Calcareous Foraminifers Research Articles

Paleoenvironmental Implications from Ichnological and Microfaunal Analyses of Bajocian Spotty Carbonates, Pieniny Klippen Belt, Polish Carpathians

The nature and distribution of trace-fossil and microbenthic assemblages in Tethyan hemipelagic carbonates and marks of the Podzamcze Formation (Bajocian, Pieniny Klippen Belt) are studied. These analyses allow the identification of (1) recurring Planolites-Chondrites, Planolites-Chondrites-Zoophycos/Teichichnus and Chondrites ichno-assemblages, and (2) poor microbenthic assemblages dominated by agglutinated foraminifers and rich microbenthic assemblages dominated by diversified calcareous foraminifers as well as ostracods. A cross correlation of trace-fossil and microbenthic assemblages with the lithology and petrography of their host sediments suggests the presence of three different paleo-oxygen levels ranging from strongly dysaerobic, moderately dysaerobic to slightly dysaerobic (or aerobic)

Feeding by asellote isopods (Crustacea) on foraminifers (Protozoa) in the deep sea

Analysis of gut contents of two deep-sea asellote isopod species, Ilyarachna hirticeps and Eurycope inermis (Munnopsidae, Asellota, Isopoda, Crustacea), showed that they were preying on benthic foraminifers. Benthic foraminifers with hard tests were more frequent in I. hirticeps guts than in E. inermis. I. hirticeps, having robust mandibles, is capable of crushing large calcareous and agglutinating foraminifers with hard tests. The presence of foraminiferal fecal pellets (stercomata), along with fine mineral particles and globigerinacean tests in I. hirticeps guts, shows that it was preying on the large, loosely agglutinating foraminifer, Oryctoderma sp. A. E. inermis swallowed whole, medium sized, calcareous foraminifers, which it apparently was unable to crush with its slender mandibles. The guts of E. inermis contained an abundance of mineral particles and globigerinacean tests. These are conjectured to be mashed remains of certain agglutinating foraminifers with soft tests, rather than being evidence of detritivory. It is suggested that feeding on foraminifers by asellotes may be common and may significantly affect the foraminiferal community.

Small foraminifers from the Middle and Upper Eocene in the Burgas District. Calcareous benthic foraminifers. Part II

This is the second paper of a series dedicated to the Eocene small foraminifera from the Burgas region (East Bulgaria). Published herein are descriptions of 23 species of calcareous foraminifers from the families of Cymbaloporidae, Asterigerinidae, Nonionidae, Chilostomellidae, Alabaminidae, Oridorsalidae, Heterolepidae, Gavelinellidae, Rotaliidae, Elphidiidae. Ten of the taxa found are new for Bulgaria. Indicated here is their distribution in the beds of the Ravnec and Mugris Formations from 19 borehole sections.

Optimum microfossil sequences and cyclic sediment patterns in Early Cretaceous pelagic strata

Three sequencing methods were used to calculate the most likely biozonation and the periodicity of sedimentary cycles in Lower Cretaceous pelagic strata of the Atlantic and Indian oceans.A database was built of 378 first and last stratigraphic occurrences of calcareous nannofossils, dinocysts, foraminifers, and geomagnetic reversals in highest Jurassic through Lower Cretaceous deep marine strata at 10 Atlantic Ocean and 3 Indian Ocean drilling sites. There are 135 different events in total, about one third of which are unique to either ocean. Using the complete data set, the quantitative stratigraphy methods STRATCOR and RASC calculated closely comparable optimum sequences of average first- and last-occurrence positions. The preferred zonal solution, based on the STRATCOR method, includes 56 events, each of which occurs at three or more sites. The events comprise 6 geomagnetic reversals, 25 nannofossils, 5 planktonic foraminifera, 8 benthic foraminifera, and 12 dinocysts occurrences. Nine assemblage zones have been recognized of Tithonian through Albian age. All but 2 of 18 nannofossil events in the Atlantic Ocean optimum sequence were reported in the same stratigraphic order in a standard Mesozoic nannofossil zonation.Our quantitative examination, using Walsh spectral analysis, of the Lower Cretaceous cyclic sequences at three Deep Sea Drilling Project (DSDP) sites in the Atlantic Ocean generally supports the hypothesis that they are the product of cyclic climatic changes controlled by the Milankovitch orbital cycles. The peaks in the power spectra usually can be related to obliquity and precession cycles; some peaks seem to correspond to the eccentricity cycle. Obliquity seems to be the most important and persistent orbital element responsible for cyclic sedimentation in the Early Cretaceous Atlantic Ocean.The actual pelagic sedimentation rates were calculated for some cores using the results of spectral analysis. The correlation of the actual pelagic sedimentation rate with cyclic patterns and the occurrence of calcareous turbidites indicate that the changes in cycle pattern are the reflection of changes in the oceanographic setting. The changes in oceanographic setting are related to relative-sea-level fluctuations. The intervals dominated by laminated limestone were deposited during higher sea-level periods.

