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2022 (vol. 22)

A larger benthic foraminiferal zonation for the Eocene of the Caribbean and central American region

 | HTML  | PDF [43,031 KB]  | DOI : 10.2110/carnets.2022.2211

 Abstract:  We have undertaken a study of the larger benthic foraminifera (LBF) of the Eocene of Jamaica that involved collecting free specimens and calibrating their occurrence against chronostratigraphy using calcareous nannofossils identified from sample splits or adjacent samples. The results have been plotted stratigraphically and allow a detailed zonation of the Eocene (14 zones) to be developed based largely on lepidocyclinids and similar forms. The zonation can be shown to be applicable to the Americas extending from northern South America, to Central America, the Caribbean and southern North America. The LBF biostratigraphy is based on the evolution of various groups. Three zones are recognized in the Ypresian, six zones in the Lutetian, three zones in the Bartonian, and two zones in the Priabonian. In order to classify the LBF we have revised the important groups used for the zonation scheme that occur in the Eocene and figure numerous examples. Our revision rearranges described genera into evolutionary, monophyletic clades to which we give the hierarchy of family and subfamily. We provide remarks on published taxa explaining how they are recognized and describe all the new taxa (two families, one subfamily, four genera and five species). The following families, genera and species are new: Butterliniana gen. nov., Helicosteginidae fam. nov., Helicostegina minor sp. nov., Helicostegina jamaicensis sp. nov., Helicostegina jeannemairae sp. nov., Pseudolepidinidae fam. nov., Orbitoininae subfam. nov., Planorbitoinella gen. nov., Polyorbitoinella gen. nov., Polyorbitoinella lilyfieldensis sp. nov., Orbitoina wrighti sp. nov., and Nephronummulites gen. nov.

Carnets Geol., vol. 22, no. 11, p. 409-565

Online since July 1, 2022

Discussion of Laya et al. (2021), Dissolution of ooids in seawater-derived fluids - an example from Lower Permian re-sedimented carbonates, West Texas, USA [Sedimentology 68(6), 2671-2706]
Bruno R.C. GRANIER & Christopher G.St.C. KENDALL

 | HTML  | PDF [5,046 KB]  | DOI : 10.2110/carnets.2022.2210

 Abstract:  This discussion reassesses earlier interpretations of calcareous turbidites from the subsurface Spraberry Formation of the Happy Field (Garza County, NW Texas). It is based on routine petrographic analyses with a standard microscope. The succession of diagenetic products in this deep water setting were a little initial cementation by low magnesian calcite (LMC) and then the partial or complete leaching of both aragonite and high magnesian calcite (HMC) allochems facilitated by the presence of a residual primary intergranular porosity. This contradicts Laya et al.'s (2021) claim that cementation left no residual intergranular porosity so further leaching of the ooids would not have been possible. Instead the study made for this discussion with the same thin sections found residual primary intergranular porosity remains as evidenced by some of their photomicrographs. Most thin sections with porous grainstones have 1) collapsed molds that exhibit evidence of little initial cementation and 2) measured permeability values that range from some mD to some tens of mD. Isopachous LMC cements occur in almost all thin sections lining the margins of most intergranular pores. As these cements do not fully fill the pores, there is permeable well-connected residual primary porosity with no significant LMC cement in the secondary moldic porosity. Compaction affects the allochems and, where these are partially leached, intergranular and moldic porosities. Dissolution of aragonite (a major component) and HMC (possibly a minor component) was probably not coeval. The order of paragenetic sequence of this discussion study was: 1) LMC cementation; 2) aragonite leaching facilitated by oxidation of the organic matter in the "biocrystals" of bioclasts and oolitic cortices; 3) compactional brecciation, which was first mechanical, and then chemical causing local collapse of the molds of some of the largest pores. It was governed by cementation initially in a shallow burial diagenetic setting and then leaching whereas chemical compaction marks a slightly deeper burial diagenetic setting. The final event was marked by oil migration into the Happy Field reservoirs, freezing the calcium carbonate diagenesis. The theory of Laya et al. (2021) of the leaching of ooids in directly "seawater-derived fluids" is unsupported by the paragenetic sequence described above.

