Ammonites


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Related to Ammonites: Amorites, Moabites

Ammonites

 

(Ammonoidea), a superorder of extinct invertebrates of the Cephalopoda class.

Ammonites lived over the entire earth from the Devonian period through the Cretaceous period inclusively. They had an external, often sculptured, shell of varying shape, divided into a number of chambers by transverse septa. The edges of the septa were usually greatly corrugated; the corrugation increased the strength of the shell. The soft body of the animal was in the last chamber, which terminated in the opening. The remaining chambers were filled with gas and played the role of a hydrostatic apparatus. They were interconnected by a cordlike growth of the soft body—the siphon—with blood vessels which provided a normal gas regime in the chambers. The diameter of the shell was as much as 2 meters.

Ammonites were widely found in the seas and were predators. Some of them swam well, and others crawled for the most part. A total of about 1,500 genera are known, as well as numerous species which quickly replaced one another over the ages. Because of this, the ammonites are one of the most important groups of “leading” fossils. The ammonites are also of interest for elucidating the patterns of individual development (ontogenesis) and its relationship to phylogenesis, since all the parts of the ammonite shell changed greatly in the process of ontogenesis.

REFERENCE

Osnovy paleontologii: Molliuski-golovonogie, [vol. 1]. Moscow, 1962.

V. N. SHIMANSKII


Ammonites

 

ammonium nitrate explosives, explosive mixtures of ammonium nitrate with combustible and explosive substances. Ammonites are secondary (brisant) explosives. Organic substances (wood flour, peat, oil cake, petroleum oils) or inorganic materials (aluminum powder, fer-rosilicon) are used as combustible substances in ammonites. Nitroglycerin and other nitrate esters, trotyl (trinitrotoluene, TNT), hexogon (cyclonite), or PETN (penta-erythrityl tetranitrate) are used as explosives.

The mixtures of ammonium nitrate with combustible substances are called dynammons; those with TNT, amatols; those with aluminum powder and TNT, ammonals; and those with hexogen, aluminum, and TNT, rock ammonites. Mixtures containing considerable amounts of liquid nitrate esters are classified as dynamites. The performance characteristics of the ammonites are heat of explosion, 2.1–8.4 megajoules per kg (500–2,000 kcal/kg); detonation rate, from 1.5–2.0 to 5–6 km/sec; blasting-charge density, 0.8–1.5 g/cm3. The manufacture of ammonites consists in preparing their components (drying, grinding, and screening) and mixing them. The resulting mixtures are packed or used for the production of cartridges.

Ammonites are used in various kinds of open-pit and underground blasting, for charging various types of ammunition (mines, bombs, and shells), and for engineer corps blasting. The advantages of ammonites over other explosives are their high chemical stability and relative safety in production, storage, and handling; disadvantages are their hygroscopicity, low water resistance, and caking tendency.

REFERENCE

Iaremenko, N. E., and B. Ia. Svetlov. Teoriia i tekhnologiia pro-myshlennykh vzryvchatykh veshchestv. Moscow, 1957. Second edition: Moscow, 1966.
References in periodicals archive ?
The spectacular proliferation of Ammonites and conodonts assemblages immediately after the end-Permian extinction corroborates well with the world-wide pattern of pelagic communities dominating the Early Triassic marine environment.
Zonation by ammonites and foraminifers of the Vraconnian-Turonian interval: A comparison of the Boreal and Tethyan domains (NW Europe/ Central Tunisia).
Thus, there is no contradiction: Numbers focuses exclusively on the Moabites who lost land to Sihon; while Judges mentions the Ammonites as well as the Moabites.
In the Hebrew Bible, Deuteronomy 23:3 notes God's command that: "An Ammonite or a Moabite shall not enter into the assembly of the LORD; even to the tenth generation shall none of them enter into the assembly of the LORD for ever.
Ammonites are fossil shells of creatures that lived in the sea as far back as 450 million years ago; they belong to a group of cephalopods, which include octopus, squid and cuttlefish.
After the counter-siege against the Ammonites, the Israelites who rejected Saul initially (8) seem to have come around to his side.
Early and Middle Cenomanian ammonites are practically absent in more proximal ramp areas of the Navarre-Cantabrian Trough and in the North Castilian Platform due to the diachronous character of the transgression (e.
As well as being a fond memory of "The Cazzy", the exhibition title refers to Sainty's practice of collecting ammonite fossils, curiously-shaped shells and crab claws from the shoreline and using their patterns and forms to create sculptures in cast-iron, bronze, aluminium, concrete and fibreglass.
This also means most people cook their camp food until it's fossilised - I've nibbled on tastier ammonites than some of the barbecued burgers we had last week.
Ammonites are a group of marine invertebrate animals, which became extinct along with most dinosaurs over 60 million years ago.
Other stars of the show are animatronic models of the Protoceratops, Oviraptor, Velociraptor, Gallimimus, Camarasaurus and the earliest living bird, Archaeopteryx, as well as fossils of pterosaurs, pliosaurs and ammonites.
Late Cretaceous ammonites from southern Alaska were used to evaluate mechanisms for sediment filling of ammonite chambers.