Micropalaeontology foraminifera Research Papers - Academia.edu (original) (raw)

This is the final scientific work of Dick Cifelli. I expect it will be of considerable interest because it spans over 150 years of foraminiferal research. It is not just an historical account, but delves into the philosophy ofclassifications and reveals a good deal about the people who made them. Over the 20 years that we were curators together of the U.S. National Museum's foraminiferal collection, we discussed the philosophy of clas sification and the resulting schemes many times. His mind had an ability to grasp the "big picture," an asset which is truly rare.

Over the last centuries, coastal areas have experienced dramatic degradations of their environmental quality, which has led to a huge reduction of marine biodiversity. The objective of the present study was to use geochemical parameters and benthic fossil foraminifera to assess environmental changes that have occurred over the last 200 years in a harbour area (Boulogne-sur-Mer, Northern France) heavily modified by human activities. A multidisciplinary approach including major and trace metals, grain-size, total organic carbon and benthic fossil foraminifera, has been performed on a 33-cm long core. The dating was carried out using the activity of 210 Pb and 137 Cs. Embayment of the area and increase of trace metals concentrations induced a shift in benthic communities. Human activities modified a sandy nearshore bank, colonized by typical marine foraminiferal species, such as Cribroelphiudium excavatum, into a sheltered environment, dominated by brackish end-members, such as Haynesina germanica. Along the sedimentary record, the interaction between meiofaunal and geochemical elements made it possible to distinguish between a pre-impacted period and an industrial period. The upper part of the core reflects better ecological conditions, indicating an environmental recovery. Our results provide baselines for future environmental bio-monitoring in the area.

Slump is a movement of unlithified mass sediment gravity flow from particular bathymetry into deeper zone of the sea which caused by slope instability or earthquake. The slope instability is caused by rapid mass sediment distribution. Later, it would create a steep body of sediment mass then trigger the landslide. The sliding mechanism is producing some internal deformation such as folding and thrust fault on its anatomy. Slump also might indicate the paleomorfology or paleobasin and the direction of sediment transport. Located on the eastern side of the East Jiwo Hill – Bayat, Central Java, Temas Hill is an ideal spot for observing the slump and its mechanism. The exact outcrop position is on the east side of Temas Hill and it has never been observed before. Clastic limestone with shallow marine fossil content is dominated the whole research zone. These rocks types are presenting Oyo Formation which builds the Southern Mountain of East Java stratigraphy. Three methods are used for revealing the slump. Measuring section method is used to define the stratigraphic unit and its thickness. Structural data for interpreting the transport aim, then the Paleontological analysis to reveal the source of slump material. The output of this research reveals some new information. Stratigraphically, the slump consists of many units and contain lots of Foraminifera - Globigerinid, Paleonumulites, Cycloclypeus sp in mudstone - grainstone which indicate the source of the slump. Local NW – SE normal fault presumably triggering the huge mass of sediment to move and create the slump.

- by Johan Edwart L. Hutabarat and +1
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- Geology, Paleontology, Sedimentology, Stratigraphy

Formation in the Zin Valley (southern Israel), Ein Mor (EM) and Hor HaHar (HH) containing the Cretaceous-Tertiary (K/T) boundary, have been analysed for benthonic foraminifera within the framework of nannofossil and planktonic... more

Foraminifera have been successful inhabitants of every aquatic environment from deep oceans to brackish water lagoons, estuaries and even rarely in fresh water streams, lakes, etc. In order to know their distribution in different offshore habitates, the present study has been undertaken 9 stations starting from Thirayshapuram to Vanthivu in two transects with necessary precautions from Gulf of Mannar, Tuticorin. Twenty five bottom sediments and water samples were collected. Benthic foraminiferal taxa belonging to four sub orders (Textularina, Milolina, Lagenina and Rotalina), 5 super families, 10 families, 11 sub families, 14 genera and 29 species have been identified. Among the 29 species, five species Ammonia beccarii, A. dentate, Spiroloculina communis, Quinquloculina seminulam and Pararotalina nipponica are considered to be abundant species of the present study. Higher diversity and population of foraminifera is noticed in the samples collected in the stations 2 to 8, because of their favorable niche. In the stations 1 and 9 the lower diversity and population may be due to the winnowing action of the waves. The substrate of present study area is seen to consist of Silty clay, Sand, Silty sand and Sand. The most accommodative substrate for higher population is Silty sand. The main ecological parameters, which govern the distribution of foraminifera of the present study area, are organic matter content and nature of the substrate. The other water parameters like temperature, salinity, pH and dissolved oxygen do not show any appreciable spatial variation among different stations and hence they do not have any ecological significance in the distribution of foraminifera.

