So far, the source of the heat lost from the earth has been assigned only to the disintegration of the radio-active elements. Besides this, heat is liberated near the surface by the processes of weathering. The decomposition of one gram of average rock is accompanied by the generation of about 120 calories. Owing to its extreme slowness, this source of heat generation is of practically no importance except locally, where for a time it may succeed in appreciably steepening the temperature gradient. The heat liberated by weathering is probably balanced by the absorption of heat at greater depths, which is involved in the processes of metamorphism. Of much greater importance is the question whether the earth can still be regarded as possessing an ancient heritage of heat dependent on its origin.

The current situation in 1982 regarding the status and validity of the Ulakhan-Sulugur section on the Aldan River as a candidate for the global stratotype section and point for the Precambrian-Cambrian (PC-C) Boundary is reviewed with details of new work since 1973 and consequent revisions of views on controversial topics on a regional, continental and intercontinental scale of stratigraphic correlations with a short note regarding accessibility.

Among the Selachians of the existing fauna, there are none of greater interest and higher morphological importance than Notidanus, Cestracion, and the recently-discovered Chlamydoselachus from Japanese seas. These are the solitary survivors of once flourishing types, whose immediate congeners are only known to Biological science through the fragmentary remains preserved in the geological record; and the value of the archaic features they present is even further enhanced by the slight information already acquired regarding the geological distribution of their numerous extinct allies.

In both north-east Shetland and the Jotunheim area of Norway two nappes of crystalline rocks occur lying one above the other and separated in time and space by orogenic sediments. These sediments were formed in part at least by erosion of the lower, and first emplaced, of the two nappes in both areas. Later emplacement of the upper nappes caused the deformation and metamorphism of these rocks. In both Norway and Shetland large quartzite conglomerates which occur immediately beneath the upper nappes have been deformed on patterns which have been determined from a study of the pebble shapes. From these patterns in both areas it is argued that the deformation was due to flow caused by pressure differences developed in the sole of the advancing nappe and possibly to extrusion from beneath the nappe.

A new taxon of nanhsiungchelyid turtle, Jiangxichelys ganzhouensis n. g. n. sp., is described on the basis of a complete shell from the latest Cretaceous of Ganzhou, Jiangxi Province, China. It is close to Hanbodgemys, but different from the latter in having a boot-shaped second marginal scute reaching the first vertebral scute, a larger first suprapygal, a large fifth vertebral extending onto the tenth peripheral, narrower lateral marginal scutes and a narrower posterior plastral lobe. This discovery adds a new element to the scanty record of nanhsiungchelyids from southern China and illustrates the diversity of the family in that area.

New chitinozoan data are presented from the classical section along the Onny River in the type Caradoc area, and from the deeper-water sections in the Shelve area, including the former British candidate GSSP for the base of the Upper Ordovician Series. The rich and well-preserved chitinozoan fauna of the Onny River has been a standard for 40 years, but new data revise some of the identifications. The assemblages are now attributed to biozones that are more readily applicable for international correlation. The main part of the section can be interpreted as belonging to the originally Baltoscandian Spinachitina cervicornis Biozone, although this is uncertain in the lower part. Within this biozone, the Fungochitina actonica Subzone has been defined. The Onny Formation at the top of the section is equated with the Acanthochitina latebrosa–Ancyrochitina onniensis Biozone; contrary to earlier reports, Acanthochitina barbata is absent. The Lower Wood Brook and Spy Wood Brook section from the Shelve Inlier yielded a great number of moderately to well-preserved chitinozoans, but a low-diversity assemblage. Their ranges have been neatly positioned against the well-known graptolite stratigraphy in the area. A local Eisenackitina rhenana Biozone? has been recognized, allowing us to suggest some international correlations.

Gravitational collapse occurs during the mature evolution of orogenic belts, but its signature is difficult to discriminate in macroscopic structures from that of pre-, syn- or late-/post-orogenic extension, so reliable mesoscopic examples are particularly useful. A composite fabric developed along a lateral thrust ramp in the Apennines reveals mesoscopic normal faults that truncate the thrust surface, overprint the S-fabric and merge downwards in a foreland-directed splay, leaving the thrust footwall undeformed. These relationships indicate syn-/late-thrusting extension, which we interpret as induced by hanging-wall gravitational collapse. Our study provides critical constraints for reconstructing the kinematic evolution of collapsing thrust fronts.

