Lines Of Weakness Research Articles

Investigation of growth responses in saprophytic fungi to charred biomass

We present the results of a study testing the response of two saprophytic white-rot fungi species, Pleurotus pulmonarius and Coriolus versicolor, to charred biomass (charcoal) as a growth substrate. We used a combination of optical microscopy, scanning electron microscopy, elemental abundance measurements, and isotope ratio mass spectrometry (13C and 15N) to investigate fungal colonisation of control and incubated samples of Scots Pine (Pinus sylvestris) wood, and charcoal from the same species produced at 300 °C and 400 °C. Both species of fungi colonise the surface and interior of wood and charcoals over time periods of less than 70 days; however, distinctly different growth forms are evident between the exterior and interior of the charcoal substrate, with hyphal penetration concentrated along lines of structural weakness. Although the fungi were able to degrade and metabolise the pine wood, charcoal does not form a readily available source of fungal nutrients at least for these species under the conditions used in this study.

Evolution of mud-crack patterns during repeated drying cycles

In mud, crack patterns are frequently seen with either an approximately rectilinear or hexagonal tiling. Here we show, experimentally, how a desiccation crack pattern changes from being dominated by 90° joint angles, to 120° joint angles. Layers of bentonite clay, a few mm thick, were repeatedly wetted and dried. When dried, the layers crack. These cracks visibly close when rewetted, but a similar crack pattern forms when the layer is redried, with cracks forming along the lines of previously open cracks. Time-lapse photography was used to show how the sequence in which individual cracks open is different in each generation of drying. The geometry of the crack pattern was observed after each of 25 generations of wetting and drying. The angles between cracks were found to approach 120°, with a relaxation time of approximately 4 generations. This was accompanied by a gradual change in the position of the crack vertices, as the crack pattern evolved. A simple model of crack behavior in a layer where the positions of previously open cracks define lines of weakness is developed to explain these observations.

The oogonial aperture of Oedogonium decipiens var. decipiens (Oedogoniales, Chlorophyta) and its systematic significance

According to traditional taxonomical criteria, the fertilization aperture in the genus Oedogonium has been classified into pore or circumcision type. To contribute with information useful to clarify the systematics of the Oedogoniales, we have studied the oogonial aperture in O. decipiens var. decipiens showing a circumcision in median position. The aperture mechanism and associated structures (line of weakness and thin layer) are similar to those previously described in O. cardiacum. The type and position of the aperture in mature oogonia was also studied in other seven Oedogonium species. In all the analyzed species, the fertilization aperture occurs along the line of weakness, but they would differ only in the opening degree of this line. Therefore, the types of oogonial aperture would not be so different as to discriminate groups of species belonging to the genus Oedogonium, in agreement with a previous molecular phylogenetic study of this group of algae.

Active crustal deformation beyond the SE margin of the Tibetan Plateau: Constraints from the evolution of fluvial systems

An integrated explanation is proposed for the Late Cenozoic crustal deformation in Yunnan, SW China, using sedimentary and geomorphological evidence from the Yangtze and Red River systems. The observed fluvial incision indicates up to ~ 15 km of crustal thickening, associated with ~ 3 km of uplift, apparently triggered at ~ 8 Ma by monsoon-induced erosion drawing mobile lower crust from beneath Tibet to the northwest. The mobile lower-crustal layer beneath Yunnan was initially very thin, but a positive feedback loop developed, whereby each incremental influx of lower-crust widened and heated this layer, facilitating the next increment. At ~ 5 Ma, the shear tractions exerted on the brittle upper-crust by this flowing lower crust became sufficient to reactivate pre-existing lines of weakness, dragging blocks of the brittle layer southward and creating the region′s modern active fault systems. This region thus provides a dramatic example of crustal deformation induced by Late Cenozoic climate change, notwithstanding its location adjoining the India–Eurasia plate boundary.