- by Ramasamy Prabhakaran
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- Micropalaeontology foraminifera

Semburan gunung lumpur telah menarik perhatian orang sejak dulu dan dikaitkan dengan legenda yang berkembang di masyarakat. Di daerah Purwodadi dan sekitarnya keberadaan gunung lumpur banyak ditemukan. Secara fisiografi daerah ini termasuk ke dalam Zona Fisiografi Randublatung yang dibatasi di bagian utara oleh Zona Rembang dan di bagian selatan oleh Zona Kendeng. Penelitian dilakukan pada Gunung lumpur (bledug) Kesongo yang terletak di Desa Kesongo dengan koordinat 7o9’ 19,93” LS – 111o 15’ 14,82” BT dan Gunung lumpur Crewek yang terletak di Desa Crewek dengan koordinat 7o 9’ 4,62” LS – 111o 6’ 47,00” BT. Beberapa contoh lumpur, batuan dan fragmen batuan seperti foraminiferal grainstone, batupasir karbonatan, fosil tulang invertebrata serta koral diambil
dari kedua tempat tersebut untuk dilakukan analisa paleontologi. Kedua gunung lumpur ini mempunyai posisi dan kenampakan morfologi yang berbeda. Gunung lumpur Kesongo berada di dataran bergelombang, berbentuk kubah berdiameter 1,3 km yang terletak di Antiklin Gabus dan
menerobos satuan batunapal yang tersingkap di permukaan sekitar gunung lumpur tersebut. Gunung lumpur Crewek berada di dataran, berbentuk bukit kecil dengan diameter kurang dari 100 m dan dikelilingi oleh endapan limpah banjir. Hasil analisa paleontologi pada lumpur dari Kesongo
menunjukkan kumpulan fosil foraminifera planktonik yang mempunyai dua kisaran umur yaitu N18-19, N14 dan N7-N9, sedangkan analisa foraminifera besar dari fragmen batuannya menunjukkan umur Miosen Awal – Tengah. Kumpulan fosil dari batunapal menunjukkan kisaran N17-19. Lumpur Crewek menunjukkan kisaran N18, N12 dan N7-8. Dari kumpulan fosil tertua yang terdapat pada masing-masing gunung lumpur maka diperkirakan lumpur di Gunung lumpur Kesongo berasal dari Formasi Tawun bagian bawah dengan fragmen batuan yang diterobos berasal dari Formasi Wonocolo dan Ngrayong, sementara batunapal yang berada di sekitarnya termasuk ke dalam Formasi Mundu. Lumpur pada Gunung lumpur Crewek berasal dari Formasi Tawun.

- by Salahuddin Husein and +1
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- Paleontology, Stratigraphy, Structural Geology, Tectonics

A phylogeny of 54 Recent and fossil species of Soritacea (Foraminifera) was used to test the hypothesis that endosymbiosis has driven the evolution of the clade. Endosymbiosis with photosynthetic eukaryotes is the plesiomorphic condition for the entire clade Soritacea. Living species dwell in tropical-subtropical, shallow-water habitats and are characterized by the possession of rhodophyte, chlorophyte, or dinophyte photosymbionts. Two distinct changes in endosymbiont type are recognized when endosymbiont type is mapped in the cladogram of Soritacea: (1) a change from rhodophyte to chlorophyte endosymbionts occurred in the stem lineage of the least inclusive clade containing New clade B, Orbiculinida, and Soritida; and (2) a change from chlorophyte to dinophyte endosymbionts occurred in the stem lineage of the least inclusive clade containing New clade G, New clade H, New clade I, Sorites, Amphisorus, and Orbitolites. When habitat and ontogeny are optimized on the cladogram of Soritida, the acquisition of dinophyte endosymbionts appears as a key innovation that facilitated a switch in habitat from free-living to attached living on nonphytal and phytal substrata. A subsequent change in the attached habitat from nonphytal to predominantly phytal (seagrasses and macroalgae) substrata is accompanied by a peramorphic trend in the megalospheric tests. The diversiﬁcation (adaptive radiation) of the crown Soritida subclade resulted from the interplay between the acquisition of a key innovation (dinophyte endosymbionts) and the subsequent change in the ecology of the group (radiation to phytal substrates).

- by Susan Richardson
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- Benthic foraminifera, Foraminifera, Micropalaeontology foraminifera

- by chaima grira
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- Geology, Geophysics, Paleoclimatology, Paleoceanography

Aptian – Albian planktonic foraminifera were studied from seven boreholes MK 1, MK 2, MK 3, MK 4, MK 5, MK 6 and MK 7 drilled in Cote d'Ivoire sedimentary basin. The latest Aptian was identified in holes by very small size planktonic assemblages represented by Hedbergella maslakovae, Hedbergella similis Globigerinelloides duboisi and Globigerinelloides clavatus. Albian planktonic assemblage was characterized by Ticinella primula, Ticinella roberti, Ticinella

Despite the well documented clear relationships between modern assemblages and their ecological controls, there is scarce information on the distribution patterns of benthic foraminifera in paralic temperate environments of the Southeast Pacific. This is the main constraint for the implementation of these organisms as bioindicators of ecological, sedimentological, palaeoecological and physical -chemical parameters in these latitudes. In this context, the aim of this work is to record, for first time, the distribution of benthic foraminifera within a channel of a temperate estuary from Southeast Pacific and its relation to the salinity parameter.

