Acid maceration
Encyclopedia
Acid maceration is a technique to extract organic
microfossils from a surrounding rock
matrix
using acid
.
Hydrochloric acid
or acetic acid
may be used to extract phosphatic fossil
s, such as the small shelly fossils, from a carbonate
matrix.
Hydrofluoric acid
is also used in acid macerations to extract organic fossils from silicate
rocks. Fossiliferous rock may be immersed directly into the acid, or a cellulose nitrate film
may be applied (dissolved
in amyl acetate
), which adheres to the organic component and allows the rock to be dissolved around it.
Organic matter
Organic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...
microfossils from a surrounding rock
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
matrix
Matrix (geology)
The matrix or groundmass of rock is the finer grained mass of material in which larger grains, crystals or clasts are embedded.The matrix of an igneous rock consists of finer grained, often microscopic, crystals in which larger crystals are embedded. This porphyritic texture is indicative of...
using acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
.
Hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
or acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
may be used to extract phosphatic fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s, such as the small shelly fossils, from a carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
matrix.
Hydrofluoric acid
Hydrofluoric acid
Hydrofluoric acid is a solution of hydrogen fluoride in water. It is a valued source of fluorine and is the precursor to numerous pharmaceuticals such as fluoxetine and diverse materials such as PTFE ....
is also used in acid macerations to extract organic fossils from silicate
Silicate
A silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...
rocks. Fossiliferous rock may be immersed directly into the acid, or a cellulose nitrate film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
may be applied (dissolved
Dissolution (chemistry)
Dissolution is the process by which a solid, liquid or gas forms a solution in a solvent. In solids this can be explained as the breakdown of the crystal lattice into individual ions, atoms or molecules and their transport into the solvent. For liquids and gases, the molecules must be compatible...
in amyl acetate
Amyl acetate
Amyl acetate is an organic compound and an ester with the chemical formula CH3COO[CH2]4CH3 and the molecular weight 130.19 g/mol. It has a scent similar to bananas and apples which is not detectable by all people. The compound is the condensation product of acetic acid and 1-pentanol...
), which adheres to the organic component and allows the rock to be dissolved around it.