The Geology of Jamaica is formed of rocks of

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

age. The basement consists of Cretaceous

island arc Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...

and

back-arc basin A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of ...

sequences that formed above a

subduction zone Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

. The cover is of mainly

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

shallow water

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

s, that have been uplifted due to the presence of a restraining bend along the major

strike-slip faults In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

that bound the southern edge of the

Gonâve Microplate Gonave may refer to: *Gulf of Gonâve *Gonâve Island *Gonâve Microplate See also *Gonaïves Gonaïves (; ht, Gonayiv, ) is a commune in northern Haiti, and the capital of the Artibonite department of Haiti. It has a population of about 300,00 ...

to the north of the island.

Cretaceous

Rocks of this age occur as a series of

inlier An inlier is an area of older rock (geology), rocks surrounded by younger rocks. Inliers are typically formed by the erosion of overlying younger rocks to reveal a limited outcrop, exposure of the older underlying rocks. Fault (geology), Faulting o ...

s within the younger limestones.

Rift basins

Rifting during the Paleogene led to the formation of rift basins in which thick sequences of clastic rocks were deposited that are exposed at the eastern end of the island in the John Crow and Wagwater belts.

Limestones

During the Eocene, limestone deposition started across the whole of the Nicaraguan Rise. In Jamaica the main limestone unit is the White Limestone Group, which dominates the surface exposure of the island, particularly its central parts and consists of pure limestones and

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

s. Locally the lowermost limestone is the

Yellow Limestone Group The Yellow Limestone Group is a geologic group in Jamaica. It preserves fossils dating back to the Paleogene period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainm ...

, which consists of interbedded limestones and other clastic rocks. Gonâve microplate

Restraining bend

During the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

, the northeastern margin of the Caribbean Plate began to collide with the Bahamas Platform. This caused the formation of a two new strike-slip fault zones between the island of

Hispaniola Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...

and the Mid-Cayman Spreading Center west of Jamaica, the Enriquillo-Plantain Garden fault zone and the

Walton fault zone The Walton fault zone is a major active left lateral (sinistral) strike-slip fault, forming part of the southern boundary to the Cayman Trough. It extends from the Mid-Cayman Rise spreading center in the west to Jamaica in the east. It has a total ...

. These fault zones now form part of the southern boundary of the Gonâve Microplate. The major right-stepping offset between the fault zones formed a restraining bend and led to transpression and uplift that is still active today and is the reason that the island of Jamaica is now well above sea level.

References

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