- by Leonardo D Fernández
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- Diversity, Chile, Benthic foraminifera, Estuarine Ecology

Biostratigraphic analysis of the Eocene-Oligocene transition (E-O) at the Menzel Bou Zelfa and Jhaff composite section in the Cap Bon Peninsula (North East Tunisia) allowed us to recognize a continuous planktic foraminiferal biozonation: E14 Globigerinatheka semiinvoluta Zone, E15 Globigerinatheka index Zone, E16 Hantkenina alabamensis Zone and O1 Pseudohastigerina naguewichiensis Zone. A quantitative study of benthic and planktic foraminifera assemblages was carried out and the richness and diversity of foraminifera allowed us to reconstruct the paleoenvironmental evolution from marine to terrestrial environments. From the Eocene E14 Zone, the foraminiferal association characterizes a relatively warm climate with considerable oxygen content and a dominance of keeled and spinose planktic foraminifera, which became extinct at the E/O boundary, possibly due to cooling of the planktic environment. Nevertheless, the small benthic foraminifera do not show an extinction event at the Eocene/Oligocene (E/ O) boundary, indicating that the benthic environment was not significantly affected. In the basal Oligocene O1 Zone, the benthic environment changes to a shallower setting due to cooling of the climate. These changes generated a remarkable dominance of globular forms in the planktic environment. Small benthic foraminifera apparently have a gradual extinction event, or more likely a gradual pattern of local disappearances, that could have been caused by the Oi1 glaciation.

- by shayma grira and +1
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- Paleoecology, Eocene, Marine Micropaleontology; Marine Paleoenvironments, Micropaleontology, Biostratigraphy

A development of meiofaunal data (foraminifera) from offshore area of West Lombok was conducted on 20 marine sediment samples. The samples were taken out using a grab sampler in 1997. The purpose of this study was to apply the formula of Foraminiferal Index by . Another purpose of this study was to recognize its relation of white sands of Senggigi beach that was dominated by Shlumbergerella floresiana. The result of analysis showed that the value of Foraminiferal Index (FI) was varies between 1.22 and 9.81. The low value of FI (<2) was found at sites that were close to the coastal area. The values FI >2 and <4 occur at five stations that gave indication of limited environment for coral growth. Value of FI >4 that showed good water condition was found in an area surrounding small islands of Gili Trawangan, Gili Meno, Gili Air and southern part of the study area. Based on the identification of foraminiferal specimens, the occurrence of Shlumbergerella floresiana was not abundant as it was accumulated in Senggigi beach. This result showed that this species did not come from samples studied but might come from marine sediment adjacent to the Senggigi beach ABSTRAK Pengembangan data meiofauna (foraminifera) di laut lepas sekitar Lombok Barat telah dilakukan terhadap 20 sampel sedimen dasar laut. Tujuan dari penelitian ini adalah untuk menerapkan rumus Indeks Foraminifera (FI) dari . Tujuan lain dari studi ini adalah untuk mengetahui keterkaitannya dengan hamparan pasir putih Pantai Senggigi yang didominasi oleh cangkang foraminifera, khususnya Shlumbergerella floresiana. Hasil penghitungan menunjukkan nilai Indeks Foraminifera (FI) bervariasi antara 1,22 dan 9,81. Nilai FI rendah (<2) ditemukan pada titik lokasi yang berdekatan dengan pesisir. Nilai FI >2 dan <4 terdapat pada lima titik lokasi yang memberi indikasi lingkungan terbatas bagi pertumbuhan koral. Nilai FI >4 yang menunjukkan kondisi perairan yang bagus dan dijumpai di perairan sekitar pulau-pulau kecil: Gili Trawangan, Gili Meno, Gili Air dan bagian selatan daerah penelitian. Kelimpahan Shlumbergerella floresiana tidak dominan seperti yang terakumulasi di pantai Senggigi. Hal ini menunjukkan spesies tersebut bukan berasal dari sedimen yang diteliti dan kemungkinan berasal dari sedimen yang tidak jauh dari Pantai Senggigi.

- by Kresna Dewi
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- Southeast Asian Studies, Marine Ecology, Ostracoda Systematics, Benthic foraminifera

Below are given some-of the more recent works on fo raminifera that have come to hand.

