3D modelling of geological structures is a key method to improve the understanding of the geological history of an area, and to serve as a drive for exploration. Geomodelling has been performed on a large 60000 km2 area of the Zagros fold-and-thrust belt of Iran, to reconcile a vast but heterogeneous dataset. Topography, geological surface data and dips, outcrop surveys, and well and seismic data were integrated into the model. The method was to construct a key surface maximizing the hard data constraints. The Oligo-Miocene Top Asmari layer was chosen, as this formation was regionally deposited before the main Zagros collision phase and because the numerous outcrops allow proper control of the bed geometry in the fold cores. Interpreted seismic data have been integrated to interpolate the surfaces at depth within the synclines. Several conceptual models of fold geometry have been applied to estimate the best way to convert seismic time signal to depth. Several deeper horizons down to Palaeozoic strata were deduced from this key horizon by applying palaeo-thickness maps. During the construction, the 3D interpolated surfaces could be reconverted to time, using a velocity model, and compared with previous seismic interpretations. This exercise obliged us to revise some early interpretations of seismic lines that were badly tied to wells. The 3D modelling therefore clearly improves regional interpretation. In addition, the 3D model is the only tool that allows drawing consistent cross-sections in areas where there are no seismic lines. Emerging Hormuz salt diapirs were added to the model. Dimensions and shapes of the individual diapirs were modelled using a statistical survey on the cropping out Hormuz structures. Modelling reliably demonstrated that the diapirs, when piercing, show a constant mushroom shape whose diameter depends on the stratigraphic depth of observation. This observation allowed us to exemplify relations between the pre-existing diapirs and the anticlines of the area, and to highlight the morphological changes from the inner onshore areas to the coastal and offshore areas. In addition, one of the surprising results of this study was the observation of the increasing diameter of the diapirs at the time of the Zagros collision and folding event, with growth strata and overhangs on the flanks of the diapirs.

The complex can be divided into three units, here named the Lower, Middle and Upper Layered Series respectively, on the basis of petrochemical data and correction of the dips of the layering for the effects of post-consolidational flexuring. There are no chilled margins, and the contact with the country rock consists of granular basic and ultrabasic rocks, older than the cumulates of the layered series. The intrusive mechanism is considered in the light of field and chemical data.

The following observations are the result of working over the Middle Jurassic Arcidae with a view to monographic treatment of the Corallian and Bathonian species. The monographs must of necessity be slow in appearing, and in any case they are not the place to discuss the broader conclusions to which the investigations have led. The family is one full of interest from an evolutionary point of view, but an exceptionally involved maze of controversial matter, chiefly concerning nomenclature, by which the Arcidae have been burdened, has obscured the features of interest and the phylogeny.

The plutonic crustal sequence exposed northeast of Sabzevar is part of the ophiolitic belt of Sabzevar that occurs along the northern margin of the Central Iran micro-continent. The sequence includes olivine and pyroxene gabbro with cumulate characteristics, isotropic gabbro, foliated gabbro and a diabase sheeted dyke complex cut by wehrlite and olivine websterite intrusions, and pegmatite gabbro and plagiogranite as small intrusions and dykes. The sequence is comparable to gabbros in known ophiolite complexes. Microscopic studies show an abundance of the mesocumulate and heteradcumulate textures that represent open system magma chambers, which are common in supra-subduction zones. The olivine → plagioclase → clinopyroxene → ± orthopyroxene → amphibole trend of mineralization in the gabbros, similar to mid-ocean ridge basalt (MORB), and olivine → clinopyroxene → ± orthopyroxene → plagioclase → amphibole, similar to arc rocks, indicate the diversity in the formation of these rocks, and represent petrographic evidence of their formation in a supra-subduction zone. The rocks have calc-alkaline to tholeiitic affinities, and niobium depletion in the spider diagrams of diabase that matches the patterns of island arc magma. These patterns, and the light rare earth element enrichment of the diabase and plagiogranite, suggest the effect and introduction of the fluids, originating from the subducting slab, beneath the mantle wedge. The low titanium compositions, matching those of arc diabase and plagiogranite, plot in the island arc to MORB tectonomagmatic fields, and suggest formation of the Sabzevar ophiolitic plutonic crustal sequence in a supra-subduction zone during Late Cretaceous time.

The Lower Palaeozoic rocks of Britain afford the most complete succession of graptolite faunas as yet known, but these successions are not always of uniform type, since they are controlled by different factors.

