the asmari formation is a thick carbonate sequence in zagros foreland basin. it was deposited during oligocene – early miocene ages. in order to interpret the depositional environment and sequence stratigraphy, firuzabad section were compared with 4 sections of asmari formation in the zagros basin. four different sub environments were identified in the asmari formation based on microfacies anal...

24 25 Chemical weathering and mechanical erosion are first order processes of long-term 26 tropical morphogenesis, which is still poorly deciphered for lack of time constraints. We 27 address this issue by laser-probe 39 Ar40 Ar dating of generations of cryptomelane [K128 2Mn8O16, nH2O] from the manganese ore deposit of Tambao in northern Burkina Faso. This 29 Mn deposit results from the superg...

Fossils assigned to the predominantly deep-sea asteroid family Benthopectinidae Verrill, 1894 are described and their affinities reappraised. Detailed comparative morphology of ambulacrals, adambulacrals marginal ossicles has revealed that only some extinct taxa fall within morphological range modern representatives family. These include Jurapecten hessi Gale, 2011, J. infrajurensis sp. nov. (b...

This study documents diversity decline in a once-speciose rodent clade, the family Aplodontidae, and evaluates the potential influence of three commonly suggested controls on diversity: climate change, floral change, and competitive interactions. Aplodontids first appeared in the late Eocene, diversified during the early Oligocene, declined precipitously at the end of the Oligocene such that st...

Ocean Drilling Program holes 744A and 748B represent key sections for calibration of Southern Ocean Eocene^ Oligocene biostratigraphic zonations. Sites 744 and 748 were above the carbonate compensation depth throughout this time interval and contain good planktonic foraminiferal, calcareous nannofossil, and diatom biostratigraphic records. In particular, the Southern Ocean diatom biostratigraph...

A 13-million-year continuous record of Oligocene climate from the equatorial Pacific reveals a pronounced "heartbeat" in the global carbon cycle and periodicity of glaciations. This heartbeat consists of 405,000-, 127,000-, and 96,000-year eccentricity cycles and 1.2-million-year obliquity cycles in periodically recurring glacial and carbon cycle events. That climate system response to intricat...

U-Pb ages obtained on zircons from the investigated migmatites place new constraints on the evolution of the crustal rocks in the Takab area. SHRIMP U-Pb dating of inherited zircon in the melanosome parts of mafic migmatites from the Takab complex gives a discordant age with an upper intercept of 2961±72 Ma (MSWD=0.5) and a lower intercept of 24.2±5.7 Ma (MSWD=1.7). In the concordia diagram, th...

The fossil record and systematics of phlebotomid sand flies, vectors of leishmaniasis and arbovirus in several regions of the world, strongly support that living genera existed long before the Oligocene (38 million years, myr). A common Phlebotominae ancestor was present in the Triassic period before the separations of continents (248 myr).