Editorial notice:  
Following the reading of a paper authored by J.C. Laya et al. in the journal Sedimentology, the authors submitted on 02-Nov-2021 a first discussion manuscript based on analogues. On 09-Nov-2021, this first manuscript was returned with harsh comments from three editors and ascribed the label "Reject & Resubmit". On 07-Mar-2022, the first author (BRCG) received a parcel with 40 thin sections to examine over a two weeks period. He was charged significant import taxes for this "scientific material". On 14-May-2022, the authors submitted a new discussion manuscript based on that same material that was studied by J.C. Laya et al. On 07-Jun-2022 this second manuscript was ascribed the label "Immediate Reject" without having any preliminary editorial reading. In the meantime, a claimant allegedly accused the first author (BRCG) of "serious breaches in academic publishing ethics" because he posted some photomicrographs of the material on a social network. On 05-Apr-2022 and again on 18-May-2022, this claimant addressed complains to the " Université de Bretagne Occidentale", an action that may be characterised as slander or defamation. Note that the authors were kindly granted the written permission to publish this discussion paper and another paper by the legitimate owner of the Happy Spraberry field, which also owns all material derived from any of their materials (e.g., cores). It looks like there is no evidence that it was the case for the other parties.

Carnets Geol., vol. 22, no. 10, p. 395-408

Online since June 19, 2022

A rare ammonite assemblage in the Romaniceras ornatissimum Zone (Middle Turonian) from the Uchaux Massif, Vaucluse, France

 | HTML  | PDF [7,869 KB]  | DOI : 10.2110/carnets.2022.2209

 Abstract:  The Uchaux Massif (Vaucluse, SE France) is one of the rare places in Europe where ammonites collecting can be led from a high middle Turonian through Late Turonian. That incited Alcide d'Orbigny in 1852 to quote Uchaux as "the French type of the Turonian stage" to complement the Saumur, Tourtenay, Montrichard and Tours localities mentionned in 1842 when the stage was created. In 2014, the monograph by Robaszynski et al. synthetized and actualized the informations available on the litho- and biostratigraphy of the Turonian from the Uchaux Massif. More recently, a new outcrop at Mondragon, in a place named Prés Morel, exposes the whole carbonate siltstones with Spongia of the Peyras Member (UL3). Were collected : Lewesiceras peramplum (Mantell, 1822), Romaniceras (Romaniceras) marigniacum Amédro & Châtelier, 2020, R. (Yubariceras) ornatissimum (Stoliczka, 1864), R. (Y.) kanei Jones, 1938, Collignoniceras woollgari regulare (Haas, 1946), C. carolinum (Orbigny, 1841), C. papale (Orbigny, 1841), C. turoniense (Orbigny, 1841) and a new species of Collignoniceras : C. rhodanicum Amédro, Baudouin & Delanoy sp. nov. This assemblage, unprecedented in the studied area, is characteristic of the Romaniceras ornatissimum Zone which is the third of the four ammonite zones of the middle Turonian (Tm 3). At the top of this third zone, the surprise was to find the Romaniceras marigniacum bio-horizon defined in 2020 in the southern part of the Paris Basin at the top of the Tuffeau de Bourré and at the base of the Tuffeau Jaune de Touraine. Moreover, we now think that the Peyras Member has to be fully assigned to the Romaniceras ornatissimum Zone. Lastly, the assemblage includes a rich population of Collignoniceras carolinum (24 specimens), the most important known to-day over the world. All these ammonites allow to know the spectrum of their morphological variations and show a dimorphism through the existence of micro- and macroconchs.

Carnets Geol., vol. 22, no. 9, p. 333-393

Online since June 18, 2022

The Kalkowsky Project - Chapter IV. Case study of the Happy Spraberry oil reservoirs in NW Texas (with a micropaleontologic and biostratigraphic supplement): Collapsed molds should not be treated as a category of distorted ooids
Bruno R.C. GRANIER, Christopher G.St.C. KENDALL & Daniel VACHARD

 | HTML  | PDF [6,180 KB]  | DOI : 10.2110/carnets.2022.2208

 Abstract:  The subsurface upper Spraberry Formation in NW Texas is dominantly composed of calcareous turbidites and debris-flows. The petrographic analysis of its porous grain-supported fabrics revealed the presence of controversial superimposed compaction fabrics, sometimes referred to as "distorted ooids". Based on the paragenetic sequence, it is demonstrated that these allochems were not distorted. In fact, the related zigzag and silcrow (§) patterns result from the collapse of molds, either oomolds or biomolds, in response to mechanical compaction of the fragile framework made up of isopachous Low-Mg Calcite cement surrounding these empty molds. As a side finding, this stratigraphic unit, which was said to be late Kungurian in age, is proved to be nearly 7 millions of year older.

