The presence of a set of well-known turbidite successions, deposited in progressively E-migrating foredeep basins and subsequently piled up with east vergence, makes the Northern Apennines of Italy paradigmatic of the evolution of deepwater fold-and-thrust belts. This study focuses on the early Apenninic collisional stage, early Miocene in age, which led to the accretion of the turbidites of the Trasimeno Tectonic Wedge (TTW), in the central part of the Northern Apennines. Based on the interpretation of previously unpublished seismic reflection profiles with new surface geology data and tectonic balancing, we present a detailed tectonic reconstruction of the TTW. In the study area, the TTW is characterized by a W-dipping shaly basal décollement located at a depth of 1–5 km. The tectonic wedge is c. 5 km thick at its central-western part and tapers progressively eastwards to c. 1 km. The total shortening, balanced along a 33 km long cross-section, is c. 60 km, including 20 km (40%) of internal imbrication, c. 23 km of horizontal ENE-wards translation along the basal décollement and c. 17 km of passive translation caused by the later shortening of footwall units. Deformation balancing, constrained through upper Aquitanian – upper Burdigalian (c. 21–16 Ma) biostratigraphy, provides an average shortening rate of c. 8.6 mm a–1. Internal shortening of the TTW shows an average shortening rate of c. 4 mm a–1 for this period.

Active or recently-active, large-scale quarrying operations within the Carboniferous Limestone Series of this area, and ranging in location from the near-junction areas to points about half a mile removed from the southern boundary of the main littoral Trias outcrops, have afforded excellent sections displaying remnants of a former Triassic cover. It is considered unlikely that the latter outliers, of limited dimensions, occur in areas further removed than about one-third of a mile south of the existing limits of the main Triassic outcrops.

Although the Pachycormid fish Saurostomus esocinus was known only by part of a lower jaw from the Upper Lias of Baden when it was first named by Agassiz, its principal characters have since been revealed by many incomplete specimens from the Upper Lias of Würtemberg, France, and Yorkshire, and by a well-preserved fish from Ilminster, Somersetshire, in the Charles Moore Collection, Bath Museum. The internal skeleton of the trunk and the fins, however, have not hitherto been so well seen as in a nearly complete fish from the Upper Lias of Würtemberg, prepared by Mr. Bernhard Hauff and now in the British Museum.

As a contribution to the current debate on the age of the Grampian Orogeny in the Scottish Dalradian, we comment on the valuable paper by Tanner (1995) that establishes stratigraphical continuity between the ‘Dalradian’ Ben Ledi Formation and the ‘Highland Border’ Keltie Water Formation that contains the Lower Cambrian Leny Limestone (Cowie, Rushton & Stubblefield, 1972, p. 17). Tanner's interpretation of the stratigraphy differs in detail from that of Harris & Fettes (1972). We unreservedly accept Tanner's mapping and the stratigraphical changes that follow from it: there are two units of black slate and limestone; that containing the fossiliferous limestone of Leny Old Quarry is the younger.

The Jueluotage area, which is located in the southern branch of the Eastern Tianshan and northeast of the Tarim Basin, represents a vital locality for investigating intracontinental reactivation induced by the tectonic events at the Eurasian plate margin. This study applies zircon and apatite (U–Th)/He and apatite fission-track thermochronology to the Jueluotage area in the Eastern Tianshan. Our data and thermal history modelling show that the Jueluotage area experienced Triassic–Early Jurassic (˜240–180 Ma) cooling, reflecting the closure of the North Tianshan Ocean and subsequent far-field effects of collision/accretion of the Qiangtang Block and Kunlun terrane. Following this period of fast cooling, a differential exhumation process occurred between the various tectonic belts in the Jueluotage area. The Aqishan–Yamansu belt was exposed at the surface during the Triassic–Early Jurassic cooling phase and experienced subsequent burial, which continued until Early Cretaceous time when a pulse of exhumation occurred. However, the major fault zones (Kanggurtag ductile shear zone and Aqikkuduk Fault) and Central Tianshan arc have remained tectonically stable since Early Jurassic time. No Cenozoic rapid cooling was recorded by the low-temperature thermochronology results in this study, indicating that much of the Jueluotage area was exhumed to the upper crust in the late Mesozoic period.

