A number of workers have accepted the proposition that phylogenetic relations between extant organisms can be determined only by reference to the characters of those organisms. Palaeontological data, it is said, have not been useful for developing or refuting such hypotheses. This view may be tested by reference to the respiratory mechanisms of dipnoans (lungfishes) and amphibians. The structure of the heart, lungs, and circulatory systems has been used by various authors to support the view that these are sister groups. Geological data derived from stratigraphy, palaeoecology, taphonomy, geochemistry and functional morphology of primitive dipnoans is used herein to show that these organisms did not engage in aerial respiration. The first unequivocal evidence that dipnoans had become air breathers is from aestivation burrows in Early Permian rocks of the U.S.A. The Dipnoi must have evolved this capacity at some time between the Early Devonian, when the group became well established, and the Early Permian. Similarities between the respiratory systems of extant dipnoans and amphibians must be the result of convergence, or of the derivation of the Amphibia directly from the Dipnoi. The latter view is not currently accepted by any workers in the field. Thus data from the fossil record are used to demonstrate the invalid use of some neontological data for the development of a phylogenetic hypothesis. Classifications of extant organisms depending on putative shared–derived morphological or physiological characters that cannot be adequately tested for convergence by reference to fossils, must be regarded with due caution.

Untwinned albite (Ab99.4An0.4Or0.2) grains, forming during diagenesis and very low-grade metamorphism, are common in sandstones of the Brøttum Formation (Upper Proterozoic) in the Sparagmite Region of southern Norway. These untwinned albite grains are usually clouded by vacuoles and tiny inclusions which are mostly made of carbonaceous material (although some albite grains also contain some combination of carbonates, quartz, phengite, chlorite, pyrite, halite and anatase). The presence of microcline grains replaced partly by albite indicates that the albite grains are pseudomorphs after microcline. Chessboard albite which occurs in the Brøttum Formation is suggested to be detrital in origin.

The Lower Limestone Group, which outcrops extensively on the east coast of Fife, southeast Scotland, consists of interbedded sandstones, siltstones and claystones with occasional coal seams, and limestone beds. Several of the coals have been mined economically in the past.

The sequence was deposited in a shallow-water, deltaic setting. Three facies associations have been distinguished; (1) laminated claystones, and marine bioclastic limestones, which were deposited in prodelta and marine shelf environments, (2) crudely coarsening-upward sandstone units, interpreted as delta front deposits of fluvially-dominated though wave-influenced, shallow-water deltas, and (3) interbedded clastic sedimentary rocks and coals, deposited in delta plain environments. The sequence as a whole accumulated by repeated progradation and abandonment of deltaic complexes.

Palaeosol profiles of four types are superbly preserved within the delta plain facies association. These are (1) organic soils (peats), now coal seams, (2) gley palaeosols, which formed in persistently waterlogged conditions, (3) freely drained soils which formed on a quartz sand-rich substrate, and (4) similar profiles formed by free drainage through variable substrates and involving B horizon accumulation of concretionary iron oxides. Compound palaeosols are common.

Deposition of the Lower Limestone Group was influenced by the tectonic and volcanic instability of the Fife area during Visean times. Frequent seismic events centred on active fault lines caused local uplift of parts of the normally waterlogged delta plain environment, allowing the formation of well-drained soils. Peats (coals) were best developed and least affected by oxidation in an elongate, fault bounded zone of enhanced subsidence.

The dolerite and basalt intrusions within the Lower Palaeozoic sequence of northwest Wales are largely restricted to the outcrop of Ordovician strata. Their distribution and close association with known volcano-tectonic structures were controlled by a tectonic framework of deep-seated fractures. In central and northern Snowdonia, volcanism during Caradoc times was related to the evolution of a fracture-controlled trough. An increase in the extensional stress across the trough with time is reflected in the progressive increase in basaltic magma movement during the volcanic cycle. The trough represents an attempted rift in the lithospheric plate, which failed to create an ocean basin and was subsequently aborted.

The description of sandstone samples, defined by three components, is introduced through non-parametric sample density description. The composition of a particular sample defines a direction from the origin of the Cartesian reference frame. Radial difference between individual samples then provides the measure of their similarity. A sample set can be viewed as a bundle of compositional axes with a corresponding density distribution on both the ternary diagram (or unit constant sum plane) and the positive octant of the unit sphere. Because radial differences are disproportionately displayed on the ternary diagram, radial density calculations on the sphere are to be preferred. The mode of the sample set, the implied centre of greatest data concentration, is considered to be the most meaningful representative value, as the component joint mean can lie outside the data field with certain data configurations. In addition, the component joint mean cannot provide a useful representative composition for samples drawn from a bimodal distribution. Sample density distribution not only provides a data defined approach to describe sample dispersion, but also furnishes an indication of sample sufficiency in displaying the degree to which modes are supported by surrounding observations.