Carnets Geol., vol. 22, no. 8, p. 311-332

Online since June 2, 2022

Taxonomy of the fossil calcareous algae: Revision of genera Physoporella Steinmann and Oligoporella Pia (Dasycladales)

 | HTML  | PDF [31,142 KB]  | DOI : 10.2110/carnets.2022.2207

 Abstract:  The taxonomic classification and mutual distinction of the genera Physoporella Steinmann and Oligoporella Pia (Dasycladales, green algae) have proven problematic and that has impeded their use in stratigraphy and other studies. The presence of single whorls of piriform laterals in Physoporella and double whorls in Oligoporella is considered as the main characteristic that separates these genera. According to that, diagnoses of genera and all species and varieties are changed or supplemented, and detailed descriptions are given. For this purpose the type-material from Pia's collection was re-examined and its redocumentation and reinterpretation performed. Additional information was obtained from abundant material from Croatia (Ivanščica Mt, Medvednica Mt, Žumberak Mt, Lika, Dalmatia). Only a few taxa were examined based on literature data. For all species and varieties reconstructions are given. Taxa from the Permian of East Asia are only briefly described. Among the investigated taxa, some of them have a structure that significantly differs from that present in the type species of the genera Physoporella and Oligoporella. They are separated into two new genera Ardeiporella and Neophysoporella. The revised genera Physoporella and Oligoporella, together with the newly established ones, give a clearer picture of phylogenetic relations.

Carnets Geol., vol. 22, no. 7, p. 171-310

Online since June 4, 2022

The report of a rare deformed eagle ray (Myliobatiformes: Myliobatidae) tooth plate from the Neogene of Calvert Cliffs, Maryland, U.S.A.
Stephen J. GODFREY, David J. BOHASKA & John MAISEY

 | HTML  | PDF [937 KB]  | DOI : 10.2110/carnets.2022.2206

 Abstract:  An isolated and deformed lower tooth plate of an eagle ray (Aetomylaeus sp., Myliobatidae, Myliobatiformes) is reported herein from the Miocene deposits along Calvert Cliffs, Maryland, U.S.A. Deformed myliobatid tooth plates like this, either fossil or modern, are exceedingly rare. All medial teeth are deformed/skewed such that the right side of each tooth forms an angle of about 10 degrees to the transverse axis of the dental plate. The skewed abnormal form of the teeth in USNM PAL 726325 is not thought to be the result of modern or taphonomic deformation. Rather, the deformity exhibited by USNM PAL 726325 gives every indication that successive similarly deformed teeth came about as a result of a persistent anatomical deformity of the dental lamina. From the consistency in the deformed shape of each tooth, it would appear as though the dental lamina retained this anomalous shape at least throughout the time represented by the age of the tooth plate. If this interpretation is correct, the deformity was not fatal and did not significantly impair the functionality of the tooth pavement over a protracted part (or all) of the individual's life span.

Carnets Geol., vol. 22, no. 6, p. 161-169

Online since May 10, 2022

The Kalkowsky Project - Chapter III. Significance of primary radial fabrics associated with ancient partly leached or recrystallized calcareous ooids
Bruno R.C. GRANIER & Philippe LAPOINTE

 | HTML  | PDF [1,851 KB]  | DOI : 10.2110/carnets.2022.2205

 Abstract:  Calcitic ooids and bothryoids from the Yacoraite Formation in the provinces of Jujuy and Salta (Argentina) display radial fabrics pointing to their primarily high-Mg calcite (HMC) nature. The present publication documents some specimens that are partly or fully leached or recrystallized, which raises fundamental questions about the validity of some concepts, such as the very existence of the so-called "two-phase"/"bimineralic" ooids. It is assumed here that the organic content in the oolitic cortices (and, subsequently, its degree of oxidation) is the key to explaining some differential diagenetic alterations.

Carnets Geol., vol. 22, no. 5, p. 149-160

Online since March 4, 2022

Adult morphologies of Puzosia quenstedti (Parona & Bonarelli, 1897) (Ammonoidea, Desmoceratidae) in the Albian of the South-East of France. Taxonomic implications
Jean-Louis Latil LATIL, Gérard DELANOY & Pierre DELATTRE

 | HTML  | PDF [5,643 KB]  | DOI : 10.2110/carnets.2022.2204

 Abstract:  Several adult specimens belonging to the genus Puzosia Bayle, 1878, were collected in the Albian of Lieuche (Alpes-Maritimes, France). Comparison with material from the condensed Albian levels of La Balme de Rencurel (Isère, France), in particular those described and figured by Jacob (1908), has highlighted a morphological link between the adult forms from Lieuche and the incomplete specimens from the condensed levels of the Lower-Middle Albian of south-eastern France and to identify them as Puzosia quenstedti (Parona & Bonarelli, 1897). These new details on the ontogenetic development of this species also allow new perspectives in the taxonomic treatment of Albian Puzosia species. A modified diagnosis of Puzosia quenstedti is proposed.
The presence of Douvilleiceras sp. juv. aff. D. mammillatum (Schlotheim, 1813) in superimposed overlying levels allows assignation of a Lower Albian (Douvilleiceras mammillatum Superzone) to a basal Middle Albian age (Hoplites dentatus Zone).