The Late Cretaceous – Recent West Black Sea Basin and the Eocene–Oligocene Thrace Basin are separated by the Strandja arch comprising metamorphic and magmatic rocks. Since Late Cretaceous time the Strandja arch formed a palaeo-high separating the two basins which accumulated clastic sediment of >9 km thickness. During late Eocene – early Oligocene time the marine connection between these basins existed through the Çatalca gap west of Istanbul. The Çatalca gap lies on the damage zone of a major Cretaceous strike-slip fault; it formed a 15 km wide marine gateway, where carbonate-rich sediments of thickness c. 350 m were deposited. The sequence consists of upper Eocene shallow marine limestones (SBZ18-20) overlain by upper Eocene – lower Oligocene (P16-P19 zones) pelagic marl with a rich fauna of planktonic foraminifera; the marls are intercalated with 31–32 Ma acidic tuff and calc-arenite beds. The Çatalca gap is bounded in the west by a major normal fault, which marks the eastern boundary of the Thrace Basin. Seismic reflection profiles, well data and zircon U–Pb ages indicate that the Thrace Basin sequence west of the fault is late Eocene – middle Oligocene (37–27 Ma) in age and that the fault has accommodated 2 km of subsidence. Although there was a marine connection between the West Black Sea and Thrace basins during late Eocene – early Oligocene time, no significant exchange of clastic sediment took place. Sedimentation in the Çatalca gap ended abruptly during early Oligocene time by uplift, and this eventually led to the paralic conditions in the Thrace Basin.

A brief summary is given of the origin and geological history of the Red Sea Graben area, based on personal observations in Egypt during the periods 1937–1940 and 1947–9. The author is inclined to believe that the graben zone was formed in its initial stages at the end of the L. Eocene; the movements continued at least till Pleistocene times. The mechanism of the graben is explained as a combination of regional shearing faults together with regional updoming followed by stretch-faulting.

Granitic rocks from all the exposed components of the Lake District batholith have been analysed for ammonium to look for evidence of an ammonium-rich sedimentaryprotolith. The results indicate that the ammonium content of Lake District granites is related to the type and degree of alteration experienced by the rocks. Fresh, little-altered granites from all parts of the batholith have low ammonium contents (< 30 ppm), whereas highly altered rocks contain up to 250 ppm ammonium. The most ammonium-rich rocks are highly altered specimens of Skiddaw Granite containing appreciable secondary muscovite, sericite and clay. The degree of ammonium enrichment is related to the style of alteration and host-rock lithology. Evidence for the source of ammonium is provided by strong depletion (< × 0.3) of ammonium in silty mudstones within the cordierite andgarnet hornfels zones of the Skiddaw Granite aureole. In view of the low ammonium content of some sediments and the losses known to accompany high-grade metamorphism and associated dehydration, the low primary ammonium contents of the granites are not considered to be evidence either for or against a sedimentary protolith.

In this magazine for January, 1938, there appeared a short note on the rate of sedimentation in the salt marshes of Scolt Head Island. The records then only covered two years. In a note in the Trans. Norfolk and Norwich Nat. Soc., 15, 1939, 41, some additional readings, covering four years, were published and analysed. This summer (June, 1947) I was able to measure the accretion again after a further interval of eight years, so that we now have rates and averages for two, four, and eight years. Unfortunately the line on Aster Marsh was partly destroyed during the war when it regrettably formed part of the target area for artillery fire.

The accompanying Plate represents a restoration of the skeleton of Hippopotamus minutus, Blain., which has lately been completed in the Geological Department of the British Museum (Nat. Hist.). The vertebral column and limbs are almost entirely composed of the actual bones, while the model of the skull has been built up according to the various parts obtained separately. No ribs were preserved in their entirety, neither were perfect specimens of the scapulæ or innominate bones procured. A large amount of material, including that from which the reconstruction of this skeleton has been made, was brought from Cyprus as the result of excavations carried on there by me at different times in 1901–2. The specimen was mounted and the skull modelled with great skill by Mr. P. O. Barlow, Formatore in the British Museum (Nat. Hist.).

The establishment, toward the end of the last century, of the fruitful conception of the “ cycle of erosion ” carried with it into general currency certain ideas which rest on no real foundation. Although few, nowadays, would be so rash as to doubt the validity of the cycle idea or to question its value as a principle in geology, few can demonstrate any truth in the accepted pictures of the later stages of the cycle. Geographical old age and peneplanation rest on nothing but pure deduction by a few great masters of geography and geology and a blind acquiescence by the rest of us. I say blind advisedly, because only blindness could prevent us from seeing some serious inconsistencies in the picture which have not been generally noticed. These inconsistencies have become increasingly evident in the last ten years. It is time to recognize them.

Rubidium–strontium and potassium–argon measurements on Lewisian intrusive rocks, considered to be late Scourian in age on general geological grounds, have indeed yielded dates in the range 2450–2600 m.y. This demonstrates that rocks of Scourian age that have escaped substantial Laxfordian reworking are preserved in the Eastern Gneisses of Barra. The relevant geological consequences and correlations are briefly discussed. A cross-cutting late pegmatite yields a typical Laxfordian date of 1679 m.y.