Jurassic siliceous hot-spring (sinter) deposits from Argentine Patagonia were evaluated to determine the distribution and preservation quality of their entombed microbial fabrics. Detailed study showed that the Claudia palaeo-geothermal field hosts the best-preserved sinter apron in the Deseado Massif geological province, where we also found hot-spring silica–biotic interactions extending into hydrothermally influenced fluvial and lacustrine settings. Carbonaceous material was identified by petrography and Raman spectroscopy mapping; it is inter-laminated with silica across proximal vent to distal marsh facies. The ubiquitous presence of microbial biosignatures has application to studies of hydrothermal settings of early life on Earth and potentially Mars.

Since my account (1937) of the structure of a part of Cornwall and O Devon, I have re-examined in particular the area known as Roseland between the Dodman and Porthallow at the eastern end of the Lizard Boundary. This has led to a re-interpretation of the structure which, though in part concerned with the Gramscatho Beds, applies to a large area of Cornwall and Devon. In the last few years many workers have appeared in the area and I have been frequently asked for my views on the structure and succession. It is evident that my 1937 paper has given rise to some misconception regarding these views, and it is desirable to place on record a brief summary of the main conclusions to which I have been led by my work during the last twenty years (mainly since 1951).

The Sorachi Group, composed of Upper Jurassic ophiolite and Lower Cretaceous island-arc volcano-sedimentary cover, provides a record of Late Jurassic–Early Cretaceous sedimentation and volcanism in an island-arc setting off the eastern margin of the Asian continent. Stratigraphic changes in the nature and volume of the Sorachi Group volcanic and volcaniclastic rocks reveal four tectonic stages. These stages resulted from changes in the subduction direction of the Pacific oceanic plate. Stage I in the Late Jurassic was characterized by extensive submarine eruptions of tholeiitic basalt from the back-arc basin. Slab roll-back caused rifting and sea-floor spreading in the supra-subduction zone along the active Asian continental margin. Stage II corresponded to the Berriasian and featured localized trachyandesitic volcanism that formed volcanic islands with typical island-arc chemical compositions. At the beginning of this stage, movement of the Pacific oceanic plate shifted from northeastward to northwestward. During Stage III, in the Valanginian, submarine basaltic volcanism was followed by subsidence. The Pacific oceanic plate motion turned clockwise, and the plate boundary between the Asian continent and the Pacific oceanic plate changed from convergent to transform. During Stage IV in the Hauterivian–Barremian, in situ volcanism ceased in the Sorachi–Yezo basin, and the volcanic front migrated west of the Sorachi–Yezo basin.

Graptolites from more than 60 horizons in the basinal Caradoc succession of southwest Wales, between Fishguard and Cardigan, allow recognition of the multidens, clingani and linearis biozones. The biostratigraphy permits recognition of major differences in the sedimentary rock-sequence north and south of structures associated with the Fishguard–Cardigan Fault Belt. The Penyraber Mudstone Formation, disconformably overlying the Fishguard Volcanic Group (Llanvirn), is partly of multidens Biozone age. It is succeeded south of the Newport Sands Fault by the Cwm yr Eglwys Mudstone Formation of clingani to linearis biozones age. North of the fault the Cwm yr Eglwys Mudstone Formation is replaced laterally by the northwards-thickening, sandstone turbidite-dominated Dinas Island Formation (clingani and linearis biozones). Graptolite stratigraphical distribution indicates that Dicranograptus clingani occurs only rarely within the caudatus Subzone of the clingani Biozone and that Climacograptus antiquuss.l. also does not range above the lower part of the clingani Biozone. The first occurrence of Dicellograptus morrisi, within the upper clingani Biozone, confirms its value as a marker for the morrisi Subzone, and is associated with the first occurrences of Diplacanthograptus dorotheus and Normalograptus minimus. Dicellograptus flexuosus, used to indicate the morrisi Subzone elsewhere, occurs throughout the clingani Biozone in the Cardigan area. The linearis Biozone is recognized by Climacograptus tubuliferus. Oxic bottom conditions in early and early mid-Caradoc times largely precluded the influx of, or preservation of, graptolite faunas in the Penyraber Mudstone Formation. Anoxic mudstones of the Cwm yr Eglwys Mudstone and Dinas Island formations preserve graptolite assemblages of 21 and 26 species, signalling strong open marine influences which persisted in this area until late Caradoc times. This contrasts with the shelfal faunas in the Whitland area (south Pembrokeshire), where the late Caradoc is dominated by low-diversity Normalograptus-dominated assemblages.

