Resolution Guyot (formerly known as Huevo) is a

guyot In marine geology, a guyot (pronounced ), also known as a tablemount, is an isolated underwater volcanic mountain (seamount) with a flat top more than below the surface of the sea. The diameters of these flat summits can exceed .Mid-Pacific Mountains The Mid-Pacific Mountains (MPM) is a large oceanic plateau located in the central North Pacific Ocean or south of the Hawaiian–Emperor seamount chain. Of volcanic origin and Mesozoic in age, it is located on the oldest part of the Pacific Plat ...

in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

. It is a circular flat mountain, rising above the seafloor to a depth of about , with a wide summit platform. The Mid-Pacific Mountains lie west of

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only ...

and northeast of the

Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Internati ...

, but at the time of its formation the guyot was located in the Southern Hemisphere. The guyot was probably formed by a

hotspot Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tra ...

in today's

French Polynesia )Territorial motto: ( en, "Great Tahiti of the Golden Haze") , anthem = , song_type = Regional anthem , song = "Ia Ora 'O Tahiti Nui" , image_map = French Polynesia on the globe (French Polynesia centered).svg , map_alt = Location of French ...

before

plate tectonics Plate tectonics (from the la, label= Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large t ...

shifted it to its present-day location. The

Easter Easter,Traditional names for the feast in English are "Easter Day", as in the '' Book of Common Prayer''; "Easter Sunday", used by James Ussher''The Whole Works of the Most Rev. James Ussher, Volume 4'') and Samuel Pepys''The Diary of Samuel ...

Marquesas The Marquesas Islands (; french: Îles Marquises or ' or '; Marquesan: ' (North Marquesan) and ' (South Marquesan), both meaning "the land of men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in ...

Pitcairn The Pitcairn Islands (; Pitkern: '), officially the Pitcairn, Henderson, Ducie and Oeno Islands, is a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territory in the Pacific Ocean. The four is ...

and

Society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same Politics, political authority an ...

hotspots, among others, may have been involved in the formation of Resolution Guyot. Volcanic activity has been

dated Date or dates may refer to: *Date (fruit), the fruit of the date palm (''Phoenix dactylifera'') Social activity * Dating, a form of courtship involving social activity, with the aim of assessing a potential partner **Group dating *Play date, a ...

to have occurred 107–129 million years ago and formed a

volcanic island Geologically, a high island or volcanic island is an island of volcanic origin. The term can be used to distinguish such islands from low islands, which are formed from sedimentation or the uplifting of coral reefs (which have often form ...

that was subsequently flattened by erosion.

Carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonat ...

deposition commenced, forming an

atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can ...

-like structure and a

carbonate platform A carbonate platform is a sedimentary body which possesses topographic relief, and is composed of autochthonic calcareous deposits. Platform growth is mediated by sessile organisms whose skeletons build up the reef or by organisms (usually mic ...

. The platform emerged above sea level at some time between the

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± ...

and

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded ...

ages before eventually drowning for reasons unknown between the Albian and the

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interv ...

Thermal subsidence In geology and geophysics, thermal subsidence is a mechanism of subsidence in which conductive cooling of the mantle thickens the lithosphere and causes it to decrease in elevation. This is because of thermal contraction: as mantle material cools ...

lowered the drowned seamount to its present depth. After a hiatus, sedimentation commenced on the seamount and led to the deposition of manganese crusts and

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

sediments, some of which were later modified by

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

Name and research history

Resolution Guyot was informally known as Huevo Guyot before it was renamed after the drilling ship ''

JOIDES Resolution 295px, Drillship ''JOIDES Resolution'' in 1988 The riserless research vessel ''JOIDES Resolution'' (Joint Oceanographic Institutions for Deep Earth Sampling), often referred to as the JR, is one of the scientific drilling ships used by the Interna ...