Small Foraminifers from the Middle and Upper Eocene in the Burgas District. Calcareous benthic foraminifers – Part I

A series of papers is intended to be published in which the results from the analysis of the taxonomic composition and stratigraphic significance of the small foraminiferal assemblages in the Eocene sediments from the Burgas district will be presented. The collection studied includes microfossils from the Mugris Formation and the Ravnec Formation from 19 borehole sections on the territory of Černo More Coal Basin (North of Burgas). Most of the small benthic calcareous foraminifers (50 taxa) - from family Spiroloculiniclae Wiesner to family Cibicididae Cushman are described and illustrated in this study.

The Middle‐Upper Tournaisian boundary event

The Middle‐Upper Tournaisian boundary broadly correlating with the Kinderhookian‐Osagean boundary in North America represents a level of a conspicuous lithological as well as biotic change. The decline of Chernyshinella and increased representation of eurythermal and agglutinated forms marks the end of Cherepet evolutionary cycle in calcareous foraminifers. In conodonts the decline of Siphonodella inhabiting the pelagic to hemipelagic dysphotic to aphotic environment accompanied by a widespread dispersal and diversification of nektobenthic gnathodids characterizes the end of the first Tournaisian conodont cycle. A major regression associated with important sedimentological changes marks the boundary between the middle and upper Tournaisian mega‐sequences. The above changes in fauna and lithology seem to be connected with climatic oscillations and accompanying oceanographic changes. They are a part of the broader Upper Devonian‐Lower Carboniferous cyclic scheme which appears to have been modified by a complicated interplay of cyclic and nonrecurring processes.

Redefinition of the Osagean-Meramecian Boundary in the Mississippian Stratotype Region

Analysis of fossil occurrences in late Osagean-early Meramecian stratotype beds of the upper Mississippi River Valley shows that major faunal changes occur within the Warsaw Formation, not at the underlying Keokuk-Warsaw formational contact where the Osagean-Meramecian serial boundary is presently placed. Relying on this evidence, the authors propose raising this boundary to the base of the informal upper Warsaw member described herein. The boundary is recognized by the first occurrence of the brachiopods Warsawia lateralis, Planalvus densa, Crossacanthia perlamellosa, Setigerites altonensis, and Tetracamera subcuneata, the blastoid Pentremites conoideus, and the calcareous foraminifer Globoendothyra baileyi. Use of these fossil appearances provides a more rigorous definition of the serial boundary and permits correlation beyond the Mississippi River Valley. Foraminifers suggest that the boundary falls within the middle Visean of western Europe. The stratotype section for the proposed boundary is located near the type locality of the Meramecian Series at Meramec Highlands, St. Louis County, Missouri. The lithostratigraphy of the late Osagean and early Meramecian is reviewed in key areas within the Mississippi River Valley and a new member, the Peerless Park, is proposed for a shoaling unit within the middle of the Keokuk Limestone.