The Cycladic blueschist belt, Greece, is mostly submerged below sea level and regional correlations are difficult to establish. Marbles are widespread within the belt and locally used as marker horizons to subdivide monotonous schist sequences. However, owing to the lack of distinctive petrographic characteristics, the marbles have not been used for island-to-island correlations. This study aims to investigate the potential of Sr-, C- and O-isotope compositions of marbles as a tool for unravelling the litho- and/or tectonostratigraphic relationships across the Cycladic islands, and as a proxy for the time of sediment formation. For this purpose, we have studied metamorphic carbonate rocks from the islands of Tinos, Andros, Syros, Sifnos and Naxos. Identical 87Sr/86Sr values for certain marble horizons occurring on Tinos, Andros and Sifnos are interpreted to document coeval regional carbonate precipitation. The 87Sr/86Sr values of the apparently least altered samples intersect the seawater curve multiple times within the most likely time interval of original carbonate precipitation (< 240 Ma; as indicated by previously published ion probe U–Pb zircon data) and thus an unequivocal age assignment is not possible. Very broad temporal correlations are possible, but more subtle distinctions are not feasible. On Andros, the overlapping Sr-isotope values of marbles representing the lowest and highest parts of the metamorphic succession are in accordance with a model suggesting isoclinal folding or thrusting of a single horizon, or very fast sedimentation. In contrast, distinct 87Sr/86Sr values for samples from Tinos, representing different levels of the metamorphic succession, suggest that these rocks represent a temporal succession and not the tectonic repetition of a single horizon. Based on Sr-, O- and C-isotope characteristics alone the time equivalence of marbles occurring on different islands could not be documented unambiguously. However, by using various combinations of these parameters, some occurrences can be discriminated from the overall sample population. The new data further accentuate the general potential of coupled Sr-, C- and O-isotope characteristics for identification of archaeological provenance and complement existing datasets for Aegean marbles.

The first find of microdiamond in the Nordøyane ultra-high-pressure (UHP) domain of the Western Gneiss Region (WGR) of the Scandinavian Caledonides reshaped tectonic models for the region. Nevertheless, in spite of much progress regarding the meaning and significance of this find, the history of rock that the diamonds were found in is complex and still largely ambiguous. To investigate this, we report U–Pb zircon ages obtained from the exact crushed sample material in which metamorphic diamond was first found. The grains exhibit complicated internal zoning with distinct detrital cores overgrown by metamorphic rims. The cores yielded a range of ages from the Archaean to the late Neoproterozoic / early Cambrian. This detrital zircon age spectrum is broadly similar to detrital signatures recorded by metasedimentary rocks of the Lower and Middle allochthons elsewhere within the orogen. Thus, our dating results support the previously proposed affinity of the studied gneiss to the Seve–Blåhø Nappe of the Middle Allochthon. Metamorphic rims yielded a well-defined peak at 447 ± 2 Ma and a broad population that ranges between c. 437 and 423 Ma. The data reveal a prolonged metamorphic history of the Fjørtoft gneiss that is far more complex then would be expected for a UHP rock that has seen a single burial and exhumation cycle. The data are consistent with a model involving multiple such cycles, which would provide renewed support for the dunk tectonics model that has been postulated for the region.

