Rugoglobigerina Rugosa Research Articles

Late Cretaceous Planktonic Foraminifera of the Mountainous Crimea in the MSU Earth Science Museum’s Collection

Planktonic foraminifers are widely distributed in the Upper Cretaceous deposits of the Mountainous Crimea. Marker species are of great importance for biostratigraphy and section correlation. Tests Globotruncanita stuarti (De Lapparent, 1918) and Pseudotextularia elegans (Rzehak, 1891) are used as index species for local and regional biostratigraphic scales, and tests of the genus Rugoglobigerina Brönnimann, 1952 are for the faunal layers. The article provides a systematic description of important biostratigraphic species Pseudotextularia elegans (Rzehak, 1891), Rugoglobigerina rugosa (Plummer, 1927), R. hexacamerata Brönnimann, 1952, R. milamensis Smith and Pessagno, 1973, R. macrocephala Brönnimann, 1952 и Globotruncanita stuarti (De Lapparent, 1918), on the basis of which the age of the rocks of five sections of the Mountainous Crimea was determined.

Paleoecology of the K-Pg mass extinction survivor Guembelitria (Cushman): isotopic evidence from pristine foraminifera from Brazos River, Texas (Maastrichtian)

The late Maastrichtian sediments of the Mullinax-1 and Mullinax-3 boreholes from Brazos River, Texas, offer pristine material. These cores are prime candidates for providing an extraordinary window into the ecology of Guembelitria, a key genus in the K/Pg mass extinction event, as well as information on the habitats of other neritic species. Stable oxygen and carbon isotope analyses were performed on six planktic species (Guembelitria cretacea, Globigerinelloides asper, Heterohelix globulosa, Paraspiroplecta navarroensis, Pseudoguembelina costulata, Rugoglobigerina rugosa) and three benthic genera (Gavelinella, Cibicides, and Lenticulina). Our records support the contention that Guembelitria was fully planktic, as indicated by its δ18O values, which overlap the other planktic species, despite its possible origin from a tychopelagic benthic ancestor. However, Guembelitria is distinctly ranked very low in δ13C values, which overlap the benthic records. The anomalously low δ13C values of Guembelitria may represent an isotopic disequilibrium due to fast shell growth, like in its modern analogue Gallitellia vivans. Another explanation may be that these values are attributable to a neustonic life mode in the uppermost part of the oceans, where photosynthesis is inhibited by high UV and the near absence of nutrients. Because these waters are not photosynthetically depleted, calcification using carbon directly from these waters should yield δ13C values consistent with those found in Guembelitria. The ecological strategy that Guembelitria species used to deal with the nutrient-poor surface-water environments was an opportunistic blooming during stressful times of Maastrichtian global warming events and later during the K-Pg catastrophe.

Morphological Abnormalities and Dwarfism in Maastrichtian Foraminifera from the Cárdenas Formation, Valles–San Luis Potosí Platform, Mexico: evidence of paleoenvironmental stress

During the early Maastrichtian an assemblage rich in large foraminifera, mostly composed of orbitoidal foraminifera, developed in the shallow-water deposits of the Cardenas Formation (Valles–San Luis Potosi Platform, Mexico). Among them, the most abundant is Lepidorbitoides minima, some of which display a morphologically abnormal test consisting of polyvalent forms, conical tests and budding, which could be induced by abrupt changes in environmental factors. The occurrence of the abnormalities preceded the demise of this species and of all the larger foraminiferal association in the upper part of the Gansserina gansseri Zone (early Maastrichtian). The abnormalities could be induced by environmental stress, probably related to interplay of different events such as increased terrigenous input and the transition to deeper facies due to Laramide tectonic instability before the K/P boundary. A late Maastrichtian community of dwarfed planktic foraminifera composed of Trinitella scotti Bronnimann, Plummerita reicheli Bronnimann, Rugoglobigerina cf. macrocephala Bronnimann, Rugoglobigerina hexacamerata Bronnimann, Heterohelix punctulata (Cushman), Pseudoguembelina costulata (Cushman), Pseudotextularia intermedia de Klasz, Globigerinelloides asperus Bolli, Guembelitria cretacea Cushman, Rugoglobigerina rugosa (Plummer), Rugotruncana sp., Globotruncanita stuarti (de Lapparent), and Globotruncana arca (Cushman) developed in the upper part of the sequence. This uncommon morphology could also be related to the highly stressed paleoenvironmental conditions related to global climatic change and local tectonic activity. Associated with this planktic assemblage is a deeper-water dwarfed benthic foraminiferal community composed of Gyroidinoides nitidus (Reuss), Coryphostoma incrassata (Reuss), Pseudouvigerina plummerae Cushman, P. cretacea Cushman, Bolivina cretosa Cushman, Planulina texana Cushman and Cibicides harperi (Sandidge).

