Palingenesis

(redirected from palingenetical)
Also found in: Dictionary, Thesaurus, Medical.

palingenesis

[‚pal·ən′jen·ə·səs]
(embryology)
Unaltered recapitulation of ancestral features by the developing stages of an organism.
(petrology)
In-place formation of new magma by the melting of preexisting rock material.

Palingenesis

 

a concept introduced by E. Haeckel in 1866 in his formulation of the biogenetic law; it is a term for the recapitulation of remote stages of phylogenesis in an individual’s embryonic development.

Haeckel considered the following to be examples of palingenesis: the separation of the primary germ layers and the development of the notochord, the basal plate of the cranium, the branchial arches, and the unicameral heart. He distinguished palingenesis from cenogenesis—the appearance during embryonic development of adaptive characters that obscure the manifestations of palingenesis. I. I. Shmal’gauzen observed that Haeckel examined the evolution of adult organisms in isolation from the evolution of embryos; in fact the evolution of embryos bears a regular relationship to the history of the development of adult forms and partially determines that history. Shmal’gauzen proposed to designate palingenesis by the more accurate term “recapitulation.”

REFERENCES

Shmal’gauzen, I. I. Problemy darvinizma, 2nd ed. Leningrad, 1969.
Mirzoian, E. N. Razvitie ucheniia o rekapituliatsii. Moscow, 1974.

Palingenesis

 

the formation of magmas, usually of granitic composition, through selective or complete fusion of igneous or metamorphic rocks deep in the earth. Fusion occurs when the rocks are acted upon by juvenile fluids. The magmatic melts resulting from palingenesis develop further through replacement of the rock by magma that selectively assimilates components (SiO2, K2O, Na2O, AI2O3, and others) and through the formation of injection gneisses and migmatites. Granitoid magmatism in the deep zones of geosynclines results. Palingenesis may occur in part during regressive metamorphism.

REFERENCE

Korzhinskii, D. S. “Granitizatsiia kak magmaticheskoe zameschenie.” Izv. AN SSSR: Ser. geologicheskaia, 1952, no. 2.

A. A. MARAKUSHEV