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2024 (vol. 24)
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Extraordinary trilobite collected by František Pošepný discovered after 140 years
Oldřich FATKA
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| DOI: 10.2110/carnets.2024.2411
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Abstract: This
extraordinary specimen, a well-preserved articulated thorax of a large specimen
of the middle Cambrian paradoxidid trilobite Paradoxides (Hydrocephalus)
minor (Boeck, 1827), was collected by the notable geologist František
Pošepný during an excursion to the Hřebeny mountain range, Czech
Republic, in the 1890s, and was thought to have been lost for nearly 140 years.
The trilobite originates from the Brdlavka locality, one of the easternmost
outcrops of the Jince Formation. There is no fossil
collected at this locality housed in institutional and private collections.
The recent discovery of this fossil in the Geological Pavilion of the Technical
University of Ostrava, Czech Republic, enabled its assignment to the common
species Paradoxides (Hydrocephalus) minor (Boeck,
1827). This species confirms the occurrence of the middle levels of the middle
Cambrian Jince Formation at the Brdlavka locality.
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Carnets Geol., vol. 24, no. 11, p. 173-178
Online since October 31, 2024
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A larger benthic foraminiferal zonation for the Cenozoic of the Americas
Simon F. MITCHELL, Edward ROBINSON, Ercan ÖZCAN, Mark M. JIANG & Natalie ROBINSON
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| DOI: 10.2110/carnets.2024.2410
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Abstract: The Cenozoic of the Americas does not have a zonation based on Larger Benthic
Foraminifera (LBF) unlike the Tethys where there is a shallow-water benthic
zonation. Although there were faunal exchanges, the different evolutionary
patterns between the Americas and the Tethys require separate zonations. We have
calibrated LBF, stratigraphic distributions and events in the Americas using
calcareous nannoflora (Paleocene-Eocene), planktic foraminifers
(Oligocene-Miocene) and published strontium (Sr) isotope values. We define 29 zones spanning the
Paleocene to Recent based on changing LBF assemblages and evolving lineages,
with some zonal boundaries related to global or local palaeoenvironmental
events. This will allow correlation across carbonate platforms in the tropical Americas
at a higher resolution than previously possible.
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Carnets Geol., vol. 24, no. 10, p. 163-172
Online since October 31, 2024
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Shell injuries in Densepustula Lazarev, 1982, Pennsylvanian productidine brachiopod from the Donets Basin, Ukraine
Vitaly DERNOV
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| DOI: 10.2110/carnets.2024.2409
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Abstract: Nine injured ventral valves of productidine brachiopods belonging to the genus
Densepustula Lazarev, 1982, from the Mospyne, Smolyanynivka, Belaya Kalitva, and
Kamensk formations (Upper Bashkirian-lower Moscovian, Lower and Middle Pennsylvanian) of the Donets Basin (eastern Ukraine)
were studied. Three morphological types of damage traces have been recognized: Type A) longitudinal,
sublongitudinal, and transversal thin straight or sinuous furrows, about 5-7 mm
long and 0.5-1.5 mm thick; Type B) rounded and ellipsoidal pits, about 3-4 mm in
diameter, located on the umbo, the anterior margin of the ventral valve, and the lateral slopes of the ventral valve;
and Type C) irregularly-shaped dimples on the anterior margin and in the sulcus, 2-3 mm in size. These injuries are present
on 9 out of 61 (15%) of ventral valves studied, but entirely absent from dorsal
valves (0 out of 25). The most likely producers of these damage traces
are cartilaginous fishes and parasites of unclear affinity.
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Carnets Geol., vol. 24, no. 9, p. 143-162
Online since September 20, 2024
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Tooth marks of the Great White Shark from a Pliocene outcrop of the Northern Apennines (Castell'Arquato, Italy)
Alessandro FRESCHI & Simone CAU
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| DOI: 10.2110/carnets.2024.2408
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Abstract: We
describe and analyze a rib fragment of a small cetacean from the Castell'Arquato
Plio-Pleistocene Basin (Northern Apennines, Italy) that displays various tooth
marks featuring parallel striations similar to those left by the serrated tooth
of the extant white shark, Carcharodon carcharias. The discovery
locality,
known as "Buca della Balena", was an inner-shelf marine setting where sharks
may have scavenged on drifting cetacean carcasses in Piacenzian times. The high
number of marks found on the small bone fragment suggests multiple bites by one
or more shark individuals. The rib fragment studied is one of the few
osteological specimens from the Pliocene of the Mediterranean Basin to preserve
white shark tooth marks.