'' during Leg 143 of the

Ocean Drilling Program The Ocean Drilling Program (ODP) was a multinational effort to explore and study the composition and structure of the Earth's oceanic basins. ODP, which began in 1985, was the successor to the Deep Sea Drilling Project initiated in 1968 by ...

in 1992. During that Leg, ''JOIDES Resolution'' took

drill core A modern core drill is a drill A drill is a tool used for making round holes or driving fasteners. It is fitted with a bit, either a drill or driverchuck. Hand-operated types are dramatically decreasing in popularity and cordless batter ...

s from Resolution Guyot called 866A, 867A and 867B; 866A was drilled on its summit, 867B (and the unsuccessful drilling attempt 867A) on its platform margin, and 868A on a terrace outside of the platform.

Geography and geology

Local setting

Resolution Guyot is part of the western

Mid-Pacific Mountains The Mid-Pacific Mountains (MPM) is a large oceanic plateau located in the central North Pacific Ocean or south of the Hawaiian–Emperor seamount chain. Of volcanic origin and Mesozoic in age, it is located on the oldest part of the Pacific Plat ...

, located west of

, north-northeast of the

. Unlike conventional Pacific Ocean island chains, the Mid-Pacific Mountains are a group of

oceanic plateau An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides. There are 184 oceanic plateaus in the world, covering an area of or about 5.11% of the ...

s with

guyot In marine geology, a guyot (pronounced ), also known as a tablemount, is an isolated underwater volcanic mountain (seamount) with a flat top more than below the surface of the sea. The diameters of these flat summits can exceed .) that become progressively younger towards the east. Other guyots in the Mid-Pacific Mountains are Sio South,

Darwin Darwin may refer to: Common meanings * Charles Darwin (1809–1882), English naturalist and writer, best known as the originator of the theory of biological evolution by natural selection * Darwin, Northern Territory, a territorial capital city i ...

Thomas Thomas may refer to: People * List of people with given name Thomas * Thomas (name) * Thomas (surname) * Saint Thomas (disambiguation) * Thomas Aquinas (1225–1274) Italian Dominican friar, philosopher, and Doctor of the Church * Thomas the ...

, Heezen, Allen,

Caprina ''Caprina'' is a genus of rudists, a group of marine heterodont bivalves belonging to the family Caprinidae. These stationary intermediate-level epifaunal suspension feeders lived in the Cretaceous period, from 140.2 to 70.6 Ma. The rudists b ...

Jacqueline Jacqueline may refer to: People * Jacqueline (given name), including a list of people with the name * Jacqueline Moore (born 1964), ring name "Jacqueline", American professional wrestler Arts and entertainment * ''Jacqueline'' (1923 film), ...

and

Allison Allison may refer to: People * Allison (given name) * Allison (surname) (includes a list of people with this name) * Eugene Allison Smith (1922-1980), American politician and farmer Companies * Allison Engine Company, American aircraft engine ...

. The seamount is about high and rises from a raised seafloor to a depth of about . At a depth of it is capped off by a wide rather flat and roughly circular summit platform with a high rim and a moat inside of this rim. At the margin of the platform, structures interpreted as

sea cliff Seacliff or Sea Cliff or Sea Cliffe may refer to: ;Places ''Australia'' * Seacliff, South Australia, suburb of Adelaide * Seacliff Park, South Australia, a suburb of Adelaide * Sea Cliff Bridge, in Illawarra, New South Wales ''New Zealand'' * Se ...

s or wave cut terraces have been found; at one site there is a terrace about wide, surmounted by a high cliff. Pinnacles and depressions dot the surface platform. The surface of the platform consists of

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 wh ...

that is partially covered by pelagic sediments; underwater cameras have shown the presence of rock slabs covered by ferromanganese crusts. The guyot rises from a seafloor of

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

age (201.3 ± 0.2 – ca. 145 million years ago) that might be as much as 154 million years old. Terrestrial

organic Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ Chemistry * Organic matter, matter that has come from a once-living organism, is capable of decay or is the product o ...

material on the seafloor around Resolution Guyot originated from when it was still an island, and carbonate sediments swept away from the guyot ended up on the surrounding seafloor.