Trilobites are important elements of the Devonian macrobenthos; some of them were collected in the Chefar el Ahmar Formation, from two sections located near Béni Abbès in the Saoura Valley (Ougarta Basin, Saharan Algeria). This formation is characterized by alternations of claystones and limestones, and it is considered to be late Emsian to early Frasnian in age. Only the lower part of this formation has yielded trilobites so far; their presence has been known for a long time. Phacopines clearly dominate the trilobite assemblages, with Austerops, Barrandeops, Chotecops and Phacops s.l. as the main genera. Two new species are described (Austerops salamandaroides sp. nov. and Phacops ouarouroutensis sp. nov.), while some other taxa are presented in open nomenclature. Comparisons are made with closely allied species. These new trilobite occurrences have been analysed in terms of their intra- and interspecific variability and biodiversity. The occurrence of Struveaspis maroccanica, previously known from the Saoura Valley, provides an early Eifelian age, which is also confirmed by the presence of trilobites Thysanopeltis and Koneprusites, and ostracods Bairdiocypris devonica and Bufina ?subovalis.

Geochronological, elemental and isotopic data of the Dashizhuzi granites and lamprophyre dykes from the eastern Hebei – western Liaoning on the northern North China Craton (NCC) provide an insight into the nature of their magma sources and subcontinental lithospheric mantle. The Dashizhuzi granites have an emplacement age of 226 Ma. They have enriched lithospheric mantle type 1 (EM1-like) Sr–Nd isotopic compositions, and have distinctive features of high Na2O and Sr and low Y with high Sr/Y and (La/Yb)N ratios. These characteristics show that the Dashizhuzi granites originated directly from melting of mafic lower crust composed of pre-existing ancient crustal and enriched mantle-derived juvenile crustal materials at normal continental crustal depth of 33–40 km. The lamprophyre dykes are dated at 167 Ma, and can be divided into two groups. The Group 1 dykes have variable Sr–Nd isotopic compositions and mid-ocean-ridge basalt (MORB-) like Th/U, Ba/Th and Ce/Pb ratios, whereas the Group 2 dykes have enriched Sr–Nd isotopic compositions and notable high Co, Cr, MgO and low Al2O3 characteristics. These distinctive features suggest that the Group 1 dykes were derived from a relatively fertile lithospheric mantle source (garnet-facies amphibole-bearing lherzolite) which has experienced variable degrees of asthenospheric mantle-derived melt–peridotite interaction prior to melting. However, the Group 2 dykes were derived from an ancient garnet-facies phlogopite and/or amphibole-bearing lherzolite lithospheric mantle. Thinning of the Early Mesozoic lithospheric mantle beneath the northern NCC is dominantly through melt–peridotite interaction and thermo-mechanical erosion prior to Middle Jurassic time. The chemical compositions have been modified at the bottom of the lithospheric mantle through melt–peridotite interaction processes.

The lower–upper Cenomanian boundaries interval of the Nouader site in the Aures Basin (NE Algeria) has been studied for the first time using the association of two particularly effective taxonomic groups, one macrofossil (ammonites), and the other microfossil (foraminifera). The study section is divided into two formations (Fahdene and Bahloul) and one member (Annaba). Biostratigraphicaly, six ammonite biozones and five foraminiferan biozones were identified and calibrated. The ammonite fauna allows recognition of the lower Cenomanian Mantelliceras mantelli Zone, the upper lower Cenomanian Mantelliceras dixoni Zone, the succeeding lower middle Cenomanian Cunningtoniceras inerme Zone, the Acanthoceras rhotomagense Zone and its subzones of Turrilites costatus and Turrilites acutus, followed by the upper middle Cenomanian Acanthoceras amphibolum Zone, the lower upper Cenomanian Eucalycoceras pentagonum Zone and finally the lower Turonian Pseudaspidoceras flexuosum Zone. The foraminiferan biozones are respectively: Thalmanninella brotzeni Zone, Thalmanninella reicheli Zone, Rotalipora cushmani Zone, Whiteinella archaeocretacea Zone and Helvetoglobotruncana helvetica Zone. Among 14 ammonite zones in the Tethyan domain versus 11 in the Boreal domain, seven are common to both domains. For the planktonic foraminifera the Tethyan domain has five zones, the Boreal domain also has five, with five in common. The succession of index species occurs in the same order in both Tethyan (NE Algeria and Central Tunisia) and Boreal realms (East and NW Europe). Furthermore, the supposed depositional setting is interpreted as a calm and relatively deep environment which can be located around the middle to the external platform.

