Search

The superfamily Alveolinoidea is a member of the Order Miliolida, and comprises three main families, the Alveolinidae, the Fabulariidae and the Rhapydioninidae. They are examples of Larger benthic foraminifera (LBF), which are single-celled organisms with specific characteristic endoskeletons. Alveolinoids are found globally from the Cretaceous to the present day, and are important biostratigraphic index fossils in shallow-marine carbonates. They are often associated with hydrocarbon reservoirs, and exhibit provincialism with characteristic genera often confined to one of the American, Tethyan or Indo-Pacific provinces. Previously, the systematic study of the global interrelationship between the various alveolinoid lineages has not been possible because of the absence of biostratigraphic correlation between the geographically scattered assemblages, and the scarcity of described material from the Indo-Pacific province. Here we use the literature and new material from the Americas, the French Alps, Iran, Tibet, India and South East Asia, coupled with the use of the planktonic foraminiferal zonal (PZ) correlation scheme to propose a comprehensive, global, systematic analysis of the biostratigraphic, phylogenetic and paleogeographic evolution of the alveolinoids. The alveolinoids originated in the Cretaceous in the Tethyan province. During a global sea-level low stand, a westward migration of some alveolinoids species to the Americas occurred, a behaviour previously reported in contemporaneous orbitolinid LBF. After the Cretaceous/Palaeogene (K–P) event, which saw the extinction of all Cretaceous alveolinoids, rare new forms of alveolinoids evolved again, first in the Americas and later independently in Tethys. As was found in previous studies of rotalid LBF, sea-level low stands in the Paleocene also allowed some alveolinoid forms to migrate, but this time in an eastward direction from the Americas to Tethys, and from Tethys on to the Indo-Pacific province. Alveolinoids still exist today (BorelisandAlveolinella), the former of which is cosmopolitan, while the latter is restricted to the Indo-Pacific province. Throughout their phylogenetic history, alveolinoids characteristically exhibit convergent evolution, with the repeated re-occurrence of certain morphological features. Understanding this propensity to homoplasy is essential in understanding and constructing the phylogenetic relationships within the alveolinoid superfamily.

Orthophragminids are larger benthic foraminifera (LBF) and, together with the nummulitids, were the major rock-forming foraminifera from the middle Paleocene to the late Eocene. Today, porous, LBF-bearing, Paleogene limestones, which occur globally from the Pacific and Atlantic margins of the Americas to the Indo-Pacific, form potentially valuable oil reservoirs, and their biota have formed the basis of the definition of three paleobiogeographic provinces, namely those of the Americas, Tethys, and the Indo-Pacific. The orthophragminids of the western part of the Tethyan Province have been studied extensively, however, the other provinces are less well characterized, and until now the origin and paleogeographic development of this group have not been fully articulated. New material described here allows the clear definition of a fourth, South African paleobiogeographic province, and, when combined with refined biostratigraphic dating based on new material from the Americas, Europe, South Asia and SE Asia, enables their paleogeographic and biostratigraphic evolution to be determined. Critically, the occurrence of cosmopolitan planktonic foraminifera (PF) within LBF assemblages enables the first occurrences of various LBF forms within each province to be dated relative to well-calibrated planktonic zones (PZ). From this, we infer that, like the previously studied lepidocyclinids and nummulitids, the orthophragminids originated in the Americas during the Paleocene, probably between the late Danian (PZ P1c, 63.5 Ma) and the early Selandian (PZ P3a, 61.6 Ma). By the middle Paleocene, the orthophragminids had migrated across the Atlantic to the previously isolated West African coast at the extreme of Tethys, probably during global sea-level low stands at 60.3 Ma and again at 56.4 Ma. Subsequently, the American Province again became isolated. In the Tethys, the orthophragminid migrations followed two paths: northeastward through the Tethyan corridor in the late Paleo-cene (Thanetian), and south in the earliest Eocene (Ypresian) to South Africa. The Tethyan forms evolved during the Eocene into many lineages, which in turn migrated, after a few million years of their first appearances into the Indo-Pacific, where they again became isolated and diversified further. Meanwhile the South African forms remained similar to their American ancestors in both small size and external ornamentation, while their internal evolution closely followed that of Tethys forms, as exhibited by three species of Nemkovella and Discocyclina described here from South Africa (Nemkovella mcmilliana n. sp., Discocyclina davyi n. sp. and D. africana n. sp.).

We present new biostratigraphic analyses of approximately 200 outcrop samples and review biostratigraphic data from 136 public domain exploration wells across western New Guinea. Biostratigraphic ages and palaeodepositional environments were interpreted from occurrences of planktonic and larger benthic foraminifera, together with other fossils and environmental indicators where possible. These data were compared with existing geological maps and exploration well data to reconstruct the palaeogeography of western New Guinea from the Carboniferous to present day. In addition, we used the known bathyal preferences of fossils to generate a regional sea-level curve and compared this with global records of sea-level change over the same period. Our analyses of the biostratigraphic data identified two major transgressive-regressive cycles in regional relative sea-level, with the highest sea levels recorded during the Late Cretaceous and Late Miocene and terrestrial deposition prevalent across much of western New Guinea during the Late Paleozoic and Early Mesozoic. An increase in the abundance of carinate planktonic foraminifera indicates a subsequent phase of relative sea-level rise during a regional transgressive event between the Late Jurassic and Late Cretaceous. However, sea-levels dropped once more during a regressive event between the Late Cretaceous and the Paleogene. This resulted in widespread shallow water carbonate platform development in the Middle to Late Eocene. A minor transgressive event occurred during the Oligocene, but this ceased in the Early Miocene, likely due to the collision of the Australian continent with intra-Pacific island arcs. This Miocene collision event resulted in widespread uplift that is marked by a regional unconformity. Carbonate deposition continued in platforms that developed in shallow marine settings until these were drowned during another transgressive event in the Middle Miocene. This transgression reached its peak in the Late Miocene and was followed by a further regression culminating in the present day topographic expression of western New Guinea.