The oldest rocks in the Penbegˇli-Tut inlier of southeastern Turkey belong to the Meryemuşagˇi Formation (base not seen); they are mostly clastic rocks of ?late Precambrian age, overlain with angular unconformity by unfossiliferous quartzites (270 m est.) of the Zabuk Formation. The latter unit is succeeded conformably by the Koruk Formation (Lower?/Middle Cambrian), comprising almost 200 m of dolomite and grey and red nodular limestone, and the Sosink Formation (Middle Cambrian), about 600 m of silty mudstone and sandstone with a few thin limestone beds, overlain unconformably by Cretaceous carbonates. The closest comparison is with the Derik-Mardin area, 220 km to the east, where the section is more complete. The upper Koruk Formation contains trilobites of the Pardailhania and Solenopleuropsis biozones; trilobites from the Sosink Formation indicate the Solenopleuropsis Biozone, a post-Solenopleuropsis interval, and a level with Holasaphus mesopotamicus, known only from the Derik area. Acritarchs from the highest Koruk Formation and the whole of the Sosink belong to the lower part of microflora A2, described from the Middle Cambrian of eastern Newfoundland.

Sulphur isotopes can be used as a powerful tool to trace fluid evolution and explore the formation of chimneys. To clarify the in situ S isotopic variations of sulphides at the micro-scale, we analyzed a sulphide chimney collected from the hydrothermal field in the East Pacific Rise 1–2° S using a sensitive high-mass-resolution ion micro-probe for stable isotopes (SHRIMP SI). Three mineral zones can be identified in the chimney: an external outer wall of porous anhydrite and colloform pyrite, an internal middle zone of sub-euhedral pyrite and massive chalcopyrite, and an inner zone of massive pyrite. The δ34SV-CDT values of the sulphides fall within the range 1.83–7.51 ‰ (avg. 4.05 ‰, n = 16), and S isotopic values increase from the core (3.09 ‰, n = 3) to the middle (3.78 ‰, n = 11) to the edge (6.99 ‰, n = 2). These results illustrate mineral crystallization processes and the mixing between seawater-derived S and magmatic–hydrothermal fluids during the growth of the chimney. The zones from the edge to the core are characterized by crystal morphologies of colloform/anhedral pyrite to massive pyrite with decreasing δ34S values, revealing multi-stage mineral deposition and sulphur isotopic fractionation. In contrast to the increase in δ34S values from the core to the edge in one profile (profile A), anomalously low δ34S values in fine-grained pyrite relative to chalcopyrite in another profile (profile B) in the middle zone result from S isotopic exchange between seawater SO42− and fluid H2S due to different fluid–seawater mixing, possibly caused by variations in permeability and porosity across the chimney.

Discovery of a shallow oilfield in Triassic rocks in a fenland area west of Formby, as described by Lees and Taitt (1946, pp. 307–11), led to an attempt to determine the nature of the local Carboniferous rocks, which were regarded as the most likely primary source of the oil found in the Trias.

At least twenty silicified volcanic ash beds have been identified in the Kuibis and Schwarzrand subgroups of the terminal Proterozoic Nama Group of Namibia. Nineteen of the Nama ash beds are in the Schwarzrand Subgroup in the Witputs subbasin. Two of these are in the siliciclastic-dominated lower part of the subgroup, which consists of the Nudaus Formation and Nasep Member of the Urusis Formation and comprises two depositional sequences. Identification and correlation of these ash beds are very well known based on stratigraphic position. Sixteen ash beds are contained within the carbonate-dominated strata of the Huns, Feldschuhhorn and Spitskop members of the Urusis Formation. These strata comprise four large-scale sequences and eighteen medium-scale sequences. Ash beds have been found in three of the large-scale sequences and seven of the medium-scale sequences. Correlations are proposed for these ash beds that extend over large changes in facies and stratal thickness and across transitions between the seaward margin, depocentre and landward margin of the Huns-Spitskop carbonate shelf. A study of whole rock and in situ phenocryst compositions was conducted to evaluate the feasibility of independently testing sequence stratigraphic correlations by geochemically identifying individual ash beds. Whole rock abundances of Al, Fe, Mg, K and Ti vary inversely with Si, reflecting variations in phenocryst concentration due to air fall and hydrodynamic sorting. These sorting processes did not substantially fractionate whole rock rare earth element abundances (REE), which vary more widely with Si. REE abundances are higher in samples of the Nudaus ash bed than in samples of the Nasep ash bed, independent of position in bed, phenocryst abundance, or grainsize, providing a geochemical means for discriminating between the two beds. Variations in the position of chondrite-normalized whole rock REE plots similarly support suspected correlations of ash beds between widely separated sections of the Spitskop Member. Abundances of Fe, Mg and Mn in apatite plot in distinct clusters for Spitskop ash beds that are known to be different and in clusters that overlap for ash beds suspected of correlating between sections. Abundances of REE in monazites differ for the Nudaus, Nasep and Spitskop ash beds in which these phenocrysts were identified. Multivariate statistical analysis provided a quantitative analysis of the discriminating power of different elements and found that whole rock abundances of Ge, Nb, Cs, Ba and La discriminate among the whole rock compositions of the Nudaus and Nasep ash beds and the Spitskop ash beds that are thought to correlate between sections. Each of the above geochemical signatures, by itself, is not definitive because the differences between beds are comparable to the variability within beds and because some signatures are shared by beds known to be different. Taken together, however, weight-of-evidence arguments based on multiple components and phases can successfully discriminate among Nama ash beds. Results from this study support sequence stratigraphic correlations of Spitskop ash beds that document stratal truncations and gaps in the record related to onlap and erosion.