The Wulanba granite, consisting of biotite monzogranite and syenogranite, is located in the southern part of the Great Xing’an Range, NE China. Whole-rock major- and trace-element geochemistry suggests the Wulanba granite is a high-K–shoshonitic, slightly peraluminous and highly differentiated I-type granite. The Sr–Nd–Hf isotopes indicate that it originated from partial melting of juvenile crust derived from the depleted mantle with a minor input of old crust. The relatively young T2DM and tDM2 ages indicate it was most likely derived from a Late Neoproterozoic to Early Palaeozoic source. We have demonstrated that the biotite monzogranite is the ore-related intrusion of the Haobugao Zn–Fe mineralization based on the following geological, geochronological and geochemical evidence: (1) the chalcopyrite/pyrite in the biotite monzogranite and the continuous mineralization of drill core ZK2508; (2) the consistence of the emplacement age of the biotite monzogranite (~141–140/138 Ma) with the skarn mineralization age (~142 Ma); and (3) the presence of rich ore-forming elements (Fe–Zn–Cu) in the biotite monzogranite, and the similar Pb compositions of the sulfides from the Haobugao deposit and the biotite monzogranite. Compared to the barren syenogranite, the fertile biotite monzogranite is more oxidized, while the edges of the apatite grains in the biotite monzogranite are more oxidized than the centres. The average F/Cl ratio of the fertile biotite monzogranite (~123.45) is much higher than that of the barren syenogranite (~73.98). We conclude that these differences reflect unique geochemical signatures, and the geochemical composition of the apatite can be used to infer the economic potential of granites.

In one of the higher nappes of the Caledonides of Troms, northern Norway, rare thin dykes of calcite marble lie subparallel to the axial surfaces of folds in multilayered marble beds. The dykes emanate from pure calcite marble layers mostly in or close to the hinge zones of these flat-lying, tight to sub-isoclinal, F3 folds. In many cases, they appear to penetrate along the axial surfaces of these same folds, and there is an up to 10° angular disparity between dyke orientation and axial surfaces. The dykes are considered to have originated, and been expelled, from parent calcite marble layers either at or shortly after the peak of amphibolite-facies metamorphism between the D2 and D3 deformation phases of the Scandian orogeny. The dykes display a dyke-parallel, dark grey to white, colour banding, the origin of which is uncertain at present. In thin-section, an equigranular texture is dominated by 2–3 mm, equant, unstrained, calcite grains with straight boundaries and low-T twin lamellae, denoting a late-stage recrystallization. A weak, oblique, calcite grain-shape orientation fabric curves into a dyke-parallel alignment along the finer-grained margins, reflecting the simple-shear deformation imposed on the host rock. Regarding the initiation of these marble dykes, it seems likely that a combination of P–T conditions and possibly partial melting processes was conducive to generating extreme ductility/superplasticity, at least locally, and that this led to the sudden expulsion of a partially molten carbonate aggregate which had momentarily attained a critical pressure and intruded preferentially along available, transient fractures prior to the imposition of the D3 simple-shear regime.

The post-impact Dalby Limestone (Kukruse; Upper Ordovician) of the Tvären crater, southeastern Sweden, has been analysed with regards to polychaetes, as represented by scolecodonts. A palaeoecological succession is observed in the Tvären-2 drill core sequence, as the vacant ecospace was successively filled by a range of benthonic, nektonic and planktonic organisms. Scolecodonts belong to the first non-planktonic groups to appear and constitute one of the most abundant fossil elements. The polychaete assemblage recorded has an overall composition characteristic of that of the Upper Ordovician of Baltoscandia. Oenonites, Vistulella, Mochtyella and the enigmatic ‘Xanioprion’ represent the most common genera, whereas Pteropelta, Protarabellites?, Atraktoprion and Xanioprion are considerably more rare. The assemblage differs from coeval ones particularly in its poorly represented ramphoprionid fauna and the relatively high frequency of ‘Xanioprion’. A taxonomic succession and changes in abundance and relative frequency of different taxa is observed from the deepest part of the crater and upwards towards more shallow water environments. The initial post-impact assemblage does not, however, necessarily represent a benthonic colonization of the crater floor. Instead it seems to be a taphocoenosis, as indicated by its taxonomic correspondence to the rim facies fauna recovered from Dalby Limestone erratics of the Ringsön island. The Tvären succession has yielded considerably richer scolecodont assemblages than hitherto recorded from the approximately coeval Lockne crater, possibly as a consequence of shallower water settings in the former area.

The peculiar tectonic structure called “boudinage” by Lohest (5, pp. 471–2), has recently been found in Unst, Shetland Islands, by Professor H. H. Read (8, pp. 134–8), who has also noted its occurrence in tie Durn Hill quartzites of Banffshire (9, p. 471).What would now be termed boudinage-structure was seen by Ramsay in North Wales, and was described in 1866 in these words (6, and. fig. 18): “In the great quarry west of the Ffestiniog and Trawsfynydd fault the cleavage dips from 45° to 50° north-west, the inclination of the beds being about 35° in the same direction, and a greenstone dyke runs through them between the cleavage-planes…, bulging and thinning off in a rapid succession of oval-shaped masses of 3 or 4 feet in length. Associated with it are quartz veins ccurring principally at the points between the separate bulgings of the greenstone.”