Regional setting

The

seafloor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

contains many guyots formed during the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Creta ...

age (251.902 ± 0.3 – 66 million years ago) in unusually shallow seas. These submarine mountains are characterized by a flat top and usually the presence of

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonat ...

platforms that rose above the sea surface during the middle

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 ...

(ca. 145 – 66 million years ago). While there are some differences to present-day reef systems, many of these seamounts were formerly

s, which still exist. These structures formed as volcanoes in the Mesozoic ocean.

Fringing reef A fringing reef is one of the three main types of coral reef. It is distinguished from the other main types, barrier reefs and atolls, in that it has either an entirely shallow backreef zone (lagoon) or none at all. If a fringing reef grows dire ...

s may have developed on the volcanoes, which then became

barrier reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Co ...

s as the volcano subsided and turned into an atoll, and which surround a

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into '' coastal lagoons'' (or ''barrier lagoons' ...

or a

tidal flat Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal f ...

. The crust underneath these seamounts tends to subside as it cools, and thus the islands and seamounts sink. Continued subsidence balanced by upward growth of the reefs led to the formation of thick carbonate platforms. Sometimes volcanic activity continued even after the formation of the atoll or atoll-like structure, and during episodes where the platforms rose above sea level erosional features such as channels and

blue hole A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock ( limestone or coral reef). Their existence was discovered in the late 20th century by fi ...

s developed. The formation of many seamounts has been explained by the

theory, which suggests that the chains of volcanoes become progressively older along the length of the chain, with an erupting volcano only at one end of the system. Resolution lies on a volcano on the

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years ...

heated from below; as the

plate Plate may refer to: Cooking * Plate (dishware), a broad, mainly flat vessel commonly used to serve food * Plates, tableware, dishes or dishware used for setting a table, serving food and dining * Plate, the content of such a plate (for example: ...

shifts it is moved away from the heat source and volcanic activity ceases, producing a chain of volcanoes that get progressively older away from those currently active. Potential hotspots involved in the formation of Resolution Guyot are the

and in some plate reconstructions the

Pitcairn hotspot The Pitcairn hotspot is a volcanic hotspot located in the south-central Pacific Ocean. Over the past 11 million years, it has formed the Pitcairn-Gambier hotspot chain. It is responsible for creating the Pitcairn Islands and two large seamounts ...

s although not all point at a presently active hotspot. More than one hotspot may have influenced the growth of Resolution Guyot, and it and Allison Guyot may have been formed by the same hotspot(s). The entire Mid-Pacific Mountains may be the product of such a hotspot.

Composition

Rocks found at Resolution Guyot include

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of a ...

of the volcano and carbonates deposited in shallow-water conditions on the volcano. Minerals found in the basalt are

alkali feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...

clinopyroxene The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...

feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feld ...

ilmenite Ilmenite is a titanium-iron oxide mineral with the idealized formula . It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printing ...

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With ...

olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers qui ...

plagioclase Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more pro ...

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals. Properties ...

and

titanomagnetite Titanomagnetite is a mineral containing oxides of titanium and iron, with the formula Fe2+(Fe3+,Ti)2O4. It is also known as titaniferous magnetite, mogensenite, Ti-magnetite, or titanian magnetite. It is part of the spinel group of minerals. The Cu ...

; the olivine, plagioclase and pyroxenes form

phenocryst 300px, Swiss side of the Mont Blanc massif, has large white plagioclase phenocrysts, triclinic minerals that give trapezoid shapes when cut through). 1 euro coins, 1 euro coin (diameter 2.3 cm) for scale. A phenocryst is an early forming, relati ...

s. Alteration has produced

analcime Analcime (; ) or analcite is a white, gray, or colorless tectosilicate mineral. Analcime consists of hydrated sodium aluminium silicate in cubic crystalline form. Its chemical formula is Na Al Si2 O6· H2O. Minor amounts of potassium and calc ...

ankerite Ankerite is a calcium, iron, magnesium, manganese carbonate mineral of the group of rhombohedral carbonates with the chemical formula . In composition it is closely related to dolomite, but differs from this in having magnesium replaced by varyi ...

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scra ...

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay part ...