Physical and chemical characteristics of particles produced by laser ablation of biogenic calcium carbonate

LA-ICP-MS analysis of the chemical composition of biogenic carbonate has many applications in the environmental sciences but the characteristics of the material produced by the ablation process are largely unknown. To fill this gap, we have undertaken a study of the chemical and physical nature of particles produced by laser ablation of biogenic carbonates. SEM imaging suggests that laser ablation produces two distinct particle populations, one consisting of microsize particles and the other of nanosize particles. A 213 nm laser gives rise to a higher proportion of microsize particles than a 193 nm laser, probably because the 213 nm laser couples less completely with carbonate material. The microsize particles appear to form by photomechanical fracturing along lines of cleavage or weakness, rather than by hydrodynamic sputtering (as is generally observed for silicates). Chemical analysis of the carbonate particles suggests that little chemical fractionation of biogenic carbonates occurs during the ablation process or during transport to the plasma. This is supported by the constancy of the fractionation factor ([X/Ca]measured/[X/Ca]true) during the course of an ablation of a carbonate standard. In contrast, changes in the fractionation factor during the first few seconds of ablation of the NIST 612 are observed for some elements. This difference in fractionation is likely to result from the different formation mechanisms of the microsize particles.

Model characterization and failure analysis of welded aluminium components including process history

There is currently a high level of interest in automotive and other industries to use aluminium extrusions for lightweight structural members. The preferred joining technology is robot controlled MIG welding to provide a fast, consistent, high-quality weld. The disadvantage, however, is that the high temperature fusion process causes metallurgical transformations adjacent to the weldline in the Heat Affected Zones (HAZ), which significantly reduce mechanical properties and provide lines of weakness. Under crash loading these zones are of special concern and techniques are needed to evaluate their performance. This paper investigates reduced mechanical properties in the HAZ of welded aluminium joints and proposes a failure law suitable for practical crash simulation of automotive structures. The work has necessitated a pragmatic approach in which a compromise is sought between the true representation of the void growth and fracture mechanisms that occur on a micro-scale and the need for a simplified macro-model appropriate for large scale CPU intensive structures. Simulation tools and techniques are also presented that enable the process history of the weld manufacture to be analyzed and results of the HAZ and modified mechanical properties to be mapped to the structural model for crash or failure analysis, thus limiting the need for extensive mechanical testing. Validation studies are presented on notched butt joints and dynamically loaded sectional welded joints.

Possible Existence of Deep-Seated Oil Deposits on Gulf Coast

Editor's Note: Originally published in AIME Transactions, this paper, which is heavily excerpted here, discusses the possibility of oil lying beneath salt domes along the US Gulf Coast. The discovery of oil in 1901 on the Spindletop dome, Texas, inaugurated a new industry on the Gulf Coast, an industry which has grown with the discovery of successive fields, until today it engages the services of thousands of workers and employs enormous capital. New fields are being discovered from time to time and doubtless some still remain to be found, though of late years, discoveries have become more infrequent. Nowadays, several hundred dry holes are drilled each year in a fruitless and blind effort to discover new fields, for as yet geologic science has developed no effectual method of locating the coastal oil deposits in advance of drilling. Moreover, despite the occasional discovery of new fields, the total production of the Gulf Coast is today no greater than it was in 1906, for the added production of the new fields has been offset by the rapid decline and more or less complete exhaustion of some of the older ones. Careful geologic work within the fields has in some cases increased the production temporarily, but has developed no really new supplies. The Gulf Coast oil industry seems to have passed its period of greatest expansion and to be declining at a fairly steady rate, and this condition is naturally viewed with alarm by the more far-sighted operators. In my opinion, the time has come for the adoption of radical and aggressive methods of prospecting; and a fraction of the money wasted yearly in drilling shallow wells in hopeless locations might well be devoted to this purpose. Many facts lead me to believe that all the salt-dome oil has had a common origin; that it has migrated up from considerable depth along lines of structural weakness; and that a deep well, properly located, stands an excellent chance of discovering the parent reservoir and thus of developing new and probably great supplies. All of the oil produced in the coastal region of Texas and Louisiana is probably associated with salt domes, though in Goose Creek, Edgerly, and one or two other fields no salt has yet been actually penetrated. As a result of the innumerable wells that have been drilled on the various domes, it is now known that a typical salt dome consists of a very thick mass of pretty pure rock salt, generally almost flat-topped, but sloping abruptly away from the rim on every side. The flat top of the salt is generally covered by rock 25 ft to several hundred feet thick, consisting chiefly of limestone, dolomite, anhydrite, or gypsum, with generally more or less sulfur. The sediments above the salt are slightly domed and those on the sides of the salt mass generally slope at angles of 30 to 60°, and in some fields at even greater angles. These sediments consist of sand, gravel, shale, and gumbo, arranged in beds so lenticular and irregular that they can seldom be correlated from one well to another.

