Granodiorite () is a coarse-grained (

phaneritic A phanerite is an igneous rock whose microstructure is made up of crystals large enough to be distinguished with the unaided human eye. In contrast, the crystals in an aphanitic rock are too fine-grained to be identifiable. Phaneritic texture fo ...

) intrusive

igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock ...

similar to

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

, but containing more

plagioclase feldspar 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 prop ...

than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from granite to

diorite Diorite ( ) is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silic ...

, including granodiorite.

Composition

According to the

QAPF diagram A QAPF diagram is a double ternary diagram which is used to classify igneous rocks based on mineralogic composition. The acronym QAPF stands for "Quartz, Alkali feldspar, Plagioclase, Feldspathoid (Foid)". These are the mineral groups used f ...

, granodiorite has a greater than 20%

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 form ...

by volume, and between 65% and 90% of the feldspar is plagioclase. A greater amount of plagioclase would designate the rock as

tonalite Tonalite is an igneous, plutonic ( intrusive) rock, of felsic composition, with phaneritic (coarse-grained) texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with alkali feldspar making up less than 10% of the total ...

. Granodiorite is felsic to intermediate in composition. It is the intrusive igneous equivalent of the

extrusive Extrusive rock refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. In contra ...

igneous

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

. It contains a large amount of

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...

(Na) and

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

(Ca) rich plagioclase,

potassium feldspar Potassium feldspar refers to a number of minerals in the feldspar group, and containing potassium: *Orthoclase ( endmember formula K Al Si3 O8), an important tectosilicate mineral that forms igneous rock *Microcline, chemically the same as orthocla ...

, and minor amounts of

muscovite Muscovite (also known as common mica, isinglass, or potash mica) is a hydrated phyllosilicate mineral of aluminium and potassium with formula K Al2(Al Si3 O10)( F,O H)2, or ( KF)2( Al2O3)3( SiO2)6( H2O). It has a highly perfect basal cleavag ...

mica as the lighter colored mineral components. Biotite and

amphibole Amphibole () is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is A ...

s often in the form of

hornblende Hornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rock ...

are more abundant in granodiorite than in granite, giving it a more distinct two-toned or overall darker appearance. Mica may be present in well-formed hexagonal crystals, and hornblende may appear as needle-like crystals. Minor amounts of

oxide minerals The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys. The hydroxide-bearing minerals are typically included in the oxide class. The minerals with complex anion groups such as the si ...

such as

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 the ...

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 ...

, and

ulvöspinel Ulvöspinel or ulvite is an iron titanium oxide mineral with formula: iron, Fe2titanium, Tioxygen, O4 or TiFe2+2O4. It forms brown to black metallic Cubic (crystal system), isometric crystals with a Mohs hardness of 5.5 to 6. It belongs to the sp ...

, as well as some sulfide minerals may also be present.

Geology

On average, the upper

continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called '' sial'' be ...

has the same composition as granodiorite. Granodiorite is a

plutonic Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form '' intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March ...

igneous rock, formed by

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 ...

of silica-rich

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

, which cools in

batholiths A batholith () is a large mass of intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, suc ...

or stocks below the Earth's surface. It is usually only exposed at the surface after

uplift Uplift may refer to: Science * Geologic uplift, a geological process ** Tectonic uplift, a geological process * Stellar uplift, the theoretical prospect of moving a stellar mass * Uplift mountains * Llano Uplift * Nemaha Uplift Business * Uplif ...

and

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

have occurred.

Etymology

The name comes from two related

rocks In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's ...

to which granodiorite is an intermediate:

and

. The ''gran-'' root comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

'' grānum'' for "

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legum ...

", an

English language English is a West Germanic language of the Indo-European language family, with its earliest forms spoken by the inhabitants of early medieval England. It is named after the Angles, one of the ancient Germanic peoples that migrated to the is ...

derivative. Diorite is named after the contrasting colors of the rock.

Banatite

Banatite is a term used informally for various rocks ranging from granite to

, but often granodiorite, that were intruded in the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

in the

Banat Banat (, ; hu, Bánság; sr, Банат, Banat) is a geographical and historical region that straddles Central and Eastern Europe and which is currently divided among three countries: the eastern part lies in western Romania (the counties of T ...

and nearby regions of present-day

Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia a ...

and

Serbia Serbia (, ; Serbian language, Serbian: , , ), officially the Republic of Serbia (Serbian language, Serbian: , , ), is a landlocked country in Southeast Europe, Southeastern and Central Europe, situated at the crossroads of the Pannonian Bas ...