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of ...

iddingsite Iddingsite is a microcrystalline rock that is derived from alteration of olivine. It is usually studied as a mineral, and consists of a mixture of remnant olivine, clay minerals, iron oxides, and ferrihydrites. Debates over iddingsite's non-defi ...

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue giv ...

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

saponite Saponite is a trioctahedral mineral of the smectite group. Its chemical formula is . It is soluble in sulfuric acid. It was first described in 1840 by Svanberg. Varieties of saponite are griffithite, bowlingite and sobotkite. It is soft ...

, serpentine and

zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These ...

. The basalts represent an

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

intraplate In geology, anorogenic magmatism is the formation, intrusion or eruption of magmas not directly connected with orogeny (mountain building). Anorogenic magmatism occurs, for example, at mid-ocean ridges, hotspots and continental rifts. This contrasts ...

suite, earlier

trachybasalt Trachybasalt is a volcanic rock with a composition between trachyte and basalt. It resembles basalt but has a high content of alkali metal oxides. Minerals in trachybasalt include alkali feldspar, calcic plagioclase, olivine, clinopyroxene and li ...

s containing

biotite Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron- endmember annite, and the magnesium-endmember phlogopite; more alum ...

have been recovered as well. The carbonates occur in the form of boundstone,

carbonate hardground Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor (Wilson and Palmer, 1992). A hardground is essentially, then, a lithified seafloor. Ancient hardgrounds are found in limestone ...

floatstone Floatstone is a type of carbonate rock. The original Dunham classification (Dunham, 1962) of limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed m ...

grainstone Under the Dunham classification (Dunham, 1962) system of limestones, a grainstone is defined as a grain-supported carbonate rock that contains less than 1% mud-grade material. This definition has recently been clarified as ''a carbonate-dominat ...

, grapestone,

oncoid Oncolites are sedimentary structures composed of oncoids, which are layered structures formed by cyanobacterial growth. Oncolites are very similar to stromatolites, but, instead of forming columns, they form approximately spherical structures. ...

s, ooliths,

packstone Under the Dunham classification (Dunham, 1962Dunham, R.J. (1962) Classification of carbonate rocks according to depositional texture. In: Classification of Carbonate Rocks (Ed. W.E. Ham), Am. Assoc. Pet. Geol. Mem., 1, 108–121.) system of limest ...

peloid Peloid is mud, or clay used therapeutically, as part of balneotherapy, or therapeutic bathing. Peloids consist of humus and minerals formed over many years by geological and biological, chemical and physical processes. Numerous peloids are avai ...

rudstone Rudstone is a type of carbonate rock. The Dunham classification (Dunham, 1962) did not consider grain size as a criterion for the description of carbonate lithologies. In an attempt to rectify this perceived deficiency, Embry & Klovan (1971) intr ...

spherulite In petrology, spherulites () are small, rounded bodies that commonly occur in vitreous igneous rocks. They are often visible in specimens of obsidian, pitchstone, and rhyolite as globules about the size of millet seed or rice grain, with a dul ...

s, and

wackestone Under the Dunham classification (Dunham, 1962Dunham, R.J., 1962. Classification of carbonate rocks according to depositional texture. In: W.E. Ham (Ed.), Classification of Carbonate Rocks. American Association of Petroleum Geologists Memoir. Amer ...

s. Alteration has formed calcite, dolomite, quartz through

silicification In geology, silicification is a petrification process in which silica-rich fluids seep into the voids of Earth materials, e.g., rocks, wood, bones, shells, and replace the original materials with silica (SiO2). Silica is a naturally existing an ...

and

vug A vug, vugh, or vugg ( ) is a small- to medium-sized cavity inside rock. It may be formed through a variety of processes. Most commonly, cracks and fissures opened by tectonic activity ( folding and faulting In geology, a fault is a pla ...

s. Dolomite alteration is particularly widespread in modern atolls and several processes have been invoked to explain it, such as geothermally driven

convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the c ...

seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appr ...

. Dissolved

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s and traces of animal burrows are found in some rock sequences with

bioturbation Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a pr ...

traces widespread.

