Australia Adjacent to Shark Bay Road beginning southeast of
Denham is an approximately long stretch of coastline composed of billions of tiny shells of the Shark Bay cockle (
Fragum erugatum), averaging less than in length. The shell deposit, between thick, has compacted and cemented in some areas into solid masses of limestone that formerly was quarried and cut into blocks used in local construction. St Andrew's
Anglican Church, the Old Pearler Restaurant, and parts of the Shark Bay Hotel in
Shark Bay were built from coquina shell blocks. The church, built in 1954, has walls infilled with coquina shell blocks between a light steel frame and a shell facing, while the Old Pearler was built in 1974–1977 with buttressed coquina shell block walls.
Brazil Recently discovered petroleum-bearing formations off the coast of northeastern Brazil hold coquina reservoirs of oil. The coquinas are generally heterogeneous in their porosity and permeability, but like other lacustrine carbonates, they are uncommonly reservoirs. Corbett et al. (2015) in their discussion of the reservoirs say the finding of the Badejo Field (
Campos Basin) in 1975 was the first hydrocarbon discovery in the coquinas of the Lagoa Feia, followed by that of the Pampo and Linguado Fields in 1978. The coquinas of the Morro do Chaves Formation were formed by non-marine bivalves and
ostracods. The shells of the bivalves, which lived in shallow oxygenated water, were transported and deposited as washout over stream fans and beaches by storms and
long-shore drift. The
palynological record of coquinas of the
Sergipe-Alagoas Basin has been analyzed and the sediments dated to the late
Barremian age; the results suggest a marine and/or brackish environment. Daniel Thompson (2013) asserts that the coquinas of the Morro do Chaves Formation include a wide range of marine mollusca characteristic of brackish environmental conditions, suggesting periodic marine ingression during the
Early Cretaceous. According to a paper by Senira Kattah published in
The Sedimentary Record, the discovery of the Lula Field by
Petrobras and partners in 2006 opened petroleum exploration in the Barremian/
Aptian pre-salt play in the offshore Santos and Campos basins, and consequently deeper coquina reservoirs have become important targets. He says the two main reservoir targets recognized for the pre-salt within the study areas are: "late rift coquinas, lacustrine
facies deposited at the Late Barremian to Early Aptian, and the younger rift/sag microbial limestones deposited during the Aptian, just before the establishment of the major evaporitic sag basin between South America and Africa." There are abundant beds of coquina in the Outer High of the
Santos Basin, similar to those from the neighboring Campos. Pre-salt stratigraphy of the Santos Basin shows lacustrine sediments composed of coarse
pelecypod (bivalve) coquina during the Barremian and Aptian sag phase of the
continental crust subsidence.
Mexico Overlying the fossiliferous sands and sandy clays of the upper
San Fernando River in northeastern Mexico is a bed of coquina limestone dating probably to the
Cenozoic era. Coquina deposits also occur in the
Baja California peninsula, including submerged "reefs". So-called coquina "reefs" occur at Punta Borrascosa, San Felipe and Coloraditos on the northeast coast of Baja California. These have been
uranium-thorium dated to the Pleistocene epoch, with an age estimated at 130,000
ybp. Semi-continuous coquina
outcrops have been found east of
Puerto Peñasco, in the shallow subtidal zone or partly submerged under
intertidal sands. Other Pleistocene outcrops occur along both coastlines of the upper
Gulf of California. On the Vizcaino Peninsula of western Baja California, the informally named "
Tivela stultorum" coquina is abundant in shells of the Pismo clam. Until analysis of the shells by U-series and amino-acids methods is concluded, this marine transgression is assigned an approximate age of 200,000 ybp. Outcrops in Bahía de San Hipolito and Bahía de Asunción are loosely consolidated, sandy
beachrock a few meters thick, found above present mean sea level. The ancient Maya built their city of
Toniná in the highlands of what is now
Chiapas in southern Mexico using native rocks to construct its
masonry buildings, among them large coquina
flagstones from which they made blocks and bricks for floors, walls, and stairways.
