The Neogene from Sites 959 and 960 contains about 20 ostracode species, including Cytherella serratula, Buntonia mackenziei, Bradleya dictyon, Agrenocythere hazelae, Poseidonamicus major, Pseudobosquetina mucronalatum, Legitimocythere acanthoderma, and Henryhowella melobesioides. These species characterize the psychrosphere that was in place in the Gulf of Guinea by at least early Miocene time.
Neogene— Quaternary sedimentary basins in SE Spain contain a record of the geodynamic evolution of the Internal Zone of the Betic Cordillera. The basement of the Internal Zone is composed of Palaeozoic and Mesozoic metasediments which have undergone variable degrees of metamorphism. The External Zones consist of largely unmetamorphosed sedimentary rocks which were deposited on the SE margin of the Iberian Plate during the Mesozoic and Early Cenozoic. Westward tectonic emplacement of these terranes onto the Iberian Plate took place between the end of the Palaeogene and the middle Miocene. In this paper, we investigate the late Miocene (Tortonian‐Messinian) stratigraphy of two basins in the Internal Zone — the Tabernas‐Sorbas and Huercal Overa Basins. We also consider some recently‐acquired structural data. The Tabernas‐Sorbas and Huercal Overa Basins are east‐west trending depressions bounded to north and south by sierras in which basement rocks are exposed. The basins contain very similar sedimentary successions in which planktonic foraminifera have been preserved. However, the faunal composition is very variable, and the observed sporadic and abrupt changes in foraminiferal populations imply palaeo‐ecologic and palaeo‐oceanographic instabilities which may be associated with local tectonism. Stratigraphic markers were affected by these changes, making precise dating difficult near the Tortonian‐Messinian boundary. Our data indicate that Messinian rocks are more widely distributed than has hitherto been suspected. A Messinian age for the prominent coral limestones in the Tabernas‐Sorbas Basin has long been accepted; similar coral limestones in the Huercal Overa Basin have previously been dated as Tortonian. However, our data show that these carbonates are of Messinian age in both basins. The origin and development of the Tabernas‐Sorbas and Huercal Overa Basins have previously been interpreted in a number of ways. Many (but not all) models favour strike‐slip movement on NE‐SW or east‐west trending basin‐bounding faults. The formation and deformation of the basins occurred during the Tortonian and Messinian, at the same time as the uplift of the sierras. The sierras are here interpreted to represent structural culminations above westward‐verging, deep‐seated thrust faults, and the basins to be lateral folds (or lateral ramps, i.e. oriented parallel to the thrust transport direction). The east‐west trending strike‐slip faults at the margin of the Sorbas‐ Tabernas Basin may be compatible with such a model. Major NE‐SW trending, left‐lateral wrench faults have been described in this area. These faults cut through late Miocene and Pliocene deposits, and are still active at the present day. Although these faults were initiated during the late Miocene, they do not appear to have influenced the development of the Tabernas‐Sorbas and Huercal Overa Basins during the early Tortonian.
La remise en état de la falunière de Grignon a permis de lever, pour la première fois, une coupe presque complète du Lutétien moyen du Bassin de Paris sous son faciès meuble. À cette occasion, des études sédimentologiques et paléontologiques ont été engagées ; les résultats des études sur les ostracodes sont présentés ici. Huit échantillons ont été analysés, plus de 6000 valves ou carapaces ont été recueillies et 87 espèces ont été distinguées dont une vingtaine laissées en nomenclature ouverte. Trois nouvelles espèces sont décrites : Paracypris keiji n. sp., Neocytherideis labyrinthoidea n. sp. et Grinioneis pachycosta n. sp. La répartition verticale des ostracodes dans les faluns de Grignon semble sans signification stratigraphique. Par contre, les associations d'ostracodes du Lutétien sont caractéristiques, aussi bien par rapport à celles de l'Yprésien que par rapport à celles de l'Auversien ou du Bartonien. Au point de vue environnemental, la diversification spécifique reflète celle des niches écologiques et la richesse en individus témoigne de l'abondance de la nourriture. Les ostracodes indiquent que la mer du Lutétien était peu profonde (de quelques décimètres à quelques mètres, probablement) et que ses eaux étaient bien éclairées, peu agitées et chaudes, au moins en été. La température estivale de l'eau était au moins égale à celle de la Méditerranée actuelle. Au point de vue paléogéographique, la parenté entre les faunes galliques (bassins de Londres, du Hampshire, de Bruxelles et de Paris) paraît beaucoup plus étroite qu'entre n'importe lesquelles de ces faunes galliques et celles du bassin d'Aquitaine. Ainsi, la majorité des espèces du Lutétien anglais sont connues dans celui du Bassin de Paris alors que la proportion des espèces communes au Bassin de Paris et au bassin nord-aquitain est faible.
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