Barite Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

needles,

calcrete Caliche () is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt. It occurs worldwide, in aridisol and mollisol soil orders—generally in arid or semiarid region ...

s, cementation forms that developed under the influence of

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does in ...

desiccation crack Mudcracks (also known as mud cracks, desiccation cracks or cracked mud) are sedimentary structures formed as muddy sediment dries and contracts.Jackson, J.A., 1997, ''Glossary of Geology'' (4th ed.), American Geological Institute, Alexandria, VA, ...

s and ferromanganese occurrences as

dendrite Dendrites (from Greek δένδρον ''déndron'', "tree"), also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the ...

s have also been found. Organic materials found in rock samples from Resolution Guyot appear to be mainly of marine origin. Some of the organic matter comes from

microbial mat A microbial mat is a multi-layered sheet of microorganisms, mainly bacteria and archaea, or bacteria alone. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few survive in desert ...

s and vegetated islands, including wood and plant remains. Clays found on Resolution Guyot are characterized as

chlorite The chlorite ion, or chlorine dioxide anion, is the halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as salts of chl ...

glauconite Glauconite is an iron potassium phyllosilicate (mica group) mineral of characteristic green color which is very friable and has very low weathering resistance. It crystallizes with a monoclinic geometry. Its name is derived from the Greek () ...

hydromica Illite is a group of closely related non-expanding clay minerals. Illite is a secondary mineral precipitate, and an example of a phyllosilicate, or layered alumino-silicate. Its structure is a 2:1 sandwich of silica tetrahedron (T) – alumin ...

illite Illite is a group of closely related non-expanding clay minerals. Illite is a secondary mineral precipitate, and an example of a phyllosilicate, or layered alumino-silicate. Its structure is a 2:1 sandwich of silica tetrahedron (T) – alumina ...

kaolinite Kaolinite ( ) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is an important industrial mineral. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahed ...

, saponite and

smectite A smectite (from ancient Greek ''σμηκτός'' smektos 'lubricated'; ''σμηκτρίς'' smektris 'walker's earth', 'fuller's earth'; rubbing earth; earth that has the property of cleaning) is a mineral mixtures of various swelling sheet sil ...

Claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too sm ...

s have also been found. Most clays have been found in the lower carbonate sequence, while the upper parts mostly lack clay deposits. Some of the clays may originate from younger volcanoes east of Resolution Guyot.

Apatite Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common ...

formed through

modification of exposed rocks underwater. Other minerals include

anhydrite Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with t ...

celestite Celestine (the IMA-accepted name) or celestite is a mineral consisting of strontium sulfate ( Sr S O). The mineral is named for its occasional delicate blue color. Celestine and the carbonate mineral strontianite are the principal sources of t ...

goethite Goethite (, ) is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the "α" polymorph. It is found in soil and other low-temperature environments such as sediment. Goethite has been well known since ancient ...

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and dr ...

limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydrox ...

and pyrite which is also present in the carbonates. Finally, mudstones have been found.

Geologic history

Although

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

has been carried out on volcanic rocks from Resolution Guyot, the basalts are heavily altered and the dates are thus uncertain. Potassium-argon dating yields ages of 107–125 million years ago while argon-argon dating indicates ages of 120–129 million years ago.

Magnetization In classical electromagnetism, magnetization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material. Movement within this field is described by direction and is either Axial or Di ...

data indicate that it was formed in the Southern Hemisphere.

Volcanic phase

Eruptions in the area built a pile of volcanic rocks, including stacks of

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

s, each of which is about thick, but there are also

breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of d ...

intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

s and

sill Sill may refer to: * Sill (dock), a weir at the low water mark retaining water within a dock * Sill (geology), a subhorizontal sheet intrusion of molten or solidified magma * Sill (geostatistics) * Sill (river), a river in Austria * Sill plate, a ...

s. The lava flows appear to have been formed years apart from each other. Resolution Guyot was also

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

ly active. This volcanic activity over 1–2 million years generated a

. Volcanic activity took place in a

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

or subtropical environment and between eruptions

weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs '' in situ'' (on site, with little or no movemen ...