The Outer Hebrides, lying off the north-west coast of Scotland, are of particular interest to the student of Pleistocene geology, on account of the grand scale on which the results of ice-action are to be seen, and because of the marine shell-beds which are to be found at the northern end of the Isle of Lewis. In the present paper no general survey ofthe glacial deposits of the Outer Hebrides will be attempted; my object is rather to drawattention to certain features of the marine fossils, as a study of the coast sections shows that a faunal sequence can be established in the Pleistocene series.

Macrofabric (stone orientation) and microfabric studies of the four tills exposed in the coastal areas of East Yorkshire indicate that the regional direction of ice movement during both the Saale and Weichsel Glaciations was from north-east to south-west. The Saale (Basement) Till was considerably modified by the advance of ice during the Weichsel Glaciation; in particular, the stones in the Basement were reorientated so that their long axes now lie at right angles to the direction of movement of the Weichsel ice sheet. The fabrics of the three Weichsel tills (Drab, Purple and Hessle) are alike, and it is suggested that all three were deposited from one composite ice sheet. The relationship of vertical joints in the Basement and Drab Tills to directions of ice movement is discussed; those in the Basement possibly originated as ac tension joints inherited from the parent ice, whereas some of those in the Drab are probably conjugate shear joints formed during post-depositional deformation of the till.

In a former publication I have dealt with the anatomy of Prolagus sardus (Wagn.), from the Sardinian and Corsican Pleistocene, in comparison with that of its Tertiary relatives. The following pages deal with the geographical distribution of Pleistocene Prolagus and its bearing on more general questions.

When Ouvier discovered, in the ossiferous breccia of Corsica, remains of a ‘Lagomys,’ which he believed to be closely related to the Siberian Lagomys alpinus, he also suggested other analogies between the faunas of the two regions—Siberia and Corsica (as well as Sardinia), and commented upon the supposed relationship between the insular Mouflon and the Siberian Argali. Similar views were expressed by B. Wagner.

Pumpelly, Loeard, and Lortet sought to establish a connection between a supposed Corsioan ‘ice-age,’ as attested by the trace of ancient glaciers, and the former existence in the island of a supposed inhabitant of cold regions, the Lagomys corsicanus. Hensel had, however, shown before, in 1856, that the affinities of Lagomys sardus from the Sardinian bone breccia are not with the recent Lagomys (Ogotona), but with a Miocene type, for which he proposed the generic name Myolagus (antedated by Prolagus, Pormel). He was in consequence inclined to assume a Tertiary age for the breccias in which the Prolagus occurred (and, indeed, for the whole of the Mediterranean bone breccias). A similar view has again been brought forward of late years.

I myself pointed out (1) that the Corsican Lagomys likewise belonged to the genus Prolagus, as indeed had already been suspected by Hensel from his inspection of Cuvier's figures; (2) that the Tertiary age of the Corsican and Sardinian breccias could not be upheld, above all, because the mollusca occurring in them, as Loeard bad shown to be the case in the ossiferous breccia of Toga, near Bastia, are still living in the neighbourhood.