Understanding the impact of tectonic activity and volcanism on long-term (i.e. millions years) evolution of shallow-water carbonate platforms represents a major issue for both industrial and academic perspectives. The southern central Mozambique Channel is characterized by a 100 km-long volcanic ridge hosting two guyots (the Hall and Jaguar banks) and a modern atoll (Bassas da India) fringed by a large terrace. Dredge sampling, geo- physical acquisitions and submarines videos carried out during recent oceanographic cruises revealed that sub- marine fl at-top seamounts correspond to karsti fi ed and drowned shallow-water carbonate platforms largely covered by volcanic material and structured by a dense network of normal faults. Microfacies and well- constrained stratigraphic data indicate that these carbonate platforms developed in shallow-water tropical envi- ronments during Miocene times and were characterized by biological assemblages dominated by corals, larger benthic foraminifera, red and green algae. The drowning of these isolated carbonate platforms is revealed by the deposition of outer shelf sediments during the Early Pliocene and seems closely linked to (1) volcanic activity typi fi ed by the establishment of wide lava fl ow complexes, and (2) to extensional tectonic deformation associat- ed with high-offset normal faults dividing the fl at-top seamounts into distinctive structural blocks. Explosive vol- canic activity also affected platform carbonates and was responsible for the formation of crater(s) and the deposition of tuff layers including carbonate fragments. Shallow-water carbonate sedimentation resumed during Late Neogene time with the colonization of topographic highs inherited from tectonic deformation and volcanic accretion. Latest carbonate developments ultimately led to the formation of the Bassas da India modern atoll. The geological history of isolated carbonate platforms from the southern Mozambique Channel represents a new case illustrating the major impact of tectonic and volcanic activity on the long-term evolution of shallow-water car- bonate platforms

International audience; Saint Barthélemy is the only island of the northern Lesser Antilles where it is possible to investigate in the detail the chronostratigraphy of the mixed carbonate-volcaniclastic deposits of the Paleogene Caribbean volcanic arc. Based on field mapping and new biostratigraphical and sedimentological data, we study the limestone units interbedded in the Paleogene volcaniclastic deposits. We find that four main carbonate units occur instead of previously believed six ones. Based on the ages given by the foraminifera assemblages, and taking into account the recently published 40Ar/39Ar ages of magmatic rocks, the Lower Limestone unit dates Lutetian, the Intermediate Limestone unit late (?) Bartonian-late Priabonian, the Upper Limestone late Priabonian and the Top Limestone unit early Miocene. The Paleogene carbonate beds were deposited on gently dipping submarine volcaniclastic deposits issued from emergent volcanoes, in muddy, unrimmed inner to mid-ramp setting dominated by bottom communities. A major subaerial unconformity is evidenced during the Oligocene, most probably corresponding to uplift affecting Saint Barthélemy. Our work offers a revised lithostratigraphic succession of Saint Barthélemy as a first key-point for further studies of the Paleogene Caribbean arc deposits which were dismembered following the entrance of the Bahamas Bank in the Lesser Antilles subduction zone.

The biostratigraphy and sedimentology of the outcrops and bedrock exposed in archaeological excavations around the harbour area of Beirut (~5 km 2) unlock the geological and structural history of that area, which in turn are key to understanding the hydrocarbon and hydrogeological potential of the region. A key location (Site 2) of a studied outcrop section and newly uncovered bedrock is on the northern foothill cliff of East Beirut (Achrafieh). The outcrop section of carbonates is of Eocene beds overlain by conformable Miocene beds. The excavation of the slope bordering the outcrop uncovers a bedrock section of an early Pliocene shoreline of carbonate/siliciclastic sands at its base and a beach-rock structure at top. The age of the shoreline section is dated by an assemblage of planktonic foraminifera including Sphaeroidinellopsis subdehiscens, Sphaeroidinella dehiscens, and Orbulina universa. The Eocene carbonates of Site 2 extend the coverage of the previously reported Eocene outcrops in the harbour area. They form a parasequence of thin bedded chalky white limestones that includes the youngest fossil fish deposits in Lebanon ( Bregmaceros filamentosus). The deposits are dated as early Priabonian by their association with the planktonic foraminiferal assemblage of Porticulasphaera tropicalis, Globigerinatheka barri, Dentoglobigerina venezuelana, Globigerina praebulloides, Turborotalia centralis and Borelis sp. The Middle Miocene carbonates that conformably overlie the early Priabonian parasequence, include a planktonic foraminiferal assemblage of Globigerinoides trilobus, Orbulina universa and Borelis melo. Elsewhere, in the harbour area, the preserved Eocene limestones are equally directly overlain by conformable Miocene carbonate parasequences of the Langhian - Serravallian age. Younger argillaceous limestone beds of the Mio/Pliocene age occur in the eastern central part of the harbour area and enclose an assemblage of Truncorotalia crassaformis, Globorotalia inflata, and Orbulina universa. The three markers of old and recently raised structural blocks in the harbour area are a Lutetian/Bartonian marine terrace in the south west corner, a lower Pliocene shoreline carbonate section in the north east side and a Holocene raised beach of marine conglomerates in the north east corner of the area. The locations of these paleo-shorelines, less than 2 kms apart, indicate a progressive platform narrowing of North Beirut since the Paleogene. This study underpins the geological complexity of the region and contributes to understanding the underlying geology which will be needed for future archaeological, hydrocarbon and hydrogeological exploration.