Shallow carbonated facies of Taleh Zang is settled in Zagros Paleocene (Lorestan basin). According to basin conditions such as depth changes, sedimentation rate and other tectonic and sediment factors, this formation has settled locally along with Amiran, Kashkan and Shahbazan facies with different thickness from semi-deep to deep. Based on carried out studies sediments of Taleh Zang lime formation in Badamak stratigraphy section was measured with 185 m thickness (real thickness). Among 110 samples, 15 genus and 10 species of benthic foraminifera were determined. Regarding carried out studies and introduction of 3 bio zone, including 2 assemblage zones and 1 Acro-zone, the age of late Paleocene (Thanetian) and lower Eocene (Ypresian) were considered for this stratigraphy section.

- by Peiman Rajabi
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- Geology, Iranian Studies, Biostratigraphy, Micropaleontology

Spodnokriedový paleokras v bradle čorštynskej jednotky severne od Zázrivej (pieninské bradlové pásmo, oravský úsek, severné Slovensko) Abstract: New locality with well preserved palaeokarst surface was discovered north of the Zázrivá village in the Orava sector of the Pieniny Klippen Belt. The klippe belongs to the Czorsztyn Succession and is known among the local settlers as "Erdútsky kostol". The outcropping succession starts with red nodular limestone of the Czorsztyn Limestone Formation of the Kimmeridgian to the Middle Tithonian age, followed by the Dursztyn Limestone Formation. The latter consists of red bedded micritic limestones of the Korowa Limestone Member and white micritic limestones of the Sobótka Limestone Member. Stratigraphically, the succession covers the time span from the Kimmeridgian to the Early Berriasian. The Sobótka Limestone Member displays unusual succession of calpionellids and is terminated by uneven palaeokarstic surface domi-nated by hummocky...

- by Roman Aubrecht
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- Albian, Calpionellids, Lower cretaceous, Micropalaeontology foraminifera
- by grira chaima
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- Geology, Geophysics, Paleoclimatology, Paleoceanography

The Neocomian– Barremian sediments (Fahliyan and Gadvan Formations) of the Zagros area consist of limestone and shale and are deposited on a carbonate shelf. We studied the Neocomian–

- by Massih Afghah
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- Micropalaeontology foraminifera

Pelagic ecosystem function is integral to global biogeochemical cycling, and plays a major role in modulating atmospheric CO2 concentrations (pCO2). Uncertainty as to the effects of human activities on marine ecosystem function hinders projection of future atmospheric pCO2. To this end, events in the geological past can provide informative case studies in the response of ecosystem function to environmental and ecological changes. Around the Cretaceous–Palaeogene (K–Pg) boundary, two such events occurred: Deccan large igneous province (LIP) eruptions and massive bolide impact at the Yucatan Peninsula. Both perturbed the environment, but only the impact coincided with marine mass extinction. As such, we use these events to directly contrast the response of marine biogeochemical cycling to environmental perturbation with and without changes in global species richness. We measure this biogeochemical response using records of deep-sea carbonate preservation. We find that Late Cretaceous Deccan volcanism prompted transient deep-sea carbonate dissolution of a larger magnitude and timescale than predicted by geochemical models. Even so, the effect of volcanism on carbonate preservation was slight compared with bolide impact. Empirical records and geochemical models support a pronounced increase in carbonate saturation state for more than 500 000 years following the mass extinction of pelagic carbonate producers at the K–Pg boundary. These examples highlight the importance of pelagic ecosystems in moderating climate and ocean chemistry.

- by Michael Henehan and +1
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- Palaeoclimatology, Paleoclimatology, Paleoclimate, Cretaceous life