The Upper Devonian (Frasnian) conodont sequence in the Lime Creek Formation of north-central Iowa and comparison with Lime Creek ammonoid, brachiopod, foraminifer, and gastropod sequences

The Upper Devonian (Frasnian) conodont fauna of the Lime Creek Formation of north-central Iowa is dominated by species of Polygnathus. Patterns of species composition and abundance are consistent with the Polygnathus biofacies described from the Frasnian of the Northwest Territories of western Canada. Consequently, the standard Frasnian conodont zones, defined on sequences developed in the Palmatolepis biofacies, are not applicable to the Lime Creek sequence. The Lime Creek conodont sequence correlates with Zones 4, 5 and Faunal Interval 7 of the Frasnian conodont sequence in the Alberta Rockies and with similar sequences in the southwestern United States. The Pb elements of Palmatolepis semichatovae Ovnatanova and Ancyrognathus? deformis (Anderson) are described and illustrated for the first time.In the Lime Creek Formation of north-central Iowa, brachiopods of the lowermost part of the Nervostrophia thomasi Zone of Day (1989a) occur in Zone 4, brachiopods of most of the N. thomasi, Douvillina arcuata, and Cyrtospirifer whitneyi Zones span conodont Zone 5, and the Elita inconsueta and Iowatrypa owenensis Zones occur in Faunal Interval 7. Species of the ammonoid Manticoceras and of the gastropods Floyda, Turbonopsis, and Westerna are restricted to Faunal Interval 7. Species of the calcareous foraminifer Nanicella first occur in Zone 5, and are joined by species of Multiseptida high in Zone 5.

Calcareous foraminifers from the Bashkirian stratotype (Middle Carboniferous, south Urals) and their significance for intercontinental correlations and the evolution of the Fusulinidae

The stratotype for the Bashkirian Stage of the Soviet Middle Carboniferous is located on the Askyn River in Gornaya Bashkiria (western slope of south Urals). Twenty-four rock samples, mostly from the lower part of the section, yielded abundant and diverse assemblages of calcareous foraminifers which are systematically described and illustrated here for the first time.The foraminiferal assemblage from the Siuransky Horizon at the base of the Bashkirian is essentially identical to that from the top of the underlying Lower Carboniferous Serpukhovian Stage. Thus, foraminifers do not provide a basis for identifying the Soviet Lower–Middle Carboniferous boundary. This notwithstanding, the presence of the foraminiferGlobivalvulina bulloides(Brady) (=G. moderataReitlinger) and the conodontIdiognathodus parvus(Dunn) in both the upper Serpukhovian and Bashkirian indicates that the base of the Bashkirian can be no older than medial to late Morrowan of the North American succession. The primitive fusulinidPseudostaffella(Pseudostaffella) appears at the bases of the lower Bashkirian Akavassky Horizon and the North American Atokan Series. The base of the Akavassky is interpreted to be somewhat older than early Atokan, however, becausePs.(Pseudostaffella) appeared in the Urals in phylogenetic continuity with its immediate ancestor, whereas in most of North America it was an immigrant.The type Bashkirian succession contains a seemingly complete phylogeny from advanced eostaffellids to primitive fusulinids.Plectostaffella jakhensis, immediate ancestor to the fusulinids, arose from a member of theEostaffella postmosquensisplexus in the late Serpukhovian.Plectostaffella jakhensis, in turn, gave rise toPs.(Semistaffella)variabilisin the early Bashkirian (late Siuransky), from which evolvedPs.(Ps.)antiquashortly thereafter (earliest Akavassky). An as yet unidentified but advanced species ofPs.(Pseudostaffella) is the most likely ancestor to late BashkirianNeostaffella ivanovi. The evolutionary series leading from theE. postmosquensisplexus to primitiveNeostaffellaapparently developed exclusively in the Eurasian–Arctic faunal realm, asPl. jakhensis, Ps.(Semistaffella)variabilis, andPs.(Ps.)antiquaare unknown in the Midcontinent–Andean region. DiversePs.(Pseudostaffella) spp. appeared in the latter area pursuant to an adaptive radiation aided by periodic interchange between faunal realms.