Mount Dromedary pluton is one of several predominantly monzonite plutons and smaller intrusive bodies which constitute the Dromedary igneous complex in southeastern New South Wales. The pluton exhibits a striking arrangement of petrographically, but not always chemically, distinct zones ranging from mafic monzonite at the outside to quartz monzonite in the centre. The rocks display a mineralogical and geochemical integrity which indicates a consanguineous relationship. Minor compositional discontinuities between zones, together with observed and inferred minor intrusive zone boundaries, suggest that each zone has to some extent evolved independently. Negative Eu anomalies in REE abundance patterns show that some of the zones have been affected by fractionation of feldspar, but complementary accumulates are not found at the present levels of exposure. The pattern of zoning can be explained by a process of shallow fractional crystallization in which variations within zones are the result of lateral accretion of alkali feldspar as well as settling and/or lateral accretion of mafic phases at lower levels in the intrusion and upward displacement of fractionated magma. The parental magma of the pluton probaby originated by partial melting of an alkali basalt composition with an amphibolite mineralogy at the base of the crust.

Stratigraphically and geographically restricted ocellar komatiite flows at Kambalda, Western Australia, appear to represent the products of ground melting of sulphidic sediments by komatiites in lava channels that localized the Fe–Ni–Cu sulphide ores. An immiscible sulphide liquid formed and gravitationally separated from the melted sediment (xenomelt), the resultant buoyant silicate liquid being partly or wholly assimilated by the turbulently convecting komatiite magma. Rarely, the xenomelt gravitationally migrated to the top of flows, and overflowed into the less turbulent lava levees where it collected to form a separate layer overlying a komatiitic layer within a single flow. There was selective preservation of the hybrid felsic layer, as an upper ocellar unit within an ocellar komatiite flow, in lava levees flanking lava channels. The ocellar unit is enriched in elements previously concentrated in the sediments, and shows U–Th–Pb isotopic systematics akin to the underlying sediments. Moreover, the partitioning relationships of U and Pb between the immiscible xenomelt and sulphide liquid enhances the range of U/Pb ratios for components of the ocellar unit, thus allowing sufficient spread of modern uranogenic Pb isotopic ratios to form isochrons, albeit imprecise ones. The range and similarity of model Th/U data from these flows (2.8−3.9) and adjacent sulphidic sediments (2.3−4.4; mostly 2.8−3.9) contrasts with the generally invariable Th/U within Kambalda ultrabasic–basic flows (3.6−3.9), and further supports the ground-melting hypothesis.

The Oruanui eruption was the largest known outburst of Taupo volcano, New Zealand, and is among the larger Quaternary eruptions documented. The eruption deposits are variously known as the Oruanui, Wairakei, Kawakawa Tephra, or Aokautere Ash formations, and represent a bulk volume probably exceeding 500 km3. Four new 14C age determinations on carbonized vegetation in the non-welded Oruanui ignimbrite are combined to give a conventional age of 22590±230 yr b.p. Compared with the previously accepted figure of 20000 yr b.p., this new age resolves the anomaly of apparently older 14C ages being obtained from a demonstrably younger New Zealand deposit, and strengthens correlation of this eruption with an Antarctic ice-core acid anomaly. The trace of this eruption has great potential as a time-plane marker in the Antarctic just prior to the last glacial maximum. The close similarity in ages between the Oruanui and a comparable sized eruption (Ito/Aira-Tn) in Japan suggests that this period of activity may represent the best chance of resolving any linkages between large-scale explosive silicic volcanism and climate changes.

A detailed survey of the patterns of regional deformation in North Wales has revealed the presence of several discrete, linear zones of anomalous deformation. These zones are distinguished by atypical finite strain values, intense tight to isoclinal folding, non-axial planar cleavages and high metamorphic gradients. A history of prolonged tectonic activity along these zones is indicated by their influence on sedimentation and volcanism. It is proposed that these zones reflect the deformation of the Lower Palaeozoic cover above pre-existing basement fractures. These basement fractures form a framework which divides North Wales into a series of blocks and sub-blocks. The end-Caledonian deformation is explained by a transpression model dominated by SE-directed shear with minor components of strike-slip localized in these zones. The application of this model to other parts of the Welsh Basin is briefly considered.