This study presents a detailed stratigraphic record of the Paleocene–Eocene Thermal Maximum (PETM) in the Gamba area of the Tethyan Himalaya, a carbonate-platform succession originally deposited along the southern margin of the eastern Tethys Ocean. The Paleocene-Eocene boundary interval is marked by a negative carbon isotope excursion at the boundary between members 3 and 4 of the Zongpu Formation. The succession is erosionally truncated at this surface, which is overlain by an intraformational carbonate conglomerate, and only the upper part of the PETM interval is preserved. Foraminiferal assemblages of Shallow Benthic Zone 4 are present below the conglomerate bed, but are replaced by assemblages of Shallow Benthic Zone 6 above the conglomerate. Depositional facies also change across this surface; below the disconformity, floatstones and packstones containing nummulitid forams record progressive transgression in an open-marine environment, whereas restricted or lagoonal inner-ramp deposits containing Alveolina and Orbitolites are typical above the disconformity. The prominent negative excursion observed in the δ13C of whole-rock carbonate (− 1.0‰ at Zongpu, − 2.4‰ at Zengbudong) and organic matter (− 24.7‰, at Zengbudong) is correlated to the characteristic PETM carbon isotope excursion. This major negative excursion in shallow-marine carbonates may have partly resulted from syndepositional alteration of organic matter. The erosional unconformity can be constrained to the lower PETM interval (between 56 and 55.5 Ma), and is identifiable throughout the Tethyan Himalaya. This widespread disconformity is attributable to tectonic uplift associated with the southward migration of an orogenic wave, originated 3 ± 1 Ma earlier in the middle Paleocene at the first site of India-Asia continent-continent collision. A possible eustatic component of the pre-PETM sea-level fall, which resulted in the excavation of incised valleys filled during the subsequent sea-level rise when the conglomerate bed was deposited, remains to be assessed.

During the Paleocene–Eocene Thermal Maximum (PETM, ~56 Ma), a large, negative carbon-isotope excursion (CIE) testifies to a massive perturbation of the global carbon cycle. Shallow-marine settings are crucial to understand the environmental and ecological changes associated with the PETM and the connection between continental and open-marine environments. Detailed sedimentological, paleontological, and geochemical analysis of a quasi-continuous succession of shallow-marine carbonates in the Tethys Himalaya of southern Tibet indicates that a relative rise in sea level coincided with PETM onset, continued through PETM core, and terminated with a regression at PETM recovery. At PETM onset, corresponding to the SBZ4/SBZ5 boundary, no obvious impact on biota and specifically on larger benthic foraminifera (LBF) is observed. The major biotic change occurs later on at PETM recovery, corresponding to the SBZ5/SBZ6 boundary. Our data suggest that relative sea level, rather than temperature, exerted the main control on benthic biota during the PETM. Although the δ13Corg values of organic matter are similar in the deep sea and shallow-marine continental margins, the δ13Ccarb value of bulk carbonates are significantly 13C-depleted, which we attribute to environmental change driven by relative sea-level fluctuations.

Members of the Larger Benthic Foraminiferal (LBF) family Orbitolinidae occured from the Cretaceous to the Paleogene, however, they were most diverse during the mid-Cretaceous, and dominated the agglutinated LBF assemblages described from limestones of that period. Various orbitolinid species have been used to zone and date lithologies formed in the shallow, warm waters of the Aptian to the Early Cenomanian, and many, sometimes inaccurate, generic and sub-generic nomenclatures have been proposed to differentiate the often subtle morphological changes that orbitolinids exhibit over time. Until now, it has not been possible to develop an effective global overview of their evolution and environmental development because descriptions of specimens from Asia have been relatively rare. Following our recent study of over 1800 orbitolinid-rich thin sections of material from 13 outcrops of the Langshan Limestone, from the Southern Tibetan Plateau, and from the Barito Basin, South Kalimantan, Indonesia, it has been possible to compare the stratigraphic ranges of these orbitolinids with previously described Tethyan and American forms, based on the use of a planktonic zonal (PZ) scheme, itself tied to the most recent chronostratigraphic scale. This has allowed the reconstruction of the phylogenetic and paleogeographic evolution of the orbitolinids from their Valanginian origin in the Tethys. Although Tethys remained the paleogeographic focus for the orbitolinids, it is inferred here for the first time that a bi-directional paleogeographic migration of some orbitolinid genera occurred from Tethys to the Americas and also to the Western Pacific region. Our observations and dating confirm that global marine regressions in the Aptian were coincident with, and may well have facilitated, these orbitolinid transoceanic migrations. However, migration stopped after rising sea-level in the Early Albian appears to have again isolated these provinces from each other. Tectonic forces associated with the subduction of the Farallon Plate and further sea-level raises led to the opening of the Western Interior Seaway in the North America, which correlates with, and may have been the cause of, the Middle Albian (top of PZ Albian 2) extinction of the American orbitolinids. The extinction of the orbitolinids revealed that the Western Pacific province was split into two sub-provinces, with extinction occurring at the end of the Early Albian (top of PZ Albian 1) in the Northwest Pacific sub-province, and at the end of the Albian (top of PZ Albian 4) in the sub-province that is today South East Asia (on the margins and west of the Wallace Line). The final virtual extinction of the orbitolinids occurred at the end of the Cenomanian in the Tethyan province, which coincides with, and may have been caused by, global anoxic oceanic events that correlate with a near-peak Mesozoic eustatic sea-level high-stand that led to the overall global collapse of the paleotropical reef ecosystem at that time.