Kinematic analysis of tension gashes in an exposure of the Moine Series indicates that the fractures resulted from a tectonic movement directed from north to south, unrelated to that responsible for the nearby Caledonian Moine Thrust.

Organic petrography and geochemical analyses have been carried out on shales, carbonaceous shales and coals of the Shemshak Group (Upper Triassic–Middle Jurassic) from 15 localities along the Alborz Range of Northern Iran. Thermal maturity of organic matter (OM) has been investigated using vitrinite reflectance, Rock-Eval pyrolysis and elemental analysis of kerogen. Reflectance of autochthonous vitrinite varies from 0.6 to 2.2% indicating thermally early-mature to over-mature OM in the Shemshak Group, in agreement with other maturity parameters used. The shales of the Shemshak Group are characterized by poor to high residual organic carbon contents (0.13 to 5.84%) and the presence of hydrogen-depleted OM, predominantly as a consequence of oxidation of OM at the time of deposition and the hydrogen loss during petroleum generation. According to light-reflected microscopy results, vitrinite/vitrinite-like macerals are dominant in the kerogen concentrates from the shaly facies. The coals and carbonaceous shales of the Shemshak Group show a wide range in organic carbon concentration (3.5 to 88.6%) and composition (inertinite- and vitrinite-rich types), and thereby different petroleum potentials. Thermal modelling results suggest that low to moderate palaeo-heat flow, ranging from 47 to 79 mW m−2 (57 mW m−2 on average), affected the Central-Eastern Alborz basin during Tertiary time, the time of maximum burial of the Shemshak Group. The maximum temperature that induced OM maturation of the Shemshak Group seems to be related to its deep burial rather than to a very strong heat flow related to an uppermost Triassic–Liassic rifting. The interval of petroleum generation in the most deeply buried part of the Shemshak Group (i.e. Tazareh section) corresponds to Middle Jurassic–Early Cretaceous times. Exhumation of the Alborz Range during Late Neogene time, especially along the axis of the Central-Eastern Alborz, where maximum vitrinite reflectance values are recorded, probably destroyed possible petroleum accumulations. However, on the northern flank of the Central-Eastern Alborz, preservation of petroleum accumulations may be expected. The northern part of the basin therefore seems the best target for petroleum exploration.

Palaeoproterozic metasedimentary rocks, also referred to as khondalites, characterized by Al-rich minerals, are extensively exposed in the nucleus of the Yangtze craton, South China block. Samples of garnet–sillimanite gneiss in the khondalite suite were collected from the Kongling complex for Nd isotopic and elemental geochemical study. These rocks are characterized by variable SiO2 contents ranging from 35.71 to 58.07 wt%, and have low CaO (0.45–0.84 wt%) but high Al2O3 (18.56–29.04 wt%), Cr (174–334 ppm) and Ni (42.5–153 ppm) contents. They have high CIW (Chemical Index of Weathering) values (90.4–94.7), indicating intense chemical weathering of the source material. The samples display light rare earth elements (LREE) enrichment with negative Eu anomalies (Eu/Eu*=0.40–0.68), and have flat heavy rare earth elements (HREE) patterns. The high contents of transition elements (e.g. Cr, Ni, Sc, V) and moderately radiogenic Nd isotopic compositions suggest that the paragneisses might be those of first-cycle erosion products of predominantly mafic rocks mixing with small amounts of felsic moderately evolved Archaean crustal source. Geochemical and Nd isotopic compositions reveal that at least some of the protoliths of Kongling khondalite were sourced from local pre-existing mafic igneous rocks in a continental arc tectonic setting. Combined with documented zircon U–Pb geochronological data, we propose that the Palaeoproterozoic high-pressure granulite-facies metamorphism, rapid weathering, erosion and deposition of the khondalites in the interior of the Yangtze craton might be related to a Palaeoproterozoic collisional orogenic event during 2.1–1.9 Ga, consistent with the worldwide contemporary orogeny, implying that the Yangtze craton may have been an important component of the Palaeoprotorozoic Columbia supercontinent.