United States Florida Coquina deposits in Florida occur mostly along the eastern coast of the peninsula. This coquina is named the
Anastasia Formation after
Anastasia Island, where the Spanish quarried the rock to construct the
Castillo de San Marcos, the fortress they built to defend
St. Augustine. The Anastasia Formation stretches from just north of St. Augustine in
St. Johns County to southern
Palm Beach County. The formation and associated sand form part of the
Atlantic Coastal Ridge, a
Pleistocene barrier island chain that extends from
Duval County to
Dade County. Other coquina deposits are found in the state, but only in limited areas. The Anastasia Formation is naturally exposed in a number of places along the east coast including
Washington Oaks Gardens State Park,
Gilbert's Bar House of Refuge,
Hutchinson Island in
Martin County and
Blowing Rocks Preserve, owned by
The Nature Conservancy, in Martin County. Still occasionally
quarried or
mined, and used as a building stone in
Florida for over 400 years, coquina forms the walls of the Castillo in St. Augustine. The stone made a very good material for building forts, particularly those built during the period of heavy cannon use. Because of coquina's softness, cannonballs would sink into, rather than shatter or puncture the walls. The first
Saint Augustine lighthouse, built by the Spanish, was also made of coquina. Coquina was used as building stone in St. Augustine as early as 1598 for construction of a powder house. This was the beginning of a building tradition that extended into the 1930s along Florida's Atlantic Coast. In the St. Augustine vicinity, the Castillo de San Marcos,
Fort Matanzas, the old city gates, the
Cathedral, Spanish and British Period residential structures, property line walls and tombs were constructed of coquina quarried on Anastasia Island. To the south in
New Smyrna, a
large storehouse and wharf were constructed of coquina at the 1770s
Andrew Turnbull colony. Around 1816, John Addison constructed a kitchen house of coquina on his plantation on the
Tomoka River. The material was also used in the construction of sugar mill buildings on sugar plantations in the 1820s and 1830s. Examples are the
Bulow,
Dunlawton and
New Smyrna sugar mills. In these early structures, the porous coquina was protected by lime plaster. With the exception of a few residences that have been restored in St. Augustine, the coquina masonry of these structures is today exposed to the elements and is slowly deteriorating.
North Carolina Coquina has a very limited distribution in southeastern
North Carolina. The best known outcrop is located in
New Hanover County, near
Fort Fisher, along the southern tip of North Carolina's coast. It is one of the few naturally occurring outcrops in the
coastal plain region of North Carolina, described as "a low-relief plain underlain by beds of shallow-marine, estuarine, shoreline, and fluvial sediments" in
The Geology of the Carolinas. These sediments were deposited during numerous episodes of sea level rise and fall over hundreds of thousands of years. The coastlines of the
Tidewater region of North Carolina change constantly in response to wind and wave action, sedimentary deposition, tidal movements, and changes in sea level. Although the inner coastal plain is considered to be more stable, the coastal plain was inundated by repeated marine transgressions due to fluctuating sea levels during the late
Pliocene and early Pleistocene. Historical records and extant buildings, foundations, basements, and retaining walls indicate that coquina was being mined in North Carolina by at least 1760, evidenced by the extant architectural ruins at the colonial-era
Clear Springs Plantation near
New Bern.
Sedgeley Abbey, an 18th-century
plantation house on the lower
Cape Fear River was built of locally quarried coquina. The house, which once swas surrounded by a vast tract of land directly across the river from
Orton, was described by local historian and author James Sprunt as "the grandest colonial residence of the Cape Fear". Sprunt compared Sedgeley Abbey in dimensions and appearance to the two-story, cellared,
Governor Dudley mansion that still stands in
Wilmington. Like many southern plantations, Sedgeley Abbey was abandoned after the
Civil War and fell into disrepair. The vacant house was demolished in the 1870s and the coquina rubble was burned and spread on the fields as fertilizer. A cellar eight feet deep carved into solid coquina was located during archaeological investigations on the site of the former
plantation in 1978. ==Other uses==