715:(Unit F) occurs stratigraphically above, separated from the underlying calcareous sandstone by an irregular, erosional contact. Sedimentary structures vary within the calcarenite from trough cross-bedding to wavy bedding to low-angle planar cross-bedding, suggesting substantial changes in flow velocities at the time of deposition. The lithologies in Unit F were originally described by Woodring in 1957 as the Alhajuela Sandstone Member of the Caimito Formation. However, based on the age constraints presented below for the Alajuela Formation, this attribution to the late Oligocene—early Miocene Caimito Formation is no longer supported. The stratigraphic thickness of Interval 3 was not measured in the study by MacFadden et al. (2017), but was reported by Woodring (1957) as being approximately 85 metres (279 ft).
504:
642:
1408:
791:
767:
775:
783:
373:
552:
1436:
719:
878:
898:
1422:
1010:
314:
380:
990:
596:
metres (3.3 to 19.7 ft)), with an average thickness of about 3 metres (9.8 ft). The amalgamated conglomerates are generally clast-supported, but locally matrix-supported, with the coarse grain fraction rarely exceeding 5 centimetres (2.0 in) in diameter. Weathered exposures of the conglomeratic horizons erroneously appear matrix-supported due to
1919:
763:(GABI), the mainly southward migration of North American biota to South America. The timing of the GABI has been a matter of debate between paleontologists and while some researchers define the GABI in the Early Pliocene (4 to 5 Ma), others observe earlier phases of migration in the Middle Miocene, around 15 to 13 Ma.
637:
grains. The sandstone is locally tuffaceous and exhibits, in some exposures, low-angle, dm-thick bedforms that are internally massive and dip perpendicularly to the overall attitude of the
Alajuela Formation. Otherwise, the sandstone appears massive and highly bioturbated, containing a lower density
595:
Within the basal-most
Interval 1, laterally-extensive horizons of amalgamated conglomerate lenses fine upwards into fine-to-medium grained sandstones, truncated by erosional contacts with overlying units. The best exposed amalgamated conglomerate exhibits substantial variability in thickness (1 to 6
563:
While
Woodring originally described the formation in two members, MacFadden et al. (2017) define three distinct lithological intervals in the composite section, measured in proximity to the fossil localities on the southern extent of Lago Alajuela, of the formation. The succession starts with a more
714:
The base of
Interval 3 is marked by a cm-scale gradational contact between an underlying shell lag in Interval 2 and an overlying fine-grained calcareous sandstone with lithics and occasional trough cross-bedding and ripple marks (Unit E). A calcarenite occasionally interbedded with sandy limestone
693:
sandstone of Unit A lithologies or a laterally discontinuous unit of clast-supported conglomerate (Unit C). This interval typically occurs well above lake levels in the study area and is covered by vegetation. Consequently, continuous fresh exposures exhibiting diagnostic sedimentary structures are
632:
The amalgamated conglomerates contain the most abundant vertebrate fossils, both well-preserved remains of marine vertebrates (e.g., sharks) and highly weathered remains of terrestrial vertebrates. The conglomerate exhibits a dm-scale gradational contact with a poorly sorted, fine-to-medium-grained
664:
One exposure of
Interval 1, within the 9–14 m levels of the composite section, includes a moderately sorted, fine-medium grained tuffaceous sandstone with distinctive mm- to cm thick horizontal bedding and wavy laminations (Unit B). Scour and fill structures with dm-scale widths and occasional mud
542:
and a lens of sandy limestone formerly designated the
Chilibrillo limestone member of the Caimito Formation. The upper member was described as the former Alhajuela sandstone member of the Caimito Formation. The author estimated the thickness of the formation to be 115 to 145 metres (377 to
1870:; Jones, Douglas S.; Jud, Nathan A.; Moreno Bernal, Jorge W.; Morgan, Gary S.; Portell, Roger W.; Pérez, Victor J.; Moran, Sean M.; Wood, Aaron R. (2017), "Integrated Chronology, Flora and Faunas, and Paleoecology of the Alajuela Formation, Late Miocene of Panama",
638:
of molluscan molds than the underlying conglomerate. Original molluscan shell material and marine vertebrate fossils are present but rare. No terrestrial vertebrate remains have been found within the sandstone horizons of Unit A.