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

formation and potentially

mass wasting Mass wasting, also known as mass movement, is a general term for the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in ...

generated layers of clay, rock debris and alteration products such as

laterite Laterite is both a soil and a rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by ...

. Erosion eventually flattened the volcanic island to form a platform. It is possible that magmatic intrusions (

s) formed later in the history of Resolution Guyot.

Platform carbonates and reefs

Between the

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago). The Hauterivian is preceded by t ...

(ca. 132.9 – ca. 129.4 million years ago) and

(ca. 113 – 100.5 million years ago), about of carbonate was deposited on the volcanic structure, eventually completely burying it during the Albian. About 14 individual sequences of carbonates have been identified in drill cores. The carbonate sedimentation probably began in the form of

shoal In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It ...

s surrounding a volcanic island and lasted for about 35 million years, accompanied by perhaps of subsidence. It is likely that the present-day carbonate platform contains only a fraction of the originally deposited carbonate, most of the carbonate having disappeared. During this time, Resolution Guyot underwent little latitudinal plate motion; from the magnetization it appears that it was stably located at about 13° southern latitude between the Hauterivian and Aptian. Its carbonate platform cannot be reconstructed as only small parts have been studied, but some conclusions can be made. The Resolution platform was surrounded by

barrier island Barrier islands are coastal landforms and a type of dune system that are exceptionally flat or lumpy areas of sand that form by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a fe ...

s but featured only a few

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic processes—deposition (geology), deposition of ...

s; unlike present-day atolls which were rimmed by reefs Cretaceous platforms were rimmed by sand shoals and on Resolution Guyot drill cores into the rim have only found sediment accumulations and no reefs. Analysis of the carbonate layers has identified that several environments existed on the platform, including

swash Swash, or forewash in geography, is a turbulent layer of water that washes up on the beach after an incoming wave has broken. The swash action can move beach materials up and down the beach, which results in the cross-shore sediment exchange. ...

beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shell ...

es, lagoons,

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...

es,

mudflat Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal f ...

sabkha A sabkha ( ar, سبخة) is a coastal, supratidal mudflat or sandflat in which evaporite-saline minerals accumulate as the result of semiarid to arid climate. Sabkhas are gradational between land and intertidal zone within restricted coastal p ...

sand bar In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It ...

s and washover fans from

storm A storm is any disturbed state of the natural environment or the atmosphere of an astronomical body. It may be marked by significant disruptions to normal conditions such as strong wind, tornadoes, hail, thunder and lightning (a thunderstorm), ...

s; at times there were also open-marine conditions. Some environments on Resolution Guyot were

hypersaline A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing that of ocean water (3.5%, i.e. ). Specific microbial species can thrive in hig ...

at times, probably implying that they had only limited water exchange with the surrounding ocean. Islands formed from sand bars, resembling those of the

Bahama Banks The Bahama Banks are the submerged carbonate platforms that make up much of the Bahama Archipelago. The term is usually applied in referring to either the Great Bahama Bank around Andros Island, or the Little Bahama Bank of Grand Bahama Island ...

. Records from Hole 866A indicate that settings at a given site were not stable over longer time periods. The Cretaceous Apulian Carbonate Platform in Italy and the Urgonian Formation in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan ar ...

have been compared to the Resolution Guyot carbonates. All these platforms were located in Tethyan seas and several formations in these three carbonate environments are correlated; for example, the fauna identified on Resolution Guyot resembles that from other Northern Hemisphere platforms. Analogies also exist to platforms in

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in ...

. File:Cook Islands IMG 6127 (8453057558).jpg, alt=Very shallow water over a white seafloor with a green island in the background beneath blue sky and scattered clouds, A beach and shallow water,

Cook Islands ) , image_map = Cook Islands on the globe (small islands magnified) (Polynesia centered).svg , capital = Avarua , coordinates = , largest_city = Avarua , official_languages = , langu ...