Maastrichtian North Atlantic warming, increasing stratification, and foraminiferal paleobiology at three timescales

Analysis of 944 single specimens of three species of late Maastrichtian planktonic foraminifera (Racemiguembelina fructicosa, Contusotruncana contusa, and Rugoglobigerina rugosa) from 38 samples spanning the last 3 Myr of the Cretaceous shows consistent isotopic trends through time, consistent isotopic differences among taxa, and high within‐sample isotopic variability throughout. Within‐sample variability does not change systematically through time for any taxon, but average δ18O values decrease by ∼1.5‰, and average δ13C values diverge up section. Comparing taxa, average δ18O values are similar within most samples, but average δ13C values generally decrease from R. fructicosa to R. rugosa to C. contusa. In addition, the within‐sample variability of individual δ13C measurements is larger for R. fructicosa than for either C. contusa or R. rugosa, an observation which is consistent with a photosymbiotic habitat for R. fructicosa. In terms of Maastrichtian paleoceanography the negative δ18O trend of ∼1.5‰ corresponds to a temperature increase of ∼6°C, and the divergence of δ13C values up section suggests an increasingly stratified water column in the western Atlantic through the late Maastrichtian. We suggest that these trends are best explained by increasing import of South Atlantic waters into the North Atlantic and an intensification of the Northern Hemisphere polar front.

Middle Campanian–lowermost Maastrichtian nannofossil and foraminiferal biostratigraphy of the northwestern Australian margin

The middle–late Campanian was marked by an increase in the bioprovinciality of calcareous microfossil assemblages into distinct Tethyan, Transitional, and Austral Provinces that persisted to the end of the Maastrichtian. The northwestern Australian margin belonged to the Transitional Province and the absence of key Tethyan marker species such as Radotruncana calcarata and Gansserina gansseri has led petroleum companies operating in the area to use the locally developed KCCM integrated calcareous microfossil zonation scheme. The KCCM zonation is a composite scheme comprising calcareous nannofossil (KCN), planktonic foraminiferal (KPF) and benthonic foraminiferal (KBF) zones. This paper presents the definitions and revisions of Zones KCCM8–19, from the highest occurrence (HO) of Aspidolithus parcus constrictus to the lowest occurrence (LO) of Ceratolithoides aculeus, and builds on our previous early–late Maastrichtian study. The presence of a middle–upper Campanian disconformity is confirmed by microfossil evidence from the Vulcan Sub-basin, Exmouth and Wombat plateaus, and the Southern Carnarvon Platform. In the Vulcan Sub-basin and on the Exmouth Plateau (ODP Hole 762C) the hiatus extends from slightly above the LO of common Rugoglobigerina rugosa to above the LO of Quadrum gothicum. On the Wombat Plateau (ODP Hole 761B) it spans from above the LO of Heterohelix semicostata to above the LO of Quadrum gothicum; and in the Southern Carnarvon Platform the disconformity has its longest duration from above the HO of Heterohelix semicostata to above the LO of Quadrum sissinghii. A significant revision of the events which define Zones KCCM18 and 19 was necessary owing to the observation that the LO of Ceratolithoides aculeus occurs below the HOs of Archaeoglobigerina cretacea and Stensioeina granulata incondita and the LO of common Rugoglobigerina rugosa. In the original zonation these events were considered to be coincident.

