Punctuated anagenesis and the importance of stratigraphy to paleobiology

Paleobiology ◽  
1991 ◽  
Vol 17 (2) ◽  
pp. 167-188 ◽  
Author(s):  
Norman MacLeod
Keyword(s):  
Environmental Changes ◽  
Accumulation Rate ◽  
Marine Invertebrate ◽  
Sediment Accumulation ◽  
Phenotypic Change ◽  
Phenotypic Evolution ◽  
Accumulation Rates ◽  
Depositional History ◽  
Upper Miocene ◽  
Sea Level Fluctuations

The depositional history of Upper Miocene through Recent sediments from DSDP Site 214 (Ninetyeast Ridge, Indian Ocean) is reexamined. Samples of the Globorotalia tumida planktic foraminiferal lineage, originally obtained from these sediments by Malmgren et al. (1983), serve as the empirical basis for the recognition of punctuated anagenesis as a distinct mode of phenotypic evolution and have been the subject of numerous additional investigations. However, conclusions reached by previous authors depend strictly on the validity of the original chronostratigraphic interpretation of these sediments. Graphic correlation analysis of first- and last-appearance datum levels for a total of 41 planktic foraminiferal, radiolarian, and calcareous nannoplankton taxa provides evidence for a more complex depositional history at this deep-sea site than originally believed. Based on a conservative model of variation in the pattern of sediment accumulation rates, the lowermost portion of the studied section (6.5-4.3 Ma) represents an interval of temporally condensed sediment accumulation (1.88 cm/1,000 yr) followed by an interval (4.3-2.8 Ma) of temporally expanded sediment accumulation (3.97 cm/1,000 yr). This interval, in turn, is followed by a depositional hiatus or an extremely condensed interval, at least 800,000 yr in duration, which is followed by another relatively condensed (1.36 cm/1,000 yr) interval from 2.0 Ma-Recent. Although this chronostratigraphic reinterpretation deviates substantially from the original, which recognized Site 214 as being both temporally continuous and exhibiting a constant sediment accumulation rate from the Upper Miocene through the Upper Pliocene, it is more consistent with expectations based on Neogene eustatic sea-level fluctuations and global surveys of Neogene hiatus distributions. Age assignments for samples of the Gr. tumida lineage based on the revised chronostratigraphic model reverse some findings of previous investigators with respect to the distinctiveness of phenotypic evolutionary rates characterizing the transition from Gr. plesiotumida to Gr. tumida. Finally, a brief survey of similar marine invertebrate lineage studies shows that changes in the rate of phenotypic evolution often appear to coincide with major physical changes in the paleoceanographic environment. Such correspondences may be due, at least in part, to the effect of these environmental changes on sediment accumulation rates. Paleobiologists who seek to understand patterns of phenotypic change over time must remove the effects of variations in sediment accumulation rates from their data before evolutionary hypothesis testing and remain aware of the limitations imposed on their interpretations by the uncertain nature of chronostratigraphic inference.

scholarly journals High-resolution magnetostratigraphy of the upper Nacimiento Formation, San Juan Basin, New Mexico, USA: implications for basin evolution and mammalian turnover

2017 ◽  
Author(s):  
Caitlin Leslie ◽  
Daniel J. Peppe ◽  
Thomas E. Williamson ◽  
Dario Bilardello ◽  
Matthew Heizler ◽  
...  
Keyword(s):  
New Mexico ◽  
North America ◽  
Accumulation Rate ◽  
Global Climate ◽  
Sediment Accumulation ◽  
San Juan ◽  
Accumulation Rates ◽  
Fluvial System ◽  
San Juan Basin ◽  
Geomagnetic Polarity