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Carnets Geol., vol. 24, no. 8, p. 135-141
Online since July 24, 2024
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Octahedronoides tethysianus n.gen., n.sp., enigmatic clusters of microspheres at the Jurassic-Cretaceous transition
Bruno R.C. GRANIER
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| DOI: 10.2110/carnets.2024.2407
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Abstract: In
the literature, numerous accounts exist of microspheres scattered in the pelagic
environments of the Tethys realm at the Jurassic-Cretaceous transition. These
microspheres are commonly associated with genera such as Cadosina, Colomisphaera,
or Stomiosphaera, and attributed to calcareous dinocysts. On the
other hand, there are few records of the microsphere, initially described as Cadosina
minuta Borza, 1980, which are arranged
in small clusters, likely comprising six cells. This distinctive grouping
and its architecture preclude attribution to the calcareous dinocysts. A new
genus and a new species (as Octahedronoides tethysianus n.gen., n.sp.) are introduced to define these
clusters of leiospheres, which are here reascribed to the acritarchs.
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Carnets Geol., vol. 24, no. 7, p. 127-133
Online since May 8, 2024
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A new fossil psychodomorphan fly from Lower Barremian Lebanese amber elucidates the relationship of the Tanyderinae stat. nov. within the Psychodidae
Dany AZAR, Sibelle MAKSOUD, Di-Ying HUANG, Mounir MAALOUF & Chen-Yang CAI
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| DOI: 10.2110/carnets.2024.2406
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Abstract: A new species, Nannotanyderus granieri sp. nov.,
belonging to the Tanyderidae (Diptera, Nematocera), from Lower Barremian amber
of Bqaatouta (Lebanon), is characterized, described, figured, and its
taxononomic position discussed. The possible confusion regarding the attribution of new fossils to either the Tanyderidae or the Psychodidae,
in addition to the results of recent molecular phylogenies, have led us to re-evaluate
the taxonomic position of the Tanyderidae and to consider it as a subfamily
within the Psychodidae. The fossil described herein is a tiny tanyderine sensu
nov. species, and the second one belonging to the genus Nannotanyderus
from Lebanese amber. A tentative molecular phylogeny of recent Psychodidae and
an exhaustive catalogue of fossil Tanyderinae stat. nov. are provided.
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Carnets Geol., vol. 24, no. 6, p. 113-125
Online since April 1, 2024
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Nomenclatural Note, p.
126
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The Kalkowsky Project - Chapter VI. A panorama of synsedimentary broken ooids
Bruno R.C. GRANIER & Philippe LAPOINTE
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[3,988 KB]
| DOI: 10.2110/carnets.2024.2405
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Abstract: Broken
ooids are known to occur in both aragonitic and calcitic ooids with radial
fabrics. In the literature, it has been suggested that synsedimentary breakage could be related to
attrition/mechanical impacts, hypersalinity, or desiccation. However, this paper demonstrates that none of the aforementioned phenomena provides a valid
explanation. Although the exact process remains unknown (potentially involving some synsedimentary
recrystallization), it is shown that: 1) the breakage is genetically linked to the radial
fabrics; 2) the ratio of ooid breakages increases with the relative thickness of the radial cortical
layers; 3) fracture growth in broken ooids proceeds centripetally.
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Carnets Geol., vol. 24, no. 5, p. 91-112
Online since February 29, 2024
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A new record of ground sloth in the Ribeira de Iguape valley, southeastern Brazil
Artur CHAHUD, Gabriella da C. PEREIRA, Paulo R. de O. COSTA & Mercedes OKUMURA
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[377 KB]
| DOI: 10.2110/carnets.2024.2404
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Abstract: In the early 1980s, an assemblage of extinct and extant
vertebrates was collected from the Abismo Ponta de Flecha, a vertical cave in southern S o Paulo, Brazil, for archaeological, geological, and paleontological analyses. While materials identified as
ground sloths have been referenced in earlier publications, they have never been thoroughly described. In this study, we provide the first detailed description of a large, previously unidentified taxon
found in Brazil, interpreted herein as belonging to the family Nothrotheriidae. Although direct dating of the specimen was not possible, other dated occurrences from the Ribeira de Iguape Valley
suggest that it may have inhabited the region during the Late Pleistocene, coinciding with the local presence of a dense forest cover.
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Carnets Geol., vol. 24, no. 4, p. 83-89
Online since January 31, 2024
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The Kalkowsky Project - Chapter V. Asymmetric ooids from the Yacoraite Formation (Argentina)
Bruno R.C. GRANIER & Philippe LAPOINTE
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[2,420 KB]
| DOI: 10.2110/carnets.2024.2403
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Abstract: Asymmetric ooids
are documented in a brackish Maastrichtian to Danian paleolake in NW Argentina.
Their distinctive asymmetric growth pattern is likely related to an uneven
distribution of the Extracellular Polymeric Substances (EPS) around the coated
allochem, within which calcite fibers (i.e., the 'fibrite') have grown. This
pattern is unlikely to be mistaken for that of other 'eccentric' ooids, such as
wobbly ooids, spiny ooids, hiatus ooids, half-moon ooids, 'broken' ooids sensu
lato, or collapsed oomolds (referred to as 'distorted' ooids).