2089:
Geology and
Paleontology of Canal Zone and Adjoining Parts of Panama - 306F Description of Tertiary Mollusks (Pelecypods: Propeamussiidae to Cuspidariidae; Additions to Families Covered in P 306-E; Additions to Gastropods;
706:. A minimum of three coarsening-upward sequences is preserved in Interval 2, and although the litharenite appears massive in most exposures, trough cross-bedding and low-angle planar cross-bedding are evident locally.
616:
comprise the minor component of the coarse fraction. Fossil invertebrate remains primarily consist of internal and external molds of mollusk shells preserved in fine-grained sand matrix as well as some original
694:
relatively rare. The dominant lithology in
Interval 2 appears to be a well-cemented, fine-grained litharenite that coarsens upwards into a medium-grained sand, capped by a shell lag horizon of fragmented
731:
Analysis of Sr/Sr ratios, obtained from original shell material from marine fossils, provided an age of 9.77 ± 0.22 Ma for the formation, placing it in the
Tortonian. In the commonly used
604:
shell material. Prior to such dissolution, the coarse fraction would likely have been dominated by mollusk shells, whereas well-rounded, pebble- to cobble-sized volcanic fragments (welded
1511:
2065:
Geology and
Paleontology of Canal Zone and Adjoining Parts of Panama - 306E Description of Tertiary Mollusks (Additions to gastropods, scaphopods, pelecypods: Nuculidae to Malleidae)
806:, demonstrates seaway connections existed through central Panama during the Late Miocene. Strontium ratios also suggest the Alajuela Formation overlaps in time with the richly
1449:
807:
2041:
Geology and Paleontology of Canal Zone and Adjoining Parts of Panama - 306D Description of Tertiary Mollusks (Gastropods: Eulimidae, Marginellidae to Helminthoglyptidae)
1969:
Geology and Paleontology of Canal Zone and Adjoining Parts of Panama - 306A Geology and description of Tertiary mollusks (Gastropods: Trochidae to Turritellidae)
681:, are preserved that cut across and deform bedding horizons. The infilling of these burrows consists of the same fine tuffaceous sand of overlying horizons.
665:
drapes are present near the erosional contact with the underlying Unit A lithologies. No body fossils are present in this unit, but rare and well-preserved
538:
Woodring (1970) divided the elevated Alhajuela Formation into two members; a lower member consisting of the former calcareous sandstone member of the
2017:
Geology and Paleontology of Canal Zone and Adjoining Parts of Panama - 306C Description of Tertiary Mollusks (Gastropods: Columbellidae to Volutidae)
2199:
1993:
Geology and Paleontology of Canal Zone and Adjoining Parts of Panama - 306B Description of Tertiary Mollusks (Gastropods: Vermetidae to Thaididae)
2144:
503:
372:
641:
760:
492:
2194:
2184:
2154:
2121:
2097:
2072:
2048:
2024:
2000:
1976:
520:
744:
732:
422:
1628:
2179:
2174:
1829:
1810:
1794:
1778:
1762:
1746:
1730:
1714:
1698:
1679:
1663:
1647:
1218:
227:
220:
810:
Late Miocene Gatún Formation to the north, with which the Alajuela Formation shares many invertebrate faunal elements.
759:
The Alajuela Formation is an important Late Miocene unit, as it represents a faunal and floral assemblage before the
702:(Unit D). The density of shell fragments at the top of the coarsening-upwards sequences locally approaches that of a
2204:
266:
491:. The fauna is of paleontological significance as an insight into the ecosystem of Central America preceding the
551:
1248:
1230:
1176:
790:
584:
461:
129:
1236:
766:
511:
The Alajuela Formation, in older literature also referred to as Alhajuela Formation, was first described as a
1074:
531:
was described. In 1970, Woodring elevated the member to a formation. The Alajuela formation crops out in the
2189:
2149:
1272:
1254:
1116:
528:
1278:
1266:
1224:
1200:
1188:
774:
1092:
1086:
1020:
803:
782:
565:
453:
208:
1370:
1134:
2164:
1930:
Rodríguez Reyes, Oris; Gasson, Peter; Thornton, Carolyn; Falcon Lang, Howard J.; Jud, Nathan A. (2017),
1413:
1242:
1194:
556:
1260:
1284:
2169:
1881:
1080:
1333:
1182:
1152:
1441:
1345:
689:
The base of Interval 2 exhibits a highly irregular, erosional contact with either a poorly sorted,
426:
532:
329:
2159:
1296:
1206:
1454:
1302:
799:
301:
1909:
1351:
1000:
739:, typically starting at 10.3 Ma, although MacFadden et al. correlate this age with the latest
718:
539:
516:
441:
430:
161:
1949:
1899:
1889:
1128:
1026:
512:
1867:
1460:
818:
The formation has provided a diverse faunal and floral assemblage, with invertebrates as
1885:
579:
sandstones and calcarenites, representing a transition from tide-dominated, potentially
1904:
1383:
897:
888:
877:
613:
259:
559:
of 82 m (269 ft) of the Alajuela Formation. Fossil localities are indicated.