FEEDING ADAPTATIONS OF THE FORAMINIFERAN CIBICIDES REFULGENS LIVING EPIZOICALLY AND PARASITICALLY ON THE ANTARCTIC SCALLOP ADAMUSSIUM COLBECKI.

The calcareous foraminifer Cibicides refulgens is a conspicuous and abundant component of the epifaunal community living on the valves of the free-swimming Antarctic scallop, Adamussium colbecki. Examination of this association using light microscopy, scanning electron microscopy, radiotracer, and resin-casting/sectioning techniques, demonstrates that the foraminifer possesses a combination of morphological and physiological adaptations, unique among benthic calcareous foraminifera, which enhance its ability to acquire nutrients in an otherwise oligotrophic and seasonal environment. Three distinct modes of nutrition are employed: (1) grazing the algae and bacteria living upon the scallop shell surface, (2) suspension feeding through the use of a pseudopodial net deployed from a unique superstructure of agglutinated tubes which form an extension to the calcareous test, and (3) parasitism by eroding through the scallop's shell, and using free amino acids from the highly concentrated pool in the extrapallial cavity.

Calcareous Foraminifers from the Humboldt Oolite of Iowa: Key to Early Osagean (Mississippian) Correlations between Eastern and Western North America

Tuberculate foraminifers dominate the calcareous microfauna of the early Osagean Humboldt Oolite in north-central Iowa. This assemblage, previously unknown east of the Transcontinental Arch, occurs commonly in western North America, thus facilitating foraminiferal correlations between that area and the Midcontinent. Analysis of early Osagean microfossil occurrences within the Cordillera permits definition of an informal Zone of Tuberculate Foraminifers (ZTF) composed, in ascending order, of the subzones (1) Tuberendothyra tuberculata, (2) Spinoendothyra spp., (3) Inflatoendothyra spp., and (4) Eoforschia moelleri group-Paradainella spp. Comparison of the Humboldt microfauna to this succession indicates that an hiatus probably separates the oolite from the underlying Gilmore City Limestone, which contains a pre-ZTF assemblage. This break, which lies at the Kinderhookian-Osagean boundary, can be recognized widely in the western-shelf seaway where ZTF assemblages generally have been misinterpreted as late rather than early Osagean. Faunal gaps higher in the ZTF suggest that shelf sedimentation at some localities in the Cordillera may have been interrupted again later in the early Osagean. In Eurasia, the Humboldt assemblage best correlates to the late Tournaisian Kizel horizon and equivalent beds of the Russian Platform, Urals, and Ukraine. Newly named taxa include the alga Cylindrofolia glenisteri and the problematic Asphaltina? macadami.

Carboniferous and Early Permian biogeography

Research Article| January 01, 1985 Carboniferous and Early Permian biogeography Charles A. Ross; Charles A. Ross 1Gulf Oil Exploration & Production Company, P.O. Box 36506, Houston, Texas 77236 Search for other works by this author on: GSW Google Scholar June R. P. Ross June R. P. Ross 2Department of Biology, Western Washington University, Bellingham, Washington 98225 Search for other works by this author on: GSW Google Scholar Geology (1985) 13 (1): 27–30. https://doi.org/10.1130/0091-7613(1985)13<27:CAEPB>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Charles A. Ross, June R. P. Ross; Carboniferous and Early Permian biogeography. Geology 1985;; 13 (1): 27–30. doi: https://doi.org/10.1130/0091-7613(1985)13<27:CAEPB>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract During the Carboniferous, changes in the biogeographical distribution of shelf-dwelling, benthic marine invertebrates were made in response to changes in physical paleogeography and climatic variations. Calcareous foraminifers and bryozoans are principal examples of the general trends during the Early Carboniferous, which show that Tournaisian and early and middle Visean faunas were broadly cosmopolitan in a circumequatorial belt and that latitudinal diversity gradients were relatively minor. During the later part of the Visean and early part of the Namurian, the Hercynian orogeny, caused by the collision of Euramerica with Gondwana, disrupted these cosmopolitan equatorial faunal patterns. This was also a time of progressively cooler temperatures throughout the world, of dramatic reduction in faunal diversity, and of high rates of extinction of both species and genera.During middle Carboniferous time, strongly provincial faunas were common. Spasmodic, but limited, dispersals gave a few widespread genera significantly different stratigraphic ranges in different provinces so that Tethyan and non-Tethyan distributions are recognizable. Faunal diversity gradually increased during the middle Carboniferous and then declined at the end of the epoch with additional high levels of extinction of species and genera.During late Carboniferous time, several new faunal lineages became well established. Some filled vacant ecological niches; however, others took advantage of the increase in the number of niches that became available because of gradually warming climates. Provinciality continued to be pronounced. Diversity gradually increased and continued to do so through the Early Permian. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Calcareous foraminifera from the Ordovician of Baltoscandia