Instantaneous deformation and kinematics of the India-Australia Plate

SUMMARY Active intraplate deformation of the India‐Australia Plate is now being captured by far-field global positioning system (GPS) measurements as well as measurements on a few islands located within the deforming zone itself. In this paper, we combine global and regional geodetic solutions with focal mechanisms of earthquakes to derive the present-day strain field of the India‐Australia Plate. We first compile an updated catalogue of 131 Indian intraplate earthquakes (M > 5) spanning the period between the two Asian mega earthquakes of Assam 1897 and Sumatra 2004. Using Haines and Holt’s numerical approach applied to a fully deformable India‐Australia Plate, we show that the use of GPS data only or earthquakes data only has severe drawbacks, related, respectively, to the small number of stations and the incompleteness of the earthquakes catalogue. The combined solution avoids underestimation of the strain inherent to the Kostrov summation of seismic moments and provides details that cannot be reached by pure GPS modelling. We further explore the role of heterogeneity of the India‐Australia Plate and find that the best model, in terms of geodetic vectors fit, relative distribution of strain, style and direction of principal strain from earthquakes, is obtained using the surface heat-flow as a proxy for rheological weakness of the oceanic lithosphere. The present-day deformation is distributed around the Afanasy Nikitin Chain in the Central Indian Basin (CIB)—where it is almost pure shortening—and within the Wharton Basin (WB) off Sumatra—where it is almost pure lateral strike-slip. The northern portion of NinetyEast ridge (NyR) appears as a major discontinuity for both strain and velocity. The new velocity field gives an India/Australia rotation pole located at 11.3 ◦ S, 72.8 ◦ E( −0.301 ◦ Myr −1 )o verlapping with previous solutions, with continental India moving eastward at rates ranging from 13 mm yr −1 (southern India) to 26 mm yr −1 (northern India) with respect to Australia. Taking into account the intraplate velocity field in the vicinity of the Sumatra trench, we obtain a convergence rate of 46 mm yr −1 towards N18 ◦ Ea tthe epicentre of the 2004 Aceh megaearthquake. The predicted instantaneous shortening in the CIB and WB and extension near Chagos-Laccadive are in good agreement with the finite deformation measured from plate reconstructions and seismic profiles, suggesting a continuum of deformation since the onset of intraplate deformation around 7.5‐8 Ma. Since no significant change in India convergence is detected at that time, we suggest that the intraplate deformation started with the trenchward acceleration of Australia detaching from India along a wide left-lateral oceanic shear band activating the NyR line of weakness as well as north‐south fracture zones east of it. The predicted total amount of left lateral finite strain along these faults is in the range 110‐140 km.

Re-reading the new regionalism: A sympathetic critique

This paper provides a sympathetic critique of the new regionalism—currently one of the leading debates taking place in English-speaking human geography. By unpacking the new regionalism from its dual origins in economic geography and political science, the paper engages with some of its inherent lines of weakness by: developing a critique arguing that it is inappropriate on the part of the new regionalism to neglect the role of the state in the resurgence of regions in the reconstituted capitalist space economy; exploring the accusation that the new regionalism has become enmeshed in multifaceted scalar politics and associated tangled policy hierarchies; and, arguing that, through policy-transfer programmes, path- dependency, social capital and soft institutionalism, the new regionalism has been constructed on inadequate foundations. Finally, in developing this sympathetic theoretical and methodological critique towards the new regionalism, this paper speculates on how new regionalists should actually go about ‘doing’ regional regulation.

New evidence for Afro-Arabian plate separation in southern Afar

Abstract The May 2000 earthquake cluster, around 10° N and 41° E in southern Afar, has been studied using high quality data from 12 temporary and permanent broadband seismic stations deployed in the area. 140 earthquakes have been located using P- and S-wave arrival times, a well-constrained velocity model, and a double-difference location algorithm. Source mechanisms and moment magnitudes for the four largest events (M > 4) have been obtained from moment tensor inversion. There is no clear alignment of the epicentres along a fault zone; however, the events are clustered slightly southeast of Mount Amoissa along WNW-ESE extension of the Ayelu-Amoissa (Abida/Dabita) lineament. Focal mechanisms show fault motion along WNW-ESE to east-west striking normal faults, with extension oblique to the orientation of the Main Ethiopian Rift. The non-double-couple components of the source mechanisms range from 18–25%, suggesting that the seismic activity is of tectonic origin and not volcanic. Source depths are ≤7 km, in good agreement with estimates of the elastic thickness of the Afar lithosphere. We suggest that the Gewane earthquake swarm represents remnant strain accommodation along a previous line of weakness in southern Afar related to the separation of Arabia from Africa because the focal mechanisms show north-south extension similar to many of the events in central Afar at the triple junction where Arabia is presently rifting away from Africa.