2138:
1931:
1427:
1146:
868:
524:
468:
344:
79:
27:
1940:
1491:
1290:
1032:
965:
961:
740:
690:
484:
418:
40:
1894:
471:, of which it derives its name, and preserves a rich fossil faunal assemblage of
467:
The formation crops out in a small area along the southern and western shores of
1833:
1814:
1798:
1782:
1766:
1750:
1734:
1718:
1702:
1683:
1667:
1651:
1632:
1515:
1387:
1009:
957:
921:
736:
677:
666:
656:
645:
569:
564:
than 25 metres (82 ft) thick basal package of interbedded, clast-supported
414:
54:
36:
1923:
1953:
1403:
1339:
1158:
1050:
1038:
917:
908:
597:
576:
99:
64:
2112:
281:
268:
242:
229:
2087:
2063:
2039:
2015:
1991:
1967:
1379:
1327:
1311:
1307:
1212:
989:
981:
952:
913:
827:
823:
748:
699:
671:
650:
601:
572:
480:
449:
445:
410:
204:
194:
104:
48:
31:
1913:
1872:
1375:
634:
609:
575:, grading into an approximately 85 metres (279 ft) thick package of
150:
94:
89:
74:
69:
59:
1918:
1164:
1110:
1104:
1098:
1068:
1062:
1044:
946:
835:
819:
703:
695:
622:
618:
580:
457:
406:
109:
84:
1140:
1122:
862:
839:
626:
472:
434:
319:
1364:
1170:
842:. Fossilized wood fragments occur also in the Alajuela Formation.
789:
781:
773:
765:
717:
640:
550:
535:
along the southwestern shores of and on islands in Lake Alajuela.
502:
488:
1922:
Material was copied from this source, which is available under a
507:
Map of the Panama Basin with the Alajuela Formation in light blue
976:
935:
930:
831:
722:
Sr/Sr ratios provided an age of 9.77 ± 0.22 Ma for the formation
605:
476:
1936:
gen. et sp. nov.: a new Miocene malpighialean tree from Panama"
1008:
988:
896:
876:
523:
geologist W.P. Woodring in 1957. The member was named after
587:
to a wave-dominated, shallow water carbonate environment.