Abstract. Ordovician erratic boulders from northern Germany have yielded uniserial calcareous foraminifers which were previously unknown from the Baltoscandian Ordovician. They represent at least two new species which are provisionally placed in the genus Saccamminopsis Sollas, 1921.

Abyssal foraminifers, including two new genera, encrusting the interior of Bathysiphon rusticus tubes

Empty or sediment-filled tubes of the large agglutinated foraminifer Bathysiphon rusticus de Folin, 1886 occur abundantly in an abyssal epibenthic sledge sample taken in the northeast Atlantic. More than half of the tubes are coated inside and outside with a variably developed deposit rich in iron and manganese. They also bear on their inner surfaces an unusual assemblage of encrusting Foraminifera or Foraminifera-like rhizopods. Most of the 26 forms present are restricted to this habitat and other potential substrates carry only a sparse fauna of attached foraminifers. The majority of the forms are agglutinated and many contain protoplasm suggesting that they were alive when captured. Two are described as new species and genera, 14 are identified to species or genus, the remainder are left unidentified. Minute (<100 μm) calcareous foraminifers, including microforaminifers, are an important element in the assemblage. The foraminifers probably encrust the tube interiors because they provide a smooth and sheltered substrate. Some species, for example, the microforaminifers, may also be obtaining food, presumably bacteria, from the surfaces. There is some evidence that the protozoans are attracted by the presence of an iron-manganese coating. A comparison of the Bathysiphon tube foraminifers with previously described encrusting assemblages from deep-sea iron-manganese nodules reveals some interesting similarities. However, there are also some notable discrepancies for which explanations are offered.

Biostratigraphy of Tallahatta Formation (Eocene) in Eastern Gulf Coastal Plain and Revised Age for Claiborne Stage: ABSTRACT

Five continuous core holes drilled downdip of the outcrop belt of the Tallahatta Formation from western Georgia to western Alabama yielded calcareous inner neritic sand and clay containing calcareous nannofossils and foraminifers. The occurrence of these biostratigraphically useful groups in the subsurface Tallahatta allows the reliable dating of the entire formation; this has been difficult in the past because of the dominance in the outcrop belt of heavily leached, noncalcareous coarse clastics and sparsely fossiliferous siliceous clay and silt. Fossiliferous sand at the base of the Tallahatta generally overlies carbonaceous clay of the Hatchetigbee Formation. These lowest Tallahatta strata contain calcareous nannofossils diagnostic of Zone NP12 of Martini; overlying these strata are beds placed in Zone NP13. The uppermost Tallahatta beds in the core holes and in the Little Stave Creek outcrop section in western Alabama are assigned to Zone NP14; no positive evidence for strata belonging to Zone NP15 was found. Erosion surfaces separate the sediments belonging to each of the three calcareous nannofossil zones. On the basis of foraminiferal assemblages, the strata belonging to Zone NP12 and the lower part of Zone NP13 are interpreted as probably representing shallow-marine deposits; sediments in the upper part of Zone NP13 and Zone NP14 were probably deposited in somewhat deeper inner-shelf environments. Zones NP12 and NP13 are normally placed in the lower Eocene of the intercontinental correlation charts, whereas Zone NP14 has been considered entirely early Eocene, entirely middle Eocene, or straddling the boundary. Most of the Tallahatta Formation, including those strata considered to represent the basal Meridian Sand Member, is therefore of early Eocene age. As the Tallahatta is the lowest formation of the Claiborne Group, the base of the Claibornian Stage is thus placed within the early Eocene, and the Sabinian-Claibornian Stage boundary in Alabama and Georgia does not correspond to the early middle Eocene boundary. End_of_Article - Last_Page 1462------------

