Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Home > Acritarch
Acritarchs are small organic structures found as fossils. In general, any small, non- acid soluble (i.e. non carbonate, non-silicate) organic structure that can not otherwise be accounted for is an acritarch. Most acritarchs are surely remains of single celled lifeforms. They are found in sedimentary rocks from the present back into the Precambrian. They are easily isolated from limestones with hydrochloric acid, and can also be isolated from silica rich rocks using hydrofluoric acid. They are excellent candidates for index fossils to be used for formation dating in the Palaeozoic and when other fossils are not available. They are also useful for palaeoenvironmental interpretation. Acritarchs include the remains of several quite different kinds of organisms including bacteria and dinoflagellates. The nature of the creatures associated with older acritarchs is generally not clear, though many are probably related to unicellular marine algae.Acritarchs are known from 1400 Ma and had achieved considerable diversity by 1300Ma. Diversity crashed during the Sturtian- Varanger glacial event around 800Ma. Diversity increased again during the Ediacaran period. Diversity declined suddenly at the end of the Precambrian. The acritarchs show their greatest diversity during the Cambrian, Ordovician, Silurian and Devonian. The nature of some Acritarchs can be identified by their structure. A few can be tentatively identified by the presence of specific chemicals associated with the fossils.
External links
PaleontologyPaleontology (palaeontology is the British spelling) is the study of the developing history of life on earth, of ancient plants and animals based on the fossil record, evidence of their existence preserved in rocks. This includes the study of body fossils
GeologyGeology (from Greek γ&eta ge "the earth") and λογος logos "word", "reason")) is the science and study of the Earth, its composition, structure, physical properties, history, and the processes that shape it. Geolog
BotanyBotany is the scientific study of plants. As a branch of biology, it is also sometimes referred to as plant science(s or plant biology . Botany covers a wide range of scientific disciplines that study the growth, reproduction, metabolism, development, dis
ArchaeologyArchaeology or archeology ( American English) is the study of human cultures through the recovery, documentation and analysis of material remains, including architecture, artefacts, biofacts, human remains, and landscapes. The goal of archaeology is to sh
Fossils
Read more »