File:ISS-26 Tidal flats and channels on Long Island, Bahamas.jpg, alt=Orange islands cut by deep blue channels ending in blue ocean in the upper part of the image and beginning in a whiter lagoon in the lower part of the image, Spaceborne image of mudflats and tidal channels on present-day

Long Island, Bahamas Long Island is an island in The Bahamas that is split by the Tropic of Cancer. It is one of the Districts of the Bahamas and is known as the most scenic island in the Bahamas. Its capital is Clarence Town. The population of Long Island is 3,094 i ...

; the former morphology of Resolution Guyot has been compared to that of the present-day Bahamas. File:Suwarrow Anchorage Island.jpg, alt=Vegetated green island rising from above the deep blue sea, Vegetated island on

Suwarrow 200px, Map of Cook Islands with Suwarrow near the middle Suwarrow (also called Suvorov, Suvarou, or Suvarov) is an island in the northern group of the Cook Islands in the south Pacific Ocean. It is about south of the equator and north-northw ...

Water temperatures in the early

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ag ...

(ca. 125 – ca. 113 million years ago) are inferred to have been . The platform was exposed to southeasterly

trade wind The trade winds or easterlies are the permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisp ...

s which left its northern side sheltered from waves, except from storm-generated ones. These waves, wind and

tidal current Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can ...

s acted to shift sediments around on the platform. Storms formed beaches on the platform, although the interior parts of the platform were effectively protected by the surrounding shoals from storm influence. Some patterns in the sedimentation indicate a seasonal climate. When the climate was

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...

, gypsum deposition took place. Through the history of the platform

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardise ...

variations led to changes in the accumulating carbonate sediments, with typical facies and sequences forming in the carbonate layers. The Selli event, an

oceanic anoxic event Oceanic anoxic events or anoxic events (anoxia conditions) describe periods wherein large expanses of Earth's oceans were depleted of dissolved oxygen (O2), creating toxic, euxinic (anoxic and sulfidic) waters. Although anoxic events have not h ...

, is recorded at Resolution Guyot as is the Faraoni event. The Selli event left a

black shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

layer and may have caused a temporary interruption in carbonate accumulation before the platform recovered. During the Albian-Aptian some carbonates became dolomites. Life on Resolution Guyot included

alga Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from u ...

e - both

green Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 Nanometre, nm. In subtractive color systems, used in painting and color printing, it is created by ...

and red algae and species forming

s -,

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biv ...

s including

rudist Rudists are a group of extinct box-, tube- or ring-shaped marine heterodont bivalves belonging to the order Hippuritida that arose during the Late Jurassic and became so diverse during the Cretaceous that they were major reef-building organisms ...

s, bryozoans,

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secre ...

echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...

echinoid Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

foraminifer Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly ...

s, gastropods,

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not a ...

serpulid The Serpulidae are a family of sessile, tube-building annelid worms in the class Polychaeta. The members of this family differ from other sabellid tube worms in that they have a specialized operculum that blocks the entrance of their tubes ...

worms,

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

s and

stromatolith Stromatolites () or stromatoliths () are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). Th ...

es.

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s of animals have been found in the drill cores. Rudists and sponges have been identified as

bioherm A reef knoll is a land-based landform that comprises an immense pile of calcareous material that accumulated on a previously existing ancient sea floor. At the time of its accumulation it may have had enough structure from organisms such as sponges ...

builders; rudist families found on Resolution include

caprinidae Caprinidae is a family of rudists, a group of unusual extinct saltwater clams, marine heterodont bivalves Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater mollus ...

of the genus ''

'', coalcomaninae, monopleuridae and

requieniidae Requieniidae is a family of rudists, in the order Hippuritida, which lived from 155.7 to 66.043 million years ago. Taxonomy Placed by the WoRMS and Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to fac ...

. Well developed microbial mats grew in some places.

Plant Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...

remnants have been found in the carbonate sediments, probably reflecting the existence of vegetation-covered islands on the platform. Vegetation probably occurred in swamps and marshes as well.