Lower Paleocene deposits in the San Juan Basin document one of the best records of mammalian change and turnover following the Cretaceous-Paleogene extinctions and are the type section for the Puercan (Pu) and Torrejonian (To) North America Land Mammal age biozones (NALMA). One of the largest mammalian turnover events in the early Paleocene occurs between the Torrejonian 2 (To2) and Torrejonian 3 (To3) NALMA biozones. The Nacimiento Formation are the only deposits in North America where the To2-To3 mammalian turnover can be constrained, however the precise age and duration of the turnover is poorly understood due to the lack of a precise chronostratigraphic framework. We analyzed paleomagnetic samples, produced a 40Ar/39Ar detrital sanidine age, and developed a detailed lithostratigraphy for four sections of the upper Nacimiento Formation in the San Juan Basin, New Mexico (Kutz Canyon, Escavada Wash, Torreon West and East) to constrain the age and duration of the deposits and the To2-To3 turnover. The polarity stratigraphy for the four sections can be correlated to chrons C27r-C26r of the geomagnetic polarity time scale (GPTS). Using the local polarity stratigraphy for each section, we calculated a mean sediment accumulation rate and developed a precise age model, which allows us to determine the age of important late Torrejonian mammalian localities. Using the assigned ages, we estimate the To2-To3 turnover was relatively rapid and occurred over ~120 kyr (-60/+50 kyr) between 62.59 and 62.47 Ma. This rapid duration of the mammalian turnover suggests that it was driven by external forcing factors, such as environmental change driven by the progradation of the distributive fluvial system across the basin and/or changes in regional or global climate. Additionally, comparisons of the mean sediment accumulation rates between the sections that span from the basin margin to the basin center indicate that sediment accumulation rates equalized across the basin from the end of C27r through the start of C26r, suggesting an accommodation minima in the basin associated with the progradation of a distributive fluvial system into the basin. This accommodation minimum also likely led to the long hiatus of deposition between the Paleocene Nacimiento Formation and the overlying Eocene San Jose Formation.

Global wind-induced change of deep-sea sediment budgets, new ocean production and CO 2 reservoirs ca . 3.3-2.35 Ma BP

1988 ◽  
Vol 318 (1191) ◽  
pp. 487-504 ◽  
Keyword(s):  
Large Scale ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Distribution Patterns ◽  
Trade Wind ◽  
Accumulation Rates ◽  
Deep Sea Sediment ◽  
Late Pliocene ◽  
High Productivity ◽  
Sediment Fraction

The late Pliocene phase of large-scale climatic deterioration about 3.2-2.4 Ma BP is well documented in a number of (benthic) δ 18 O records. To test the global implications of this event, we have mapped the distribution patterns of various sediment variables in the Pacific and Atlantic Oceans during two time slices, 3.4-3.18 and 2.43-2.33 Ma BP. The changes of bulk sedimentation and bulk sediment accumulation rates are largely explained by the variations of CaCO 3 -accumulation rates (and the accumulation rates of the complementary siliciclastic sediment fraction near continents in higher latitudes). During the late Pliocene, the CaCO 3 -accumulation rate increased along the equatorial Pacific and Atlantic and in the northeastern Atlantic, but decreased elsewhere. The accumulation rate of organic carbon (C org ) and net palaeoproductivity also increased below the high-productivity belts along the equator and the eastern continental margins. From these patterns we may conclude that (trade-) wind- induced upwelling zones and upwelling productivity were much enhanced during that time. This change led to an increased transfer of CO 2 from the surface ocean to the ocean deep water and to a reduction of evaporation, which resulted in an aridification of the Saharan desert belt as depicted in the dust sediments off northwest Africa.

Implications of rapid sediment accumulation in a small New England salt marsh

1992 ◽  
Vol 29 (9) ◽  
pp. 2013-2017 ◽  
Author(s):  
R. Scott Anderson ◽  
H. W. Borns Jr. ◽  
D. C. Smith ◽  
C. Race
Keyword(s):  
Salt Marsh ◽  
New England ◽  
Sea Level ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Sediment Supply ◽  
Greenhouse Warming ◽  
Accumulation Rates ◽  
Marsh Sediment ◽  
England Salt Marsh

The sediment accumulation rate within a small Spartina alterniflora marsh in Maine has been determined by measuring the amount of peat accretion on top of human-produced boards protruding from an exposed face of the marsh. Boards are at depths of 50–140 cm, suggesting sediment accumulation rates of 6.2–7.0 mm/year. Based on these data and a review of other relevant studies, aggradation in small marshes such as Shipyard Cove should be able to keep pace marginally with the anticipated sea-level rise due to "greenhouse" warming, given sufficient sediment supply. Local 19th century land clearance and subsequent erosion, activities that are greatly reduced today, probably supplied the bulk of the inorganic marsh sediment.

