Foraminifera from the nearshore turbulent zone, western North America

Lankford, Robert R.; Phleger, Fred B.

doi:10.2113/gsjfr.3.3.101

Cited by 65 publications

(30 citation statements)

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“…Lee (1974) made the same point in discussing experiments conducted by Muller (1975). Similarly, Lankford and Phleger (1973) indicated that the zoogeographic distribution of nearshore foraminifera of western North America could not be related to a single environmental variable, but only to properties of coastal-water masses.…”

Section: Discussionmentioning

confidence: 95%

Ecology and systematics of foraminifera in two Thalassia habitats, Jamaica, West Indies

Buzas¹,

Smith²,

Beem³

1977

Smithsonian Contributions to Paleobiology

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Section: Discussionmentioning

confidence: 95%

Ecology and systematics of foraminifera in two Thalassia habitats, Jamaica, West Indies

Buzas¹,

Smith²,

Beem³

1977

Smithsonian Contributions to Paleobiology

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“…The upper depth limit of R. columbiensis is near the inner/outer neritic biofacies boundary (50 m). This species is commonly attached to sea grasses, marine plants, carapaces, chitons, drifting wood, shells, and pebbles (Smith, 1964;Delaca and Lipps, 1972;Lankford and Phleger, 1973;Dobson and Haynes, 1973;Langer, 1993). Rare planktic foraminifers, Globorotalia and Turborotalia, occur near the base of the uppermarl unit in the Rosalina biofacies indicating a connectionwith the proto-Gulf that was deep enough to allow these organisms to enter the Blythe Basin (McDougall and MirandaMartínez, 2014).…”

Section: Cibola Areamentioning

confidence: 99%

Punctuated Sediment Discharge during Early Pliocene Birth of the Colorado River: Evidence from Regional Stratigraphy, Sedimentology, and Paleontology

Dorsey

O’Connell

McDougall

et al. 2018

Sedimentary Geology

114

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The Colorado River in the southwestern U.S. provides an excellent natural laboratory for studying the origins of a continent-scale river system, because deposits that formed prior to and during river initiation are well exposed in the lower river valley and nearby basinal sink. This paper presents a synthesis of regional stratigraphy, sedimentology, and micropaleontology from the southern Bouse Formation and similar-age deposits in the western Salton Trough, which we use to interpret processes that controlled the birth and early evolution of the Colorado River. The southern Bouse Formation is divided into three laterally persistent members: basal carbonate, siliciclastic, and upper bioclastic members. Basal carbonate accumulated in a tidedominated marine embayment during a rise of relative sea level between ~6.3 and 5.4 Ma, prior to arrival of the Colorado River. The transition to green claystone records initial rapid influx of river water and its distal clay wash load into the subtidal marine embayment at ~5.4-5.3 Ma. This was followed by rapid southward progradation of the Colorado River delta, establishment of the earliest through-flowing river, and deposition of river-derived turbidites in the western Salton Trough (Wind Caves paleocanyon) between ~5.3 and 5.1 Ma. Early delta progradation was followed by regional shut-down of river sand output between ~5.1 and 4.8 Ma that resulted in deposition of marine clay in the Salton Trough, retreat of the delta, and re-flooding of the lower river valley by shallow marine water that deposited the Bouse upper bioclastic member. Resumption of sediment discharge at ~4.8 Ma drove massive progradation of fluvial-deltaic deposits back down the river valley into the northern Gulf and Salton Trough.These results provide evidence for a discontinuous, start-stop-start history of sand output during initiation of the Colorado River that is not predicted by existing models for this system. The underlying controls on punctuated sediment discharge are assessed by comparing the depositional chronology to the record of global sea-level change. The lower Colorado River Valley and Salton Trough experienced marine transgression during a gradual fall in global sea level between ~6.3 and 5.5 Ma, implicating tectonic subsidence as the main driver of latest Miocene relative sea-level rise. A major fall of global sea level at 5.3Ma outpaced subsidence and drove regional delta progradation, earliest flushing of Colorado River sand into the northern Gulf of California, and erosion of Bouse basal carbonate and siliciclastic members. The lower Colorado River valley was re-flooded by shallow marine waters during smaller changes in global sea level ~ 5.1-4.8 Ma, after the river first ran through it, which requires a mechanism to stop delivery of sand to the lower river valley. We propose that tectonically controlled subsidence along the lower Colorado River, upstream of the southern Bouse study area, temporarily trapped sediment and stopped delivery of sand to the lower river valley and nort...

