, Porcupine Mountains State Park, Upper Peninsula of Michigan]]

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.{{cite journal|last1=Kelly|first1=William C.|last2=Nishioka|first2=Gail K.|title=Precambrian oil inclusions in late veins and the role of hydrocarbons in copper mineralization at White Pine, Michigan|journal=Geology|date=May 1985|volume=13|issue=5|pages=334–337|doi=10.1130/0091-7613(1985)13<334:POIILV>2.0.CO;2|bibcode=1985Geo....13..334K }} Together, the Copper Harbor, Nonesuch, and Freda make up the Oronto Group.Scott W. Imbus and others, "Organic geochemistry and sedimentology of middle Proterozoic Nonesuch Formation - hydrocarbon source rock assessment of a lacustrine rift deposit," in Lacustrine Basin Exploration, Tulsa, Okla.: American Association of Petroleum Geologists, p.197-208 The Nonesuch is Middle Proterozoic, with an estimated age of approximately 1.1 billion years. It was deposited in the Midcontinent Rift.Albert B Dickas, “Midcontinent rift system: Precambrian hydrocarbon target,” Oil and Gas Journal, 15 October 1984, p.151-159. The Nonesuch beds contain common organic carbon and pyrite.