The present study deals with the identification of larger benthic foraminifera, establishing microfacies and the digenetic analysis of Margalla Hill Limestone based on field and petrographic data from the Sajikot Waterfall Section, District Abbottabad, Pakistan. The Margalla Hill Limestone predominantly composed of nodular limestone along with subordinate marl and shale is about 172m thick at Sajikot Waterfall Section in Hazara Basin, Lesser Himalayan region of Pakistan. The strata are horizontal to nearly vertical in this section. The lower contact of this formation is observed with Patala Formation of Paleocene age while its upper contact is not exposed in our studied section. Important species of benthic foraminiferal assemblages identified in this formation after a detailed petrographic study are Nummulites atacicus, Nummulites mamillatus, Nummulites globulus, Lockhartia tipperi (Davies), Lockhartia conditi, Lockhartia conica, Lockhartia diversa, Assilina granulose (d'Archaic), Assilina subspinosa, Assilina laminose, Ranikohtalia sahni (Davies), Ranikothalia nuttalli (Davies, 1927), Ranikhothalia sindensis, Discocyclina ranikotensis, Discocyclina dispansa, Operculina patalensis, Kathina selveri , Idalina sinjarica, Setia tibetica, Orbitosiphon punjabensis, Laffittenia bibensis, and Laffittenia erki. Following Microfacies of Margalla Hill Limestone have been recognized after the detailed sedimentological and paleontological studies; Foraminiferal Mudstone Microfacies (SMHMF- I), Foraminiferal Mudstone to Wackstone Microfacies (SMHMF- II), Foraminiferal Wackstone Microfacies (SMHMF- III), Foraminiferal Wackstone to Packstone Microfacies (SMHMF-IV). Based on the microfacies assemblages, the Margalla Hill Limestone is interpreted to have been deposited in the foraminiferal shoal and inner ramp to the proximal outer ramp area of the Tethyan carbonate platform. The larger benthic foraminiferal assemblages suggest that this formation represent the biostratigraphic interval equivalent to the Shallow Benthic Zone (SBZ 8-11) of Serra-Kiel et al. (1998) representing Ypresian stage of Lower Eocene. Stage III of the carbonate platform of Scheibner et al. (2005) has also been established in the studied section. The diagenetic features observed in the Margalla Hill Limestone at the studied section are pressure dissolution (Stylolites), calcite-filled microfractures, multiple calcites veins, disorientation/ dislocation of the bioclasts, micritization, neomorphism and fossils dissolution.

- by Miroslava Jamrichova
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- Albian, Calpionellids, Lower cretaceous, Micropalaeontology foraminifera

The origin and function of a biomineralised skeleton in many of the non-motile groups of plankton remains an open question. Morphological diversity within these groups has often been explained by its relevance to hydrodynamic behaviour, principally buoyancy and settling. Consequently, ecological and evolutionary patterns of morphology have been associated with changes in surface water properties, but these hypotheses have rarely been critically assessed. Computational Fluid Dynamics simulations present a way to quantify the relative effect of size (maximum diameter), shape of the test and density (ratio between calcite and cavity volumes) of the specimen on settling velocity, as all variables can be manipulated independently. Here we interrogate the morphological diversity in planktic foraminifera as model organisms to explore the range of evolutionary options open to plankton to modulate settling velocity under varying environmental conditions. The evolutionary changes in morphology required to accommodate physical changes in the upper water column due to environmental changes, such as increased temperature, are small compared to the ecophenotypic variability of the population. In the modern ocean, the pattern of species distribution with depth is not likely to be determined by hydrodynamics as it is inconsistent with predictions based on settling velocity. These results suggest that intrinsic constraints on size, shape and calcification, such as heritage, exposure of the symbionts to light or oxygen diffusion into the cell, are likely to be more important than hydrodynamic function in determining the depth distribution and test morphology of planktic foraminifera.

- by Emily Rayfield
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- Evolutionary Biology, Geology, Ecology, Micropaleontology
- by Joan M Spaw and +4
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- Evolutionary Biology, Geology, Paleoceanography, Ecology

For the first time in Ukraine in Callovian and Cretaceous sediments the microforaminifers were
found. They were established during the study of Mesozoic sediments palynocomplexes of
17 outcrops and wells Volyno-Podolska plate, Ukrainian Shield, the outstirts of Donbass, Priazov,
Black Sea basin and the Crimea. The method of preprocessing sediments for microforaminifers
was corrected. The paleontological characteristics Callovian, Berriasian, Aptian, Albian, Cenomanian,
Turonian, Coniacian, Сampanian and Maastrichtian deposits for microforaminifers
showed in four phototables is augmented.
Key words: microforaminifers, Callovian and Cretaceous sediments, Ukraine.

- by Olena Shevchuk
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- Micropalaeontology foraminifera

The Văcăroaia Formation outcropping at Buciumeni village contains a rich assemblage of deep-water agglutinated foraminifera. We report the occurrence of 33 species, including two new species: Cyclammina buciumensis and Reticulophragmium... more

- by Ileana-Monica Crihan
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- Micropalaeontology foraminifera