LATE CRETACEOUS FORAMINIFERA, PALEOENVIRONMENTS, AND PALEOCEANOGRAPHY OF THE ROSARIO FORMATION, SAN ANTONIO DEL MAR, BAJA CALIFORNIA, MEXICO

The 315 m of Rosario Formation exposed at the San Antonio del Mar (SADM) section (Baja California, Mexico) contains moderately-to-well preserved benthic and planktic foraminifera, calcareous nannofossils, and molluscs. Nannofossils suggest most of the SADM section was deposited within a narrow interval of the late Campanian (CC21-CC22), whereas foraminifera and molluscs suggest a younger maximum age (younger than the Globotruncana ventricosa Zone) and allow deposition over a longer interval of time. Planktic foraminifera at SADM represent common Tethyan taxa. They are largely restricted to the lower and middle portions of the section and comprise 0-~40% of foraminiferal assemblages. Stable isotopic analyses of Rugoglobigerina rugosa yield δ 18 O v-PDB values from −2.27‰ to −2.82‰ corresponding to salinity-corrected paleotemperature estimates of 26–30°C for the Late Cretaceous eastern Pacific. These estimates are as warm as modern tropical temperatures and are similar to tropical paleotemperature estimates from δ 18 O analyses of exceptionally preserved Maastrichtian samples; however, they are considerably warmer than most tropical Campanian-Maastrichtian estimates. Benthic foraminifera indicate outer shelf paleo-depths with a slight increase in depth or decrease in benthic oxygen levels in the upper parts of the interval studied. The change in the benthic assemblage corresponds to an ~1‰ positive shift in benthic δO 18 , suggesting a relationship between benthic assemblages and an inferred increase in the local intensity of upwelling.

Late Cretaceous foraminifera from Hikurangi Plateau, New Zealand

Rock samples dredged from the Hikurangi Plateau, the large volcanic plateau currently being subducted beneath the North Island of New Zealand, at (1) 37°27.3′S, 178°0′W; (2) 37°22′S, 179°01′W; (3) 36°06′S, 178°22.5′W, include basalt, volcanic breccia and rare fossiliferous sediment. Late Cretaceous foraminifera occurring in two samples from a large volcanic feature at Site 1 provide the only pre-Miocene paleontological ages ever obtained from the plateau. Sites 2 and 3 proved non-fossiliferous. One of the Site 1 samples, a calcareous volcanic breccia, contains a dominantly planktic fauna with Heterohelix globulosa, H. cf. navarroensis, Globigerinelloides volutus and Rugoglobigerina rugosa, together with rare calcareous and agglutinated benthics. It is dated with high confidence as early-mid Campanian to mid-Maastrichtian, and more tentatively as mid-Maastrichtian, and is correlated with the Haumurian Stage in New Zealand. The second sample, studied only in thin section, contains an apparently nearly identical fauna, with undetermined species of Globigerinelloides, Heterohelix and Rugoglobigerina sp. Faunal similarity suggests that it is approximately the same age as the first sample. Both assemblages contain more than 95% planktic individuals, indicating a fully oceanic depositional site. Low faunal diversity (only 4 or perhaps 5 planktic taxa present) and lack of tropical or subtropical forms strongly suggest a relatively high paleolatitude for the site.

Biogeographic patterns in terminal Cretaceous planktonic foraminifera from Tethyan and warm transitional waters