In order to establish the relationship between the smooth, microperforate praehedbergellid forms of the genus Blefuscuiana with the younger, macroperforate and muricate forms typical of Hedbergella, two similar taxa but with the different characters of the two genera, are studied here: Blefuscuiana praetrocoidea (Kretchmar & Gorbachik) and its descendant Hedbergella trocoidea (Gandolfi), the type species of Hedbergella, and which typifies the Hedbergellidae.B. praetrocoidea was only found in the Early Aptian in the North Tethys. H. trocoidea ranges from the Late Aptian to Early Albian (?M. Albian) and is a cosmopolitan species. It evolves into Ticinella roberti (Gandolfi), a Late Aptian–Albian species with fused portici. The evolution of the Praehedbergellidae into the Hedbergellidae appears to be related to a relative sea-level rise in the Late Aptian and Albian (and the opening of the Proto-Atlantic) which provided a number of deep-water niches which the Hedbergellidae occupied.

Drowning unconformities and their related strata are important records of key tectonic and environmental events throughout Earth’s history. In the eastern Bird’s Head region of West Papua, Indonesia, Middle Miocene strata record a drowning unconformity present over much of western New Guinea, including several offshore basins. This study records platform carbonate strata overlain by mixed shallow- and deep-water units containing benthic and planktonic foraminiferal assemblages in several outcrop locations across the eastern Bird’s Head region. These heterolithic beds are interpreted as drowning successions that are terminated by a drowning unconformity. We define a succession exposed along the Anggrisi River in the eastern Bird’s Head as a stratotype for carbonate platform drowning in the Bird’s Head, analogous to similar faunal turnovers identified in its offshore basins. Detailed facies analyses, biostratigraphic dating, and paleoenvironmental interpretations using larger benthic and planktonic foraminifera collected from the Anggrisi River succession help to constrain the drowning event recorded onshore as beginning in the Burdigalian and ending in the Serravallian. The cause of platform drowning in the Bird’s Head is attributed to a reduction in the rates of carbonate accumulation due to the presence of excess nutrients in the depositional environment. Already foundering carbonate platforms due to environmental deterioration were left vulnerable to submergence and eventually succumbed to drowning. Low rates of carbonate production were outpaced by the rate of relative sea-level rise caused by high-amplitude oscillations in global glacio-eustatic sea-level change and/or regional tectonic subsidence. The duration of the drowning event across the entire Bird’s Head region is interpreted to have lasted a duration of approximately 9.5 My, between 18.0 and 8.58 Ma. This has implications when interpreting timings of sedimentary basin fill across western New Guinea and in other basins where carbonate platform drowning is recorded.

Access to new material from South Africa, Corsica, Cyprus, Syria and Sumatra has allowed a systematic biostratigraphic comparison and correlation of the miogypsinids from the Mediterranean–West Africa and the Indo-Pacific provinces, and for the first time from South Africa. Twelve new species have been identified: Neorotalia tethyana, Miogypsinella bornea, Miogypsina subiensis, M. niasiensis, M. regularia, M. samuelia, Miolepidocyclina banneri, Miogypsinella cyprea, Miogypsina mcmillania, M. africana, M. ianmacmilliana and M. southernia . The palaeogeographical evolution of the miogypsinids started with a trans-Atlantic migration of Neorotalia from the Americas, where miogypsinids had originated. The eastward migration followed two paths: one to the south towards South Africa, where a distinct phylogenetic lineage, but similar to that found in America, developed but went extinct in the Burdigalian; the other to the north, through the Mediterranean corridor. During the Chattian and Aquitanian significant miogypsinid forms evolved in the Mediterranean from the morphologically distinct Mediterranean Neorotalia and migrated, within a few million years of their first appearance, into the Indo-Pacific, where they diversified further. The tectonically driven closure of the seaway between the Mediterranean and the Indo-Pacific in the Burdigalian triggered the extinction of Mediterranean miogypsinids in the Langhian. Miogypsinids survived in the Indo-Pacific into the Serravallian.