Micropaleontologic Analysis of Navarin Basin, Bering Sea, Alaska: ABSTRACT

Navarin basin, a large structural basin filled in places with more than 12,000 m of sediment, underlies the Bering Sea continental shelf about 100 km from the Koryak coast, U.S.S.R. The shelf in this region is relatively flat with a pronounced shelf-slope break at about 200 m. In contrast, the continental slope is incised by three large canyons. Little is known about the sediment and microbiota in the Navarin basin province because preveious work in the Bering Sea has been concentrated in the eastern and southern areas. More than 100 gravity cores and grab samples were collected during the summer of 1980 from the basin, adjacent slope, and nearby canyons in water depths ranging from about 80 to 3,300 m. Cores as long as 6 m contain predominantly clastic mud and sand. This preliminary U.S. Geological Survey sampling program is the first attempt in the Navarin province in which the three microorganism groups--diatoms, radiolarians, and foraminifers--are used to obtain paleogeographic information and to establish age-datum planes. Diatoms, the most abundant micro-organisms in the cores, are useful for defining glacial events and sea level fluctuations, and for establishing depth of deposition. Radiolarians are more abundant in the deeper shelf area, and are used to delineate paleogeographical boundaries and biostratigraphic events in the Navarin province. Calcareous foraminifers are abundant in the cores from even the deepest stations, but diversity is low. Shallow-water benthic foraminifers recovered in deep water indicate downslope movement of sediment. Study of these three micro-organism groups provides a more complete picture of the benthic and planktonic communities and thereby leads to a more accurate paleoecologic interpretation of Navarin basin. End_of_Article - Last_Page 975------------

Alguns microfosseis da formação Piauí (neocarbonífero), bacia do Parnaíba

The Piaui Formation at 4 localities in eastern and western Parnaiba Basin contains a varied microfauna which includes: arenaceous and calcareous foraminifers, conodonts, bryozoans, ostracods, crinoid columnals, holothurian sclerites, echinoid spines, microgastropods, microbivalves, scolecodonts, sponge spicules, fish plates, teeth, otholits and bone fragments and plant remains. The foraminifers include about 25 different species, i.a.: Tolypammina sp. cf. T. gersterensis, .Ammovertella inclusa, Sorosphaera? cooperensis, Hyperammina sp. cf. H. sappintonensis, H. sp. cf. H. rockfordensis, Orthovertella? sp., Globivalvulina bulloides and Calcitornella sp. A and B. Conodonts present in the fauna are: Cavusgnathus lautus, Cavusgnathus gigantus, Cavusgnathus sp., Idiognathodus magnificus, Idiognathodus delicatus, Ozarkodina delicatula, Gnathodus bassleri and fragments probably of Euprioniodina. The microfauna, particulary the conodonts, indicate an early-middle Pennsylvanian age the Piaui" Formation at the localities examined.

