paragenesis
(pærəˈdʒɛnɪsɪs)
Pl. -geneses (-ˈdʒɛnɪsiːz).
[mod. f. Gr. παρα- beside, side by side + γένεσις genesis.]
1. Biol. a. The production in an individual organism of characters belonging to two different species, as in hybridism.
| 1890 in Cent. Dict. |
b. spec. Hybridism in which the offspring is partially sterile.
| 1892 Syd. Soc. Lex., Paragenesis: see Paragenesia. Paragenesia, a term applied by Broca to the comparative sterility of hybrids, which consists in their being sterile with similar hybrids, but fertile with members of either parent species. |
c. A name for subsidiary or unusual modes of reproduction: see paragamy.
2. The occurrence together of different minerals, esp. as reflecting the conditions of their formation; a set of minerals occurring together or with a given mineral; also, the sequence and periods of formation of the constituent minerals. [So named by Breithaupt in Ger. 1849.]
| 1853 Edin. New Philos. Jrnl. LIV. 324 By the paragenesis of minerals he [sc. Breithaupt] understands the more or less definite mode of association, by means of which he endeavours to determine their relative age. 1855 Dana Min. i. 239. 1865 Page Handbk. Geol. Terms 350 Paragenesis of Minerals. 1871 J. H. Collins Handbk. Mineral. Cornwall & Devon 71 A more strict paragenesis would deal with those groups of minerals which are immediately associated with each other. 1878 Lawrence tr. Cotta's Rocks Class. 3 What was termed by Breithaupt Paragenesis. By this is meant the law of mutual association or repulsion of certain minerals. 1894 Thinker V. 342 By paragenesis, or by some form of pseudomorphism, one mineral may be changed into another. 1934 Q. Jrnl. Geol. Soc. XC. 338 Sillimanite has been abundantly developed alongside some quartz veins... This paragenesis forms a selvedge between quartz veins and the biotite-muscovite-schist. 1951 Mineral. Mag. XXIX. 677 The paragenesis sylvine-halite - magnesite - quartz - anhydrite - (carnallite)..first makes its appearance in the halite zone. 1954 R. L. Parker tr. Niggli's Rocks & Mineral Deposits iv. 128 Another method..consists in constructing theoretical (so-called normative) mineral associations..to constitute idealized parageneses under certain physical-chemical conditions. 1966 E. W. Heinrich Geol. of Carbonatites vii. 233 (caption) Paragenesis (from oldest to youngest): (1) some cerite.., (2a) bastnäsite.., (2b) monazite, (3) parisite, (3b) sahamalite. 1974 Nature 22 Nov. 336/1 The mineral parageneses of alkali pegmatites are not considered in detail. |