â â â  abstract â  in this study, 129 samples of the qom formation in kaltakeh, south east mahneshan, were investigated. the thickness of qom formation in the examined section is 565m and comprises of limestone, sandy limestone, marl, shale and argillaceous limestone . at this locality, the qom sediments disconformably overlies the lower red formation and underlies the upper red formation. amon...

The Open University's repository of research publications and other research outputs Calcification and growth processes in planktonic foraminifera complicate the use of B/Ca and U/Ca as carbonate chemistry proxies Journal Article (2016). Calcification and growth processes in planktonic foraminifera complicate the use of B/Ca and U/Ca as carbonate chemistry proxies. Copyright and Moral Rights fo...

[1] Fossil foraminifera are critical to paleoceanographic reconstructions including estimates of past episodes of methane venting. These reconstructions rely on benthic foraminifera incorporating and retaining unaltered the ambient isotopic compositions of pore fluids and bottom waters. Comparisons are made here of isotopic compositions of abundant live and fossil foraminifera (Uvigerina peregr...

A 5'-terminal region of 1600-1800 base pairs was amplified, cloned, and sequenced in the large subunit rDNA (LSU rDNA) of four species of foraminifera. These sequences were compared with the homologous regions of 16 eukaryotic taxa in order to establish the phylogenetic position of foraminifera. Analysis of 610 unambiguously aligned bases shows that foraminifera branch closely to plasmodial and...

Foraminifera have one of the best known fossil records among the unicellular eukaryotes. However, the origin and phylogenetic relationships of the extant foraminiferal lineages are poorly understood. To test the current paleontological hypotheses on evolution of foraminifera, we sequenced about 1,000 base pairs from the 3' end of the small subunit rRNA gene (SSU rDNA) in 22 species representing...

Larger symbiont-bearing foraminifera are prominent and important producers of calcium carbonate in modern tropical environments. With an estimated production of at least 130 million tons of CaCO(3) per year, they contribute almost 5% of the annual present-day carbonate production in the world's reef and shelf areas (0-200 m) and approximately 2.5% of the CaCO(3) of all oceans. Together with non...

Paleocene–Eocene warming and changes in oceanic hydrography should have significantly impacted the ecology of marine microorganisms, both at the surface and on the seafloor. We analyzed several key characteristics of foraminifera from two Shatsky Rise (ODP Leg 198) cores spanning the P/E boundary including the maximum test diameters of the largest calcareous trochospiral benthic foraminifera an...

Major negative oxygen isotopic anomalies in planktonic foraminifera are associated with deep-sea anoxic mud layers (sapropels) deposited 9000 and 80,000 years ago in the eastern Mediterranean. The isotopic depletion in surface-dwelling foraminifera is significantly greater than in mesopelagic foraminifera. This difference in isotopic response suggests that surface-water salinities were drastica...

This paper focuses on modelling and visualisation of mineral shells of foraminifera (unicellular aquatic, mainly marine, organisms). Our recent model follows the moving reference approach of theoretical modelling of foraminiferal shells. This model introduces three important aspects of simulations, i.e. non-circular chamber shapes (in 2D), allometry of chambers and three dimensional simulation ...