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formation towering 70 feet (21 m) over the surrounding range land. The
Western Interior Seaway is believed to have behaved similarly to a giant estuary in terms of water mass transport. Riverine inputs exited the seaway as coastal jets, while correspondingly drawing in water from the Tethys in
185:, some 1,000 km (620 mi) wide. At its deepest, it may have been only 800 or 900 metres (2,600 or 3,000 ft) deep, shallow in terms of seas. Two great continental watersheds drained into it from east and west, diluting its waters and bringing resources in eroded
1050:
Da Gama, Rui O.B.P.; Lutz, Brendan; Desjardins, Patricio; Thompson, Michelle; Prince, Iain; Espejo, Irene (November 2014). "Integrated paleoenvironmental analysis of the
Niobrara Formation: Cretaceous Western Interior Seaway, northern Colorado".
407:
formations. There is great variety in the shells and the many distinct species have been dated and can be used to identify specific beds in those rock formations of the seaway. Many species can easily fit in the palm of the hand, while some like
424:
493:
769:
Lowery, Christopher M.; Leckie, R. Mark; Bryant, Raquel; Elderbak, Khalifa; Parker, Amanda; Polyak, Desiree E.; Schmidt, Maxine; Snoeyenbos-West, Oona; Sterzinare, Ericfa (1 February 2018).
232:
At the end of the
Cretaceous, continued Laramide uplift hoisted the sandbanks (sandstone) and muddy brackish lagoons (shale), thick sequences of silt and sandstone still seen today as the
730:
454:
163:. In time, the southern embayment merged with the Mowry Sea in the late Cretaceous, forming a completed seaway, creating isolated environments for land animals and plants.
418:. The shells of the genus are known for being composed of prismatic calcitic crystals that grew perpendicular to the surface, and fossils often retain a pearly luster.
986:
Boyles, M.J.; Scott, A.J. (1982). "Comparison of Wave-Dominated
Deltaic Deposits and Associated Sand-Rich Strand Plains, Mesaverde Group, Northwest Colorado".
476:
381:
fossils are very common; it was probably a major participant in the surface ecosystem, though it was found in only the southern reaches of the seaway.
271:
The
Western Interior Seaway was a shallow sea, filled with abundant marine life. Interior seaway denizens included predatory marine reptiles such as
236:, while low-lying basins between them gradually subsided. The Western Interior Seaway divided across the Dakotas and retreated south towards the
86:
to the east. At its largest extent, it was 2,500 feet (760 m) deep, 600 miles (970 km) wide and over 2,000 miles (3,200 km) long.
19:
1177:
Kauffman, Erle G.; Caldwell, W.G.E. (1993). "The
Western Interior Basin in Space and Time". In Caldwell, W.G.E.; Kauffman, Erle G. (eds.).
625:
1005:
Kauffman, E.G. (1984). "Paleobiogeography and evolutionary response dynamic in the
Cretaceous Western Interior Seaway of North America".
387:(oyster-like bivalve molluscs) were well-adapted to life in the oxygen-poor bottom mud of the seaway. These left abundant fossils in the
225:
the south and Boreal waters from the north. During the late
Cretaceous, the Western Interior Seaway went through multiple periods of
1223:
953:
614:
467:
735:
729:
Slingerland, Rudy; Kump, Lee R.; Arthur, Michael A.; Fawcett, Peter J.; Sageman, Bradley B.; Barron, Eric J. (1 August 1996).
1253:
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that had stout legs for swimming through water and tiny wings used for marine steering rather than flight; and the tern-like
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could be well over a meter in diameter. Entire schools of fish sometimes sought shelter within the shell of the giant
1263:
1248:
1158:
1125:
597:
771:"The Late Cretaceous Western Interior Seaway as a model for oxygenation change in epicontinental restricted basins"
533:
748:
1183:. Volume 39 of Geological Association of Canada Special Paper. St. John's, NL: Geological Association of Canada
847:
822:
770:
226:
554: – Inland sea that existed in North America during the mid- to late Jurassic Period of the Mesozoic Era
954:"Recent Discoveries of Cretaceous Marine Vertebrates on the Eastern Margins of the Western Interior Seaway"
615:"Relation of unconformities, tectonics, and sea-level changes, Cretaceous of Western Interior, U.S.A.; in"
178:
land populations, allowing a temporary mixing of newer species before again separating the populations.
1258:
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897:
217:
121:
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specimen, an exceptionally well-preserved specimen that drowned in the
Western Interior Seaway.
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252:
182:
171:
128:
By the late
Cretaceous, Eurasia and the Americas had separated along the south Atlantic, and
83:
650:
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1006:
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transgressed south over western North America; this formed the Mowry Sea, so named for the
51:
8:
392:
193:
on the eastern shores of the seaway; the western boundary, however, consisted of a thick
1064:
863:
Frazier, William J.; Schwimmer, David R. (1987). "The Tejas Sequence: Tertiary—Recent".
