Using Acids to Extract Calcareous Microfossils from Carbonate Rocks

Moura, Jorge Costa de; Rios-Netto, Aristóteles de Moraes; Wanderley, Maria Dolores; Sousa, Fernando Pereira de

doi:10.2307/1486124

Cited by 13 publications

(8 citation statements)

References 2 publications

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“…The other half of the samples was treated with the acetic acid method. In the past two decades, acetic acid has been used to separate calcareous microfossils from carbonates (Lethiers and Crasquin-Soleau, 1988; Costa de Moura et al, 1999; Lirer, 2000; Tur et al, 2001; Kariminia, 2004; Crasquin-Soleau and Kershaw, 2005); here we used the procedure suggested by Kariminia (2004) but slightly modified, by diluting the HAc to 90%–95%, compared to the 99.99% HAc concentration used by Kariminia (2004). The immersed samples were kept reacting in a heating sand bath with temperature 75°C–80°C.…”

Section: Methodsmentioning

confidence: 99%

Latest Permian deep-water foraminifers from Daxiakou, Hubei, South China

Zhang

2015

J. Paleontol.

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A latest Changhsingian (latest Permian) foraminiferal fauna composed of 19 species (belonging to 10 genera) was recovered from the Daxiakou section in Xingshan County, Hubei Province, South China. Compared to contemporaneous faunas in South China, the Daxiakou fauna displays unique features: (1) nodosariids are the dominant forms in abundance and diversity; and (2) the most abundant forms have elongate and flattened tests, and include Geinitzina, Howchinella, and Ichthyolaria. The predominance of flattened elongate tests and their smaller size suggest that these foraminifers possibly lived in an oxygen-depleted, deep-water environment. Seven new species, Nodosaria quinquecostata n. sp., Howchinella inflata n. sp., H. hubeiensis n. sp., H. complanata n. sp., H. xiangxiensis n. sp., Ichthyolaria celsa n. sp., and Pseudotristix elongata n. sp. are described.

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Section: Methodsmentioning

confidence: 99%

Latest Permian deep-water foraminifers from Daxiakou, Hubei, South China

Zhang

2015

J. Paleontol.

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“…To obtain more and better preserved specimens, we also used a different preparation method to extract foraminifera from carbonate rocks with dilute acids. According to Moura et al (1999), the best results are obtained when soaking in 0.1 M HCl for 60-120 min. We kept the samples in 0.1 M HCl for an average of 90 min.…”

Section: Methodsmentioning

confidence: 99%

Foraminiferal biostratigraphy and paleoenvironmental reconstruction at the Yaxcopoil‐1 drill hole, Chicxulub crater, Yucatán Peninsula

Arz

Alegret

Arenillas

2004

Meteorit & Planetary Scien

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Abstract-The Yaxcopoil-1 (Yax-1) drill hole comprises Cretaceous limestones and calcarenites, the K/P boundary cocktail unit (including impact breccia), and a Danian marly clay layer overlain by calcareous marls. The biostratigraphy, paleobathymetry, and environmental turnover across the K/P interval were inferred after analyzing the planktic and benthic foraminiferal assemblages. The Cretaceous samples only contain a few poorly preserved planktic foraminifera of a middle Campanian to Maastrichtian age, while low-diversity benthic foraminiferal assemblages suggest a sufficient nutrient supply to the sea floor and a shallow neritic, occasionally stressed environment. The impact breccia and the redeposited suevite are overlain by a 46 cm-thick dolomitic calcareous sandstone unit that contains scarce, reworked planktic foraminiferal specimens. This unit probably represents the uppermost part of the initial infill of the crater. The uppermost centimeters of this unit are bioturbated, and its top represents a hiatus that spans at least the G. cretacea, Pv. eugubina, and part of the P. pseudobulloides biozones. This unit is overlain by a 3-4 cm-thick marly clay layer that represents a condensed layer. Benthic foraminiferal assemblages suggest a low food supply to the sea floor and environmental instability during the deposition of the marly clay layer. The increase in diversity of the assemblages indicates that the environmental conditions improved and stabilized from the G. compressa biozone toward the A. uncinata (P2) biozone. The Danian planktic and benthic foraminiferal assemblages indicate a deeper, probably bathyal environment.

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“…[3] Isolating foraminifera from the bulk ocean sedimentary matrices consisting of terrestrial, organic, and siliceous components is a necessary preliminary step of paleoceanographic studies. A number of methodologies that involve the use of chemical agents have therefore been employed to expedite the transformation of sediment into a useable micropaleontological sample [Barker et al, 2003;de Moura et al, 1999;Lirer, 2000;Pak et al, 2004]. Aggressive chemical treatment may, however, influence the integrity of the (paleoceanographic) signal extracted [Ganssen, 1981], either through dissolution of reactive layers within test calcite [Vetter et al, 2013] or through weakening and subsequent disintegration of shells.…”

Section: Rationalementioning

confidence: 99%

The effect of chemical pretreatment of sediment upon foraminiferal‐based proxies

Feldmeijer

Metcalfe

Scussolini

et al. 2013

Geochem Geophys Geosyst

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[1] Paleoceanographic studies routinely combine different foraminiferal proxies (i.e., weight, abundance, trace metal, and stable isotope measurements) into a cohesive narrative. The application of chemical treatment to disaggregate ocean sediments in the most efficient way to isolate the fossils of foraminifera from the other sediment components is dictated by the time available and the material used. Yet few studies have aimed to test both the physical and geochemical effects associated with such practices. In this study, we use samples with different sedimentological characteristics (i.e., varying percentages of CaCO 3 and of terrigenous material) to test the impact upon these proxies of three processing methods and a control: (1) no chemicals (contol run); (2) soaking in sodium hexametaphosphate (CalgonV R ); (3) soaking in hydrogen peroxide; and (4) soaking in a sodium pyrophosphate. The samples were analyzed for faunal abundance, shell weight, stable isotope ( 18 O, 13 C), and trace metal (Mg/Ca) geochemistry for four species of planktonic foraminifera (Globigerina bulloides, Globigerinoides ruber, Globorotalia inflata, and Globorotalia menardii). Results show that apart from the CalgonV R solution, the values of faunal abundance, shell weight, Mg/Ca, and stable isotopes are similar irrespective of the cleaning treatment utilised and therefore warrant cross-comparison of results obtained with different preparation techniques. The use of CalgonV R in pretreatment shows statistically different values for only foraminiferal shell weight.

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Using Acids to Extract Calcareous Microfossils from Carbonate Rocks

Cited by 13 publications

References 2 publications

Latest Permian deep-water foraminifers from Daxiakou, Hubei, South China

Latest Permian deep-water foraminifers from Daxiakou, Hubei, South China

Foraminiferal biostratigraphy and paleoenvironmental reconstruction at the Yaxcopoil‐1 drill hole, Chicxulub crater, Yucatán Peninsula

The effect of chemical pretreatment of sediment upon foraminiferal‐based proxies

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