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 ?
In the Salt and Surghar Range the Smithian-Spathian climatic deterioration seriously affected the life in the marine realm, especially the Ammonites and conodonts, and also on land gymnosperm dominated floras replaced the lycopod-dominated communities of the Dienerian-Smithian interval (Hermann et al., 2012).
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.
In the verses that follow, (7) we are told that the spirit of God came to Saul, and some 370,000 men were mustered to battle against the Ammonites. This divine power and vast army is certainly excessive if only for the siege of a single city.
New occurrences of Late Albian ammonites near Amurrio (Ziorraga locality) and Ordunte (Balmaseda locality), and in the Leioa area (Ondiz locality) are currently under study and are here only considered to put the Albian-Cenomanian change in the ammonite associations into a proper context.
(4.) Penelope Lively, Dancing Fish and Ammonites (New York: Viking, 2013), 42.
Both archaeological and epigraphic evidence points to significant economic, political, and social changes among the Ammonites in the southern Levant from the late eighth through sixth centuries BCE, says Tyson, and he focuses on that period to understand and explain the changes in light of imperial practice.
"[W]hile Old Age, Life and Times, Memory, Reading and Writing, and Six Things each rate a chapter in Dancing Fish and Ammonites, the important people in her life--her late husband, two children, six grandchildren and a best friend--figure only peripherally.
Not until the last few decades did paleontologists fully accept this "catastrophism." Most scientists now believe a meteor impact did in the dinosaurs, as well as the ammonites, extinct mollusks to which Kolbert devotes a loving chapter.
I'd walk along the beach and pick up fossils of ammonites and I couldn't help but be affected by the natural shapes.