Latest Barremian - early Aptian chronostratigraphy and sedimentary evolution of the northwestern Maestrat Basin

Since the second half of the 19th century, the Arcillas de Morella Formation (late Barremian) has yielded abundant vertebrate fossil material from several outcrops of the Morella region (Maestrat Basin, Castellon, eastern Spain). Several historical specimens of fossil reptiles, so far unpublished or not studied in detail, are housed in the Museo Nacional de Ciencias Naturales in Madrid (Spain). In fact, many of the first dinosaur specimens discovered in Spain, from Morella, are part of the vertebrate palaeontology collection of that institution. Herein, this sauropod material is described and discussed in order to study the diversity of the sauropod fauna during the late Barremian on the Maestrat Basin. The specimens include both axial and appendicular elements. The systematic study of this material suggests the presence of indeterminate titanosauriforms, some of which have somphospondylan and ‘laurasiform’ affinities. Comparative analysis of two isolated humeri from Morella (MNCN 59703 and MNCN 68484) and a humerus subsequently found in this area, indicates the presence of three titanosauriform taxa in the upper Barremian of the Maestrat Basin, two of which have somphospondylan affinities. The sauropod diversity of the Arcillas de Morella Formation recognized herein, in particularly considering the titanosauriforms, is greater than that previously considered, at least three taxa.

Early Cretaceous (late Barremian – early Aptian) fissure fill deposits near Balve, North Rhine Westphalia, Germany, have yielded a rich continental vertebrate fauna over the course of the last two decades. More than 250 fragmentary specimens, including more than 150 osteoderms (i.e., granicones), represent the late Early Cretaceous helochelydrid Helochelydra nopcsai, which had previously been reported from the UK, France, and Spain. The new material mostly differs from that from the type section by exhibiting a reduced to absent entoplastral scute and by displaying distinct cranial scute sulci, both of which are interpreted as intraspecific variation. Although morphological insights are limited, the new material reveals that the visceral cavity extends anteriorly and posteriorly to the bridge, a relatively novel feature previously reported for an eclectic mix of compsemydids, pleurosternids, and other helochelydrids. The available sample of granicones reveals great shape diversity, but a morphometric analysis concludes that no distinct morphotypes exist.

Temperature controlled deposition of early Cretaceous (Barremian–early Aptian) black shales in an epicontinental sea

Diverse palynomorph assemblages of spores, pollen grains and dinoflagellate cysts have been yielded from the palynological analyses of 115 ditch cutting samples covering the Valanginian– Cenomanian succession encountered in Hamza-1X well, Matruh Basin, north Egypt. The complex sit- uations in the north Western Desert requires more revisited palynozones for better understanding of the subsurface successions therein. Consequently, the first downhole palyno-events will be very helpful in solving some issues concerning the age determination and correlation. Seventy palynomorph species (47 spores and pollen grains; 23 dinoflagellate cyst species) were identified from all the productive samples which used to divide the studied succession into numerous sporomorph and dinoflagellate biozones based on the last occurrence datum for the recovered marker taxa. Four sporomorph inter- val biozones and six dinoflagellate cyst interval biozones were differentiated from the same studied stratigraphic succession. The four sporomorph biozones are presented, in ascending order as follows: Aequitriradites spinulosus and Impardecispora apiverrucata Interval Zone (late Valanginian– early Barremian), Pilosisporites trichopapillosus I. Z. (late Barremian), Murospora florida I. Z. (early Aptian–late Aptian), and Elaterosporites klaszii I. Z. (early Albian– early Cenomanian). The seven dinoflagellate cysts biozones are Muderongia simplex I. Z. (late Valanginian–early Barremian), Pseudoceratium anaphrissum I. Z. (late Barremian– early Aptian), Cribroperidinium edwardsii I. Z. (early Aptian), Subtilisphaera perlucida I. Z. (late Aptian), Oligosphaerdium complex I. Z. (early– late Albian), Dinopterygium cladoides and Coronifera oceanica Assemblage Zone (early Cenomanian). From the palaeoclimatic point of view, the studied interval could be differentiated into two climatic intervals; the lower arid interval that comprises the Alam El Bueib Formation and dominated by the arid xerophyte elements like Sphaeripollenites and Classopollis. The upper humid interval represents the Alamein, Dahab, Kharita and Bahariya formations that is dominated by the humid hygrophyte elements, such as Murospora, Crybeolsporites, Elaterosporites, Afropollis and Deltoidospora.

Cretaceous aeolian deposition is important for understanding variations of the tropical−subtropical atmospheric circulation under the greenhouse background. Nevertheless, detailed records revealing the response of aeolian deposition to rising atmospheric CO2 are still lacking. To shed light on their linkage, we examined the Early Cretaceous stratigraphic evolution of the Hekou Group in the Baiyin-Jingyuan Basin, northern China, using multiple methods. The results indicate that the lower Hekou Group is characterized by a transition from submerged alluvial to shallow lacustrine deposition. Overlying these facies is loess-like deposition without bedding, distinguished by grain-size distribution, surface microtextures, and geochemical analysis, which is followed by palustrine deposition. In the palustrine deposition, aeolian sand-dune and sand-sheet deposition can be identified, which gradually developed upward in the Hekou Group, with intercalated wet interdunes, damp interdunes, and pebble-sand sheetflood beds. Finally, aeolian sand dunes and sand sheets dominated the upper Hekou Group. Overall, the upward-changing facies indicated the development of aeolian deposition from an aqueous environment, revealing a long-term paleoclimatic shift from semi-humid, semi-arid to extremely arid, which reflects the expanded aeolian activity in East Asia during the Early Cretaceous. Furthermore, various records were combined to investigate the expanding aeolian activity in East Asia, which indicates a west−east-trending arid belt that was wider than the modern counterpart during the late Barremian−Early Aptian and late Aptian−Early Albian, respectively. These stepwise expansions of aeolian activity were mainly driven by rising atmospheric CO2, which strengthened the subsiding branches of Hadley circulation and the subtropical high, eventually leading to intensified aridification.