1924:
Creative Commons Attribution 4.0 International License
798:
The abundance of marine fossils from the Alajuela and
2111:
Stewart, R.H.; Stewart, J.L.; Woodring, W.P. (1980),
1598:
1596:
1586:
1584:
1574:
1572:
1478:
1476:
1450:
List of fossiliferous stratigraphic units in Panama
747:for the estimated age of the Arajuela Formation is
358:
350:
340:
335:
325:
307:
297:
258:
219:
214:
200:
190:
185:
175:
167:
157:
145:
135:
125:
21:
1562:
1560:
1624:
1622:
1620:
1618:
1616:
1614:
1612:
1610:
1608:
735:classification, this corresponds to the earliest
1643:
1641:
786:Mollusk mold fossils of the Alajuela Formation
2114:Geologic Map of the Panama Canal and Vicinity
1825:
1823:
1694:
1692:
8:
770:Vertebrate fossils of the Alajuela Formation
844:
778:Calcitic fossils of the Alajuela Formation
379:
18:
1903:
1893:
1153:Trigoniocardia (Apiocardia) cf. simrothi
893:
1472:
1249:Trachycardium (Dallocardia) dominicense
853:
1147:Trachycardium (Dallocardia) phlyctaena
794:Fossil wood of the Alajuela Formation
7:
1069:Anadara (Tosarca) cf. tectumcolumbae
179:>110 m (360 ft) (total)
633:sandstone with abundant lithic and
181:82 m (269 ft) (composite)
1219:Pecten (Oppenheimopecten) colpotus
14:
1340:Turritella (Bactrospira) altilira
1213:Lirophora (Lirophora) falconensis
761:Great American Biotic Interchange
493:Great American Biotic Interchange
139:
1917:
1434:
1420:
1406:
1261:Dosinia (Dosinia) aff. ponderosa
1111:Dosinia (Dosinia) aff. ponderosa
378:
371:
312:
171:25 km (9.7 sq mi)
1934:Panascleroticoxylon crystallosa
1267:Dosinia (Dosinia) delicatissima
830:and vertebrate fauna including
456:deposited in a tidal-dominated
1243:Anadara (Rasia) cf. fissicosta
745:South American land mammal age
733:North American land mammal age
1:
2145:Geologic formations of Panama
1231:Lamelliconcha cf. aequicincta
479:(among which fossil teeth of
2200:Geography of Panamá Province
1895:10.1371/journal.pone.0170300
1854:Rodríguez Reyes et al., 2017
1602:MacFadden et al., 2017, p.24
1482:MacFadden et al., 2017, p.23
1391:
1356:
1315:
1055:
1005:
985:
969:
939:
873:
755:Paleontological significance
260:Approximate paleocoordinates
16:Geologic formation in Panama
1590:MacFadden et al., 2017, p.8
1578:MacFadden et al., 2017, p.7
1566:MacFadden et al., 2017, p.6
1545:MacFadden et al., 2017, p.4
1129:Chione (Chionopsis) tegulum
648:of the Alajuela Formation:
440:The formation overlies the
387:Alajuela Formation (Panama)
2221:
1141:Tivela (Tivela) mactroides
1954:10.1163/22941932-20170178
1463:of northern South America
1279:Periglypta cf. caribbeana
1177:Lindapecten buchivacoanus
1099:Anadara (Rasia) dariensis
975:
861:
366:
26:
1237:Ventricolaria harrisiana
675:and vertically oriented
2195:Shallow marine deposits
2185:Conglomerate formations
1334:Ficus carbesea carbesea
1075:Argopecten venezuelanus
2155:Paleontology in Panama
2086:Woodring, W.P (1982),
2062:Woodring, W.P (1973),
2038:Woodring, W.P (1970),
2014:Woodring, W.P (1964),
1990:Woodring, W.P (1959),
1966:Woodring, W.P (1957),
1384:?Phyllanthaceae indet.
1273:Panopea parawhitfieldi
1255:Cyathodonta gatunensis
1117:Pholadomya falconensis
1093:Macrocallista maculata
1021:Negaprion brevirostris
1013:
993:
901:
881:
795:
787:
779:
771:
723:
661:
560:
508:
1845:Woodring, 1959, p.212
1554:Woodring, 1970, p.317
1536:Woodring, 1970, p.299
1414:Earth sciences portal
1225:Florimetis trinitaria
1201:Nodipecten colinensis
1189:Arca (Arca) imbricata
1105:Corbula (Varicorbula)
1012:
992:
918:cf. Dugongidae indet.
900:
880:
793:
785:
777:
769:
721:
644:
557:stratigraphic section
554:
506:
2180:Limestone formations
2175:Sandstone formations
1527:Woodring, 1957, p.12
1087:Leopecten gatunensis
1081:Dinocardium robustum
914:cf. Carnivora indet.
804:Chucunaque Formation
423:NALMA classification
37:Earliest Hemphillian
1886:2017PLoSO..1270300M
1868:MacFadden, Bruce J.
1512:Alhajuela Formation
1442:Paleontology portal
1371:Panascleroticoxylon
1135:Mytilus canoasensis
966:Tomistominae indet.
962:Testudinidae indet.