scholarly journals Combined Magnetostratigraphy From Three Localities of the Rainstorm Member of the Johnnie Formation in California and Nevada, United States Calibrated by Cyclostratigraphy: A 13 R/Ma Reversal Frequency for the Ediacaran

2021 ◽  
Vol 9 ◽  
Author(s):  
Kenneth P. Kodama
Keyword(s):  
United States ◽  
High Resolution ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Critical Time ◽  
Sediment Accumulation Rate ◽  
Accumulation Rates ◽  
Field Reversal ◽  
South Central ◽  
Reversal Frequency

A combined magnetostratigraphy for the Rainstorm Member of the Ediacaran Johnnie Formation was constructed using the sediment accumulation rates determined by rock magnetic cyclostratigraphy for three localities of the Rainstorm Member to provide a high resolution, time-calibrated record of geomagnetic field reversal frequency at a critical time period in Earth history. Two previously reported magnetostratigraphy records from Death Valley, California, the Nopah Range and Winters Pass Hills (Minguez et al., 2015), were combined with new paleomagnetic and cyclostratigraphic results from the Desert Range locality of the Rainstorm Member in south central Nevada, United States . The Johnnie oolite marker bed is at the base of each of the three sections and allows their regional correlation. The Nopah Range and Desert Range localities have similar sediment accumulation rates of ∼5 cm/ka, so their stratigraphic sections can be combined directly. The Winters Pass Hills locality has a higher sediment accumulation rate of 8.4 cm/ka, therefore its stratigraphic positions are multiplied by 0.6 to combine with the Desert Range and Nopah Range magnetostratigraphy. The thermal demagnetization results from the Desert Range locality isolates characteristic remanent magnetizations that indicate two nearly antipodal east-west and shallow directions and a mean paleopole (11.7˚N, 348.4˚E) that is consistent with “shallow” Ediacaran directions. The Desert Range also yields a magnetic susceptibility rock magnetic cyclostratigraphy that records short eccentricity, obliquity, and precession astronomically-forced climate cycles in the Ediacaran. The high-resolution combined magnetostratigraphy with nearly meter-scale stratigraphic spacing (nominally 23 ka, based on the Desert Range sediment accumulation rate), indicates 11 polarity intervals in a cyclostratigraphy-calibrated duration of 849 ka, indicating a reversal frequency of 13 R/Ma. The Rainstorm Member records the Shuram carbon isotope excursion, hence its age is ∼574 Ma. Given the recent cyclostratigraphy-calibrated reversal frequency of 20 R/Ma from the Zigan Formation (Levashova et al., 2021) at 547 Ma, our results show that reversal frequency was high but fluctuated during the Ediacaran.

scholarly journals Evaluating the historical sedimentation patterns in two different Mediterranean deep environments (Sardinia and Sicily Channels)

2019 ◽  
Vol 20 (3) ◽  
pp. 542 ◽  
Author(s):  
NOUR EL HOUDA HASSEN ◽  
NAFAÂ REGUIGUI ◽  
MOHAMED AMINE HELALI ◽  
NEZHA MEJJAD ◽  
ABDELMOURHIT LAISSAOUI ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Water Depth ◽  
Accumulation Rate ◽  
Sediment Cores ◽  
Sediment Accumulation ◽  
Inverse Correlation ◽  
Accumulation Rates ◽  
Deep Sediment ◽  
210Pb And 137Cs ◽  
Excess 210Pb

The sediment accumulation rate in the Sardinia and Sicily channels in the central part of the Mediterranean Sea was studied by using short-lived radionuclides (210Pb and 137Cs) in two deep sediment cores. Different sedimentation regimes were identified indicating substantial differences in accumulation rates and historical patterns. The 210Pb-derived mean accumulation rate found in the Strait of Sardinia was 0.05 g.cm-2.y-1, lower than that in Sicily Channel (0.1 g.cm-2.y-1) suggesting an inverse correlation with water depth. Excess 210Pb inventories were 24 ± 1 and 6.0 ± 0.4 kBq.m-2, while the fluxes to the sediment were 745 ± 31 and 188 ± 11 Bq.m-2.y-1 in Sicily and Sardinia channels, respectively. 137Cs failed to use for the validation of the established chronologies, while its inventories found 450 Bq.m-2 and 355 Bq.m-2 in the Sicily and Sardinia channel, respectively.