Elevated whole-rock concentrations in Cr, Ni and V as well as the occurrence of detrital chrome spinel suggest an input of (ultra)mafic detritus into the Eocene elastic sediments of Samothraki Island. Detrital chrome spinel chemistry indicates a mixed source of MOR-type peridotites and supra-subduction zone (SSZ) peridotites, and minor volcanic rocks, supposedly island-arc basalts and MORB-type rocks, most likely derived from Vardarian ophiolites. Wackestones from the southwest of Samothraki contain a moderately well-preserved calcareous microfossil assemblage, comprising Nummulites fabianii (PREVER), Nummulites striatus (BRUGUIERE), Pellatispim sp., and Operculina sp., indicating an early Priabonian age (Late Eocene). The sedimentation of the Eocene succession was influenced by regional tectonic and volcanic activity. The rocks have been deposited contemporaneous with the extensional exhumation of the eastern Rhodope Massif.

The larger benthic foraminiferal family Lepidocyclinidae has been described extensively in the literature, with occurrences ranging from the middle Eocene in the Americas to the late Miocene (or possibly early Pliocene) in the Indo-Pacific Tethyan sub-province. Lepidocyclinids originated in the Americas but related forms are reported from West Africa from the middle Eocene-early Oligocene pointing to an eastward migration. This migration continued within the Tethys until the lepidocyclinids finally colonized the Indo-Pacific in the late early Oligocene. Various lepidocyclinid species have been used to zone and date the Neogene (particularly in the Indo-Pacific), and many, sometimes confusing, generic and suligeneric nomenclatures have been proposed to differentiate the often subtle morphological changes that have been observed to occur with time. Until now, it has not been possible to develop an effective global view of the evolution and migration of the lepidocyclinids because descriptions of specimens from the American province have been relatively rare. Here we present descriptions of new samples from 37 wells drilled off South America, and present a systematic comparison of the Lepidocyclinidae from the South America and the Tethyan sub-provinces of the Mediterranean-West Africa and the Indo-Pacific. Among the 87 specimens illustrated from the two provinces, 45 are recorded in America, including three new taxa, Lepidocyclina (Nephrolepidina) braziliana, Lepidocyclina (Nephrolepidina) americana and Eulepidina parkinsonia, and one new unnamed species of Eulepidina. By comparing the stratigraphic ranges of the South American specimens with previously described Tethyan forms, the phylogenetic evolution of the lepidocyclinids is reconstructed from their mid-Eocene origin in the Americas to their late Miocene (or possibly early Pliocene) extinction in the Indo-Pacific. Systematic comparisons enabled us to trace the timing and route of the paleogeographic migration of the lepidocyclinids from the Americas, through the Tethyan/Mediterranean corridor, and into the Indo-Pacific region. Our observations confirm that the series of global regressions in the middle Eocene and early Oligocene facilitated transoceanic migration of larger benthic foraminifera between the American and the Tethyan provinces. However, this migration stopped after rising sea-level in the early Oligocene separated the provinces. Subsequently, larger benthic foraminifera exhibited independent but similar lines of evolution. The resulting examples of parallel evolution led to some taxonomic confusion in the literature that we seek to resolve.

Low-latitude carbonate platforms dominated the southern and northern margins and microplates of western Tethys during the Early Jurassic. However, these have proved difficult to date in the past partly due to a lack of study but also a perception of low biotic diversity following the Triassic-Jurassic extinction event. Detailed logging and sampling of seven continuously exposed sections of Lower Jurassic shallow-marine carbonates in Gibraltar, Morocco, Tunisia, Greece, Italy, and in Spain reveals the occurrence of 12 benthic foraminifera species. These taxa are described and illustrated, and include: one new speciesTextulariopsis sinemurensis, new records for the Early Jurassic, and new records for this region. Five new biozones for the late Hettangian to early Pliensbachian time interval are erected from the consecutive appearance of benthic foraminifera within these sections, from top to base:Lituosepta compressa, Lituosepta recoarensis, Everticyclammina praevirguliana, Siphovalvulina colomi andSiphovalvulina gibraltarensis. This has enabled the correlation of these sections for the first time from the northern and southern Tethys margins and from the Apuleian and Pelagonian microplates within Tethys. The foraminiferal occurrences indicate a similarity of associations from the southern and northern shallow carbonate shelves of Tethys, whilst reflecting the relative isolation of the Apuleian and Pelagonian microplates within Tethys. The foraminifera show a progressive diversification of forms through the late Hettangian to early Pliensbachian interval that is interpreted to reflect the evolutionary recovery and diversification of these biotas following the Triassic-Jurassic extinction event.

The role of fossil planktonic foraminifera as markers for biostratigraphical zonation and correlation underpins most drilling of marine sedimentary sequences and is key to hydrocarbon exploration. Biostratigraphic and Geological Significance of Planktonic Foraminifera unifies existing biostratigraphic schemes and provides an improved correlation reflecting regional biogeographies. It presents a comprehensive analysis of existing data on fossil planktonic foraminifera genera and their phylogenetic evolution in time and space. Coverage includes presentation and discussion of rarely studied thin sections of planktonic foraminifera, allowing for new developments in dating planktonic foraminifera in carbonates and expanding their usefulness in hydrocarbon exploration.

