Evidence for punctuated gradualism in the Late Neogene Globorotalia tumida lineage of planktonic foraminifera

Paleobiology ◽  
1983 ◽  
Vol 9 (4) ◽  
pp. 377-389 ◽  
Author(s):  
Björn A. Malmgren ◽  
W. A. Berggren ◽  
G. P. Lohmann
Keyword(s):  
Late Miocene ◽  
Planktonic Foraminifera ◽  
Total Duration ◽  
Morphologic Change ◽  
Stratigraphic Sequence ◽  
Evolutionary Patterns ◽  
Early Pliocene ◽  
Late Neogene ◽  
History Of ◽  
Test Shape

The warm-water planktonic foraminiferal Globorotalia tumida lineage has been studied in a 10-Myr-long stratigraphic sequence (Late Miocene through Recent) from the Indian Ocean to determine long-term evolutionary patterns through the lineage's history, and particularly to study in great detail the evolutionary transition from G. plesiotumida to G. tumida across the Miocene/Pliocene boundary. Sampling resolution was very good, between 5 × 103 and 15 × 103 yr across the Miocene/Pliocene boundary and about 2 × 105 yr otherwise. The test shape was analyzed in edge view, permitting determinations of variation in inflation and elongation of the test. Shape was analyzed quantitatively using eigenshape analysis. This method represents the greatest proportion of variation observed among a collection of shapes by the least number of different shapes. The Late Miocene (10.4-5.6 Myr B.P.) populations exhibited only minor fluctuations in shape that did not result in any net phyletic change. This period of stasis was followed by an 0.6-Myr-long period (between 5.6 and 5.0 Myr B.P.) of gradual transformation of the Late Miocene morphotype (G. plesiotumida) into the Early Pliocene morphotype (G. tumida). The populations were again more or less in stasis in the Pliocene and Pleistocene (5.0 Myr to the present day), so that no major modifications of the newly evolved Early Pliocene morphotype occurred during these 5 Myr. Thus it would appear that the G. tumida lineage, while remaining in relative stasis over a considerable part of its total duration underwent periodic, relatively rapid, morphologic change that did not lead to lineage branching. This pattern does not conform to the gradualistic model of evolution, because that would assume gradual changes throughout the history of the lineage. It also does not conform to the punctuational model, because (1) there was no speciation (lineage branching) in this lineage and (2) the transition was not rapid enough (<1% of the descendant species' duration according to definition). For this evolutionary modality we propose the term “punctuated gradualism” and suggest that this may be a common norm for evolution—at least within the planktonic foraminifera.

scholarly journals Molluscan diversification and extinction on opposite sides of the Isthmus of Panama

1992 ◽  
Vol 6 ◽  
pp. 144-144
Author(s):  
Jeremy B. C. Jackson ◽  
Peter Jung
Keyword(s):  
Late Miocene ◽  
Eastern Pacific ◽  
Tropical Eastern Pacific ◽  
Early Pliocene ◽  
Isthmus Of Panama ◽  
Late Neogene ◽  
Tropical America ◽  
The Caribbean ◽  
First Time ◽  
Final Closure

Molluscs are the most diverse and abundant tropical American macrofossils, but their distributions and evolution are not well understood. Classic studies by Olsson and Woodring documented a rich Late Miocene to Early Pliocene “Gatunian” fauna throughout the Caribbean and tropical Eastern Pacific, with many species in common between the oceans. This fauna was divided by formation of the Isthmus of Panama, and diverged into distinct Pacific and Caribbean faunas sometime thereafter. Diversity also decreased by about half in the Caribbean. However, the timing, rates and correlation of these major biological changes with changes in environmental conditions have not been resolved because of imprecise dating and taxonomy and failure to consider problems of sampling and biofacies in biological comparisons. We used the newly revised late Neogene stratigraphy for Panama and Costa Rica to date for the first time the radiation and extinction of molluscs on opposite sides of the Isthmus. Data include occurrences throughout tropical America for nearly 100 species of the Strombina-group (Gastropoda, Columbellidae) and for more than 500 gastropod and bivalve genera from 240 Late Miocene to Pleistocene isthmian collections.All evidence suggests that final closure of the Isthmus of Panama occurred between 3.5 and 2.5 My. Subgeneric divergence between the oceans was well developed, and trans-isthmian species were rare by the Early Pliocene, at least 2 Ma before final closure. Caribbean diversity remained high until 1.8 to 1.5 Ma when massive but selective extinction occurred. This was at least 1 Ma after final closure of the Isthmus, and may be correlated with onset of slightly cooler Caribbean sea surface temperatures in the Pleistocene. In contrast, Eastern Pacific diversity did not decline, and even increased during the Pleistocene.