A section from the Ultrahelvetic units of Upper Austria comprises the transition from light-gray, upper-bathyal to middlebathyal carbonates of Early Turonian age towards red-colored carbonates of the Middle Turonian. The total-organic-carbon content is very low throughout the section, but benthic foraminifera associations, especially high abundance of Tappanina laciniosa, indicate repeated phases of enhanced organic-matter flux and decreased oxygen concentrations at the seafloor. The overlying reddish layers are enriched in iron oxides and hydroxides and pyrite and may represent paleo–redox fronts that were related to periods of well oxygenated bottom waters, reduced sedimentation rates, and degradation of organic matter in the underlying sediments. Cyclic sedimentary packages consist of four marlstone–limestone couplets with upward-increasing bedding thickness, red carbonates at the base, and a gray limestone bed at the top. Based on carbon isotope stratigraphy, these packages reflect the 400 kyr eccentricity cycle, with the four marlstone–limestone couplets representing the 100 kyr cycle. Three 400-kyr-cycle boundaries are preceded by horizons with high T. laciniosa abundance and are followed by a paleo-redox front and red-bed deposition. Thus, there is indication of the temporary presence of a local oxygen-minimum zone during enhanced production at the end of each 400 kyr cycle, possibly linked to sea-level fluctuations. Organic-carbon fluxes seem to have decreased immediately above the cycle boundaries. Recycling of organic carbon could be responsible for the distinct carbon-isotope minima at the base of each cycle. Accumulation rates based on our orbital model suggest a switch from relatively uniform sedimentation rates in the Early Turonian to cyclic fluctuations of sedimentation rates in the Middle Turonian. The occurrence of three 400 kyr cycles between the main carbon-isotope excursions points to a 1.2 Myr periodicity, which may reflect the Earth’s long obliquity cycle. A long-term
increase in bottom-water aeration from the Early to the Middle Turonian is evident from the increasing dominance of red sediments.

- by Ines Wendler and +2
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- Oceanography, Diagenesis, Benthic foraminifera, Alps

In this study, the Eocene carbonate succession including Margalla Hill Limestone and Chorgali Formation representing the lower units of the Early Eocene Cherat Group have been investigated in the Margalla Hill Ranges and Hazara-Kashmir Basin. The field sections included, 1) Shahdara Section (Islamabad), 2) Khaira Gali Section (Galiat-Abbottabad) and 3) Yadgar Section (Muzaffarabad-Azad Jammu & Kashmir). Lithologically, these formations are comprised of predominant limestone units with occasional shale interbeds at places. Some notable fauna from the foraminiferal assemblage includes; Assilina spinosa, A. subspinosa, A. dandotica., A. granulosa, Lockhartia conditi, L. tipperi, Nummulites atacicus, N. globulus, N. mamillatus, Discocylina sp., Ranikothalia sp. etc. Presence of all these biostratigraphically significant shallow benthic foraminifera confirms that the deposition of Margalla Hill Limestone and Chorgali Formation occurred in Shallow Benthic Zones (SBZ 5/6 - SBZ12) of Ypresian time. The integrated depositional environment for Early Eocene Margalla Hill Limestone and Chorgali Formation from the studied sections is interpreted to occur between restricted inner ramp and distal mid ramp settings of carbonate platform. Restricted inner ramp, shoal, proximal mid ramp and distal mid ramp are important facies types represented by varying depositional textures of the studied carbonate succession. A very preliminary approach towards establishing stable isotopic stratigraphy at Paleocene/ Eocene boundary in one of the studied sections i.e. Yadgar Section is initiated. This study encounters a decrease in δ18O values along with pronounced decline in δ13C indicating quiet abrupt global extinction phenomenon at Paleocene/ Eocene Boundary.

- by Khawaja Hasnain Iltaf
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- Biostratigraphy, Benthic foraminifera, Eocene, Foraminifers

The fundamental niche comprises the range of environmental variables under which a species can live. Specialist species have narrower fundamental niches than do generalists. Thus, specialists benefit from homogeneous environments while generalists can exploit heterogeneous ones. The challenge is distinguishing relative specialists from generalists in a sedimentary rock succession. This is overcome by taking replicate samples from several horizons in a heterogeneous formation and comparing species' mean percentage abundances using analysis of variance (ANOVA). The mean proportional abundances of specialists will differ between horizons in a heterogeneous succession, while those of generalists will not. The Globorotalia fohsi robusta Zone Middle Miocene Cipero Formation of Trinidad, western central Atlantic Ocean, consists of alternating, diffuse layers of light to dark grey clays. Five replicates of 40 g each were taken from four horizons across a light-to dark-grey cycle. They were picked entirely clean of benthic foraminifera, of which they yielded 5186 specimens in 153 species. Total recovery was dominated by Brizalina cf. tectiformis, with lesser Globocassidulina subglobosa, Pleurostomella alazanensis and Planulina wuellerstorfi. ANOVA applied to each species in turn indicated three species groups: 64 accessory species (each represented by ≤3 specimens, ≤0.06% of total recovery); 21 specialist species, for which mean percentage abundance varied significantly between at least two horizons; and 68 generalist species, for which mean percentage abundances did not differ across the horizons. It might be thought that ANOVA would preferentially assign a specialist status to less abundant species. However, this did not happen; of the four most abundant species, P. alazanensis was a specialist, while B. cf. tectiformis, G. subglobosa and P. wuellerstorfi were generalists. The mean percentage abundance of the specialist species did not differ from that of the generalists. Both specialist and generalist species have palaeoenvironmental applications. The generalist nature of P. wuellerstorfi shows that bottom current strength probably did not differ across the four horizons. The occurrence of the specialist and opportunistic Epistominella exigua in the lowest horizon indicates an interlude of seasonal phytodetrital flux, while sequential increases in the mean percentage abundance of the specialists Oridorsalis umbonatus and Uvigerina auberiana show that the organic carbon flux increased across the four horizons.