791:
58:
into two landmasses for 34 million years. The ancient sea, which existed from the early
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296:(believed to be 10 metres (33 ft) long); and advanced bony fish including
212:
deposition suggests that the seaway was warm and tropical, with abundant calcareous
1068:
868:
795:
744:
216:. Remnants of these deposits are found in northwest Kansas. A prominent example is
181:
At its largest, the Western Interior Seaway stretched from the Rockies east to the
133:
557:
229:, when the bottom water was devoid of oxygen and the water column was stratified.
1072:
548: – Large lake in central North America at the end of the last glacial period
335:
137:
63:
59:
872:
731:"Estuarine circulation in the Turonian Western Interior seaway of North America"
704:
189:
that formed shifting delta systems along its low-lying coasts. There was little
147:
The earliest phase of the seaway began in the mid-Cretaceous when an arm of the
260:
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201:. The western shore was thus highly variable, depending on variations in
152:
624:(Memoir 36, Interregional unconformities and hydrocarbon accumulation).
928:. A Large Predatory Fish from the Late Cretaceous Western Interior Sea"
483:
444:
384:
373:
129:
103:
519:
338:
that secreted the chalky platelets that give the Cretaceous its name,
159:. In the south, the Gulf of Mexico was originally an extension of the
117:
1008:
Jurassic-Cretaceous biochronology and paleogeography of North America
323:
248:
209:
202:
94:
79:
67:
24:
1120:(Third ed.). New York: Columbia University Press. p. 172.
657:(5th ed.). Belmont, CA: Brooks/Cole, Cengage Learning. p.
1145:
West Coast Fossils: A Guide to the Ancient Life of Vancouver Island
503:
331:
319:
304:
276:
251:, parts of the Western Interior Seaway still occupied areas of the
240:. This shrunken and final regressive phase is sometimes called the
190:
1014:. Vol. 27. Geological Association of Canada. pp. 273–306
542: – Major seaway of North America during the Cretaceous Period
263:, rather than with the previous event responsible for the seaway.
140:. The Western Interior Seaway may be seen as a downwarping of the
132:
on the west coast of the Americas had commenced, resulting in the
259:. Later transgression, however, was associated with the Cenozoic
110:
99:
23:
Map of North America with the Western Interior Seaway during the
1088:"Bulletin 19: The Geology of Ness and Hodgeman Counties, Kansas"
16:
Prehistoric inland sea that split the continent of North America
1202:
1118:
Bringing fossils to life : an introduction to paleobiology
1049:
1032:
Benton, S.C. (1994). "The Pterosaurs of the Niobrara Chalk."
842:(2nd ed.). Belmont, Calif.: Wadsworth Pub. p. 643.
349:
The seaway was home to early birds, including the flightless
221:
728:
749:
10.1130/0016-7606(1996)108<0941:ECITTW>2.3.CO;2
186:
1218:
768:
487:, an ancient bivalve from the Cretaceous of South Dakota.
961:
Saskatchewan Geological Survey Summary of Investigations
592:. New York: W.H. Freeman and Company. pp. 487–489.
308:, and the massive 4-to-5-metre (13 to 16 ft) long
144:
ahead of the growing Laramide/Rockies mountain chain.
648:
515:
1026:
840:
The changing earth: exploring geology and evolution
653:
The Changing Earth: Exploring Geology and Evolution
1142:
898:"Giant predatory shark fossil unearthed in Kansas"
1053:Palaeogeography, Palaeoclimatology, Palaeoecology
1230:
1176:
862:
318:. Other sea life included invertebrates such as
560: – A Jurassic-Cretaceous cratonic sequence
1140:
675:
1092:Bulletin of the University of Kansas—Lawrence
951:
921:
705:"Monument Rocks, the Chalk Pyramids - Kansas"
365:shared the sky with large pterosaurs such as
279:. Other marine life included sharks such as
952:Cumbaa, Stephen L.; Tokaryk, Tim T. (1999).
626:American Association of Petroleum Geologists
985:
612:
1224:Cretaceous paleogeography, southwestern US
136:, the early phase of growth of the modern
649:Monroe, James S.; Wicander, Reed (2009).
583:
581:
579:
577:
575:
573:
1115:
1004:
116:
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18:
1180:Evolution of the Western Interior Basin
1141:Ludvigsen, Rolf; Beard, Graham (1997).
817:. New York: W.H. Freeman. p. 516.
812:
613:R.J. Weimer (1984). J.S. Schlee (ed.).
606:
587:
468:Rocky Mountain Dinosaur Resource Center
1231:
895:
865:Regional Stratigraphy of North America
837:
806:
736:Geological Society of America Bulletin
570:
78:. The two land masses it created were
642:
361:, an early avian with a toothy beak.
255:, submerging the site of present-day
174:, each time rejoining the separated,
89:
1085:
536: – Geology of the area in Utah
124:, located 25 miles south of Oakley.