419:Latest Clarendonian
403:Alhajuela Formation
278: /
239: /
41:Latest Clarendonian
28:Stratigraphic range
1629:Alajuela Formation
1502:Geologic Map, 1980
1388:Sapindaceae indet.
1207:Tucetona pectinata
1195:Hyotissa haitensis
1014:
994:
958:Cheloniidae indet.
922:Tayassuidae indet.
902:
889:Cormohipparion sp.
882:
796:
788:
780:
772:
724:
662:
621:shell material of
561:
509:
460:to shallow marine
427:geologic formation
399:Alajuela Formation
243:9.2124°N 79.5936°W
22:Alajuela Formation
2205:Panama Canal Zone
1811:Woodring Loc. 84a
1747:Woodring Loc. 82a
1664:Woodring Loc. 90a
1648:Woodring Loc. 85a
1397:
1396:
1001:Hemipristis serra
869:Gomphotherium sp.
743:. The equivalent
540:Caimito Formation
517:Caimito Formation
442:Caimito Formation
431:Panama Canal Zone
415:Early Hemphillian
395:
394:
162:Caimito Formation
2212:
2131:
2130:
2129:
2119:
2107:
2106:
2105:
2100:, pp. 1–312
2095:
2082:
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2075:, pp. 1–128
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2051:, pp. 1–198
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1979:, pp. 1–186
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1830:Woodring Loc. 88
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1808:
1802:
1795:Woodring Loc. 89
1792:
1786:
1779:Woodring Loc. 86
1776:
1770:
1763:Woodring Loc. 87
1760:
1754:
1744:
1738:
1731:Woodring Loc. 82
1728:
1722:
1715:Woodring Loc. 76
1712:
1706:
1699:Woodring Loc. 77
1696:
1687:
1680:Woodring Loc. 79
1677:
1671:
1661:
1655:
1645:
1636:
1626:
1603:
1600:
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1588:
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1444:
1439:
1438:
1437:
1430:
1425:
1424:
1423:
1416:
1411:
1410:
1409:
1380:Malvaceae indet.
1312:Solenidae indet.
1308:Mactridae indet.
1291:Caryocorbula sp.
1285:Semele chipolana
1033:Carcharhinus sp.
1027:Sphyrna mokarran
845:
800:Gatún Formations
614:silicified woods
382:
381:
375:
318:
316:
315:
293:
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289:
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248:9.2124; -79.5936
244:
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51:
19:
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2027:, pp. 1–82
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1492:Area Calculator
1490:
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1481:
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1470:
1461:Pebas Formation
1455:Curré Formation
1440:
1435:
1433:
1426:
1421:
1419:
1412:
1407:
1405:
1402:
1376:Fabaceae indet.
1357:
1320:
1319:
1318:
1317:
1316:
1297:Hexacorbula sp.
1159:?Diplodonta sp.
816:
757:
729:
712:
687:
600:dissolution of
593:
549:
501:
391:
390:
389:
388:
385:
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383:
313:
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302:Panamá Province
286:
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57:
47:9.99–9.55
46:
45:
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34:
17:
12:
11:
5:
2218:
2216:
2208:
2207:
2202:
2197:
2192:
2190:Tidal deposits
2187:
2182:
2177:
2172:
2167:
2162:
2157:
2152:
2150:Neogene Panama
2147:
2137:
2136:
2133:
2132:
2108:
2083:
2059:
2035:
2011:
1987:
1963:
1948:(4): 437–455,
1927:
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1847:
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1803:
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1452:
1446:
1445:
1431:
1417:
1401:
1398:
1395:
1394:
1392:
1390:
1367:
1361:
1360:
1358:
1355:
1346:Crucibulum sp.
1330:
1324:
1323:
1321:
1314:
1303:Psammacoma sp.
1183:Amusium toulae
1065:
1059:
1058:
1056:
1054:
1051:Rhinoptera sp.
1039:Myliobatis sp.
1016:
1015:
1006:
1004:
996:
995:
986:
984:
979:
973:
972:
970:
968:
949:
943:
942:
940:
938:
933:
927:
926:
924:
909:Dinohippus sp.
904:
903:
894:
892:
884:
883:
874:
872:
865:
859:
858:
855:
852:
849:
815:
814:Fossil content
812:
756:
753:
728:
725:
711:
708:
686:
683:
592:
589:
548:
545:
543:476 ft).