The Shah Kuh Formation, a latest Barremian – Early Aptian carbonate platform of Central Iran (Khur area, Yazd Block)

An Early Cretaceous mesofossil flora is described from the lower part of the Almargem Formation (late Barremian-early Aptian) from Torres Vedras (NE of Forte da Forca), Portugal. The flora is the oldest mesofossil flora containing angiosperm remains to be described in detail based on well-preserved flower, fruit and seed remains. In addition to angiosperms, the mesofossil flora also includes megaspores, sporangia and tiny leaves of spore-bearing plants. There are also twigs, cone fragments and seeds of conifers and seeds assigned to the BEG group. In total about 100 species have been distinguished. Most abundant in terms of plant fragments identified, are spore-bearing plants and conifers. Although only about 18 % of the specimens can be attributed to angiosperms, angiosperm diversity is unexpected high considering the age of the flora. Angiosperms account for about 62 % of all species recognized. Angiosperm diversity is mainly at the level of ANA-grade angiosperms, eumagnoliids and in a few cases early diverging lineages of monocots. Eudicots are subordinate. Twenty new genera and 28 new species of angiosperms are established (Anaspermum operculatum gen. et sp. nov., Appofructus nudus gen. et sp. nov., Appomattoxia minuta sp. nov., Burgeria striata gen. et sp. nov., Canrightia elongata sp. nov., Choffaticarpus compactus gen. et sp. nov., Dejaxia brevicolpites gen. et sp. nov., Dinisia portugallica gen. et sp. nov., Eckhartia brevicolumella gen. et sp. nov., Eckhartia longicolumella sp. nov., Eckhartia intermedia sp. nov., Eckhartianthus lusitanicus gen. et sp. nov., Eckhartiopsis parva gen. et sp. nov., Gastonispermum antiquum sp. nov., Goczania rugosa gen. et sp. nov., Goczania inaequalis sp. nov., Goczania punctata sp. nov., Ibrahimia verminculata gen. et sp. nov., Juhaszia portugallica gen. et sp. nov., Kempia longicolpites gen. et sp. nov., Kvacekispermum costatum sp. nov., Mcdougallia irregularis gen. et sp. nov., Nicholsia brevicolpites gen. et sp. nov., Piercipollis simplex gen. et sp. nov., Reyanthus lusitanicus gen. et sp. nov., Samylinaea punctata gen. et sp. nov., Teebacia hughesii gen. et sp. nov., Vedresia elliptica gen. et sp. nov.). Comparison with results of a palynological study from the same horizon that yielded the mesofossil flora shows a marked underestimation of angiosperm diversity in the palynoflora, a pattern that has also been recognized elsewhere.

Supplementary material 2 from: Joyce WG, Evers SW, Ren S, Rollot Y, Schwermann AH (2023) The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones. Fossil Record 26(1): 117-133. https://doi.org/10.3897/fr.26.102128

Figure 4 from: Joyce WG, Evers SW, Ren S, Rollot Y, Schwermann AH (2023) The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones. Fossil Record 26(1): 117-133. https://doi.org/10.3897/fr.26.102128

Summary The Fingerdjupet sub-basin has been an under explored region in the SW Barents Sea. The objective of this study is to investigate the Lower Cretaceous evolution of the Fingerdjupet sub-basin in order to better understand the development of accommodation space through time and its effect on steering and deposition of possible reservoir and source rocks in the area and the link to the neighboring Bjørnøya basin. The methodology includes interpretation of seismic reflection data and generating time structural and thickness maps to investigate the faults for timing, growth, reactivation, and its effect on sediment steering. From the observations we can infer that most of the south-western part of the sub-basin was affected by the Late Jurassic - Early Cretaceous rifting phase. During the Late Hauterivian – Early Barremian, a thick clinoform wedge got deposited in the central part of the basin. Renewed extensional fault activity occurred in the Late Barremian – Early Aptian. By the early Albian the faulting had ceased and a regional unconformity evolved which marked the transition from rifting to tectonic subsidence and the passive infill of a thick Albian marine succession.

Figure 8 from: Joyce WG, Evers SW, Ren S, Rollot Y, Schwermann AH (2023) The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones. Fossil Record 26(1): 117-133. https://doi.org/10.3897/fr.26.102128

Figure 6 from: Joyce WG, Evers SW, Ren S, Rollot Y, Schwermann AH (2023) The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones. Fossil Record 26(1): 117-133. https://doi.org/10.3897/fr.26.102128

Figure 2 from: Joyce WG, Evers SW, Ren S, Rollot Y, Schwermann AH (2023) The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones. Fossil Record 26(1): 117-133. https://doi.org/10.3897/fr.26.102128

Figure 1 from: Joyce WG, Evers SW, Ren S, Rollot Y, Schwermann AH (2023) The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones. Fossil Record 26(1): 117-133. https://doi.org/10.3897/fr.26.102128

Supplementary material 1 from: Joyce WG, Evers SW, Ren S, Rollot Y, Schwermann AH (2023) The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones. Fossil Record 26(1): 117-133. https://doi.org/10.3897/fr.26.102128