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Fodinichnia
Fodinichnia (singular fodinichnion) are trace fossils formed by deposit feeders as they excavate the sediment in search of food.Allaby A & Allaby M (1999) Oxford Dictionary of Earth Sciences. They tend to have repeated patterns (e.g. '' Chondrites'') or spreites (e.g. '' Rhizocorallium''), the shape reflecting the systematic feeding strategy used by the organism as it scours the sediment. Deposit feeding often results in structures with no overlapping parts, as the deposit feeder optimises its nourishment intake by avoiding going over the same area more than once. This avoidance behavior is called phobotaxis. The shape of fodinichnia can yield evidence of the depositional environment of the sediment in which they were made. For example, a trace with highly sinuous branches may reflect nutrient-poor conditions where the organism needed to ingest more sediment in order to acquire the same amount of nutriment that a straighter branch in a nutrient-rich environment would. Reference ...
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Trace Fossil
A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. The study of such trace fossils is ichnology and is the work of ichnologists. Trace fossils may consist of impressions made on or in the substrate by an organism. For example, burrows, borings (bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints and feeding marks and root cavities may all be trace fossils. The term in its broadest sense also includes the remains of other organic material produced by an organism; for example coprolites (fossilized droppings) or chemical markers (sedimentological structures produced by biological means; for example, the formation of stromatolites). H ...
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Trace Fossils
A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. The study of such trace fossils is ichnology and is the work of ichnologists. Trace fossils may consist of impressions made on or in the substrate by an organism. For example, burrows, borings ( bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints and feeding marks and root cavities may all be trace fossils. The term in its broadest sense also includes the remains of other organic material produced by an organism; for example coprolites (fossilized droppings) or chemical markers (sedimentological structures produced by biological means; for example, the formation of stromatolites). ...
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Trace Fossil Classification
Trace fossils are classified in various ways for different purposes. Traces can be classified taxonomically (by morphology), ethologically (by behavior), and toponomically, that is, according to their relationship to the surrounding sedimentary layers. Except in the rare cases where the original maker of a trace fossil can be identified with confidence, phylogenetic classification of trace fossils is an unreasonable proposition. Taxonomic classification The taxonomic classification of trace fossils parallels the taxonomic classification of organisms under the International Code of Zoological Nomenclature. In trace fossil nomenclature a Latin binomial name is used, just as in animal and plant taxonomy, with a genus and specific epithet. However, the binomial names are not linked to an organism, but rather just a trace fossil. This is due to the rarity of association between a trace fossil and a specific organism or group of organisms. Trace fossils are therefore included in an ''i ...
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Deposit Feeders
Detritivores (also known as detrivores, detritophages, detritus feeders, or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, vertebrates and plants that carry out coprophagy. By doing so, all these detritivores contribute to decomposition and the nutrient cycles. They should be distinguished from other decomposers, such as many species of bacteria, fungi and protists, which are unable to ingest discrete lumps of matter, but instead live by absorbing and metabolizing on a molecular scale (saprotrophic nutrition). The terms ''detritivore'' and ''decomposer'' are often used interchangeably, but they describe different organisms. Detritivores are usually arthropods and help in the process of remineralization. Detritivores perform the first stage of remineralization, by fragmenting the dead plant matter, allowing decomposers to perform the second stage of remineraliz ...
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Chondrites (genus)
''Chondrites'' is a trace fossil ichnogenus, preserved as small branching burrows of the same diameter that superficially resemble the roots of a plant. The origin of these structures is currently unknown. ''Chondrites'' is found in marine sediments from the Cambrian period of the Paleozoic onwards. It is especially common in sediments that were deposited in reduced-oxygen environments. Morphology There are four recognized ''Chondrites'' ichnospecies, however, aberrant forms of unknown Taxonomy (biology), taxonomic affinity have been discovered. The fossils are made of infilled dendritic rootlike burrows. The branching angles are 30° to 40°, while a shaft diameter varies between 0.1 mm and 10 mm, remaining constant within a single system. ''Chondrites'' is classified as a fodinichnia, fodinichnion. Occurrence First appearing during the Cambrian, ''Chondrites'' is still produced today. It is one of the most common ichnotaxa throughout the fossil record and is widely d ...
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Spreite
Spreite, meaning Lamina (leaf), leaf-blade in German (or spreiten, the plural form in German language, German) is a stacked, curved, layered structure that is characteristic of certain trace fossils. They are formed by invertebrate organisms tunneling back and forth through sediment in search of food. The organism moves perpendicularly just enough at the start of each back-and-forth pass so that it avoids reworking a previously tunneled area, thereby ensuring that it only makes feeding passes through fresh, unworked sediment. Two types of spreiten are generally recognized. Protrusive spreiten result from movement of the organism away from its burrow entrance (i.e., a downward movement in vertical burrows), whereas retrusive spreiten result from movement towards the burrow entrance (i.e., an upward movement in vertical burrows). Vertical burrows with retrusive spreiten are also referred to as "escape burrows", as they represent attempts by the organism during periods of high sedime ...
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Rhizocorallium
''Rhizocorallium'' is an ichnogenus of burrow, the inclination of which is typically within 10° of the bedding planes of the sediment. These burrows can be very large, over a meter long in sediments that show good preservation, e.g. Jurassic rocks of the Yorkshire Coast (eastern United Kingdom), but the width is usually only up to 2 cm, restricted by the size of the organisms producing it. It is thought that they represent fodinichnia as the animal (probably a polychaete) scoured the sediment for food. Ichnogenus The ichnogenus ''Rhizocorallium'' Zenker 1836 includes three ichnospecies: ''Rhizocorallium jenense'' Zenker 1836 representing straight, short U-shaped spreite Spreite, meaning Lamina (leaf), leaf-blade in German (or spreiten, the plural form in German language, German) is a stacked, curved, layered structure that is characteristic of certain trace fossils. They are formed by invertebrate organisms tunn ...-burrows commonly oblique to bedding plane, and only rare ...
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Sedimentary Depositional Environment
In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock record. In most cases, the environments associated with particular rock types or associations of rock types can be matched to existing analogues. However, the further back in geological time sediments were deposited, the more likely that direct modern analogues are not available (e.g. banded iron formations). Types of depositional environments Continental * – type of Fluvial deposit. Caused by moving water in a fan shape (Alluvial Fan) and containing mostly impermeable and nonporous sediments well sorted. * . Often in deserts and coastal regions and well sorted, large scale cross-beds * – processes due to moving water, mainly streams. Common sediments are grav ...
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