An occurrence of kyanite pseudomorphing andalusite, from the Urungwe District of Southern Rhodesia, is described. The pseudomorphs, which include some of the largest of their kind so far recorded, occur in profusion in certain Pre-Cambrian pelitic schists. The original andalusite was completely converted to kyanite during regional metamorphism but the shape of the original crystals was perfectly preserved. This, together with the habit of the kyanite within the pseudomorphs, shows that the change took place under conditions of insignificant shearing stress.

In the Scottish Lower Carboniferous limestones there are known to occur at least sevenspecies of Dicyclic Inadunate crinoids belonging to the family Poteriocrinidae, one of the main characters of which is the possession of five simple unbranched arms. One species is also known from the Carboniferous of the Isle of Man. Two of the Scottish species have been assigned to the genus Ulocrinus, viz. U. globularis de Koninck and U. doliolus Wright. The former species is now referred to U. bockschii (Geinitz), which has priority, and the Scottish specimens as they commonly occur appear to be indistinguishable from it. The cup in these two species is specially characteristic, the shape being for the most part globular and the anal area, while sometimes of normal character, is more commonly occupied by a large RA with anal X and rt surmounting it and comparatively small. The arms are rather long, uniserial, and formed of narrow cuneiform brachials (Plate XIV, Figs. 1–6). (Bather, 1916–17; Wright, 1927, 1936.)

The progress of modern discovery, both in Palæontology and Zoology, has been steadily tending to bridge over the gap which seemed at one time to separate the past from the present life-history of our globe, and has brought each more closely into relationship with the other than seemed possible fifty years ago.

An interesting occurrence of highly potassic lavas and hypabyssal intrusives of assumed Tertiary age is described from North Johore. The thickest lava flow is gravitatively differentiated showing a basal horizon of potassic ankaramite and basanite grading up into highly potassic bolitized flow tops of leucite-tephrite composition. Evidently the parent magma was close to a biotite pyroxenite in composition and possibly an assimilation product of peridotite by granite.

Although the ammonoid Durvilleoceras is apparently very close in its morphology to early Triassic genera, it comes from a formation that underlies formations with early Triassic and late Permian faunas, and appears to be of late Middle Permian age. New occurrences of the ammonoid support this thesis. Conjecturally, the genus may have inhabited deep cold waters of the southern hemisphere during the Permian Period, before giving rise to genera found in shelf deposits of the early Triassic. Alternatively, if really Triassic in age, Durvilleoceras indicates a major low-angle thrust, previously unsuspected, that has repeated Triassic sequences for a length of over 450 km before disruption by the Alpine Fault. No evidence is yet known to support this alternative.

Allogenic biotite flakes, together with fish and conodont remains, are concentrated into bands at particular horizons within Upper Ludlovian rocks of Woolhope and other Welsh Borderland areas; and are present but more scattered within the Aymestry Limestone and Dayia Beds. Metamorphic rocks of Malvernian type appear to have provided the source of the biotite.

—The field impression of a high degree of uniformity in the composition of the intrusive Karroo dolerites over a vast area is confirmed by new chemical and microscopical studies. The pyroxene characteristic of the dolerites is a typical pigeonite, which, however, does not display any twinning on (100). The plagioclase is potash-free, usually a labradorite, but it has been observed that a homogeneous crystal of plagioclase may be in twin position to another homogeneous crystal of a very differently composed plagioclase. The close resemblance of the doleritic liquid to the artificial liquid taken by Bowen to represent basaltic liquid is noted, and his conclusion that pyroxene and feldspar should crystallize simultaneously in natural basaltic liquid is confirmed.

Conceivably the doleritic liquid was quite original and not a differentiate of any earlier liquid. However, analogies like those with the tholeiites and similar hypabyssal rocks of Great Britain suggest that in South Africa, as in Great Britain, the liquids of these hypabyssal rocks were derived from the slightly more femic plateau-basalt.

On that assumption the question of the mode of differentiation arises. The fractional crystallization of plateau-basalt, as now described by Bowen and other leaders, does not appear competent to explain the abnormally low soda of one of the analyzed dolerites, nor the excess of soda and total alkalies in plateau-basalt respectively over the soda and total alkalies of the Karroo dolerite. Further, the settling-out of early olivine does not explain the excess of (total) FeO in plateau-basalt over the (total) FeO in the Karroo dolerite. The actual relations indicate the need of renewed examination of the theory of magmatic differentiation by crystal-fractionation. In any case many more data are required before it is possible to decide upon the precise relation of the Karroo dolerite to a parental magma. Possibly such additions to knowledge may annul present difficulties in the way of accounting for the composition of the dolerite.

More than twenty years ago, whilst engaged in the study of the Lower Carboniferous rocks of Westmorland, I noticed the occurrence of certain small concretionary nodules of very compact texture in the dolomites near the base of the succession in the neighbourhood of Shap.