The ballistic performance of narrow fabrics

Woven fabrics are widely used in soft body armour. The ballistic performance of a range of narrow fabrics was determined and compared to that of wider fabric panels. In contrast to conventional ballistic fabrics, it was found that the performance of narrow fabrics was highly sensitive to changes in fabric specification. Furthermore, it was shown that square weave fabrics may not necessarily be superior to unbalanced fabrics in narrow fabric form. It was also confirmed that narrow fabrics absorb more energy than wider fabric panels when undergoing direct ballistic impact, particularly when gripped in a two-sided configuration. Ways were sought of utilising these improvements in performance when the narrow fabrics are brought together to make full-width armour panels. Potentially, the observed improvements in performance could have been offset by the lines of weakness between adjacent fabric strips or by the weight of the structure required to grip on two sides. However, after investigating a number of potential solutions, significant improvements in the performance-to-weight ratios over simple fabric armour were achieved using an assembly of narrow fabrics attached to a lightweight composite frame.

Of Boars, Rhapsodes, and the Uses of Culturalist Error

C LASSIFICATORYSYSTEMS WORKA WEIRD MAGIC upon the world. Their enforcement of arbitrary division and homogenization is the constant work of language: these forces have a power to trap the swarming anarchy of detail that attention confronts everywhere. Culturally-defined schemata are as guilty of this as any other variety, and the attempt to characterize national or ethnic cultures as unities susceptible to summary has had a particularly troubling history. Culturalist logic has retained a peculiar aesthetic force since the earliest days of colonialism, and even the most monstrous sadnesses of the drive to empire have been obscured by the radiance of imagined structures. Although it is not difficult for academics to move beyond over-hasty categories -we do so at the urgings of something almost instinctual-the various critiques performed by recent postcolonial criticism have been revelatory. Old habits of mind have been deployed in new ways, movements of cultural force and subversion traced and delineated, and literature (if not Weltliteratur) given a reality and a bittersweet history that one could never have suspected from the well-meant abstractions of core classes everywhere. The European canon is no enemy to the mainstream of such criticism, just a foil against which the complex literary engagements of the colonial periphery are analyzed. The civilizational frameworks that separated the cultural globe into Manichean spheres of light and dark have been unwoven, not to vitiate Europe, but to understand the processes by which imperial ideologies hide complexity. But how does one read these insights back into an analysis of the traditional canon? Even if many of the insights of postcolonial practice are too specific to the histories of the decolonizing world to be of much use in the analysis of the main line of the classical tradition, these insights need not leave the frameworks of the European past as mere ghostly hulks, suited only for abandonment to the recesses of deep storage. An understanding of literary tradition in the wake of transcended schemata can be superior to an understanding that had never been subjected to the bland authority of culturalist essentialisms. Objects fracture along lines of weakness, both in the physical world and in the ideational. Understanding the nature of a literary-theoretical system's failure allows us better to measure the weights of culture beneath which it groaned. Sys-

Porous tubular structures with controlled fibre orientation using a modified electrospinningmethod

Electrospinning offers an avenue to produce small diameter tubes made out of nanofibres.However, to date, most tubes from electrospun fibres have been either random fibres orfrom sheets that were rolled into tubes. Although there have been suggestions of gettingtubes made of circumferentially aligned fibres, this is the first time that a method used tocreate a tube made of diagonally aligned electrospun fibres has been described. This tubewas formed by depositing fibres on a rotating tube during electrospinning to give aresultant tube with uniform thickness and superior all round mechanical strength withoutany line of weakness. A knife-edged auxiliary electrode was given a charge that wasopposite to that of the charge given to the needle to create an electrostatic field thatencouraged fibre alignment on a rotating tube collector. A tubular structure made ofnanofibres aligned in a diagonal direction was produced through electrospinning.