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“…It is generally agreed that predation and export via ingestion (intentional or accidental) are only small contributors to fluctuations of foraminiferan communities (Lankford and Phleger 1973;Young and Young 1977).…”

Section: = P(t) -R(t) (2~)mentioning

confidence: 99%

Carbonate dissolution and temporal abundances of Foraminifera in Long Island Sound sediments

Green

Aller

1993

Limnology & Oceanography

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The dynamics of benthic Foraminifera assemblages can be used to examine carbonate dissolution processes in nearshore sediments and as a general assay of physical-chemical factors affecting survival of juvenile benthos. Abundances of total Foraminifera (live and dead) fluctuate regularly throughout the year in Long Island Sound (LIS) mud deposits, with highest numbers in spring-summer and lowest in winter. Essentially all forams disappear each year. Pore-water undersaturation with respect to carbonate minerals coincides with periods of rapid disappearance of forams and suggests that these fluctuations reflect a balance between the rate of production-recruitment and the rates of death and dissolution of the calcareous tests of the animals. Reworking by macrofauna in LIS central basin sediments inhibits accumulation or depletion of pore-water solutes and is responsible for minimizing pore-water carbonate saturation states. Quantitative estimates of seasonal patterns of foram dissolution with a simple mass balance model give a minimum average annual flux of Caz+ in LIS sediments of -6 mmol Ca2+ m-2 d-1 (due solely to Foraminifera dissolution). Abandoned tests have a maximum mean residence time of -86+ 13 d. Dissolution-precipitation of forams may significantly affect benthic ZCO, fluxes and likely accounts for a large proportion (>30%) during some seasons or at some locales. Other organisms with carbonate tests of similar size, particularly juvenile bivalves, may also be affected by periods of undersaturated pore waters. Conditions promotinn dissolution of tests may represent an important source of mortality for calcareous meiofauna.Relatively little attention has been focused on carbonate dissolution in estuarine and shelf sediments because shallow marine waters are generally saturated with respect to calcite and aragonite, the common low-temperature polymorphs of CaC03 (Morse 1983). If, however, this state of saturation does not continue below the sediment-water interface, there are important consequences for the preservation of carbonate shells and processes sensitive to changes in pH and alkalinity. Several previous studies have concluded that substantial dissolution occurs in nearshore sediments underlying supersaturated water (e.g. Aller 1982;Walters and Burton 1990). Dissolution results primarily from organic matter or mineral oxidation and the corresponding increases in acids such as H2CO3, HNO,, and H2S04.In the present study, we investigated carbonate dissolution in surface sediments of Long AcknowledgmentsWe thank P. D. Rude, H. Vigil, B. Rizitello, M. Sun, Q. Xia, S. Wirick, J. Mackin, and I. Stupakoff for assistance in the field. P. D. Rude provided additional help in the laboratory. We also thank R. Keir for a review.

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Foraminifera from the nearshore turbulent zone, western North America

Cited by 65 publications

References 0 publications

Ecology and systematics of foraminifera in two Thalassia habitats, Jamaica, West Indies

Ecology and systematics of foraminifera in two Thalassia habitats, Jamaica, West Indies

Punctuated Sediment Discharge during Early Pliocene Birth of the Colorado River: Evidence from Regional Stratigraphy, Sedimentology, and Paleontology

Carbonate dissolution and temporal abundances of Foraminifera in Long Island Sound sediments

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