Biogeographic patterns in terminal Cretaceous planktonic foraminifera have been analyzed from their faunal compositions at a time-slice spanning the upper parts of the calcareous nannofossil Micula prinsii Zone (approximately the latest 20–60 k.y. of the Cretaceous) at DSDP sites from low (16°) through middle (37°) paleolatitudes in either the Northern or the Southern Hemisphere. The study is based on relative abundance data of 26 species at Sites 356, 516F, 525A and 527 from the South Atlantic Ocean, Sites 384 and 548A from the North Atlantic and Sites 465A and 577A from the North Pacific. Cretaceous-Tertiary (K-T) boundary sections at Site 516F and 577A are poorly preserved, which prevented quantitative faunal analysis. Two major faunal assemblages, one Tethyan Assemblage and one Transitional Assemblage, are distinguished from the quantitative distribution patterns. The Tethyan Assemblage, dominating at Sites 465A, 356 and 384, is composed of Heterohelix striata, Globotruncana aegyptiaca, Pseudoguembelina kempensis, P. costulata, an undescribed form of Heterohelix with relict apertural flanges along medium suture, Rugoglobigerina hexacamerata and Trinitella scotti. Among these species P. kempensis, P. costulata and H. sp. exhibit enhanced abundances at Site 465A and constitute a Warm Tethyan Subassemblage, whereas R. hexacamerata and T. scotti, which are most abundant at Sites 356 and 384, represent a Cool Tethyan Subassemblage. Seven species show greater relative abundances at Sites 525A and 527 and are referred to a Warm Transitional Subassemblage: Abathomphalus mayaroensis, Gublerina cuvillieri, Pseudotextularia elegans, Rugoglobigerina rugosa, Racemiguembelina fructicosa, Globotruncana arca and Planoglobulina acervulinoides. In addition, an assemblage, marked by the Heterohelix glabrans-H. carinata complex, H. globulosa, Globigerinelloides multispina and Rosita contusa, may represent a “shallower-water” subassemblage within warm Transitional waters (Site 548A).

Foraminiferal Distribution in the Saratoga Chalk of Arkansas

ABSTRACT The Saratoga (early Navarroan) is a variably sandy and argillaceous chalk, which crops out only in southwestern Arkansas. It thins from 60 feet (18 m) to pinchout both northeasterly and southwesterly. It is the basal unit of the Navarro Group in Arkansas, lying unconformably on the Marlbrook Marl and reportedly unconformably beneath the Nacatosh Sand. The Saratogan foraminiferal fauna has been well established, but the sampling has been at or near the type locality, and no observations of relative abundance have been made. The objectives of the present study are to update the benthic taxonomy, extend the sampling laterally and vertically, gather populational data by statistical counts, and seek information on faunal distribution, paleobiofacies, and depositional environment. Of these only the statistical counts, paleobiofacies, and depositional environment are reported here. Species distribution was determined by statistical counts of 14 samples at three localities along the outcrop. The fauna of all samples was dominated by Cibicidoides alleni (Plummer), Rugoglobigerina rugosa (Plummer), and Anomalinoides pinguis Jennings, suggesting a Cibicidoides-Rugoglobigerina-Anomalinoides paleobiofacies for the Saratoga. The combined frequency of these taxa averages 42% for the 14 samples. A secondarily prominent group of two to ten, changing species combine to average 22% of the sample populations. Taxonomic changes in this group suggest secondary paleobiofacies indicative of geographic separations. The remaining portion of the sample populations is distributed among approximately 40 species, which change from sample to sample so that more than 100 taxa are involved. The species distribution is strongly skewed. On average, 82% of the species encountered in a sample have a frequency of less than 3%. The arithmetic mean of frequencies encountered in sample populations ranges from 1.49 to 2.71, and the average of these averages is 1.9. The standard deviation ranges from 2.75 to 5.32. Plankton-benthos ratio, and comparable biofacies indicate a middle to lower neritic paleoenvironment. Simple diversity measures were disappointing. Statistical induction measures were not attempted. The extreme rarity of miliolids suggests medial paleolatitude for the depositional environment.

Differential dissolution of Upper Cretaceous planktonic foraminifera from a temperate region of the South Atlantic Ocean