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Carnets Geol., vol. 24, no. 3, p. 75-82
Online since January 20, 2024
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The Central South Atlantic: The origin of its waters, its evolution and effects beyond
Ricardo L.M. AZEVEDO, Rogério L. ANTUNES, Mauro D.R. BRUNO, Thomas R. FAIRCHILD & Dimas DIAS-BRITO
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| DOI: 10.2110/carnets.2024.2402
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Abstract: The primitive sea that occupied the
Central South Atlantic (CSA), part of the intra-Gondwana rift during the Early
Cretaceous, allowed precipitation of an extensive and thick layer of evaporites,
the Ibura Salt, followed by the deposition of a prominent Albian carbonate
package. Although the shallow platform facies do not contain classical benthic
Tethys markers, the pelagic open sea carbonates are essentially dominated by
planktonic elements coming from the Tethys Realm. This condition led some
researchers to think that Tethys waters also contributed to salt formation, an
idea that clashes with the geotectonic model of northward separation of Africa
and South America and ingression of predominantly Austral marine waters. Now, a new controversy arises as to the age of this salt layer when trying to position
bio-events and lithological and chemostratigraphic markers from these rocks with
respect to established data for the Global Boundary Stratotype Section and Point for the
Aptian/Albian boundary (GSSP-Alb). Biochronostratigraphic information on
planktonic foraminifera points to an Aptian age as opposed to the earliest
Albian traditionally accepted for the carbonate section that overlies the giant
salt layer. On the other hand, stratigraphic and geochronological data suggest
an age of 113 Ma for the base of the salt, very near to the 113.2 0.1 Ma
arbitrated for the GSSP-Alb. In this study, we adopt the base of the evaporite
bed as the Aptian/Albian boundary in the CSA, Equatorial South Atlantic (ESA),
and northeastern Brazilian interior basins (BNE) as well. Based on these
criteria, a broad review and the integration of available information have led to new
interpretations regarding the earliest phase of these segments of the South
Atlantic and adjacent areas. Initially, during the Aptian-Albian transition, an
ephemeral interior sea within Brazil, drawing its waters from the north, would
have contributed to salt deposition in the intra-Gondwana rift (evaporitic
stage of the CSA). Afterward, but still within the earliest Albian, the
evaporitic system evolved into a carbonate gulf when the northern barrier, the
Exception Zone (EZ), disappeared. The lagoonal circulation pattern that then
formed in the CSA created a hypersaline and warm outflow plume that swept across
the marine bottom of the ESA and part of the Tethys Sea. Paleoceanographic
events registered at Site 545, Mazagan Plateau, support this new hypothesis and
illustrate the potential complexity of correlation of organic-rich deposits in
which local influences have been greater than global ones. This long, narrow,
and continuous carbonate gulf disappeared at the end of the Albian with the
arrival of southern waters from the Meridional South Atlantic (MSA), and the
South Atlantic became consolidated as a proto-ocean.
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Carnets Geol., vol. 24, no. 2, p. 29-74
Online since January 20, 2024
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Paleoenvironmental changes preceding the onset of the Messinian
salinity crisis in the western Mediterranean Sea (pre-evaporitic Messinian of
the Melilla-Nador Basin, NE Morocco)
Hanane BAHAJ, Nadia BARHOUN, Naima BACHIRI TAOUFIQ, Jihad RAHMOUNA, Soukaina TARGHI, Naima BERRY, Jean-Pierre SUC & Speranta-Maria POPESCU
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[1,534 KB]
| DOI: 10.2110/carnets.2024.2401
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Abstract: In order to contribute
to the understanding of the evolution of marine and continental environments, preceding the onset of the Messinian salinity crisis in the western Mediterranean, we
conducted an integrated study of the pre-evaporitic Messinian sedimentary series in the Melilla-Nador basin. Three sections have been carried out in the marl-diatomite
series and were the subject of a detailed biostratigraphic and palynological study. The study of planktonic foraminifera, pollen, dinocysts, and palynofacies allowed us
to characterize the evolution of these environments. From 6.83 to 6.52 Ma, the marine environment was relatively open, calm, probably subject to the action of upwellings
and received periodic continental inputs. Starting 6.52 Ma, the abundance and diversity of planktonic foraminifera decreased. Continental inputs gradually dominate,
alternating with marine ones, and reflecting a succession between proximal and distal neritic environments. The surface water conditions were warm. After 6.35 Ma, began
the degradation of marine conditions. The continental environment shows an open vegetal landscape dominated by herbaceous plants, reflecting a tropical to arid
subtropical climate, slightly less dry than that of the South Rifian Corridor. This study confirms the existence of several parameters that contributed to the
deposition of the cyclical marl-diatomite series: on the one hand, the hot and dry climate favored the reduction of the plant landscape and therefore erosion
(continental inputs); on the other, the tectonics (volcanism and uplift).
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Carnets Geol., vol. 24, no. 1, p. 1-27
Online since January 17, 2024
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