Earliest calcareous foraminifera

WE present here evidence that early Palaeozoic calcareous foraminifera existed and were relatively complex (multilocular and multiserial) in form but that they have been regarded formerly as calcareous algae. The early part of the invertebrate fossil record during the Cambrian period seems to show a striking contrast between the abundance of highly developed organisms such as the trilobite arthropods and the paucity of simpler forms such as the foraminiferal protozoans. Foraminifera are very small acellular animals with an important role in marine food chains1 and it is reasonable to expect them to have been a significant component of the benthic fauna throughout the Palaeozoic. Yet few foraminifera have been reported from the Lower Palaeozoic and those described from the Cambrian are mainly simple forms with unmineralised tectinous or agglutinated tests2–4. Some more complex agglutinated forms are known from the Upper Cambrian5, but the first generally recognised calcareous foraminifer is the uniserial Saccaminopsis from the late Ordovician4. Consequently, the assumptions that Lower Palaeozoic foraminifera were primitive and mainly non-calcareous have been taken as bases for inferences concerning the early evolution of the group3–4 and the paradoxical, yet apparently inescapable, conclusion has been drawn that Cambrian foraminifera are very scarce.

Progress toward Reconciliation of Lower Mississippian Conodont and Foraminiferal Zonations

Research Article| September 01, 1974 Progress toward Reconciliation of Lower Mississippian Conodont and Foraminiferal Zonations Paul Brenckle; Paul Brenckle 1Research Center, Amoco Production Company, Tulsa, Oklahoma 74102 Search for other works by this author on: GSW Google Scholar H. Richard Lane; H. Richard Lane 1Research Center, Amoco Production Company, Tulsa, Oklahoma 74102 Search for other works by this author on: GSW Google Scholar Charles Collinson Charles Collinson 2Illinois State Geological Survey, Urbana, Illinois 61081 Search for other works by this author on: GSW Google Scholar Geology (1974) 2 (9): 433–436. https://doi.org/10.1130/0091-7613(1974)2<433:PTROLM>2.0.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Paul Brenckle, H. Richard Lane, Charles Collinson; Progress toward Reconciliation of Lower Mississippian Conodont and Foraminiferal Zonations. Geology 1974;; 2 (9): 433–436. doi: https://doi.org/10.1130/0091-7613(1974)2<433:PTROLM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Calcareous foraminifers and algae and conodonts indicate that the late Osagean Keokuk Limestone near its type section correlates with Visean strata in Belgium. This discovery necessitates shifting the Mamet foraminiferal zonal scheme so that the Keokuk is no older than Zone 10 and possibly as young as Zone 13, rather than corresponding to Zones 8 and 9. The occurrence of the conodonts Eotaphrus burlingtonensis and Polygnathus mehli near the top of the Burlington Limestone in its type area suggests that the Tournaisian-Visean boundary probably corresponds with the Burlington-Keokuk contact. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Biology and Ecology of Marginopora vertebralis (Foraminiferida), Great Barrier Reef

SYNOPSIS. Marginopora vertebralis Quoy and Gaimard is a large calcareous Foraminiferida adapted to euphotic sedimentary basins associated with tropical reefs. This and other species of foraminiferids commonly are abundant and loosely bind substrate sediments with their pseudopods to reduce erosion by waves and currents. Three stages of shell construction, embryonic, laminate and reproduction chamber stages, characterize major changes in the growth of individuals. A flexostyle in the embryonic apparatus and reproductive chambers that are well developed are reported for the 1st time in this species and genus. Reproduction in M. vertebralis is primarily asexual and reproductive activity is greatest during the late spring on the Great Barrier Reef. Reproductive maturity requires a year and commonly longer.M. vertebralis is host to at least one species and perhaps several species of zooxanthellae‐dinoflagellates of which the most common is Gymnodinium rotundatum in its motile form. These zooxanthellae are abundant in the protoplasm of M. vertebralis, give the living foraminifer a distinctive yellow‐brownish green color, and apparently are symbiotic. M. vertebralis and perhaps other large calcareous foraminifers which are hosts to similar zooxanthellae‐dinoflagellates may have an important ecologic relationship to hermatypic corals in serving as an alternate host in the life cycle of this symbiotic group. Such a symbiotic and alternate‐host relationship may explain the similar geographic distributions of large calcareous foraminifers and reef‐building hermatypic corals.