| 释义 |
▪ I. prograde, a.|ˈprəʊgreɪd|
[f. pro-1 1 + retrograde a. and n.]
1. Petrol. Of a metamorphic change: resulting from an increase in temperature or pressure. Opp. retrograde a. 3 e.
1967K. G. Cox et al. Introd. Pract. Study Crystals x. 200 The volatile constituents, H2O and CO2, are expelled from the rocks with rising temperature and cease to be available for the formation of low-temperature minerals (usually rich in H2O and CO2) when the temperature declines at the end of prograde metamorphism. 1977A. Hallam Planet Earth 174 The metamorphism of sedimentary rocks..involves the production of water vapor, carbon dioxide and other gaseous substances... This type of metamorphism is called prograde metamorphism, and takes place principally in response to increasing temperature.
2. Astr. From west to east; anticlockwise as seen from north of the ecliptic; = direct a. 3. Opp. retrograde a. 1 a.
1969Nature 19 July 243/2 Once in a prograde orbit, the tides on the Earth would begin to push the Moon outwards to its present position. 1977Ibid. 3 Mar. 15/3 The overhead motion of the Sun relative to an observer fixed on the surface [of Venus] is prograde with a speed of about 4 m s—1.
▪ II. prograde, v. Physical Geogr.|prəʊˈgreɪd|
[f. pro-1 1 + retrograde v.]
a. intr. Of a shore or shoreline: to undergo progradation.
1909W. M. Davis in Geogr. Jrnl. XXXIV. 303 After having maturely retrograded the cliffs, the waves have prograded the strand-plain. The strand-plain broadens a little opposite each valley, for now that the shore-line is prograding, the rivers have opportunity of building their deposits forward. 1929H. Meredith East Anglia ii. 63 Its beach progrades in inverse proportion to the retrograding of the Ness itself. 1954W. D. Thornbury Princ. Geomorphol. xvii. 443 Beach features are particularly ephemeral forms along a retrograding shore line, but along a shore line that is advancing seaward or is prograding they may be semipermanent. 1967Oceanogr. & Marine Biol. V. 123 Thus valley train material extending seaward off Alaska has prograded almost to the headlands. 1978Nature 17 Aug. 655/1 During the Campanian, fluvial, deltaic and coastal plain systems prograded eastwards across marine strata such that by the end of the Campanian (∼69 Myr bp) the area of marine deposition was greatly restricted.
b. trans. To cause to prograde.
1909[see sense a]. 1919D. W. Johnson Shore Processes v. 223 Just so long as the current aggrades (builds up) the seabottom offshore, the waves will prograde (build forward) the shore. 1939Revelle & Shepard in P. D. Trask Rec. Marine Sediments iv. 279 The coarse material carried to the sea by rivers may temporarily prograde the shore, forming deltas. 1968R. W. Fairbridge Encycl. Geomorphol. 133/1 Marine Deposition Coasts. These are another type of Secondary coasts that have been prograded by waves and currents.
Hence proˈgraded ppl. a., proˈgrading vbl. n. and ppl. a.
1910Jrnl. Geol. XVIII. 166 The prograding of the shore beyond the headland. 1918Trans. & Proc. N.Z. Inst. L. 215 Some of the material is thrown up on the beach, so that the shore-line advances seawards, leaving a prograded strip of new land. 1919D. W. Johnson Shore Processes v. 223 Following Davis we may call any shore which is experiencing such a long-continued advance into the sea, a prograding shore, and distinguish it from the more usual retreating or retrograding shore. The prograding of a shoreline..may continue for a few years, a few centuries, or many thousands of years. 1940Geogr. Jrnl. XCVI. 261 Occasional deep lows, locally called pits and containing water, are scattered about amongst the shingle. They were usually found during rapid prograding to the lee of bends. 1968R. W. Fairbridge Encycl. Geomorphol. 895/2 (caption) Prograded spit, Whananaki Inlet, Northland, New Zealand. 1978Nature 12 July 131/1 The environment was interpreted as a prograding tidal estuary where shelf deposits pass upwards into fields of migrating dunes and megaripples. |