Calcareous agglutinating foraminifera and other larger benthic foraminifera from two formations in central Lebanon confirm the presence of Late Jurassic and Early Cretaceous age carbonates below the continental Lower Cretaceous “basal sandstone”. The lowermost formation, the Bikfaya Formation, is characterized by the presence of Buccicrenata sp., Alveosepta (Redmondellina) powersi ( Redmond ), A. (A) Jaccardi ( Schrodt ), Pseudospirocyclina maynci Hottinger and Rectocyclammina chouberti Hottinger of Kimmeridgian age; while the overlying Salima Formation is characterized by Everticyclammina kelleri ( Henson ), E. contorta Redmond , Bramkampella arabica Redmond and Riyadhella regularis Redmond of Berriasian age. Trocholina alpina ( Leupold ) and Nautiloculina oolithica Mohler and Reichel are long-ranging species which occur throughout the Salima Formation, whereas Neotrocholina valdensis Reichel of Berriasian — Valanginian age appears in the upper beds of the formation below the “basal sandstone”. The resulting assemblage compares closely with taxa described from Iraq, the United Arab Emirates and Saudi Arabia, and confirms for the first time in central Lebanon a Kimmeridgian age for the basal 25 m of the Bikfaya Formation and a Berriasian-Valanginian age for the Salima Formation.

Benthic foraminifera are described for the first time from the Gibraltar Limestone Formation of the Rock of Gibraltar. The new species Siphovalvulina colomiS. gibraltarensisRiyadhella praeregularis occur with Duotaxis metula Kristan, Everticyclammina praevirguliana Fugagnoli, Siphovalvulina sp.,an atypically early example of Textulariopsis sp., and Nodosaria sp. Microflora are present as the probable cyanobacterium Cayeuxia ?piae Frollo, the alga Palaeodasycladus ?mediterraneus (Pia), and the disputed alga Thaumatoporella ?parvovesiculifera (Raineri). The foraminifera compare most closely with poorly-known taxa from Italy, Spain and Morocco, and are consistent with an Early Jurassic (Sinemurian) age for the upper part of the &62;460-m-thick Gibraltar Limestone. Most are textulariids and more primitive than species well known from the later Early Jurassic (Pliensbachian) of the Mediterranean region, especially Morocco and Italy. The biota as a whole is characteristic of inner carbonate platform environments widespread along the rifted western margins of the Early Jurassic Tethys, notably those recorded from Morocco, Italy and Greece as well as southern Spain.

The full stratigraphic range of Buccicrenata is here emended to include the Kimmeridgian to Cenomanian and its origin Is placed in the Upper Jurassic of the Middle East. Subsequently, the genus spread in the palaeotropics (probably during Aptian time) to inhabit North Africa and Central America from Venezuela to Texas. Throughout the evolutionary development of the genus, the characteristic long, low and depressed, kidney-shaped chambers are present in the later part at least of the initial planispiral. A new species, Buccicrenata primitiva n.sp., is proposed.

Larger benthic foraminifera from the upper part of the lower Miocene to the middle Miocene, upper Burdigalian-Serravallian (Tf1-Tf2), from previously unstudied sections in East Kalimantan are described and figured. Lepidocyclina praedelicata is described as a new species. This comprises a new ancestral link in the evolution of the Lepidocyclina from L. praedelicata in the early Miocene (Burdigalian; uppermost Te to lower Tf1) into L. delicata in the middle Miocene (Serravallian; Tf2). Analysis of the larger benthic foraminifera has allowed accurate dating of the carbonate sections studied using the East Indian Letter Classification.

A new correlation is proposed between the “Letter Stages” of the Far East, the Planktonic Foraminiferal Zones of the Oligocene-Miocene and the European Stages. Constructive criticisms are invited.

A new and distinctive genus of hauraniid foraminifera has been found in Liassic rocks of the island of Socotra (Yemen) and of the United Arab Emirates; both are believed to be of Toarcian age.

Mass extinctions are recognized through the study of fossil groups across event horizons, and from analyses of long-term trends in taxonomic richness and diversity. Both approaches have inherent flaws, and data that once seemed reliable can be readily superseded by the discovery of new fossils and/or the application of new analytical techniques. Herein the current state of the Cretaceous-Tertiary (K-T) biostratigraphical record is reviewed for most major fossil clades, including: calcareous nannoplankton, dinoflagellates, diatoms, radiolaria, foraminifera, ostracodes, scleractinian corals, bryozoans, brachio-pods, molluscs, echinoderms, fish, amphibians, reptiles and terrestrial plants (macrofossils and palynomorphs). These reviews take account of possible biasing factors in the fossil record in order to extract the most comprehensive picture of the K-T biotic crisis available. Results suggest that many faunal and floral groups (ostracodes, bryozoa, ammonite cephalopods, bivalves, archosaurs) were in decline throughout the latest Maastrichtian while others (diatoms, radiolaria, benthic foraminifera, brachiopods, gastropods, fish, amphibians, lepidosaurs, terrestrial plants) passed through the K-T event horizon with only minor taxonomic richness and/or diversity changes. A few microfossil groups (calcareous nannoplankton, dinoflagellates, planktonic foraminifera) did experience a turnover of varying magnitudes in the latest Maastrichtian-earliest Danian. However, many of these turnovers, along with changes in ecological dominance patterns among benthic foraminifera, began in the latest Maastrichtian. Improved taxonomic estimates of the overall pattern and magnitude of the K-T extinction event must await the development of more reliable systematic and phylogenetic data for all Upper Cretaceous clades.