A note on the troughs in the Three Gorges channel of the Changjiang River, China

The reaches of the Changjiang River between Baidicheng and Fengjie of Sichuan province and Nanjinguan and Yichang of Hubei province, collectively called the Three Gorges channel, are about 200 km long. More than 90 deep troughs occur in this part of the Changjiang River, which cumulatively cover 45% of the Three Gorges channel. This study investigated the geomorphological features of the troughs in the channel. The troughs were formed by fluvial downcutting along lines of tectonic weakness. The deepest points are normally located in tectonic zones of high intensity where joints and fissures, longitudinal and transverse to the stream flow direction, intersect.

Migration of fluids controlled by equidistant fracture systems: an example from Central Europe (Czech Republic, Slovakia and Austria)

An extensive system of equidistant, N–S-trending linear zones has been identified to cut across crystalline and sedimentary units of the Bohemian Massif, Czech Republic and peripheral parts of the Alpine-Carpathian chain in Austria and Slovakia. The system represents the lines of weakness that were periodically reactivated and provided conduits for hydrothermal fluids of deep-seated origin. Post-Variscan fluid events were recorded through lineament-associated occurrences of volcanic intrusions, calcareous tufas, mineralised veins and hydrothermal karst that occur along these lineaments. Discharges of mineral and thermal waters, warm subsurface brines and the gas fluxes along some lineaments demonstrate present-day activity of the system. N–S-trending linear zones distinguished in Central Europe are comparable to apparently similar linear systems in Arabia, Africa and Russia.

SHRIMP baddeleyite age for the Fraser Dyke Swarm, southeast Yilgarn Craton, Western Australia

Recent high‐resolution aeromagnetic data have delineated an extensive swarm of undeformed northeast‐trending dolerite dykes in the southeastern Yilgarn Craton, known previously only from isolated exposures in surface mining operations. Owing to parallelism of the dykes to the Fraser Mobile Belt, the eastern segment of the Albany‐Fraser Orogen, the swarm is referred to here as the Fraser Dyke Swarm. Ion‐microprobe dating of baddeleyite from a granophyric segregation in the centre of one dyke yields a mean 207Pb/206Pb age of 1212 ± 10 Ma (95% confidence limits). The location of the Fraser Dyke Swarm, adjacent and parallel to the Fraser Mobile Belt, suggests that the dykes may have been emplaced into lines of weakness that originated during tectonic loading and downwards flexure of the craton margin. This is the first evidence of ca 1210 Ma mafic dykes and associated crustal‐scale extension in the southeast Yilgarn Craton, although the age is similar to those reported recently for dolerite and quartz diorite dykes in the central and southern part of the craton, suggesting that a genetic relationship may exist between intrusions in the two areas.

Short communication Refinement and characterisation of a thermodynamically stable β-[Ni(Al,Ti)]–β′-[Ni2 AlTi]–γ′-[Ni3 (Al,Ti)] metal–metal composite

The Ni–Al–Ti system contains three intermetallic phases, γ′, β, and β′ which have complementary properties. The objective of the present investigation was to coextrude these three phases to form a metal–metal composite (MeMeC) and investigate the mechanical properties and failure mechanisms of such a material. High strengths, comparable with that of the strongest constituent phase, have been recorded for the MeMeC material. Strength is maintained at a constant level up to 500°C above which it falls progressively. The compressive strain to failure is considerably greater that that expected for monolithic β or β ′ phases. It has been shown that the interfaces between nominally single phase regions provide lines of weakness along which cracks propagate during compressive loading. Preliminary attempts to strengthen the interfaces by a 24 h heat treatment at 900°C have been carried out.

The evolution of the Central North Sea Rift

Data drawn from regional 3D seismic coverage in the UK North Sea and 2D surveys from adjacent areas illustrate the sequential development of Triassic, Jurassic and Cretaceous rifting across the Norwegian, Danish and UK North Sea. The North Sea Rift system is described as a failed rift of Jurassic-Triassic age formed on a basement transected by Palaeozoic lines of weakness developed principally along NE-SW ‘Caledonide’ and NW-SE ‘Trans-European Fault Zone’ trends. The principal effect of these Palaeozoic lineaments has been to offset the development of extensional sub-basins within the rift in an en echelon fashion. The Triassic–Early Cretaceous history of the North Sea records a westward migration of the rift axis. During the Late Jurassic, a significant rotation of kinematic vectors resulted in an overprint of the pre-existing basin fabric throughout the Central North Sea–Outer Moray Firth area. Fault, isopach and stratigraphic data illustrate the effects of kinematic axis rotation during Jurassic rifting on the Late Jurassic–Cretaceous basin fill. The Jurassic polyphase rifting history of the North Sea is explained by a variation on a ‘vector triangle’ model proposed by earlier workers. On all scales, structural geometries within the Central North Sea are primarily attributable to basement extension and salt tectonics. The role of the inherited Palaeozoic basement grain during extension has been to offset the extensional structures and sub-basins in an en-echelon, relay manner, forming the fundamental structural components of the basin.