Stratophenetic tracing of phylogeny using SIMCA pattern recognition technique: a case study of the late Neogene planktic foraminiferaGloboconellaclade

Paleobiology ◽  
1994 ◽  
Vol 20 (1) ◽  
pp. 52-65 ◽  
Author(s):  
Kuo-Yen Wei
Keyword(s):  
Pattern Recognition ◽  
Morphological Variability ◽  
Principal Component ◽  
Pattern Recognition Technique ◽  
Evolutionary Patterns ◽  
Continuous Increase ◽  
Late Neogene ◽  
History Of ◽  
Classification Procedures ◽  
Recognition Technique

The Plio-Pleistocene planktic foraminiferal sequence of theGloborotalia(Globoconella)puncticulata-inflataclade in Deep Sea Drilling Project Site 588, dated at 4.36 Ma to 0.05 Ma, records the branching history of theG. inflatalineage from the ancestralG. puncticulatalineage. The gradational nature of the divergence and the enormous morphological variability inherent in theG. inflatalineage have elicited different views on taxonomy and phylogeny of this clade. A pattern recognition technique, soft independent modeling of class analog (SIMCA), was used as an objective quantitative stratophenetic methodology to reconstruct the phylogenetic history.Typical specimens of two species,G. puncticulataandG. inflata,were identified from a stratigraphic level dated at 2.76 Ma. Principal component models were built to characterize the morphometric patterns of the two morphotypes using SIMCA. TheGloboconellaspecimens of the next lower and higher adjacent stratigraphic levels were evaluated against the models and classified into one of the two morphotypes. The newly classified specimens were then used to build new models for further tracing of lineages in lower and upper sections, respectively. Progression of such training and classification procedures through stratigraphic intervals resulted in a reconstruction of the evolutionary patterns of the two lineages. Cladogenesis gave rise to the descendant lineage,G. inflata,at about 3.5 Ma. The two co-existing species,G. inflataandG. puncticulata,differ only in size and show similarity in most characters at the beginning of their divergence. Other characters began to diverge later, at various rates. The gradients between planktic and benthic foraminiferal δ18O values show a continuous increase during the late Pliocene. The succession fromG. puncticulatatoG. inflataduring the same time correlates with the progressively increased vertical stratification in temperature of surface waters.Globorotalia puncticulatabecame extinct at 2.35 Ma when the temperature gradient further increased, corresponding to the onset of extensive glaciation in the Northern Hemisphere.

scholarly journals Baffin Bay late Neogene palynostratigraphy at Ocean Drilling Program Site 645

2021 ◽  
Vol 58 (1) ◽  
pp. 67-83
Author(s):  
Aurélie M.R. Aubry ◽  
Anne de Vernal ◽  
Paul C. Knutz
Keyword(s):  
Surface Waters ◽  
Late Miocene ◽  
Early Pleistocene ◽  
Ocean Drilling Program ◽  
Cold Surface ◽  
Early Pliocene ◽  
Baffin Bay ◽  
Ocean Drilling ◽  
Tundra Vegetation ◽  
Late Neogene

