Cenozoic geochronology

Berggren, William A.; Kent, Dennis V.; Flynn, John J.; Couvering, John A. Van

doi:10.1130/0016-7606(1985)96<1407:cg>2.0.co;2

Cited by 1,008 publications

(844 citation statements)

References 14 publications

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“…In considering these events, the stratigraphic position of this boundary, in foraminifer zone P6, nannofossil zone NP10 (Berggren et al, 1985), at or near the Clarkforkian-Wasatchan land-mammal age boundary (Gingerich, 1980(Gingerich, , 1989aButler et al, 1987), and within magnetochron C24R (Aubry et al, 1988), is more important than the assignment of a numerical age.…”

Section: Environmental Changesmentioning

confidence: 99%

Global change at the Paleocene-Eocene boundary: climatic and evolutionary consequences of tectonic events

Rea

Zachos

Owen

et al. 1990

Palaeogeography, Palaeoclimatology, Palaeoecology

193

101

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Rea, D. K., Zachos, J. C., Owen, R. M. and Gingerich, P. D., 1990. Global change at the Paleocene-Eocene boundary:climatic and evolutionary consequences of tectonic events. Palaeogeogr., Palaeoclimatol., Palaeoecol., 79: 117-128.Events of the Paleocene-Eocene boundary provide the clearest example to date of how a tectonic event may have global climatic consequences. Recent advances permit well-constrained stratigraphic determination of several events that occurred at that boundary, in chron C24R: a many-fold increase in sea-floor hydrothermal activity, a global warming, a reduction in the intensity of atmospheric circulation, a conversion to salinity-driven deep ocean circulation, a marked lightening of oceanic 313C values, extinction and evolution of both benthic foraminifera and land mammals, and important plate-boundary reorganizations including the outpouring of the east Greenland volcanics and the initiation of the oceanic rift between Norway and Greenland.We hypothesize that enhanced sea-floor hydrothermal activity occasioned by global tectonism resulted in a flooding of the atmosphere with COz, causing a reduced pole-to-equator temperature gradient and increased evaporation at low latitudes. Increased formation of warm, salty, probably low-nutrient waters coupled with the warm temperatures at high latitudes occasioned a salinity-driven, rather than temperature-driven, deep-water circulation. This newly-evolved ocean circulation pattern changed the apportionment of global heat transport from the atmosphere to the ocean, with concomitant changes in the circulation intensity of both. Reduced intensity of atmospheric circulation resulted in lower oceanic biological productivity and enhanced seasonality of climate on the continents. A major extinction event among benthic foraminifera was probably a response to the new low-nutrient and chemically changed bottom waters, and endemism following rapid evolution and dispersal of mammalian orders may have been in response to the new continental climate regime.

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Section: Environmental Changesmentioning

confidence: 99%

Global change at the Paleocene-Eocene boundary: climatic and evolutionary consequences of tectonic events

Rea

Zachos

Owen

et al. 1990

Palaeogeography, Palaeoclimatology, Palaeoecology

193

101

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“…The presence of Globorotalia truncatulinoides and Globigerinita iota (Keller, 1978) in Sample 126-790C-20X-3, 36-41 cm, indicates that the sediment at this level is <1.88 Ma ( Table 2; Berggren et al, 1985). Another useful datum is the LO of Globorotalia tosaensis in Sample 126-790A-2H-CC; according to Keller (1979a), this species disappears in the northwest Pacific ca.…”

Section: Holes 790a 790b and 790cmentioning

confidence: 99%

“…Published radiometric dates suggest that the Pliocene/Pleistocene boundary is < 2 Ma (Berggren et al, 1985). Within the numerical zonal scheme of Blow (1969), this limit corresponds to the N21/N22 boundary.…”

Section: Quaternarymentioning

confidence: 99%

“…The extinction of G. venezuelana was dated at 2.7 Ma in the tropical northwest Pacific (Keller, 1979a); the Berggren et al, 1985). In addition to the species listed in the other Pliocene samples, Sample 126-792B-8X-4,70-72 cm, contains specimens of Globigerina decoraperta and dextral G. multicamerata (F0 N17, ca.…”

