Search results for "Neogene"

Sedimentary and diagenetic markers of the restriction in a marine basin: the Lorca Basin (SE Spain) during the Messinian

1998

Abstract The Lorca Basin (southeastern Spain) is part of a chain of small marginal Neogene basins located in the structurally active Betic area. The Upper Miocene (Messinian) sequence is composed of a thick diatomite-bearing series (Tripoli Unit) overlain by the Main Evaporites, analogous to the classical succession that records the main events during the Salinity Crisis in the Mediterranean region. The shallow restricted conditions of this region amplified the sedimentary responses to local and global forcings. An integrated approach using sedimentology, micropalaeontology, stable isotope geochemistry and organic geochemistry has been applied to the Tortonian/Messinian succession of the Lo…

Growth pattern of underlithified strata during thrust-related folding

2004

Abstract Asymmetric anticlines with overturned or steeply dipping forelimbs and gently dipping backlimbs are generally interpreted as thrust-related folds. Fold asymmetry occurs as a consequence of forelimb rotation. If deformation takes place in environments dominated by submarine sedimentation, the limbs coincide with the slope (depositional surface) and rotation reflects slope steepening. If folds are nucleated in poorly or unlithified deposits, growth geometry also depends on the properties of the media, such as cohesion and the angle of internal friction. For cohesionless deposits, the tilting of the slope influences the equilibrium of the soft sediments, resulting in gravity-driven fl…

The interation of compressional and extensional tectonics during the Sicily Chain building

2012

The weak and superfast Cretan detachment, Greece: exhumation at subduction rates in extruding wedges

2002

Low-angle normal faults (detachments) are only efficient agents for bringing rocks from 40–>100 km depth back to the Earth’s surface if they operate with extreme slip rates exceeding 20 km Ma −1 . Here we propose a slip rate of ≧20–30 km Ma −1 for the Cretan detachment in the Aegean, Greece. The Cretan detachment and the subjacent subduction thrust bounded an extruding wedge above the Miocene Hellenic subduction zone. During exhumation the high-pressure rocks in the wedge were not significantly deformed. Very low shear coupling at the bounding faults (which are therefore weak) is needed to prevent significant deformation in the extruding wedge. The proposed slip rate of ≧20–30 km Ma −1 is s…

Fossil representatives of the family Greenideidae (Hemiptera, Aphidoidea) from the Miocene of Europe

2002

Abstract Four new aphid species (Hemiptera, Aphidoidea, Greenideidae) are described on the basis of imprints in oil-shales from the Miocene of Europe (Rubielos de Mora, Spain; Vishnevaya Balka 〚Stavropol〛, Russia): Eutrichosiphum europaeum nov. sp., Greenidea hispanica nov. sp., Greenideoida (Pentatrichosiphum) turolensis nov. sp. and Mollitrichosiphum rubusensis nov. sp. All the taxa are placed within recent genera of the subfamily Greenideinae. Miocene representatives of this subfamily have been found in the south of Europe. Later changes of climatic conditions limited its geographic range to south-eastern Asia, where it is now represented by over 130 species of seven genera.

Patterns of Old World Hipparionine Evolutionary Diversification and Biogeographic Extension

1990

Hipparionine horses have long been united evolutionarily by the presence of three toes per digit, having high crowned cheek teeth with cement, and isolated proto-cones on upper cheek teeth (Christol, 1832). Geochronologically they have further been recognized as the preeminent large mammal “index” fossils for late Neogene Old World deposits. Their abundance in later Neogene mammal faunas has prompted the production of a staggering body of systematic and interpretive literature during the last 150 years. In the last 40 years there has been an increasing number of attempts to reorganize parts of Old World hipparionine systematics by regional studies of variable scope including Europe in gener…

Palaeophylloxera nov. gen., The firstfossil specimen of the family Phylloxeridae (Hemiptera, Phylloxeroidea); Lower Miocene of Spain

1999

A fossil alate aphid from the Lower Aragonian (Lower Miocene) deposits of Rubielos de Mora (Teruelprovince) in eastern Spain is described as Palaeophylloxera seilacheri nov. gen. and sp. It is the first fossil specimen described within the Family Phylloxeridae. The principal differences between this genus and other representatives of the Phylloxeridae (and also the extinct Elektraphididae) are the apparent presence of an oblique vein on the hind wing, the presence of distinctly visible transverse striae on antennal segment III, and the peculier venation on the fore wings.

Eomyops noeliae sp. nov., a new Eomyidae (Mammalia, Rodentia) from the Aragonian of Spain

2009

Abstract A new species of Eomyops, Eomyops noeliae, is described. from the locality MT-20A (Morteral section, Magro basin, eastern Spain). It is intermediate in size between the large eomiid, E. hebeiseni, and the small species of the group E. catalaunicus, E. bodvanus and E. oppligeri. The age range is Lower Aragonian. MT-20A is located between deposits that contain Megacricetodon primitivus and M. collongensis. Morphologically, E. noeliae sp. nov. is clearly different from the rest of species of the genus, due to an important reduction of the lingual anteroloph of M1,2,3 and the labial anterolophid of M3. The lower incisor shows two parallel ridges along the enamel like the type species o…

The use of insular vertebrates in palaeogeographic reconstructions.

2009

Ba/Ca evolution in water masses of the Mediterranean late Neogene

2008

[1] A Mediterranean composite sedimentary record was analyzed for Ba/Ca ratios on carbonate shells of Orbulina universa planktonic foraminifer (Ba/Ca)carb providing the opportunity to study and assess the extent of freshwater inputs on the basin and possible impacts on its dynamics during the Tortonian to Recent period. A number of scanning electron microscope analyses and auxiliary trace element measurements (Mn, Sr, and Mg), obtained from the same samples, exclude important diagenetic effects on the studied biogenic carbonates and corroborate the reliability of (Ba/Ca)carb ratios in foraminifera calcite as indicators of seawater source components during the studied interval. A long-term t…