Tunisia, Ukraine, Russia, the North Sea area and elsewhere have yielded knowledge that the Early Cretaceous planktonic foraminifera are predominantly members of the Praehedbergellidae. The taxonomy and phylogeny of this family have been revised and refined. New generic and specific taxa have been proposed, new phylogenetic lineages have been described, and many type specimens have been imaged by scanning electron microscopy for the first time.Gorbachikella(Hauterivian–Early Aptian) gave rise toPraehedbergella(Late Hauterivian–Late Aptian), evolvingBlefuscuiana,Lilliputianella, and the planospiralBlowiellain the Barremian. The last gave rise toGlobigerinelloidesin the Aptian, from which the macroperforateAlanlordella(and its descendantPlanomalina) evolved in the Albian.Blowiellawas ancestral to taxa with radially elongated chambers (Claviblowiella, Leupoldina, Schackoina).

Improved taxonomic understanding provides important information regarding evolution, biostratigraphic distribution and palaeobiogeography. Three species of Early Cretaceous planktonic foraminifera which are of uncertain identity are Globigerina aptica AGALAROVA, Globigerina infracretacea GLAESSNER and Hedbergella aptiana BARTENSTEIN. Examination of topotype and metatype material enables these species to be better defined and their inter-relationship and stratigraphic range to be established. All three species are assigned to the genus Blefuscuiana (Praehedbergellidae). A new species, B. albiana, the descendant of B. aptiana s.s., is also recognised. © 1996 E. Schweizerbart'sche Verlagsbuchhandlung.

This Book/Chapter has been retracted as the rights have been returned to the author. The full Elsevier Policy on Book/Chapter Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy

This Book/Chapter has been retracted as the rights have been returned to the author. The full Elsevier Policy on Book/Chapter Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy

This Book/Chapter has been retracted as the rights have been returned to the author. The full Elsevier Policy on Book/Chapter Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy

This Book/Chapter has been retracted as the rights have been returned to the author. The full Elsevier Policy on Book/Chapter Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy

Publisher Summary Many of the Cretaceous lituolid species have quite limited stratigraphic ranges and are valuable as index fossils. They were joined by a new group that made its first appearance in the late Early Cretaceous, the alveolinids. These were miliolines that showed spectacular expansion in the Middle Cretaceous, proliferating in mid-latitudes, and often becoming annular or discoid and subdivided by partitions. Many of them resembled the planispiral-fusiform fusulinines of the Permian, attaining approximately the same range of sizes, but differing fundamentally in their imperforate, porcelaneous wall structure. In the Late Cretaceous new, simple rotaliines evolved into forms with complicated three-layered structures, the orbitoids. While the previous two groups had their main breeding ground in the Tethyan realm, the orbitoids showed provincialism and some were only found in the Caribbean. This chapter illustrates the taxonomy of the major large Cretaceous forams and discusses their biostratigraphic, paleoenvironmental and paleogeographic significance.

Publisher Summary The Cretaceous–Palaeogene crisis wiped out over 80% of the Maastrichtian larger benthic foraminifera. The early Palaeocene was a recovery period for larger foraminifera. As was the case during the recovery stage after previous extinctions, larger foraminifera were morphologically small and rare, and even the newly evolved foraminifera exhibited a morphological manifestation of post-crisis ecological stress. The recovery period was longer than in Tethys, and it was not before the Middle Eocene that the rotaliines developed a new evolutionary lineage; they evolved into the three-layered Lepidocyclina and Eulepidina. These forms migrated into Tethys in the Oligocene, but a reverse migration of alveolinids and discocylinids from Tethys to the American province did not occur. The nummulitids of the American province never reached the giant sizes of their analogues in the Tethyan realm. Palaeogene larger foraminifera from different localities around the world have been studied in detail by many workers. This chapter illustrates the taxonomy of the major larger Palaeogene benthic foraminifera and discusses their biostratigraphic, palaeoenvironmental and palaeogeographic significance.

Publisher Summary The first foraminifera fossils with a hard shell to appear in the fossil record are the unilocular, simple agglutinated Allogromiina. The lagenine foraminifera (with walls made of orientated calcite crystals) evolved in the Silurian, but did not show significant evolutionary diversity until the Moscovian–Kasimovian interval in the Carboniferous. chapter discusses the only truly large Palaeozoic foraminifera, the suborder Fusulinina. Members of this suborder evolved from the Allogromiina in the Silurian, with first the appearance of the Parathuramminoidea and subsequently the Moravamminoidea. The chapter presents the main features of the taxonomy of the Fusulinina, Lagenina, Involutinina, and Miliolina suborders. The chapter also discusses the biostratigraphic significance and phylogentic evolution of the geologically most important fusulinines. The chapter presents a review of their palaeoecological significance and their palaeogeographic distribution during the Palaeozoic.