Uplift and karstification

During the Albian to

(93.9 – 89.8 ± 0.3 million years ago), the carbonate platform rose above the sea by about -. This uplift episode at Resolution Guyot is part of an episode of more general tectonic changes in the Pacific Ocean, with a general uplift of the ocean floor and tectonic stress changes at the ocean margins. This tectonic event has been explained by a major change in mantle convection in the middle Cretaceous pushing the ocean floor upward and sideward. When Resolution Guyot rose above sea level, karst processes began to impact the platform. The platform became irregular and part of it was eroded away;

crusts, carbonate pinnacles, cavities,

cavern A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s containing

speleothem A speleothem (; ) is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending o ...

s and

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

s formed and exist to this day. At this stage, Resolution Guyot would have resembled a ''

makatea Makatea, or Mangaia-te-vai-tamae, is a raised coral atoll in the northwestern part of the Tuamotus, which is a part of the French overseas collectivity of French Polynesia. It is located southwest from Rangiroa to the west of the Palliser g ...

'' island. This karstic episode did not last for long, perhaps several hundred thousand years, but structures left by the karstic phase such as sinkholes and carbonate pinnacles can still be seen on the surface platform of Resolution Guyot. During periods of emergence, freshwater flowed through and modified the carbonates.

Drowning and post-drowning evolution

Resolution Guyot drowned either about 99 ± 2 million years ago or during the Maastrichtian (72.1 ± 0.2 to 66 million years ago), although a hiatus in shallow carbonate deposition appears to date back to the Albian that may reflect a long pause in deposition or increased erosion. The end Albian period was characterized by widespread cessation of carbonate sedimentation across the western Pacific. It is possible that carbonate sedimentation later continued until

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

(83.6 ± 0.2 – 72.1 ± 0.2 million years ago)-Maastrichtian times. The platform was certainly submerged by

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58) times. Other carbonate platforms in the Pacific drowned especially at the end of the Albian, for unknown reasons; among the proposed mechanisms are overly nutrient rich or turbid waters, the disappearance of reef-forming species and a subsequent failure of them to return, and overly fast sea level rise. Resolution Guyot was never far enough south to end up beyond the

Darwin point An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can grow ...

at which carbonate deposition stops. The Resolution Guyot platform rose above sea level before the drowning, and there is no indication that carbonate deposition recommenced when the platform subsided; similarly other Mid-Pacific Mountains emerged before drowning. There is disagreement about whether Resolution Guyot was close enough to the

equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can al ...

and nutrient rich equatorial waters to drown at the time when carbonate sedimentation ceased. After the drowning, crusts formed by ferromanganese and by phosphate-modified rocks developed on exposed surfaces at Resolution Guyot. Several different layers of phosphate modification have been observed during the Albian alone and this process may have begun when the platform was still active; water within the rocks may have triggered phosphatization at this stage. The ferromanganese deposition probably only began in the Turonian-Maastrichtian, when the seamount had subsided to a sufficient depth. Manganese-encrusted Cretaceous limestones have been found within the pelagic sediments. As at other guyots in the Pacific Ocean

sedimentation commenced later; the

foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly ...

fossils indicate an age of

to Pliocene for such sediments. These sediments reach thicknesses of in Hole 866B and consist of a Quaternary (last 2.58 million years), a thin early

Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

(2.58 – 0.0117 million years ago) and a thick Pliocene layer. Some of the sediments take the form of pelagic limestones. In

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of ...

(66 to 23.03 million years ago) sediments ostracods have been found. Carbonates were dissolved and replaced by dolomite already during the Aptian and Albian. Around 24 million years ago at the Paleogene-

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. ...

(23.02 – 2.58 million years ago) boundary, a second pulse of dolomite formation took place; perhaps sea level changes associated with global climate change triggered this second pulse. The formation of the dolomites was probably aided by the fact that seawater can percolate through Resolution Guyot, which may be responsible for the formation of fluid vent structures on the surface of the seamount.

Notes

References

Sources

* * * * * * * * * * * * * * * * * * * * * * * * * {{featured article Guyots Cretaceous volcanoes Seamounts of the Pacific Ocean