The Yankee Joe Formation is a

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

exposed in the Blackjack Mountains, Arizona, US. The age of the formation is between 1474 and 1436 million years, and

detrital zircon geochronology Detrital zircon geochronology is the science of geochronology, analyzing the age of zircons deposited within a specific sedimentary rock, sedimentary unit by examining their inherent radioisotopes, most commonly the uranium–lead dating, uranium ...

of its

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

s provides clues for reconstruction the

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...

Rodinia Rodinia (from the Russian родина, ''rodina'', meaning "motherland, birthplace") was a Mesoproterozoic and Neoproterozoic supercontinent that assembled 1.26–0.90 billion years ago (Ga) and broke up 750–633 million years ago (Ma). wer ...

Description

The Yankee Joe Formation consists of of

argillaceous Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay mineral ...

(

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

-rich) sediments.

Detrital zircon geochronology Detrital zircon geochronology is the science of geochronology, analyzing the age of zircons deposited within a specific sedimentary rock, sedimentary unit by examining their inherent radioisotopes, most commonly the uranium–lead dating, uranium ...

establishes a minimum age for the formation of 1474 ± 13 million years. The overlying Blackjack Formation is intruded by the Ruin Granite, with a radiometric age of 1436 ± 2 million years, thus constraining the age of the Yankee Joe to 1474 to 1436 million years. The formation was originally assigned to the Hess Canyon Group, in which it overlies the

White Ledges Formation The White Ledges Formation is a geologic formation that crops out in central Arizona, US. Detrital zircon geochronology establishes a maximum age for the formation of 1726 million years ( Mya), in the Statherian period of the Precambrian. The for ...

and is in turn overlain by the Blackjack Formation. The formation is divided into three informal

members Member may refer to: * Military jury, referred to as "Members" in military jargon * Element (mathematics), an object that belongs to a mathematical set * In object-oriented programming, a member of a class ** Field (computer science), entries in ...

. The lower member is of brown to maroon

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

, with some

arkose Arkose () or arkosic sandstone is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose. Components ...

and

graywacke Greywacke or graywacke ( ) is a variety of sandstone generally characterized by its hardness (6–7 on Mohs scale), dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or sand-size lithic fragments set i ...

at the base of the member. The middle member is of tan to white mudstone with some

silty Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

. The upper member is of brown

slate Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...

that grades upwards into

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

-rich arkose. The formation erodes to a slope and is visibly folded. The formation is interpreted as a nearshore fluvial and tidal deposit. It has been heavily deformed by thrusting that produced ~50% shortening. The formation was deposited in a large basin, the Yankee Joe — Defiance basin, which is contemporaneous with the Picuris basin. Detrital zircon age spectrums and isotope ratios from the formation support a reconstruction of the

, in which Australia was a source of sediments for southwestern

Laurentia Laurentia or the North American craton is a large continental craton that forms the Geology of North America, ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of ...

History of investigation

The formation was first named by D.E. Livingston in 1969 for outcroppings north of

Globe, Arizona Globe ( "Place of Metal") is a city in and the county seat of Gila County, Arizona, Gila County, Arizona, United States. As of the 2020 United States census, 2020 census, the population of the city was 7,249. Globe was founded c. 1875 as a mini ...

. Michael F. Doe and coinvestigators proposed removing the Yankee Joe and Blackjack into the Yankee Joe Group.

References

{{reflist Geologic formations of Arizona Precambrian United States Mudstone formations of the United States