Analyses of marine and terrestrial palynomorphs of Ocean Drilling Program (ODP) Site 645 in Baffin Bay led us to define a new biostratigraphical scheme covering the late Miocene to Pleistocene based on dinocyst and acritarch assemblages. Four biozones were defined. The first one, from 438.6 m below sea floor (mbsf) to 388 mbsf, can be assigned a late Miocene to early Pliocene age (>4.5 Ma), based on the common occurrence of Cristadinium diminutivum and Selenopemphix brevispinosa. Biozone 2, spanning from an erosional unconformity to a recovery hiatus, is marked by the highest occurrences (HOs) of Veriplicidium franklinii and Cristadinium diminutivum, which suggest an early Pliocene age >3.6 Ma (∼4.5 to ∼3.6 Ma). Biozone 3, above the recovery hiatus and up to 220.94 mbsf, corresponds to a late Pliocene or early Pleistocene age based on occurrences of Bitectatodinium readwaldii, Cymatiosphaera? icenorum, and Lavradosphaera canalis. Finally, between 266.4 and 120.56 mbsf, Biozone 4, marked by the HO of Filisphaera filifera, Filisphaera microornata, and Habibacysta tectata, has an early Pleistocene age (>1.4 Ma). Our biostratigraphy implies that horizon b1 of the Baffin Bay seismic stratigraphy corresponds to the recovery hiatus at ODP Site 645, which suggests a very thick Pliocene sequence along the Baffin Island slope. Dinocyst assemblages and terrestrial palynomorphs in our records indicate that the late Miocene and (or) early Pliocene were characterized by relatively warm coastal surface waters and boreal forest or forested tundra vegetation over adjacent lands. In contrast, the early Pleistocene dinocyst assemblages above the recovery hiatus indicate cold surface waters, while pollen data suggest reduced vegetation cover on adjacent lands.

Late Neogene carbonate productivity and terrigenous input in the central Western Pacific Warm Pool (IODP Site U1488)

2020 ◽  
Author(s):  
Anna Joy Drury ◽  
Thomas Westerhold ◽  
Ana Christina Ravelo ◽  
Ivano Aiello ◽  
Roy Wilkens ◽  
...  
Keyword(s):  
High Resolution ◽  
Late Miocene ◽  
Warm Pool ◽  
Western Pacific ◽  
Early Pleistocene ◽  
Western Pacific Warm Pool ◽  
Early Pliocene ◽  
Pacific Warm Pool ◽  
Late Neogene ◽  
Regional Processes

&lt;p&gt;As the largest modern reservoir of oceanic heat, the Western Pacific Warm Pool (WPWP) plays an important role in atmospheric and oceanic circulation patterns. Little is known about how regional deposition patterns have changed over the past 10 Ma. To understand the interplay between regional processes and global climate evolution in the WPWP, we explore the late Neogene evolution of biogenic (carbonate/siliceous) versus terrigenous deposition.&lt;/p&gt;&lt;p&gt;We collected high-resolution (2 cm/~0.5 kyr) X-Ray fluorescence (XRF) core scanning data at IODP Site U1488 (Exp. 363) in the central WPWP. These data were especially useful for estimating the carbonate, siliceous and terrigenous components below 65 m CCSF, where the shipboard track data were less robust. The shipboard splice was verified and revised using the Ba/Sr ratio to ensure a continuous composite section down to ~330 m revised CCSF-A at Site U1488. Fe and Si likely reflect terrigenous and partially biogenic silica components. We calibrated the high-resolution ln(Ca/K) record to %CaCO&lt;sub&gt;3&lt;/sub&gt; using discrete shipboard %CaCO&lt;sub&gt;3&lt;/sub&gt; measurements.&lt;/p&gt;&lt;p&gt;Fe and Si decrease, whilst ln(Ca/K) increases downcore, in agreement with shipboard data showing increasing %CaCO&lt;sub&gt;3&lt;/sub&gt; and decreasing terrigenous/siliceous input&amp;#173;. During the late Pleistocene, the site shows high amplitude %CaCO&lt;sub&gt;3&lt;/sub&gt;, Fe and Si cycles superimposed on low carbonate. The amplitude decreases during the early Pleistocene-mid Pliocene, although clear variability remains. The early Pliocene-late Miocene is dominated by high CaCO&lt;sub&gt;3&lt;/sub&gt; (80-90%). The %CaCO&lt;sub&gt;3&lt;/sub&gt;, Fe and Si variability is considerably reduced, although clear obliquity-precession interference patterns are visible, in addition to longer-term ~400 kyr eccentricity modulation. The high-carbonate interval at IODP Site U1488 likely reflects the early Pliocene to late Miocene Biogenic Bloom (LMBB). The expression of the LMBB in the WPWP is distinctly different to the Atlantic and eastern equatorial Pacific. This indicates that although productivity was enhanced during the late Miocene-early Pliocene, regional processes determined the exact expression and timing of the LMBB in different areas.&lt;/p&gt;

Late Neogene Climates in Australia: Fossil Pollen- and Spore-based Estimates in Retrospect and Prospect

