48:
40:
84:
684:
678:
Kulik, NA, Postnov AV Geology, petrography and mineralogy in archaeological research . - Methods of Earth and Man in archaeological research : Comprehensive
Training Manual. - Novosibirsk: Novosibirsk State University, Institute of Archaeology and Ethnography SB RAS, 2010. - S.
232:
processes are more efficient in the rounding of sedimentary grains. Experimental studies have shown that the angularity of sand-sized detrital quartz can remain virtually unchanged after hundreds of kilometers of fluvial transport.
255:
in major rivers tend to exhibit a high degree of roundness. Alluvium from small rivers is less rounded. Deposits of ephemeral streams exhibit little rounding with angular clasts.
75:
of sedimentary particles. It is expressed as the ratio of the average radius of curvature of the edges or corners to the radius of curvature of the maximum inscribed sphere.
500:"Physical controls on sand composition and relative durability of detrital minerals during ultra-long distance littoral and aeolian transport (Namibia and southern Angola)"
319:
245:. The degree of roundness points to the range and mode of transport of clastic material, and can also serve as a search criterion in mineral exploration, especially for
47:
193:
An example of this practical use has been applied to the roundness of the grains in the Gulf of Mexico in order to observe the distance from the source rocks.
146:
This six-fold category characterisation is used in the
Shepard and Young comparison chart and the Powers chart but the Krumbein chart has nine categories.
183:
Angularity (A) and roundness (R) are but two parameters of the complexity of a clast's generalised form (F). A defining expression is given by:
263:
270:, which contain variably rounded fragments in a finely-ground matrix of pulverized rock. The clasts originate in deeper formations in
405:
Whalley, W.B. Surface textures. (2003) In, Encyclopedia of
Sediments and Sedimentary rocks, Ed. G.V. Middleton, Kluwer, p.712-717
614:
652:
Multi-Stage
Construction of the Little Cottonwood Stock, Utah: Origin, Intrusion, Venting, Mineralization, and Mass Movement
186:
F=f(Sh, A, R, Sp, T) where f denotes a functional relationship between these terms and where Sh denotes the shape, Sp the
17:
637:
390:
271:
452:
416:
330:
iron deposit in Sweden, Cuajone and
Toquepala in Peru; El Salvador in Chile; Mt. Morgan in Australia; and
172:
pebble will obviously round much faster, and over a shorter distance of transport, than a more resistant
584:
The Nature and Origin of Pebble Dikes and
Associated Alteration: Tintic Mining District (Ag-Pb-Zn), Utah
95:
Rounding, roundness or angularity are terms used to describe the shape of the corners on a particle (or
31:
453:"Fluvial or aeolian grains? Separation of transport agents on Mars using earth analogue observations"
150:
299:
236:
716:
267:
721:
711:
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39:
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and/or magmatic water flash boils. The clasts have been rounded due to thermal spallation,
8:
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165:
72:
633:
610:
523:
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149:
Rounding of sediment particles can indicate the distance and time involved in the
112:
52:
323:
311:
87:
Schematic representation of difference in grain shape. Two parameters are shown:
417:"Provenance of opaque minerals in coastal sands, western Gulf of Mexico, Mexico"
237:
Paleogeographic value of determining the degree of roundness of clastic material
331:
315:
246:
218:
60:
56:
672:
Mountain
Encyclopedia. - Moscow: Soviet Encyclopedia, 1987. - Vol. 3 - S. 553.
476:
436:
705:
266:
are dikelike bodies found in intrusive environments, usually associated with
177:
161:
83:
650:
582:
123:
typically use a simple visual chart with up to six categories of roundness:
291:
242:
563:
119:. Although roundness can be numerically quantified, for practical reasons
660:
283:
592:
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187:
88:
515:
382:
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120:
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Roundness is an important indicator of the genetic affiliation of a
275:
252:
100:
675:
Geological dictionary . - M. : Nedra, 1978. - T. 2. - S. 29.
279:
258:
222:
214:
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173:
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96:
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or stream beds by the action of current flow, wave impact,
104:
539:"Experimental abration; 3, Fluviatile action on sand"
176:
pebble. The rate of rounding is also affected by the
153:
of the sediment from the source area to where it is
310:; Urad, Mt. Emmons, Central City, Leadville, and
274:systems, and have been brought up explosively by
703:
414:
201:Abrasion occurs in natural environments such as
259:Clast rounding in non-sedimentary environments
160:Speed of rounding will depend on composition,
605:Bates, Robert L. and Julia A. Jackson, eds.,
628:Guilbert, John M. and Charles F. Park, Jr.,
624:
622:
562:
435:
424:Boletín de la Sociedad Geológica Mexicana
334:in Argentina contain these pebble dikes.