Stratigraphic fluctuations of carbon isotope values of terrestrial organic matter within the Upper Cretaceous (Cenomanian–Santonian) sequence in the Obira area of Hokkaido, Japan, record distinctive δ13C fluctuations for the Cenomanian–Turonian boundary, the Middle Turonian, the upper Turonian–lower Coniacian, and the Santonian. A biostratigraphic framework of the age-diagnostic taxa (ammonoids, bivalves and planktic foraminifers) indicates that these δ13C fluctuation events are comparable with those recorded in δ13C data of terrestrial organic matter in Japan and marine carbonates in Europe. These correlations reinforce the utility of these δ13C events in terms of global chemostratigraphy. In particular, the δ13C patterns within the overall positive interval of the Cenomanian–Turonian boundary event are highly conformable between marine and terrestrial records. The consistent nature of these different records of δ13C fluctuation patterns demonstrates that the terrestrial organic δ13C data mirror the global-scale δ13C patterns in the carbon reservoir of ocean–atmosphere–terrestrial biosphere during the Cenomanian–Turonian boundary event. In addition, global correlation of short-term marine and terrestrial organic δ13C fluctuations of the Upper Cretaceous sequence indicate that the magnitude of several terrestrial organic δ13C events appears more amplified than that of coeval marine carbonate δ13C events. This correlation is interpreted to mean that the effects of local CO2 emission into the atmosphere by release of terrestrial methane hydrate or biomass burning of terrestrial vegetation in the hinterland of the NE Asian region have been superimposed on the global δ13C trend and resulted in the terrestrial organic δ13C records of the Yezo Group.

The Neoproterozoic Jiangnan orogenic belt records the accretion and collision between the Yangtze and Cathaysia blocks in South China. The orogen is divisible into three units: a northeastern domain (also referred to as the Huaiyu or Shuangxiwu domain), a central domain (Jiuling domain) and an undifferentiated southwestern domain. Detrital zircons from the oldest sequences (Shuangqiaoshan, Lengjiaxi, Fanjingshan and Sibao groups) in the central and southwest domains yield similar age spectra with major age populations at c. 875–820 Ma, along with minor Palaeo- to Mesoproterozoic and Archaean ages. The dominance of detrital ages close to the deposition ages of the units, along with juvenile zircon Hf isotopic compositions and arc-like whole-rock compositional data, indicate the sedimentary units accumulated adjacent to a convergent plate margin magmatic arc. The presence of Mesoproterozoic and older zircons, both as detritus in the units and as xenocrysts within igneous rocks displaying a subduction-related signature, along with the compositional data, place the magmatic arc along a continental margin. In the northeastern domain, the oldest coeval sequence (Shuangxiwu and Qigong groups) and arc igneous suites are dated at c. 970–850 Ma, and lack older detritus and xenocrysts, indicating they represent an accreted oceanic arc system.

The Caledonian deformation of the Brabant Massif and the Rügen Early Palaeozoic has been compared by structural analysis including strain determinations, X-ray texture analysis, illite crystallinity and vitrinite reflectivity. Both areas have experienced weak internal deformation under anchimetamorphic to very low-grade metamorphic conditions. The deformation of the Brabant Massif is characterized by (a) a pronounced diagenetic foliation which resulted from compaction and weak extensional tectonics; (b) tilting or weak folding of the Cambrian strata around the Cambrian/Ordovician boundary without internal deformation; (c) a main phase of Caledonian deformation in the Lower Devonian which was associated with open folding and an axial-plane pressure solution cleavage; (d) bending of Caledonian structures from northwest–southeast to northeast–southwest. The internal deformation appears homogeneous with decreasing strain values towards upper structural levels. The strain ellipsoid is predominantly prolate with the main axis of extension parallel to the bedding–cleavage intersection lineation. It is interpreted as the result of superposition of compaction, tectonic shortening and volume loss through pressure solution. The Rügen Early Palaeozoic is less deformed and less metamorphosed under anchizonal conditions. While the upper structural level is almost undeformed, towards the deeper structural levels a spaced and then a continuous slaty cleavage is developed which is successively crenulated by a fracture cleavage. The internal deformation appears inhomogeneous due to several thrust zones with somewhat higher strain values. Outside the thrust zones strain values increase towards lower structural levels, but not significantly. The strain ellipsoid is prolate with a strongly varying orientation of the X-axis. The structural inventory of both areas is comparable with other fold-and-thrust belts. While the Rügen Palaeozoic represents an imbricated thrust-fan of an upper structural level with discrete thrusts and inhomogeneous strain, the Brabant Massif represents a deeper structural level dominated by folding and more homogeneous internal deformation.

Reptilian bones, first observed by Mr. C. I. Gardiner in 1935, are found in two quarries in the Chipping Norton Limestone (top of Inferior Oolite, fusca and zigzag hemerae). These two quarries are the New Park Quarry, about 2½ miles N.W. of Stow-on-the-Wold, and the Oakham Quarry which lies about a mile W.N.W. of Little Compton. The bones occur in a hard cream-coloured limestone which is worked for road-metal. Fossils other than reptilian remains are not common, but among those found in the New Park Quarry is an ammonite determined by Mr. J. W. Tutcher as Parkinsonia neuffensis Oppel. The great majority of the bones come from the New Park Quarry, but the Oakham Quarry yielded certain of the crocodilian, theropod, and sauropod bones.