1997 ◽  
Vol 45 (3) ◽  
pp. 425 ◽  
Author(s):  
M. K. Macphail
Keyword(s):  
Western Australia ◽  
Late Miocene ◽  
World Ocean ◽  
Mean Annual Precipitation ◽  
Future Research ◽  
Spores And Pollen ◽  
Late Pliocene ◽  
Early Pliocene ◽  
Northern Margin ◽  
Late Neogene

Australian sites that are claimed to preserve evidence of fossil spores and pollen for Late Neogene (Late Miocene, Pliocene) climates, mostly lack one or both of the prerequisites, i.e. accurate dating and continuous preservation of plant microfossils. Nevertheless, the available data confirm that climatic gradients closely parallelled those of the present day in direction although not in strength: broad-scale vegetation successions are ecologically consistent with long-term cooling and (middle to high latitudes) drying trends in global climate. Although it is rarely possible to establish precise meteorological values for the individual sites along these gradients, climatic envelopes can be estimated for many localities. For example, during the Late Miocene–Pliocene, mean annual precipitation along the northern margin appear to range from 600 mm to 1500 mm in the Kimberley region of north-western Western Australia to above 2000–3000 mm on the Atherton Tableland, north-eastern Queensland. If these and other estimates are correct, then environments along the northern margin show only gradual (unidirectional?) change or did not fall below biologically critical thresholds during the Late Miocene and Early Pliocene but began to approach modern values during Late Pliocene time. Whether the observation implies that meteorological controls at this time were similar to modern synoptic scale systems is unknown. Climates along the southern margin were more labile. For example, there is unequivocal evidence that Early Pliocene climates in the Bass Strait region were effectively more humid and warmer than at present, possibly resembling conditions now found on the northern New South Wales and southern Queensland coast. This phase was preceded (weak evidence) and succeeded (strong evidence) by less temperate conditions during the Late Miocene and Late Pliocene respectively. Forcing factors appear to include changes in relative sea level, orographic effects and, speculatively, remote events such as the isolation and reconnection of the Mediterranean Sea to the world ocean. One promising direction for future research is provided by a recently located onshore basin in Western Australia which preserves an extraordinarily long (100 m), detailed sequence of Late Neogene palynofloras.

Paleoenvironmental evolution of the Guercif basin (south Rifain corridor, northern morocco). Implications for the Messinian salinity crisis

2003 ◽  
Vol 174 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Driss Dayja ◽  
Gérard Bignot
Keyword(s):  
Benthic Foraminifera ◽  
Planktonic Foraminifera ◽  
Mediterranean Area ◽  
Time Interval ◽  
Messinian Salinity Crisis ◽  
Marine Deposits ◽  
Late Neogene ◽  
History Of ◽  
The Mediterranean ◽  
Upper Tortonian

Abstract Foraminiferal biostratigraphic and paleoenvironmental results from the MDS1 borehole of the Guercif basin reveal the detailed history of its paleogeographic evolution during the late Neogene. Four biostratigraphic events are recognised based on the study of planktonic foraminifera. In addition to the placement of the Tortonian-Messinian boundary at 798 m depth, they also allow correlation of the MSD1 borehole with other late Miocene sections in the Mediterranean area. The diversity of benthic foraminifera is significant in the studied borehole. 111 species assigned to 55 genera, were identified. Three successive assemblages of benthic foraminifera were recognised, each one conveying a different paleoenvironmental information. They thus recorded a number of fundamental changes in the environmental and water mass characteristics of the Guercif basin. Following the oldest upper Tortonian transgressive marine deposits found at the bottom of the borehole, marls accumulated at lower epibathyal to upper mesobathyal depths (~400 to ~800 m). They recorded sea-floor dysoxia and associated stratification of the water column for the time interval between ~7.5 and ~7.3 Ma. During the latest Tortonian-early Messinian the basin experienced a rapid shallowing, first from the previously bathyal environments to deep neritic (~100 to ~200 m), and to shallow neritic afterwards (0 to ~30 m). The total absence of any foraminifera in the conglomerates situated at the top of the study borehole suggests that these sediments were deposited in subaerial environments. At this time the connection between the Atlantic Ocean and the Mediterranean Sea through the South Rifain Corridor was stopped. This local event contributed to the establishment of the particular conditions of the Messinian salinity crisis.

Sign in / Sign up

Export Citation Format

Share Document