500:
497:
444:and comprises
393:
392:
386:
377:
376:
370:
369:
368:
367:
364:
363:
360:
356:
355:
352:
348:
347:
342:
338:
337:
333:
332:
327:
323:
322:
309:
305:
304:
299:
295:
294:
262:
256:
255:
223:
217:
216:
212:
211:
202:
198:
197:
192:
188:
187:
183:
182:
177:
173:
172:
169:
165:
164:
159:
155:
154:
147:
143:
142:
137:
133:
132:
127:
123:
122:
115:
114:
113:
108:
103:
98:
93:
88:
83:
78:
73:
68:
63:
58:
53:
52:
24:
23:
15:
13:
10:
9:
6:
4:
3:
2:
2217:
2206:
2203:
2201:
2198:
2196:
2193:
2191:
2188:
2186:
2183:
2181:
2178:
2176:
2173:
2171:
2168:
2166:
2163:
2161:
2158:
2156:
2153:
2151:
2148:
2146:
2143:
2142:
2140:
2123:
2116:
2115:
2109:
2099:
2092:
2091:
2084:
2074:
2067:
2066:
2060:
2050:
2043:
2042:
2036:
2026:
2019:
2018:
2012:
2002:
1995:
1994:
1988:
1978:
1971:
1970:
1964:
1955:
1951:
1947:
1943:
1942:
1937:
1935:
1928:
1925:
1920:
1915:
1911:
1906:
1901:
1896:
1891:
1887:
1883:
1879:
1875:
1874:
1869:
1865:
1864:
1860:
1851:
1848:
1842:
1839:
1835:
1831:
1826:
1824:
1820:
1816:
1812:
1807:
1804:
1800:
1796:
1791:
1788:
1784:
1780:
1775:
1772:
1768:
1764:
1759:
1756:
1752:
1748:
1743:
1740:
1736:
1732:
1727:
1724:
1720:
1716:
1711:
1708:
1704:
1700:
1695:
1693:
1689:
1685:
1681:
1676:
1673:
1669:
1665:
1660:
1657:
1653:
1649:
1644:
1642:
1638:
1634:
1630:
1625:
1623:
1621:
1619:
1617:
1615:
1613:
1611:
1609:
1605:
1599:
1597:
1593:
1587:
1585:
1581:
1575:
1573:
1569:
1563:
1561:
1557:
1551:
1548:
1542:
1539:
1533:
1530:
1524:
1521:
1517:
1513:
1508:
1505:
1499:
1496:
1493:
1488:
1485:
1479:
1477:
1473:
1467:
1462:
1459:
1457:of Costa Rica
1456:
1453:
1451:
1448:
1447:
1443:
1432:
1429:
1428:Panama portal
1418:
1415:
1404:
1399:
1393:
1389:
1385:
1381:
1377:
1373:
1372:
1368:
1366:
1363:
1362:
1359:
1354:
1353:
1348:
1347:
1342:
1341:
1336:
1335:
1331:
1329:
1326:
1325:
1322:
1313:
1309:
1305:
1304:
1299:
1298:
1293:
1292:
1287:
1286:
1281:
1280:
1275:
1274:
1269:
1268:
1263:
1262:
1257:
1256:
1251:
1250:
1245:
1244:
1239:
1238:
1233:
1232:
1227:
1226:
1221:
1220:
1215:
1214:
1209:
1208:
1203:
1202:
1197:
1196:
1191:
1190:
1185:
1184:
1179:
1178:
1173:
1172:
1167:
1166:
1161:
1160:
1155:
1154:
1149:
1148:
1143:
1142:
1137:
1136:
1131:
1130:
1125:
1124:
1119:
1118:
1113:
1112:
1107:
1106:
1101:
1100:
1095:
1094:
1089:
1088:
1083:
1082:
1077:
1076:
1071:
1070:
1066:
1064:
1061:
1060:
1057:
1053:
1052:
1047:
1046:
1041:
1040:
1035:
1034:
1029:
1028:
1023:
1022:
1018:
1017:
1011:
1007:
1003:
1002:
998:
997:
991:
987:
983:
980:
978:
974:
971:
967:
963:
959:
955:
954:
953:Bairdemys sp.