. The term is also used in Australia in connection with Gulaga / Mount Dromedary in

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, where it is described as "a rock of intermediate composition between

quartz diorite Quartz diorite is an igneous, plutonic ( intrusive) rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less potassium feldspar. Quartz Quartz is a hard, ...

and

quartz monzonite Quartz monzonite is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock. The plagiocl ...

Occurrence

United States

Plymouth Rock Plymouth Rock is the traditional site of disembarkation of William Bradford and the ''Mayflower'' Pilgrims who founded Plymouth Colony in December 1620. The Pilgrims did not refer to Plymouth Rock in any of their writings; the first known writt ...

is a

glacial erratic A glacial erratic is glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from the Latin word ' ("to wander"), are carried by glacial ice, often over distances of hundre ...

boulder In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In c ...

of granodiorite. The

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

mountains contain large sections of granodiorite.

Egypt

Granodiorite was quarried at

Mons Claudianus Mons Claudianus was a Roman quarry in the eastern desert of Egypt. It consisted of a garrison, a quarrying site, and civilian and workers' quarters. Granodiorite was mined for the Roman Empire where it was used as a building material. Mons Claud ...

in the

Red Sea Governorate Red Sea Governorate ( ar, محافظة البحر الأحمر ) is one of the 27 governorates (States) of Egypt. Located between the Nile and the Red Sea in the southeast of the country, its southern border forms part of Egypt's border with ...

in eastern

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

from the 1st century AD to the mid-3rd century AD. Much of the quarried stone was transported to

Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus (legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...

for use in major projects such as

the Pantheon The Pantheon (, ; la, Pantheum,Although the spelling ''Pantheon'' is standard in English, only ''Pantheum'' is found in classical Latin; see, for example, Pliny, '' Natural History'36.38 "Agrippas Pantheum decoravit Diogenes Atheniensis". Se ...

and

Hadrian's Villa Hadrian's Villa ( it, Villa Adriana) is a UNESCO World Heritage Site comprising the ruins and archaeological remains of a large villa complex built c. AD 120 by Roman Emperor Hadrian at Tivoli outside Rome. The site is owned by the Republic of ...

. Additionally, granodiorite was used for the

Rosetta Stone The Rosetta Stone is a stele composed of granodiorite inscribed with three versions of a decree issued in Memphis, Egypt, in 196 BC during the Ptolemaic dynasty on behalf of King Ptolemy V Epiphanes. The top and middle texts are in Ancien ...

. The extent of Egyptian granodiorite masonry is unclear. Egypt's 6000-year history makes determining the period of usage difficult as well. Perhaps like porphyry, it was ignored by the successive dynasties of Egypt and only heavily mined during Ptolemaic or Roman times. This is evidenced by the fact that most examples of granodiorite sculpture seem to have come from later dates. However, its presence in the Rosetta Stone implies that they had considerable experience with it and the fact that only newer artifacts are found may simply be because earlier pieces were lost.

Ireland

Granodiorite is quarried in the

Newry Newry (; ) is a city in Northern Ireland, divided by the Clanrye river in counties Armagh and Down, from Belfast and from Dublin. It had a population of 26,967 in 2011. Newry was founded in 1144 alongside a Cistercian monastery, althoug ...

area of

County Armagh County Armagh (, named after its county town, Armagh) is one of the six counties of Northern Ireland and one of the traditional thirty-two counties of Ireland. Adjoined to the southern shore of Lough Neagh, the county covers an area of an ...

with the common name of 'Newry granite'.

Uses

Granodiorite is most often used as

crushed stone Crushed stone or angular rock is a form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock down to the desired size using crushers. It is distinct from naturally occurring gravel, which i ...

for road building. It is also used as construction material, building facade, and paving, and as an ornamental stone. The

is a

stele A stele ( ),Anglicized plural steles ( ); Greek plural stelai ( ), from Greek , ''stēlē''. The Greek plural is written , ''stēlai'', but this is only rarely encountered in English. or occasionally stela (plural ''stelas'' or ''stelæ''), whe ...

made from granodiorite.Image gallery: The Rosetta Stone
British Museum (2015-03-20). Retrieved on 2015-11-19. The portico columns of

in Rome are formed from single shafts of granodiorite, each 12 metres tall by 1.5 metres in diameter.

References

* .

External links

* {{Authority control Felsic rocks Granitic rocks Intermediate rocks Plutonic rocks