scholarly journals Holocene Environmental Changes in Western Hungary

Radiocarbon ◽  
2004 ◽  
Vol 46 (2) ◽  
pp. 691-699 ◽  
Author(s):  
Zsuzsanna Szántó ◽  
Zsófia Medzihradszky
Keyword(s):  
Bronze Age ◽  
Environmental Changes ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Anthropogenic Activity ◽  
Late Neolithic ◽  
Forest Clearing ◽  
Plant Cultivation ◽  
Radiocarbon Data ◽  
Middle Bronze Age

We review the reasons for change in paleoecological conditions and their effects on different cultures at the beginning and during the Holocene period in western Hungary using radiocarbon data combined with paleoecological and paleolimnological results. Two sites were investigated in the southern and northern part of the ancient bay of Balaton Lake: Keszthely-Úsztatómajor and Főnyed I. 14C dating of 2 core samples represented a chronology from 11,000 cal BC to 2000 cal BC (10,700 BP to 3700 BP) and from 6200 cal BC to 1200 cal BC (7300 BP to 3000 BP), respectively. A relatively constant inverse sediment accumulation rate was observed in both cases (23 yr/cm and 33 yr/cm, respectively). In the case of Főnyed I, a sharp break was observed in the sedimentation curve around 6000–4800 cal BC (6000 BP). Changes in the vegetation due to human activity were observed in a larger extent only at the end of Late Neolithic, with the most significant changes detected in the landscape coinciding with the presence of Lengyel III culture in the region. The appearance of higher amounts of pollen of cereals at the sites proved the presence of crop cultivation. However, the role of plant cultivation may have been limited for the ancient inhabitants of the Kis-Balaton region due to a limited amount of soil suitable for agriculture and due to the extensive water table. Further changes in vegetation were observed during the Late Copper Age (Baden culture) and the period of Early and Middle Bronze Age, respectively. Signs of forest clearing during the period have not been detected and the increased peak of Fagus indicates climatic change. The low intensity of anthropogenic activity should not be attributed to geographic isolation.

Cladocera Community Response to Experimental Eutrophication in Lake 227 as Recorded in Laminated Sediments

1994 ◽  
Vol 51 (10) ◽  
pp. 2312-2321 ◽  
Author(s):  
Brenda J. Hann ◽  
Peter R. Leavitt ◽  
Philip S. S. Chang
Keyword(s):  
Standing Crop ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Community Response ◽  
Laminated Sediments ◽  
Accumulation Rates ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Annually Laminated Sediments ◽  
Chemical Conditions

The response of pelagic zooplankton to experimental fertilization was compared with the fossil record of Cladocera obtained from the annually laminated sediments of Lake 227, Experimental Lakes Area, northwestern Ontario. Constrained cluster analysis of both total fossil Cladocera and littoral chydorid communities clearly distinguished between pre- and post-eutrophication communities and further differentiated between years of high and low nitrogen:phosphorus fertilization ratios. However, there were few chydorid species extirpations resulting from the manipulation. Total chydorid accumulation rates and indices of species diversity, richness, and equitability were relatively constant over the last century and were not affected by fertilization. Among pelagic Cladocera, Bosmina longirostris abundance declined > 60% after initial fertilization. Although harsh chemical conditions (pH > 10) may have contributed to reduced abundance of pelagic Cladocera, Bosmina populations were also naturally variable prior to manipulation. Changes in Bosmina morphology (mucrone, antennule, and carapace length) and cladoceran size ratios (Daphnia/[Daphnia + Bosmina]) suggested that zooplanktivory by fish and invertebrates exercised important control of herbivore populations. Fossil Bosmina concentration (remains∙[g dry wt]−1 or remains∙[g organic matter]−1) were significantly correlated (r = 0.66, P < 0.01, 1970–1989) to standing crop in the water column (animals∙m−2). Fossil accumulation rate (remains∙cm−2∙yr−1) was not significantly correlated to Bosmina abundance, perhaps because of errors in determining bulk sediment accumulation rates.