950:
948:
945:
944:
941:
937:
934:
932:
929:
928:
925:
923:
919:
915:
911:
910:
906:
905:
899:
895:
891:
890:
886:
885:
879:
875:
871:
870:
866:
864:
860:
856:
850:
847:
846:
843:
841:
837:
833:
829:
825:
821:
813:
811:
809:
808:fossiliferous
805:
801:
792:
784:
776:
768:
764:
762:
754:
752:
750:
746:
742:
738:
734:
726:
720:
716:
709:
707:
705:
701:
697:
692:
684:
682:
680:
679:
674:
673:
668:
659:
658:
653:
652:
647:
643:
639:
636:
630:
628:
624:
620:
615:
611:
607:
603:
599:
590:
588:
586:
582:
578:
574:
571:
567:
566:conglomerates
558:
553:
546:
544:
541:
536:
534:
530:
526:
525:Lake Alajuela
522:
518:
514:
505:
498:
496:
494:
490:
486:
485:invertebrates
482:
478:
474:
470:
469:Lake Alajuela
465:
463:
459:
455:
454:conglomerates
451:
447:
443:
438:
436:
432:
428:
424:
420:
416:
412:
408:
404:
401:, originally
400:
374:
365:
361:
357:
353:
349:
346:
345:Lake Alajuela
343:
339:
334:
331:
328:
324:
321:
310:
306:
303:
300:
296:
291:
263:
261:
257:
252:
224:
222:
218:
213:
210:
206:
203:
199:
196:
193:
189:
184:
178:
174:
170:
166:
163:
160:
156:
153:
152:
148:
144:
141:
138:
134:
131:
128:
124:
111:
106:
101:
96:
91:
86:
81:
76:
71:
66:
61:
56:
50:
42:
38:
33:
29:
25:
20:
2165:Clarendonian
2126:, retrieved
2113:
2102:, retrieved
2090:Cephalopods)
2088:
2077:, retrieved
2064:
2053:, retrieved
2040:
2029:, retrieved
2016:
2005:, retrieved
1992:
1981:, retrieved
1968:
1957:, retrieved
1945:
1941:IAWA Journal
1939:
1933:
1877:
1871:
1861:Bibliography
1850:
1841:
1806:
1790:
1774:
1758:
1742:
1726:
1710:
1675:
1659:
1550:
1541:
1532:
1523:
1507:
1498:
1487:
1369:
1350:
1344:
1338:
1332:
1301:
1295:
1289:
1283:
1277:
1271:
1265:
1259:
1253:
1247:
1241:
1235:
1229:
1223:
1217:
1211:
1205:
1199:
1193:
1187:
1181:
1175:
1169:
1163:
1157:
1151:
1145:
1139:
1133:
1127:
1121:
1115:
1109:
1103:
1097:
1091:
1085:
1079:
1073:
1067:
1049:
1043:
1037:
1031:
1025:
1019:
999:
951:
907:
887:
867:
817:
797:
758:
741:Clarendonian
730:
713:
710:Interval III
688:
676:
670:
669:, primarily
667:ichnofossils
663:
655:
649:
646:Ichnofossils
631:
594:
562:
547:Stratigraphy
537:
533:Panama Basin
529:type section
527:, where the
510:
466:
439:
407:Late Miocene
405:(Tau), is a
402:
398:
396:
359:Year defined
336:Type section
330:Panama Basin
282:9.0°N 78.2°W
209:conglomerate
149:
2170:Hemphillian
2124:, p. 1
1880:(1): 1–27,
1834:Fossilworks
1815:Fossilworks
1799:Fossilworks
1783:Fossilworks
1767:Fossilworks
1751:Fossilworks
1735:Fossilworks
1719:Fossilworks
1703:Fossilworks
1684:Fossilworks
1668:Fossilworks
1652:Fossilworks
1633:Fossilworks
1516:Fossilworks
1165:Panopea sp.
1045:Pristis sp.
936:Aves indet.