682:
497:
142:Well-rounded: corners completely rounded
82:
46:
38:
655:(MS thesis). Brigham Young University.
619:
587:(MS thesis). Brigham Young University.
580:
366:
190:and T the micro-scale surface texture.
78:
14:
704:
648:
536:
415:Kasper-Zubillaga; et al. (2016).
228:Recent studies have demonstrated that
127:Very angular: corners sharp and jagged
685:"Окатанность обломочных горных пород"
450:
91:(vertical) and rounding (horizontal).
576:
574:
372:
103:. Such a particle may be a grain of
27:The smoothness of clastic particles
24:
71:is the degree of smoothing due to
25:
733:
571:
642:
607:Dictionary of geological terms,
599:
530:
498:Garzanti; et al. (2015).
491:
444:
408:
399:
375:Petrology of Sedimentary Rocks
43:Rounded pebbles in a streambed
13:
1:
609:Anchor, 3rd ed. 1984, p. 372
359:
630:The Geology of Ore Deposits,
581:Johnson, Douglas M. (2014).
294:fluids. The ore deposits of
217:action, wind, gravitational
7:
543:American Journal of Science
457:Planetary and Space Science
451:Kapui; et al. (2018).
337:
196:
10:
738:
649:Jensen, Collin G. (2019).
300:White Pine mining district
268:porphyry-type ore deposits
29:
477:10.1016/j.pss.2018.06.007
437:10.18268/BSGM2016v68n2a10
632:Freeman, 1986, pp.83-85
373:Folk, Robert L. (1980).
290:action, or corrosion by
469:2018P&SS..163...56K
180:and energy conditions.
304:East Traverse Mountain
296:Tintic mining district
168:. For example, a soft
92:
63:
44:
564:10.2475/ajs.257.3.172
86:
50:
42:
79:Measure of roundness
30:For other uses, see
555:1959AmJS..257..172K
18:Rounding (sediment)
344:Sorting (sediment)
93:
64:
55:from the beach on
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615:978-0-385-18101-3
516:10.1111/sed.12169
16:(Redirected from
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312:Ouray, Colorado
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253:Alluvial debris
247:placer deposits
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717:Paleogeography
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683:Alexei Rudoy.
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549:(3): 172–190.
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510:(4): 971–996.
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430:(2): 323–338.
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223:erosive agents
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151:transportation
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61:Altai Republic
57:Teletskoe Lake
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9:
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722:Sedimentology
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712:Geomorphology
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661:1877/etd10951
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638:0-7167-1456-6
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504:Sedimentology
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278:or intrusive
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51:Well-rounded
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692:. Retrieved
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593:1877/etd7323
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410:
401:
377:. Hemphill.
374:
368:
292:hydrothermal
287:
272:hydrothermal
264:Pebble dikes
262:
251:
243:clastic rock
240:
227:
200:
192:
185:
182:
164:and mineral
159:
148:
145:
94:
68:
67:
320:Silver Bell
318:, Montana;
284:groundwater
136:Sub-rounded
133:Sub-angular
706:Categories
694:2011-01-30
383:2152/22930
360:References
349:Sphericity
326:; and the
221:and other
207:sand dunes
188:sphericity
178:grain size
121:geologists
89:sphericity
524:129174293
485:125572789
463:: 56–76.
332:Agua Rica
170:claystone
155:deposited
69:Roundness
32:Roundness
338:See also
280:breccias
276:diatreme
197:Abrasion
166:cleavage
162:hardness
101:sediment
73:abrasion
551:Bibcode
465:Bibcode
288:milling
230:aeolian
215:glacial
203:beaches
139:Rounded
130:Angular
117:boulder
679:39–96.
636:
613:
522:
483:
389:
328:Kiruna
322:; and
302:, and
174:quartz
113:cobble
109:pebble
53:cobble
520:S2CID
481:S2CID
420:(PDF)
316:Butte
219:creep
211:river
99:) of
97:clast
689:Knol
634:ISBN
611:ISBN
387:ISBN
308:Utah
298:and
107:, a
105:sand
657:hdl
589:hdl
559:doi
547:257
512:doi
473:doi
461:163
432:doi
379:hdl
282:as
115:or
708::
687:.
621:^
573:^
557:.
545:.
541:.
518:.
508:62
506:.
502:.
479:.
471:.
459:.
455:.
428:68
426:.
422:.
385:.
314:;
306:,
249:.
225:.
209:,
205:,
157:.
111:,
59:,
697:.
663:.
659::
595:.
591::
567:.
561::
553::
526:.
514::
487:.
475::
467::
440:.
434::
395:.
381::
34:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