Section: Hole 792bmentioning

confidence: 99%

“…7 Ma near the boundary between Zones N16/N17 (Keller, 1978(Keller, ,1979b. Sample 126-787B-5R-CC was assigned to the lower part of Zone N17 (Berggren et al, 1985). Species that have their FO ca.…”

Section: Hole 787bmentioning

confidence: 99%

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Eocene through Quaternary Planktonic Foraminifers from the Northwest Pacific, Leg 126

Herman¹

1992

Proceedings of the Ocean Drilling Program

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Eocene through Quaternary planktonic foraminifers were identified in cores recovered during Leg 126. Turbidites and volcanic ash beds are intercalated with hemipelagic sediments. Preservation of foraminifers is variable, ranging from excellent to poor and appears to have been affected by fluctuations in the carbonate compensation depth (CCD), depth of burial, changes in bottom water temperature, current velocity, sediment accumulation rates and seafloor topography. Preservation of foraminifers in Quaternary sediments is generally good, however, species abundance varies by a factor of I0 5 -10 6 and reflects dilution by volcanogenic as well as terrigenous constituents and cannot be used for paleoceanographic reconstructions. In pre-Quaternary deposits planktonic foraminiferal tests frequently exhibit dissolution effects; biostratigraphic zonation and placement of zonal boundaries is difficult owing to hiatuses, dissolution facies, extraneously deposited sediments, and discontinuous coring. The Eocene foraminiferal faunas include specimens of the Globorotalia cerroazulensis plexus, markers of Zone P16 as well as Globigerina senni and Globigerinatheka spp., which became extinct before the end of the Eocene. Six hiatuses and/or dissolution periods, probably reflecting global cooling events and/or changes in oceanic circulation patterns were recorded at Site 792. Recrystallized, poorly preserved, possibly reworked Eocene species {Globigerina senni and Globigerapsis sp.) were recorded in sediments at Site 793.

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First hominoid from the Miocene of Ethiopia and the evolution of the catarrhine elbow

Richmond

Fleagle

Kappelman

et al. 1998

Am. J. Phys. Anthropol.

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The first known fossil ape from the early-middle Miocene of Fejej, Ethiopia, is described here. The specimen, FJ-18SB-68, is a partial ulna from a locality dated by 40Ar/39Ar and paleomagnetic methods to a minimum age of 16.18 MYA. Compared to a variety of extant and fossil ulnae, FJ-18SB-68 is most similar to Turkanapithecus, Proconsul, and Pliopithecus, and appears to have been an arboreal quadruped with substantial forearm rotational mobility. Among the extant ulnae, canonical variates analysis successfully discriminates platyrrhines from catarrhines and within the latter, cercopithecoids from hominoids. Basal catarrhines (e.g., Aegyptopithecus) are platyrrhine-like in their morphology. Two basic trends appear to evolve from this generalized template: one with less mobile and more habitually pronated forearms, as seen in living and fossil cercopithecoids (including Victoriapithecus and Paracolobus), and another with greater forearm rotational mobility in fossil and modern hominoids. Primitive Miocene apes, including Proconsul, Turkanapithecus, and FJ-18SB-68, share with extant hominoids a more laterally positioned and laterally facing radial notch and an incipient trochlear keel. This morphology, along with a large insertion area for m. brachialis, suggests a departure from the more habitually pronated hand posture of monkeys and may indicate greater climbing abilities in these arboreally quadrupedal apes. Later Miocene apes, such as Oreopithecus and Dryopithecus share additional morphological features with hominoids, indicating considerable suspensory and climbing capabilities.

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Cenozoic geochronology

Cited by 1,008 publications

References 14 publications

Global change at the Paleocene-Eocene boundary: climatic and evolutionary consequences of tectonic events

Global change at the Paleocene-Eocene boundary: climatic and evolutionary consequences of tectonic events

Eocene through Quaternary Planktonic Foraminifers from the Northwest Pacific, Leg 126

First hominoid from the Miocene of Ethiopia and the evolution of the catarrhine elbow

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