| 释义 |
monoclinal, a. and n. Geol.|mɒnəʊˈklaɪnəl|
[f. Gr. µόνο-ς mono- + κλῑ́ν-ειν to bend + -al1. Cf. anti-, iso-, synclinal.]
A. adj.
a. Consisting of strata that slope in the same direction and at the same angle throughout.
In quot. 1876 the word appears to have been used with a slightly different meaning, perh. because ‘direction’ was interpreted as referring to directions in a horizontal plane rather than a vertical one.
1843W. B. & H. D. Rogers in Rep. 1st, 2nd & 3rd Meetings Assoc. Amer. Geologists & Naturalists 485 While the phrases, anticlinal dip, and synclinal dip, sufficiently express the directions of the beds, due to concave and convex flexures, we propose the term monoclinal, to signify a sameness in the direction of the dip, and shall term a mountain or valley, in which such sameness prevails, a monoclinal mountain, or monoclinal valley. 1858H. D. Rogers Geol. Pennsylv. I. 10 The ridges..are of three orders... In geological language they are of anticlinal, synclinal, and monoclinal structure. Ibid. 18 Monoclinal Valleys. 1875J. W. Powell Explor. Colorado River xi. 160 Monoclinal valleys..run in the direction of the strike between the axes of the fold—one side of the valley formed of the summits of the beds, the other composed of the cut edges of the formation. 1876Page Adv. Text-bk. Geol. iv. 83 The strata of a district, though lying at different angles, may all slope in the same way, and in such a case they are said to be monoclinal or dipping in one main direction. 1930Compt. Rend. 15th Internat. Geol. Congress 1929 II. vi. 361, I shall consider only four major types of blocks included between bounding faults: 1. Tilted or monoclinal blocks; [etc.]. 1942O. D. von Engeln Geomorphology xv. 327 Monoclinal ridges, alternating with monoclinal valleys, appear where a series of resistant and weak beds all dip in the same direction. 1957G. E. Hutchinson Treat. Limnol. I. i. 111 The channel containing Lenore Lake lies in a zone of fractured basalt on a monoclinal slope.
b. Applied to a fold consisting of a single slope connecting strata that are parallel and more or less horizontal but at different levels.
1877Le Conte Elem. Geol. (1879) 178 Such a bend is called a monoclinal fold or axis. 1880C. E. Dutton Rep. Geol. High Plateaus Utah ii. 25 The great structural features of the High Plateaus are the faults and monoclinal flexures. 1940E. S. Hills Outl. Struct. Geol. v. 111 An individual normal fault may pass either laterally or vertically into a monoclinal flexure. 1969J. Bundred Basic Geol. for Engineers iv. 115 A monoclinal fold..has basically a single undulation.
B. n.
a. A monoclinal fold.
1880C. E. Dutton Rep. Geol. High Plateaus Utah ii. 26 So close is the homology that we are justified in calling a monoclinal in some of its aspects a modified fault. The only difference for structural purposes is that in the case of a typical fault of the simplest form the shearing is along one plane, while in the monoclinal the shearing lies between two planes. 1886T. M. Reade Orig. Mount. Ranges xx. 250 The Water-Pocket flexure, one of the grandest monoclinals of the west. 1914J. Park Text-bk. Geol. ix. 140 In sharply bent monoclinals, the strata in the middle limb are generally drawn out, compressed, or deformed.
b. A monoclinal set of strata; = homocline.
1916Bull. Geol. Soc. Amer. XXVII. 92, I welcome the suggestion of the term homocline. The need of a term for this structure has long been felt in the United States Geological Survey, where confusion has been avoided in editing by using monoclinal for the homocline as distinct from monocline or monoclinal fold.
Hence monoˈclinally adv.
1858H. D. Rogers Geol. Pennsylv. I. 10 Dipping only in one direction, or monoclinally. 1880C. E. Dutton Rep. Geol. High Plateaus Utah ii. 31 At East Fork Cañon the thrown beds..are turned up monoclinally. 1968R. W. Fairbridge Encycl. Geomorphol. 483/2 At coastlines the same ancient cyclic landsurface may be monoclinally warped down to pass beneath marine sequences of Jurassic or Cretaceous rocks. |