Publisher Summary Larger foraminifera are biologically complex and highly versatile. They are both robust but can be highly specialized and therefore highly sensitive to their environment. Their study provides, as a result, considerable insights into evolutionary process as well as into the major geological mechanisms associated with extinction and recovery. Larger foraminifera also have and continue to occupy the very important ecological niche of being a reef-forming group. The worldwide distribution of carbonate biota, especially reef biota, contains important information on the environmental factors, including oceanographic parameters, which control this most sensitive of habitats. The study of the distribution patterns of this niche, over different time slices, provides valuable information on how the climate of the Earth has evolved in the past 350 Ma. Finally, the carbonate-rich shallow marine and reef environments favored by larger foraminifera are also those that may give rise to economically vital deposits of oil and gas. So larger foraminifera are now central to our ability to date, correlate and analyze the sedimentary basins that are the key to the economic well-being of the world. A detailed understanding of the taxonomy of the larger foraminifera is essential, therefore, for any applied biostratigraphic analysis.

Publisher Summary The Early Jurassic witnessed the steady evolution of the agglutinated forms from small and simple to internally complicated forms, which became abundant from the Pliensbachian onwards, thereby giving the carbonate facies of the Jurassic a characteristic that is recognizable throughout Tethys. In contrast to the Triassic benthic foraminifera, the Jurassic larger benthic foraminifera have been systematically studied on a regional scale. This chapter presents a revision of the taxonomy of the main genera of the Jurassic larger foraminifera and discusses their evolutionary lineages and phylogenetic relationships. The chapter also presents a revised biostratigraphic ages, palaeogeographic, and palaeoenvironmental interpretations. The dominant larger foraminifera of the Jurassic were the agglutinated Textulariina. The Involutinina persisted throughout, while the Miliolina were present but were mainly composed of morphologically small genera, and it was not before the Cenomanian that larger miliolines played an important role in the benthic assemblages of carbonate platforms.

The Tacipi Formation of Sulawesi was deposited during the late middle Miocene to early Pliocene in a large area of shal- low water, marine carbonate production with deeper water sediments deposited to the north. A detailed biostratigraphical study of 580 samples from 58 measured outcrop sections has led to an understanding of sequence stratigraphic and facies relationships of Cenozoic carbonates in Sulawesi, their importance as the product and record of climatic/oceanic conditions and interchange in tropical/subtropical inner shelf environments, and their role as hydrocarbon reservoirs. Fifteen larger benthic foraminifera species are described and illus- trated with one newly proposed taxon: Lepidocyclina pillaria. Analysis of the larger benthic foraminifera in relationship to the plank- tonic foraminifera allows correlation of the larger foraminiferal assemblage zones ("letter stages") of the Far East with the N zones of the Neogene based on planktonic foraminiferal evolution patterns. The co-occurrence and recognition of planktonic foraminifera and larger benthic foraminifera species in the same thin sections is a rare opportunity for correlating the biostratigraphic frameworks based on these two groups and is of regional stratigraphic importance. This has resulted in the refinement of the biostratigraphic ranges of the larger ben- thic foraminifera Katacyclocypeus and Flosculinella, and enlargement of our knowledge about the Tg and Th "letter stages".

This study of mid-Cretaceous foraminifera from the Linzhou, the Coqen and the Xigaze Basins in the southern Tibetan Plateau has provided the first high resolution biostratigraphic description of these limestones and interpretation of their paleoenvironmental settings. The fossil assemblages are dominated primarily by orbitolinid larger benthic foraminifera. We reassessed the identification of many taxa, dividing the South Tibetan sedimentary successions of Aptian to Early Cenomanian age into eight new foraminiferal biozones (TLK1 a–h): (i) (TLK1a) a shallow reefal environment corresponding to planktonic foraminifera zone (PZ) Aptian 1–2, dominated by Palorbitolina and Praeorbitolina spp.; (ii) (TLK1b) a transgressive, reefal to forereefal environment corresponding to PZ Aptian 3, characterized by the first appearance of Mesorbitolina parva; (iii) (TLK1c) a shallow reefal to backreef environment of Late Aptian (PZ Aptian 4) age, characterized by the first appearance of Mesorbitolina texana; (iv) (TLK1d) a transgressive phase of forereef to an inner neritic environment of Albian (PZ Albian 1) age, characterized by the first appearance of Cuneolina pavonia; (v) (TLKe) an open-marine reefal environment of Albian (PZ Albian 2) age, with assemblages dominated by flat to slightly conical orbitolinids, characterized by the first appearance of Palorbitolinoides hedini; (vi) (TLK1f) a shallow, open-marine reefal to forereef environment of Middle Albian (PZ Albian 3) age, dominated by flat and convex orbitolinids, and characterized by the first appearance of Mesorbitolina aperta; (vii) (TLK1g) a reefal to forereef environment of end Albian (PZ Albian 4) age, characterized by the appearance of Conicorbitolina cf. cuvillieri and Pseudochoffatella cuvillieri, and in which Early Aptian species of Praeorbitolina cf. wienandsi have been recorded for the first time from the Late Albian; (viii) (TLK1h) a shallow reefal environment of Early Cenomanian age characterized by the first appearance of Conicorbitolina sp. A and Nezzazata conica. The eight new biozones provided biostratigraphic correlation of the Langshan, Sangzugang and Takena Formations in the Lhasa terrane, while the observed evolution of the environmentally controlled microfacies corresponds closely with the current, inferred global sea-level variation of the period. The almost continuous sedimentary sequences studied allowed previously defined orbitolinid phylogenetic linages to be confirmed.