scholarly journals Quy trình gia công và phân tích hóa thạch Tảo vôi, áp dụng cho các trầm tích ven biển tỉnh Sóc Trăng

2020 ◽  
Vol 19 (4) ◽  
pp. 537-544
Author(s):  
Nguyen Thi Hong Nhung ◽  
Nguyen Thi Thuy ◽  
Nguyen Viet Hien ◽  
Nguyen Huu Manh
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Sample Preparation ◽  
Marine Sediments ◽  
Middle Pleistocene ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Sample Analysis ◽  
Smear Slide ◽  
Gephyrocapsa Oceanica

Calcareous nannofossils are very small microfossils composed of calcium carbonate. They are very good biostratigraphic markers within marine sediments by covering the Jurassic to present. The standard preparation of a sample for nannofossil analysis requires the collection of the largest quantity and the best fossils. Sample preparation accords to the following steps: i. Pounding sample; ii. Eliminating organic matter; iii. Washing sample; iv. Filter sample through the sieve; v. Eliminating clay; vi. Drying sample in an incubator; vii. Packing sample. Sample analysis accords to the following steps: i. Preparation of smear - slide; ii. Observation of morphology; iii. Determination; iv. Taking photo; v. Evaluating overall preservation and abundance of fossils; vi. Making analysis result sheet. This process is applied to study calcareous nannofossils within marine sediments in Soc Trang province. It makes much clear to understand middle Pleistocene-early Holocene ecosystem of calcareous nannofossil. In conclusion, this assemblage belongs to NN21 zone by the present of Emiliania huxleyi and Gephyrocapsa oceanica.

scholarly journals Calcareous Nanofossil of Post-Gondwana Sequence in Southern Banda Arc, Indonesia

2021 ◽  
Vol 6 (2) ◽  
pp. 86-93
Author(s):  
Angga Jati Widiatama ◽  
Lauti Dwita Santy ◽  
Rikza Nur Faqih An Nahar ◽  
Zulfiah ◽  
Winda Eka Mandiri Puteri ◽  
...  
Keyword(s):  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Relative Age ◽  
Polarizing Microscope ◽  
Banda Arc ◽  
Smear Slide

The presence of calcareous nannofossils in samples of the Post-Gondwana sequences (Kolbano and Viqueque sequence) gives guidance about the relative age of the study area located in the Outer Banda Arc, namely Timor, Rote, and Sawu Island. The study was carried out on six traverses, Timor Island traverse (Baun and Camplong), Rote Island traverse (Termanu and Central Rote), and Sawu Island traverses (West Sawu and East Sawu). There is 29 outcrop sample prepared using the smear slide method and observed using a polarizing microscope with 1000x magnification. The results of the study showed the presence of Cretaceous, Paleogene, and Neogen-Quarternary calcareous nannofossil. There are 82 species from 14 families identified in the post-Gondwana sequence. The results showed that the assemblage of calcareous nannofossil in Cretaceous characterized by the presence of Watznaueria fasciata, Watznaueria cynthae, Cyclagelosphaera brezae, Orastrum campanensis, and Micula concava. The assemblage of Paleogene calcareous nannofossil characterized by the presence of Coccolithus staurion, Chiasmolithus solitus, Discoaster minimus, Tawelus (?) magnicrassus, Chiasmolithus bidens, Prinsius africanus, Cyclicargolithus luminus, Spenolithus elongatus, Reticulofenestra umbilica, Cruciplacolithus vanheckae, and Helicospharea seminulum, and the assemblage of Neogene calcareous nannofossil characterized by the presence of Reticulofenestra pseudoumbilica, Discoaster quinqueramus, Helicosphaera princei, and Discoaster pansus. Quarternary calcareous nannofossil characterized by the presence of Ponthospaera indooceanica.

Erratum to ‘Control of sulphate and methane distributions in marine sediments by organic matter reactivity’ [Geochimica et Cosmochimica 104 (2013) 183–193]

2013 ◽  
Vol 113 ◽  
pp. 225-226 ◽  
Author(s):  
Patrick Meister ◽  
Bo Liu ◽  
Timothy G. Ferdelman ◽  
Bo Barker Jørgensen ◽  
Arzhang Khalili
Keyword(s):  
Organic Matter ◽  
Marine Sediments

scholarly journals High resolution integrated microbiostratigraphy of the Lower Jurassic (late Pliensbachian–early Toarcian) of central Italy

1998 ◽  
Vol 17 (2) ◽  
pp. 153-172 ◽  
Author(s):  
Raffaella Bucefalo Palliani ◽  
Emanuela Mattioli
Keyword(s):  
High Resolution ◽  
Evolutionary History ◽  
Central Italy ◽  
Lower Jurassic ◽  
High Potential ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Dinoflagellate Cyst ◽  
History Of ◽  
Global Events

Abstract. The integrated use of calcareous nannofossil and dinoflagellate cyst events in a study of the late Pliensbachian–early Toarcian interval in central Italy has yielded a high resolution biostratigraphy. The use of both the first and last occurrences of selected taxa belonging to the two phytoplankton groups allows the dating of the sediments with a very refined detail, even when lithologies are unfavourable to the preservation of one fossil group. The evolutionary history of calcareous nannofossils and dinoflagellate cysts during the early Jurassic and its links with global events are responsible for the high potential of this integrated biostratigraphy.

scholarly journals The calcareous nannofossil <i>Prinsiosphaera</i> achieved rock-forming abundances in the latest Triassic of western Tethys: consequences for the δ<sup>13</sup>C of bulk carbonate

2013 ◽  
Vol 10 (5) ◽  
pp. 7989-8025 ◽  
Author(s):  
N. Preto ◽  
C. Agnini ◽  
M. Rigo ◽  
M. Sprovieri ◽  
H. Westphal
Keyword(s):  
Global Ocean ◽  
Late Triassic ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Western Tethys ◽  
Carbonate Sedimentation ◽  
History Of ◽  
Calcareous Plankton ◽  
Inorganic Carbon Cycle

Abstract. The onset of pelagic biomineralization marked a milestone in the history of the long term inorganic carbon cycle: as soon as calcareous nannofossils became major limestone producers, the pH and supersaturation state of the global ocean were stabilized (the so-called Mid Mesozoic Revolution). But although it is known that calcareous nannofossils were abundant already by the end of the Triassic, no estimates exist on their contribution to hemipelagic carbonate sedimentation. With this work, we estimate the volume proportion of Prinsiosphaera, the dominant Late Triassic calcareous nannofossil, in hemipelagic and pelagic carbonates of western Tethys. The investigated Upper Triassic lime mudstones are composed essentially of microspar and tests of calcareous nannofossils, plus minor bioclasts. Prinsiosphaera became a significant component of lime mudstones since the late Norian, and was contributing up to ca. 60% of the carbonate by the late Rhaetian in periplatform environments with hemipelagic sedimentation. The increasing proportion of Prinsiosphaera in upper Rhaetian hemipelagic lime mudstones is paralleled by a increase of the δ13C of bulk carbonate. We interpreted this isotopic trend as related to the diagenesis of microspar, which incorporated respired organic carbon with a low δ13C when it formed during shallow burial. As the proportion of nannofossil tests increased, the contribution of microspar with low δ13C diminished, determining the isotopic trend. We suggest that a similar diagenetic effect may be observed in many Mesozoic limestones with a significant, but not yet dominant, proportion of calcareous plankton.

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