13:
1170:
922:Mike Everhart (February 2, 2010).
702:
14:
1275:
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1098:(18): Stratigraphy: Rocks Exposed
896:Walker, Matt (24 February 2010).
1201:
534:Geology of the Bryce Canyon area
518:
492:
475:
453:
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410:Inoceramus (Haploscapha) grandis
1214:Marine Reptiles of South Dakota
1134:
1109:
1079:
1043:
998:
979:
945:
915:
889:
856:
800:10.1016/j.earscirev.2017.12.001
683:"Oceans of Kansas Paleontology"
290:and the giant shellfish-eating
1086:Moss, Rycroft G. (May 2004) .
831:
762:
722:
696:
448:in the Western Interior Seaway
168:sea levels fell multiple times
1:
932:Oceans of Kansas Paleontology
564:
1254:Geology of the United States
1116:Prothero, Donald R. (2013).
1073:10.1016/j.palaeo.2014.05.005
54:that split the continent of
7:
873:10.1007/978-1-4613-1795-1_9
813:Stanley, Steven M. (1998).
588:Stanley, Steven M. (1999).
511:
10:
1280:
470:in Woodland Park, Colorado
1239:Cretaceous paleogeography
838:Monroe, James S. (1997).
430:Artist's impression of a
314:, larger than any modern
197:eroded eastward from the
98:A broken concretion with
44:North American Inland Sea
1264:Paleocene paleogeography
1249:Geology of North America
1149:. Harbour Pub. pp.
266:
155:, an organic-rich rock
122:Monument Rocks (Kansas)
70:(66 Ma), connected the
32:Western Interior Seaway
125:
114:
27:
779:Earth-Science Reviews
253:Mississippi Embayment
205:and sediment supply.
183:Appalachian Mountains
172:Transcontinental Arch
120:
97:
22:
1210:at Wikimedia Commons
867:. pp. 523–652.
815:Earth system history
709:www.kansastravel.org
590:Earth System History
199:Sevier orogenic belt
48:Western Interior Sea
1065:2014PPP...413...66D
1034:The Earth Scientist
792:2018ESRv..177..545L
126:
115:
90:Origin and geology
66:) to the earliest
28:
1259:Historical oceans
1244:Geology of Canada
1219:Paleo Map Project
1208:Cretaceous Seaway
1206:Media related to
882:978-1-4612-9005-6
293:Ptychodus mortoni
247:During the early
234:Laramie Formation
142:continental crust
36:Cretaceous Seaway
34:(also called the
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261:Tejas sequence
238:Gulf of Mexico
218:Monument Rocks
109:near Ekalaka,
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72:Gulf of Mexico
50:) was a large
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988:AAPG Bulletin
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1185:. Retrieved
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630:. Retrieved
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552:Sundance Sea
546:Lake Agassiz
500:Borealopelta
482:
462:Elasmosaurus
460:
443:
437:
433:Cretoxyrhina
431:
415:Platyceramus
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344:radiolarians
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161:Tethys Ocean
149:Arctic Ocean
146:
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107:Pierre Shale
76:Arctic Ocean
47:
43:
39:
35:
31:
29:
1040:(1): 22-25.
786:: 545–564.
622:AAPG Memoir
439:Squalicorax
385:Inoceramids
368:Nyctosaurus
363:Ichthyornis
358:Ichthyornis
352:Hesperornis
311:Xiphactinus
282:Squalicorax
273:plesiosaurs
208:Widespread
153:Mowry Shale
1233:Categories
1187:2022-02-13
1102:2020-11-17
849:0314095772
824:0716728826
689:2007-02-06
565:References
484:Inoceramus
445:Claosaurus
379:Pteranodon
374:Pteranodon
334:including
328:belemnites
130:subduction
104:Cretaceous
84:Appalachia
52:inland sea
46:, and the
1059:: 66–80.
1018:27 August
971:27 August
464:platyurus
393:Greenhorn
324:ammonites
316:bony fish
277:mosasaurs
249:Paleocene
210:carbonate
203:sea level
176:divergent
166:Relative
157:formation
80:Laramidia
68:Paleocene
25:Campanian
907:16 April
632:March 6,
512:See also
504:holotype
436:and two
397:Niobrara
332:plankton
320:mollusks
305:Enchodus
1151:102–103
1061:Bibcode
967:: 57–63
788:Bibcode
754:5 April
714:7 April
466:in the
257:Memphis
111:Montana
100:fossils
74:to the
1157:
1124:
937:May 5,
879:
846:
821:
665:
628:: 7-35
596:
405:Pierre
403:, and
401:Mancos
330:, and
275:, and
227:anoxia
42:, the
38:, the
1012:(PDF)
957:(PDF)
774:(PDF)
618:(PDF)
389:Kiowa
267:Fauna
222:chalk
62:(100
1155:ISBN
1122:ISBN
1020:2021
973:2021
939:2011
909:2013
877:ISBN
844:ISBN
819:ISBN
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