Strontium Isotope Ages of the Marine Merced Formation, near San Francisco, California

1998 ◽  
Vol 50 (2) ◽  
pp. 194-199 ◽  
Author(s):  
B. Lynn Ingram ◽  
James C. Ingle
Keyword(s):  
San Francisco ◽  
Sea Water ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Coastal Sediments ◽  
Supporting Evidence ◽  
Sr Isotope ◽  
Sea Level Fluctuations ◽  
Basal Portion ◽  
Fission Track Ages

The strontium isotopic compositions of foraminifers ( Elphidiella hannaiwere determined to refine the age of coastal sediments of the Merced Formation and to evaluate the relation between transgressive–regressive cycles and Pleistocene glacio-eustatic sea-level fluctuations. Relatively good age resolution (± 0.1 myr) is possible in the upper part of the section. The Sr isotope ages provide strong supporting evidence for the fission track ages of an ash layer at the top of the formation (0.45 myr), as well as recent age estimates for the mammoth fossil of ∼0.45 myr. Sr isotope ages in the upper part of the section also confirm that marine/nonmarine cyclic sedimentation in the Merced Formation is controlled by glacial–interglacial cycles. Good age resolution for the lower part of the section is not possible, due to little variation of the87Sr/86Sr ratio in global sea water between 2.4 and 4.3 myr. The age of the base of the formation is constrained only between 2.4 and 4.8 myr. Sediment accumulation rates in the upper portion of the Merced Formation (between 0 and 720 m) are significantly higher than those calculated for the basal portion (between 720 and 1670 m). The change in accumulation rate may be due to increased continental weathering rates and/or increased tectonic subsidence beginning about 0.8 myr ago.

scholarly journals Changes in Sediment Accumulation Rate in An Oxbow Lake Following Late 19Th Century Clearing of Land for Agricultural Use: A 210Pb, 137Cs, and 14C Study in Mississippi, USA

Radiocarbon ◽  
2004 ◽  
Vol 46 (2) ◽  
pp. 755-764 ◽  
Author(s):  
Gregg R Davidson ◽  
Meredith Carnley ◽  
Todd Lange ◽  
Stanley J Galicki ◽  
Andrew Douglas
Keyword(s):  
19Th Century ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Oxbow Lake ◽  
Sediment Accumulation Rate ◽  
Accumulation Rates ◽  
The West ◽  
Late 19Th Century ◽  
Modern Sediment ◽  
Agricultural Use

Sediment cores were collected from 2 sites in the forested fringe of an oxbow lake surrounded by land that was converted from forest to agricultural use in the late 19th century. The 2 sampling areas were selected to represent areas of high (West site) and low (East site) current sediment accumulation rates, based on distance from a perennially discharging stream. Modern (post settlement and land clearing) sediment accumulation rates were calculated using 210Pb and 137Cs on bulk sediment samples from 2 cores from each site. Two additional cores were collected from each site for radiocarbon analysis of twig cellulose with the assumption that most twigs in the sediment within the forested fringe fell from overhead and are contemporaneous with the sediment. Only the West site, however, yielded sufficient identifiable twig material for analysis. Modern sediment accumulation rates based on 210Pb and 137Cs fall between 0.2–0.4 cm/yr at the East site, and 0.7–1.3 cm/yr at the West site (nearest the stream inlet), with approximate agreement between the 210Pb and 137Cs methods. Modern sediment accumulation rate based on bomb-pulse 14C activity of twigs from cores from the West site is approximately 1.0 cm/yr, in agreement with the 210Pb and 137Cs results. Historic sediment accumulation rates were estimated at the West site using twigs from deeper intervals with pre-bomb 14C activity. Sediment covering approximately 1000 yr of pre-settlement sediment accumulation exhibited evidence of minor bioturbation or in-washing of reworked material, but with a clearly lower accumulation rate of less than 0.1 cm/yr.

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