737:Hemphillian
691:bioturbated
685:Interval II
678:Ophiomorpha
657:Ophiomorpha
585:environment
570:litharenite
499:Description
462:environment
433:of central
285: /
246: /
221:Coordinates
2139:Categories
2128:2019-02-09
2104:2019-02-09
2079:2019-02-09
2055:2019-02-09
2031:2019-02-09
2007:2019-02-09
1983:2019-02-09
1959:2019-02-09
1468:References
1328:Gastropods
1123:Atrina sp.
824:gastropods
802:, and the
700:gastropods
602:aragonitic
598:diagenetic
591:Interval I
583:, coastal
577:calcareous
573:sandstones
555:Composite
450:limestones
446:sandstones
287:9.0; -78.2
234:79°35′37″W
2160:Tortonian
1352:Malea sp.
1171:Pitar sp.
982:megalodon
828:echinoids
749:Chasicoan
672:Conichnus
651:Conichnus
581:estuarine
481:megalodon
458:estuarine
411:Tortonian
341:Named for
231:9°12′45″N
205:Limestone
195:Sandstone
186:Lithology
176:Thickness
146:Underlies
136:Sub-units
130:Formation
32:Tortonian
1914:28107398
1873:PLoS ONE
1400:See also
1063:Bivalves
947:Reptiles
836:reptiles
820:bivalves
696:bivalves
654:(C) and
635:feldspar
623:scallops
619:calcitic
610:andesite
495:(GABI).
354:Woodring
351:Named by
215:Location
158:Overlies
151:alluvium
140:See text
1905:5249130
1882:Bibcode
863:Mammals
857:Images
851:Fossils
840:mammals
704:coquina
627:oysters
515:of the
473:mammals
429:in the
421:in the
308:Country
273:78°12′W
191:Primary
116:↓
1912:
1902:
826:, and
612:) and
513:member
435:Panama
326:Extent
320:Panama
317:
298:Region
270:9°00′N
2118:(PDF)
2094:(PDF)
2069:(PDF)
2045:(PDF)
2021:(PDF)
1997:(PDF)
1973:(PDF)
1365:Flora
931:Birds
854:Notes
848:Group
489:flora
201:Other
2122:USGS
2098:USGS
2073:USGS
2049:USGS
2025:USGS
2001:USGS
1977:USGS
1910:PMID
1836:.org
1817:.org
1801:.org
1785:.org
1769:.org
1753:.org
1737:.org
1721:.org
1705:.org
1686:.org
1670:.org
1654:.org
1635:.org
1518:.org
977:Fish
838:and
832:fish
698:and
625:and
608:and
606:tuff
568:and
521:USGS
487:and
477:fish
452:and
397:The
362:1957
168:Area
126:Type
55:PreꞒ
1950:doi
1900:PMC
1890:doi
1832:at
1813:at
1797:at
1781:at
1765:at
1749:at
1733:at
1717:at
1701:at
1682:at
1666:at
1650:at
1631:at
1514:at
1349:,
727:Age
660:(O)
519:by
483:),
417:or
39:or
2141::
2120:,
2096:,
2071:,
2047:,
2023:,
1999:,
1975:,
1946:38
1944:,
1938:,
1908:,
1898:,
1888:,
1878:12
1876:,
1822:^
1691:^
1640:^
1607:^
1595:^
1583:^
1571:^
1559:^
1475:^
1386:,
1382:,
1378:,
1374:,
1343:,
1337:,
1310:,
1306:,
1300:,
1294:,
1288:,
1282:,
1276:,
1270:,
1264:,
1258:,
1252:,
1246:,
1240:,
1234:,
1228:,
1222:,
1216:,
1210:,
1204:,
1198:,
1192:,
1186:,
1180:,
1174:,
1168:,
1162:,
1156:,
1150:,
1144:,
1138:,
1132:,
1126:,
1120:,
1114:,
1108:,
1102:,
1096:,
1090:,
1084:,
1078:,
1072:,
1048:,
1042:,
1036:,
1030:,
1024:,
964:,
960:,
956:,
920:,
916:,
912:,
834:,
822:,
751:.
629:.
475:,
464:.
448:,
437:.
425:)
413:,
207:,
105:Pg
49:Ma
30::
1952::
1932:"
1926:.
1892::
1884::
409:(
110:N
100:K
95:J
90:T
85:P
80:C
75:D
70:S
65:O
60:Ꞓ
43:)
35:(
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