Templates from mainland Africa and the Red Sea for interpreting the early evolution of the South Atlantic

Abstract Findings drawn from the Tertiary pre-rift, rift and post-rift sequences of Africa and the Red Sea are applied to the South Atlantic margins with a view of aiding hydrocarbon exploration. In relation to gravity and magnetic prediction of top basement, template rifts tend to follow pre-existing lines of weakness and the upper crust underlying these rifts may have geophysical characteristics which are different from those of the rift flanks. Template rifts may or may not be associated with volcanicity. In sparsely volcanic rifts, syn-rift volcanism is located on rift axis structural highs. Extensive volcanism is accompanied by regional doming and erosional loss of the pre-rift section is likely in rift sectors preceded by volcanism. Consequently, it is doubtful whether pre-rift sediments are preserved beneath the major volcanics offshore from the Parana-Etendeka areas in the South Atlantic. The Kalahari Group of southern Africa is identified as a good analogue for pre-rift reservoir objectives in the South Atlantic, and facies and thickness criteria are discussed that help discriminate pre-rift sequences from rift sequences. Where sedimentation has kept pace with rift subsidence, so that fault scarp facies have not developed, then the Okavango Delta provides a useful analogue. Parallels are drawn between major sand dykes interpreted from seismic in the deepwater deposits of Lake Tanganyika and similar units within similar facies in the Recôncavo Basin of Brazil. Direct analogue links between the Red Sea and the South Atlantic are less strong, mainly because marine incursions, and salt deposition, occurred at a later structural stage in the South Atlantic. The onset of salt deposition in the Gulf of Suez-Red Sea occurred whilst rift block faulting was still in progress, and the post-rift sag phase, though partly salt filled, rapidly turned to fully-marine deposition. The earliest part of the post-rift sag phase in the South Atlantic is represented by laterally extensive lacustrine source rocks. Salt deposition in the South Atlantic occurred only after full development of the sag phase.

New goniodomacean dinoflagellates with a compound hypotractal archeopyle from the late Cenozoic:CapisocystaWarny and Wrenn, emend.

Two new species of dinoflagellate are described from the upper Cenozoic of the North Atlantic region. They are assigned to the goniodomacean genusCapisocystaWarny and Wrenn, 1997 emend., whose archeopyle uniquely forms by the extensive and exclusive dissociation of hypocystal plates.Capisocysta latanew species is recorded from the upper lower Pliocene Coralline Crag Formation of eastern England, the lower and upper Pliocene of the subsurface Great Bahama Bank, and as a living cyst from Phosphorescence Bay, Puerto Rico.Capisocysta lyelliinew species is reported from the Coralline Crag Formation of eastern England.Capisocystaprovides the only unambiguous example of a hypocystal archeopyle in the order Gonyaulacales and the only example of a hypotractal archeopyle in the division Dinoflagellata.The spherical, proximate cysts have pre-formed lines of weakness that occur exclusively on the hypocyst, where they follow plate boundaries. Upon excystment, these sutures facilitate the separate release of plates 2–6″′, ps, 1p, and 1″″. Sulcal plates 1s and rs and postcingular plate 1″′ typically remain attached to the epicyst, forming a distinctive hyposulcal tab. The single antapical plate inC. latais represented inC. lyelliiby two plates (left and right first antapical homologues) that are released separately.Capisocystahas a tropical to warm temperate distribution today. It thrived and perhaps formed blooms in tropical carbonate platform environments of the Bahamas during the Pliocene, and might prove to be a useful indicator of very warm intervals within the Pliocene of higher latitude regions including the southern North Sea basin.To facilitate discussion ofCapisocysta, several morphological terms have been modified or newly introduced. These terms more precisely describe archeopyle position and extent in dinoflagellates.