Differential dissolution susceptibility is well known in Quaternary planktonic foraminifera, but few quantitative dissolution studies have been carried out on pre-Quaternary species. A dissolution ranking scheme is proposed for 19 of the most common uppermost Cretaceous planktonic foraminifera from a temperate region of the South Atlantic Ocean. The study is based on quantitative faunal variations in an uppermost Maastrichtian segment (about 190 kyr long) from DSDP Site 527 (Leg 74) from the Walvis Ridge. A calcite dissolution index was formulated from degree of fragmentation of planktonic foraminiferal tests. Through this segment, relative abundance of benthonic foraminifera, which are generally known to be more dissolution-resistant than planktonic foraminifera, covary with degree of fragmentation, supporting that degree of fragmentation is a measure of dissolution. A prominent change from a state of moderate dissolution to a state of stronger dissolution takes place near the top of Magnetic Anomaly 30 (66.74 Ma). Some species decrease, whereas others increase, in relative abundance between these dissolution regimes, and dissolution susceptibility was ranked from quantified differences between dissolution regimes. The most susceptible species are in order, from least resistant to most resistant: Heterohelix globulosa, Globigerinelloides multispina, Rugoglobigerina rugosa, Pseudoguembelina costulata, Globotruncanita stuartiformis, and Heterohelix carinata. The following eight species are unaffected by dissolution in the sense that they show no significant difference between regimes: Heterohelix glabrans, Pseudotextularia browni, P. elegans, Racemiguembelina fructicosa, Planoglobulina brazoensis, Gublerina cuvillieri, Globotruncana arca, and Rosita contusa. The most resistant species were ranked in the following order, from least resistant to most resistant: Globigerinelloides subcarinata, Pseudoguembelina palpebra, P. polypleura, Globotruncanella havanensis, and Abathomphalus mayaroensis.

Biostratigraphy of planktic Foraminifera from the Maastrichtian white chalk of Sweden

Abstract Three bore-hole cores (30–200 m long) from the latest Cretaceous chalk of southern Sweden (Limhamn area, Skane) have been analyzed for planktic Foraminifera. The sequences are referable to the Upper Maastrichtian (Nephrolithus frequens coccolith Zone). Planktic foraminiferal assemblages, mostly dominated by Heterohelix striata and Globigerinelloides multispina, are of a typical high-latitude (Boreal) character. Rugoglobigerina rugosa and the Pseudotextularia elegans-Racemiguembelina fructicosa complex are occasionally abundant. The P. elegans-R. fructicosa complex is abundant in the uppermost parts of the sequences; this increase has been suggested by other workers to represent a climatically related migration from the Tethys. Other taxa are all rare (Hedbergella monmouthensis, Praeglobotruncana havanensis, Guembelitria cretacea, Heterohelix glabrans, Globigerinelloides sp., and Globotruncana sp.). The proportions between the two dominating species, G. multispina and H. striata, change systematic...

Distribution of Late Cretaceous Rotaliporidae and Globotruncanidae in California and Northwestern Mexico: ABSTRACT

A study of planktonic Foraminifera from the Upper Cretaceous of California and northwestern Mexico forms a basis for erecting a preliminary biostratigraphic zonation. The Praeglobotruncana stephani assemblage zone, of late Cenomanian age, is characterized by species of Rotaliporidae. Strata of early Turonian age are recognized by the first appearance of bi-keeled globotruncanids which characterize the Globotruncana imbricata assemblage zone. Within this zone occur Praeglobotruncana helvetica, G. kuepperi, and several undescribed species. The Globotruncana coronata-G. inornata assemblage zone includes rocks of late Turonian to early Senonian age and contains distinct species of Globotruncana, Clavihedbergella, and Hedbergella. The Globotruncana arca assemblage zone, of late Senonian age, contains several important stratigraphic markers, e.g., Globotruncana ventricosa, G. havanensis, G. elevata, and Rugoglobigerina rugosa. These indicate a Campanian to early Maestrichtian age. The planktonic Foraminifera which define the late Maestrichtian in other parts of North America are unrecorded in the eastern Pacific. The stratigraphic and geographic distributions of selected species of Praeglobotruncana, Globotruncana, and Rugoglobigerina are compared with those from the Atlantic Coast and Gulf-Caribbean area. This comparison suggests that Globotruncana arca, G. linneiana, G. fornicata, and several other species were cosmopolitan, whereas such species as G. calcarata were latitudinally restricted during the Late Cretaceous. The genera Abathomphalus and Plummerita are found exclusively in the Tethyan region. Globotruncana gagnebini, G. subcircumnodifer, and others are reported only from the western margin of the Atlantic Ocean; G. kuepperi, G. churchi, and G. putahensis are unknown outside of the Pacific basin. End_of_Article - Last_Page 611------------