Carnets Geol., vol. 22, no. 4, p. 119-147

Online since February 28, 2022

The Kalkowsky Project - Chapter II. Wobbly ooids in a stromatolite from the Yacoraite Formation (Argentina)
Bruno R.C. GRANIER & Philippe LAPOINTE

 | HTML  | PDF [1,375 KB]  | DOI : 10.2110/carnets.2022.2203

 Abstract:  Eccentric ooids are described from a brackish Maastrichtian paleolake in NW Argentina. The first report of such atypical coated grains was from marine Upper Jurassic strata in SE Poland. Because their growth pattern is not likely to be confused with that of other "eccentric" ooids, such as asymmetric ooids, hiatus ooids, half-moon ooids, or "broken" ooids, it is suggested here to name them "wobbly ooids".

Carnets Geol., vol. 22, no. 3, p. 111-117

Online since February 15, 2022

The genera Roloboceras Casey, 1954, and Megatyloceras Humphrey, 1949 (Ammonoidea, Ancyloceratina, Douvilleiceratidae), from the Lower Aptian of Ardèche (SE France) - Taxonomic and biostratigraphic implications
Gérard DELANOY, Cyril BAUDOUIN, Antoine PICTET, Josep MORENO-BEDMAR, Camille FRAU & Bertrand MATRION

 | HTML  | PDF [11,947 KB]  | DOI : 10.2110/carnets.2022.2202

 Abstract:  The Lower Aptian marine deposits from southern Ardèche (South-East of France) yield a rich ammonite fauna of the sub-family Roloboceratinae Casey, 1961, which dates the upper Deshayesites forbesi Zone (Roloboceras hambrovi Subzone pro parte ?). The systematic study of this Roloboceratinae fauna has improved our knowledge of Megatyloceras coronatum Rouchadzé, 1933, type species of Megatyloceras Humphrey, 1949, as well as a better understanding of the genus thanks to the examination of the species from the Anglo-Paris Basin. A new species, M. leteilensis sp. nov. is introduced, and a description of M. transiens Casey, 1961, provided, with clarifications on its possible stratigraphic position. This study also establishes that the "species" Megatyloceras ricordeanum (Orbigny, 1850) represents only a growth stage shared by several species of Megatyloceras which is doubtfully a true taxon and must, therefore, be considered as a nomen dubium. The hypothesis of sexual dimorphism in Roloboceras Casey, 1954, and Megatyloceras is advanced. The study of this Roloboceratinae fauna highlights their heterogeneous distribution throughout Lower Aptian deposits of Ardèche, showing a direct correlation with bathymetric range. The biostratigraphical distribution of both genera on the Languedoc platform shows that Roloboceras is present from the uppermost C2 segment to the C4 segment of the stable carbon-isotope record, while Megatyloceras is limited to the middle C4 segment up to the lowermost C6 segment. Both genera coexist during the C4 segment.

Carnets Geol., vol. 22, no. 2, p. 7-109

Online since February 17, 2022

Nomenclatural Note, p. 110

Comments on a small sabretooth cat in the Abismo Ponta de Flecha Cave, Vale do Ribeira, southeastern Brazil

 | HTML  | PDF [448 KB]  | DOI : 10.2110/carnets.2022.2201

 Abstract:  Vale do Ribeira, in southeastern Brazil, is known for its many caves that contain osteological material, including remains that have been referred to several extinct species. The sabertooth cat Smilodon populator was a large predator that inhabited South America during the Quaternary. A specimen that is represented in the Abismo Ponta de Flecha Cave by small forelimb bones (metacarpals and phalanges) is commented here. The metacarpals display morphological characteristics of S. populator, but are smaller than those of S. fatalis and larger than those of S. gracilis. This specimen is amongst the smallest ever found specimen of S. populator and is comparable in size to an adult lion.

Carnets Geol., vol. 22, no. 1, p. 1-6

Online since January 17, 2022

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