Cerro Aspero Batholith () is a group of

pluton 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 in southern

Sierras Pampeanas The Sierras Pampeanas (also called Central Sierras or Pampas Sierras) (English: Pampas Mountains) is a geographical region of Argentina. The Sierras Pampeanas are a chain of mountains that rise sharply from the surrounding pampa region of N ...

in central Argentina. The

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

covers an approximate area of 440 km² and lies about 50 km south of the larger Achala Batholith. The batholith contains various circular plutons emplaced by

stoping Stoping is the process of extracting the desired ore or other mineral from an underground mine, leaving behind an open space known as a stope. Stoping is used when the country rock is sufficiently strong not to collapse into the stope, althou ...

at pressures of 2 kbar or less. Alpa Corral, El Talita and Los Cerros are the three largest individual plutons and together they make up the bulk of the batholith. The most common rock type is

monzogranite Monzogranite is a plutonic rock that occupies the middle of the QAPF diagram, consisting of between 20–60% quartz, and of the remainder, between 35–65% alkali feldspar and the remainder plagioclase. Examples Pilgangoora belt, Pilbara c ...

with

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 al ...

and an igneous

texture Texture may refer to: Science and technology * Image texture, the spatial arrangement of color or intensities in an image * Surface texture, the smoothness, roughness, or bumpiness of the surface of an object * Texture (roads), road surface c ...

that is

equigranular An equigranular material is composed chiefly of crystals of similar orders of magnitude to one another. Basalt and gabbro commonly exhibit an equigranular texture Texture may refer to: Science and technology * Image texture, the spatial arrang ...

but varies from coarse grained to

porphyritic Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning ...

. The emplacement of plutons occurred in the Middle to Late

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

period.

Contact aureole Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of che ...

s for the batholith are, contrary to other batholiths, largely undeformed. The relation of the magmatic episode represented by the Cerro Aspero Batholith to the

Famatinian orogeny The Famatinian orogeny () is an orogeny that predates the rise of the Andes and that took place in what is now western South America during the Paleozoic, leading to the formation of the Famatinian orogen also known as the Famatinian belt. The F ...

is not fully understood. Alternatively it is grouped as a "Achaliano" igneous cycle. Vertical to near-vertical veins of

fluorite Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scal ...

formed in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

occur in the batholith. At most veins reach 3 meters in thickness. Collectively these veins constitute the largest reserves of fluorite in the whole

area.

References

Batholiths of South America Geology of Córdoba Province, Argentina Devonian Argentina Geology of Argentina Devonian magmatism Lithodemic units of Argentina Sierras Pampeanas {{coord, 32, 40, 00, S, 64, 00, 00, W, region:AR_type:mountain, display=title