- by Brent Wilson and +1
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- Paleontology, Paleoecology, Micropaleontology, Micropalaeontology foraminifera

The bathyal benthic foraminiferal palaeoecology east of Trinidad is currently unknown. The area is oceanographically complex, comprising a pro-delta deep-sea fan building across a transpressional plate boundary. Outflow from the Orinoco River forms a high-productivity surface plume that abuts low-productivity water of the tropical western Atlantic Ocean across a laterally extensive but sharp front. The plume's areal extent differs between the rainy and dry seasons, which are governed by the position of the inter-tropical convergence zone (ITCZ). Upper Quaternary benthic foraminifera are examined in two ~4 m-long piston cores, taken near the eastern edge of the plume. CHIRP profiles show that core BGT086 (water depth 626 m) comprised in situ material throughout, while the lower part of core BGT096 (water depth 700 m) consisted of slumped material. Benthic foraminiferal assemblages in BGT086 were examined quantitatively, while those in BGT096 were examined qualitatively only for comparison. Core BGT086 shows a transition from a low-diversity, Cibicidoides pachyderma-dominated community with subdominant Cassidulina curvata to a later high-diversity, low-dominance Bulimina alazanensis– Osangularielloides rugosa–Epistominella exigua community. The former is indicative of low-productivity, and the latter of high-productivity, surface water. The restriction of E. exigua to the core's upper part may reflect a change from an aseasonal to a seasonal organic flux. The faunal change was detected by both SHE and cluster analyses and an assemblage turnover index (ATI). It may be related to either (a) expansion of the Orinoco plume due to northward migration of the ITCZ approximately 600 yr after the end of the Younger Dryas, (b) eastward progradation of the Orinoco Delta, which would in turn push the front of the Orinoco plume eastward , or (c) both. No other boundary detected was common to all three procedures. A boundary between 124 and 130 cm below the seafloor detected by SHE analysis might equate to the 8000–7500 yr BP meltwater pulse 1C. While some specialist species were restricted to the C. pachyderma or the B. alazanensis–O. rugosa– E. exigua communities, the percentage abundance of some others, concluded to be relative generalists (e.g., Bulimina aculeata and Sphaeroidina bulloides), varied little through the core. The undisturbed section of core BGT096 showed the same general faunal succession as core BGT086. The slumped material in this core was rich in Eponides regularis, which was rare elsewhere. This species shows that the allochthonous sediment was derived from the outer shelf and upper slope (100–400 m water depth) during Late Pleistocene time.

- by Brent Wilson
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- Micropaleontology, Micropalaeontology foraminifera

Tarbour Formation is a predominately carbonate Lithostratigraphic unit that paleogeographically outcrops between the Interrior Fars and northwestern of Zagros thrust fault. In order to study the microbiostratigraphy of Tarbur ForSmation, a stratigraphic section was selected from the northwestern of Khorram Abbad and at the far end of eastern highlands of Makhmalkouh National Park. This stratigraphic section mainly consists of limestone and gray marly limestone. The rich association of benthic foraminifera and rudists reveals that the age of Tarbur Formation at the study section is Maestrichtian, the latest stage of Cretaceous. Furthermore, according to the micropaleontology data, the studied biozone is an assemblage zone equivalent to biozone-37 of Wynd (l965). KEY WORDS: Tarbur, Paleogeography, Mastrichtian, Biozone.

GONZÁLEZ-REGALADO, M.L., CIVIS, J., ABAD, M., HERNÁNDEZ, M.V., GONZÁLEZ DELGADO, J.A., RUIZ, F., RIVAS, M.R., TOSCANO, A., GARCÍA, E.X.M. (2010). Micropaleontología del testigo “Huelva” (Huelva, SO España). I: Foraminíferos bentónicos del... more

- by Antonio Toscano
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- Micropaleontology, Benthic foraminifera, Neogene, Micropalaeontology foraminifera

