What happened to the organic matter from the Upper Cretaceous succession in Guatemala, Central America?

Radmacher, Wiesława; Vásquez, Osmín J.; Tzalam, Mario; Jolomná, Mireya; Molineros, Anny; Eldrett, James S

doi:10.1016/j.marpetgeo.2021.105246

Cited by 2 publications

(2 citation statements)

References 28 publications

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“…Bottom water oxygenation may, however, be an important factor controlling the local palynological record (e.g., Pross 2001;Zonneveld et al 1997). Prolonged exposure of deposited organic matter to oxygen may cause intra-and/or post-depositional oxidation, resulting in the aerobic degradation of palynomorphs (e.g., Zonneveld et al 1997Zonneveld et al , 2008Radmacher and Uchman 2020;Radmacher et al 2021). While the benthic foraminifera recovered from the present material are indicative of a highly oxygenated environment, aerobic degradation of palynomorphs was most likely not an important consideration.…”

Section: An Oligotrophic Continental Shelf Settingmentioning

confidence: 76%

“…The lack of any physical signs of reduced sedimentation rates (e.g., glauconite, hardgrounds, fossil accumulations) suggests a relatively high sedimenta-tion rate that hindered sediment oxygen penetration, thus impeding organic matter degradation (Zonneveld et al 1997). Additionally, aerobic degradation would have resulted in the oxidation of translucent woody material and its transformation into opaque phytoclasts, leading to the dominance of the latter in microscopic plant debris assemblages (e.g., Tyson 1993;Radmacher et al 2021); this is not observed here. The scarcity of organic-walled dinoflagellate cysts is even more surprising, considering that the other microplankton groups (calcareous nannofossils and foraminifers) are well represented.…”

Section: An Oligotrophic Continental Shelf Settingmentioning

confidence: 99%

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Middle Campanian (Late Cretaceous) sea-level rise; microfossil record of bathymetric changes

Fąfara,

Dubicka,

Niechwedowicz

et al. 2023

Acta Geologica Polonica

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A Middle Campanian (Late Cretaceous) eustatic sea-level rise recorded in the Belgorod succession (Russia; eastern North European Basin) was analyzed. The succession, dated for the Gavelinella annae and Globorotalites emdyensis foraminiferal zones (corresponding to the ‘ Inoceramus’ azerbaydjanensis–‘ Inoceramus’ vorhelmensis inoceramid Zone), records the deposition of pure chalk, with only trace terrigenous material. Its distal offshore position limited terrestrial nutrient delivery, driving oligotrophic conditions that influenced benthic foraminifera and organic-walled phytoplankton communities. Eustatic changes are recorded by planktonic foraminifera and additionally reflected in phytoclast abundance, organic-walled dinoflagellate cysts (dinocysts), calcareous dinoflagellate cysts (c-dinocysts), and δ 13C and δ 18O fluctuations. Most indices were primarily driven by variable terrestrial organic matter and freshwater influxes, acting as a function of sea depth and land topography.

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Section: An Oligotrophic Continental Shelf Settingmentioning

confidence: 76%

Section: An Oligotrophic Continental Shelf Settingmentioning

confidence: 99%

Middle Campanian (Late Cretaceous) sea-level rise; microfossil record of bathymetric changes

Fąfara,

Dubicka,

Niechwedowicz

et al. 2023

Acta Geologica Polonica

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“Larger” Benthic Foraminifera of the Cenomanian. A Review of the Identity and the Stratigraphic and Palaeogeographic Distribution of Non-Fusiform Planispiral (Or Near-Planispiral) Forms

Simmons¹,

Bidgood²

2023

Actapalrom

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A key but challenging task for biostratigraphers is to provide a biozonal/bioevent framework for geological correlation. Species of Larger Benthic Foraminifera (LBF) are important biostratigraphic markers in depositional environments where classical biostratigraphic fossils such as planktonic micro- and macrofossils are rare or absent – e.g., tropical-subtropical shallow water platforms. However, a lack of taxonomic rigour in identifying some LBF species, together with a lack of good age-calibration of their occurrences, has given rise to artificially extended biostratigraphic and paleogeographic ranges for many taxa, diluting their usefulness. In this study, the occurrences of Cenomanian LBF belonging to a “planispiral morphogroup”, both agglutinated and calcareous, have been critically evaluated to determine (i) identity; (ii) stratigraphic range; and (iii) palaeogeographic distribution. Since the last major review of the group in 1985, a voluminous literature has appeared reporting occurrences and adding new taxa. An extensive review of some 600+ published items on Cenomanian planispiral LBF – mostly published after 1985 – and a critical review of the confidence in species identification and age-calibrations therein, has led us to identify 39 taxa (three in “open” status) which appear to have distinct identity. The vast majority of these records are from Neotethys although some also occur in (or are endemic to) the Caribbean/West Atlantic and the Eastern Pacific. The quality of the published taxonomic data is variable and many published records based on identity can be discounted or termed “unconfirmed”. Likewise, many records (confirmed or otherwise) are poorly age-calibrated due to lack of corroborating biostratigraphy or chemostratigraphy, or by using circular reasoning. We summarise and illustrate the main defining characteristics of each taxon and their possible confusion species, including new taxa described since the mid-1980s. We publish new, more confident, age-ranges for these taxa – confirmed by identity and/or age-calibration – and identify where published range data may be unreliable. Paleogeographic distribution maps for each taxon are also provided. Particular stratigraphic issues around the Cenomanian- Turonian boundary are observed due to the difficulty of identifying that boundary, or its preservation, in shallow marine carbonate settings. Although most Cenomanian planispiral LBF are somewhat long-ranging, an increase in diversity throughout the middle – late Cenomanian has shown potential for biostratigraphic resolution to at least substage level using this group. Integration of the planispiral taxa with other LBF morphogroups, after similar treatment, will yield even higher biostratigraphic resolution of Cenomanian LBF and provide a sound basis for biozonation (both local and global), correlation, and age calibration.

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What happened to the organic matter from the Upper Cretaceous succession in Guatemala, Central America?

Cited by 2 publications

References 28 publications

Middle Campanian (Late Cretaceous) sea-level rise; microfossil record of bathymetric changes

Middle Campanian (Late Cretaceous) sea-level rise; microfossil record of bathymetric changes

“Larger” Benthic Foraminifera of the Cenomanian. A Review of the Identity and the Stratigraphic and Palaeogeographic Distribution of Non-Fusiform Planispiral (Or Near-Planispiral) Forms

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