ABSTRACT A section from the Ultrahelvetic units of Upper Austria comprises the transition from light-gray, upper-bathyal to middlebathyal carbonates of Early Turonian age towards red-colored carbonates of the Middle Turonian. The total-organic-carbon content is very low throughout the section, but benthic foraminifera associations, especially high abundance of Tappanina laciniosa, indicate repeated phases of enhanced organic-matter flux and decreased oxygen concentrations at the seafloor. The overlying reddish layers are enriched in iron oxides and hydroxides and pyrite and may represent paleo–redox fronts that were related to periods of well oxygenated bottom waters, reduced sedimentation rates, and degradation of organic matter in the underlying sediments. Cyclic sedimentary packages consist of four marlstone–limestone couplets with upward-increasing bedding thickness, red carbonates at the base, and a gray limestone bed at the top. Based on carbon isotope stratigraphy, these packages reflect the 400 kyr eccentricity cycle, with the four marlstone–limestone couplets representing the 100 kyr cycle. Three 400-kyr-cycle boundaries are preceded by horizons with high T. laciniosa abundance and are followed by a paleo-redox front and red-bed deposition. Thus, there is indication of the temporary presence of a local oxygen-minimum zone during enhanced production at the end of each 400 kyr cycle, possibly linked to sea-level fluctuations. Organic-carbon fluxes seem to have decreased immediately above the cycle boundaries. Recycling of organic carbon could be responsible for the distinct carbon-isotope minima at the base of each cycle. Accumulation rates based on our orbital model suggest a switch from relatively uniform sedimentation rates in the Early Turonian to cyclic fluctuations of sedimentation rates in the Middle Turonian. The occurrence of three 400 kyr cycles between the main carbon-isotope excursions points to a 1.2 Myr periodicity, which may reflect the Earth’s long obliquity cycle. A long-term increase in bottom-water aeration from the Early to the Middle Turonian is evident from the increasing dominance of red sediments.

- by Michael Wagreich
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- Geology, Oceanography, Diagenesis, Benthic foraminifera

For the first time in Ukraine in Callovian and Cretaceous sediments the microforaminifers were found. They were established during the study of Mesozoic sediments palynocomplexes of 17 outcrops and wells Volyno-Podolska plate, Ukrainian Shield, the outstirts of Donbass, Priazov, Black Sea basin and the Crimea. The method of preprocessing sediments for microforaminifers was corrected. The paleontological characteristics Callovian, Berriasian, Aptian, Albian, Cenomanian, Turonian, Coniacian, Сampanian and Maastrichtian deposits for microforaminifers showed in four phototables is augmented.

- by Olena Shevchuk
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- Micropalaeontology foraminifera, Geological

This study mainly involves the biostratigraphy and microfacies analysis of the Lockhart Limestone from two different sections i.e. Yadgar Section, Muzaffarabad, and Nammal Road Section, Mianwali, Western Salt Range. The second part of the study includes the correlation of both sections. Both sections were studied in detail during field investigations and were also petrographically analyzed. Both sections report significant abundance of genus Miscellinidae, especially the species Miscellanea miscella, present throughout the whole thickness. Furthermore, genus Lockhartia and genus Ranikothalia are also found quite abundantly. The basal part of Lockhart Limestone in Yadgar Section represents a restricted lagoonal or tidal flat environment. The middle part is characterized by shallow shelfal waters with moderate circulation and genera which indicate an open lagoon, lagoonal channel and subtidal environments. The upper part is characterized by higher energy sediments with reworked fossils, closely packed together displaying a shift toward shoreface, representing a depositional setting of tidal flat environment. The environment of Lockhart Limestone at Nammal Road Section is comparable to Yadgar Section, but the facies shift pattern varies. Here, the bulk thickness of the Lockhart Limestone is characterized by the reworked fossils and relatively higher energy deposits, typical of shoal environment. The major portion of middle part is characterized by lagoon deposits. As a whole both sections represent inner ramp settings.

Middle Eocene carbonates and mixed carbonate-siliciclastic deposits occur in disconnected outcrops in the San Jacinto Fold Belt in northern Colombia. Three lithofacies were distinguished: A) claystones and siltstones with planktonic components; B) packstones/rudstones with red algae and claystone-siltstone rip-up clasts in medium to thick plane-parallel, plane-convex, and channel-shaped beds; and C) poorly-bedded rhodolith rudstones with minor larger benthic foraminifers. The latter are interpreted as rhodolith beds accumulated in middle-ramp settings. Lithofacies B consists of bioclasts from the middle ramp redeposited as sediment gravity flows in individual beds and in small channel-lobe systems in the outer ramp and slope. The autochthonous sedimentation basinward from the middle ramp was dominated by hemipelagic claystones and siltstones (Lithofacies A). In outcrops with exposure of vertical successions, these facies are arranged in a transgressive pattern. The limited continuity of outcrops prevents any assessment of the original extension of ramps and lateral dimensions of channel-lobe systems. Comparison with modern tropical rhodolith beds suggests that the middle Eocene carbonate factories in the southern Caribbean developed on ramps under mesotrophic conditions.

- by Edward Salazar
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- Sedimentary geology and stratigraphy, Carbonates, Caribbean, Eocene Fossils

Researchers are invite's to send us reprints of their recent pubhcations on foraminifera to aid us in the compilation of this list. These reprints will be for warded to the Todd Library at the National Museum of Natural History for use by... more