A thick succession of continental redbeds was deposited in a 50 km wide intra-arc basin on the Andean active continental margin in the Atacama region of northern Chile during early Cretaceous times. Upper Jurassic to early Cretaceous marine limestones were buried by the seaward progradation of a succession of coastal dunes, saline lakes and sandflats. Aeolian dune fields migrating towards the east across these coastal plains became stabilized by the growth of vegetation. Interdune alluvial areas between the sand dunes and dune fields developed into extensive alluvial braid plains which were in turn superimposed by alluvial fans. These fans were inundated by a regionally extensive saline lake produced by tectonic or volcanic damming of the sedimentary basin. This lake dried up leaving a large area of playa-lake mudflats. The climate was warm and semi-arid with a low and seasonal rainfall. Parts of the area supported a substantial vegetation of woody plants, together with a vertebrate fauna of dinosaurs, pterosaurs and crocodiles. The continental redbeds were derived from a volcanic source and were deposited on continental crust in a deep but narrow, north-south elongated, fault-bounded graben. This extensional basin formed in an intra-arc setting within an active andesitic volcanic chain. Upwards-coarsening sedimentary successions were the product of uplift of the fault-bounded margins of the basin.

The Kap Edvard Holm Complex is an early Tertiary layered gabbro situated on the western side of the Kangerdlugssuaq fjord. Layered olivine gabbros in the Taco Point area are cut by several wehrlitic sill-like bodies which comprise a late ultramafic suite. An intrusive wehrlitic facies in the inner part of the bodies consists of olivine (+minor chrome-spinel) orthocumulate with clinopyroxene oikocrysts and interstitial plagioclase, kaersutite and phlogopite. A replacive facies which occurs in the marginal zones is texturally similar to the intrusive facies but contains no chromespinel and is more feldspathic, varying from a melanocratic olivine gabbro to a feldspathic wehrlite. It occurs where the sills wedge out laterally, in the lower contact zones where finger structures are widely developed, and in the upper contact zones where wehrlitic pipes feed melanocratic sheets, called parasol structures, which preferentially follow mafic layers in the host olivine gabbro. The wehrlites formed by the intrusion of hot, hydrous, ultrabasic magma into consolidated layered olivine gabbro. The replacive facies was formed by the volume for volume metasomatic replacement of olivine gabbro; dissolution of plagioclase was accompanied by crystallization of olivine. Some clinopyroxene was initially resorbed and later reprecipitated during this process. The relatively dense pore magma migrating upwards was restricted to pipes and spread out laterally when it encountered readily replaced mafic layers, while below the sills gabbro was replaced en masse and finger structures were formed. Similar late ultramafic suites occur in ophiolites, and their presence in the Kap Edvard Holm Complex supports suggestions that it acted as an ocean ridge type magma chamber during the initiation of early Tertiary sea floor spreading in the North Atlantic.

Carbon isotope and magnetic polarity stratigraphic results from the Cambrian-Ordovician Boundary section at Xiaoyangqiao, near Dayangcha, Jilin Province, China, in comparison to a contemporaneous section at Black Mountain, Australia, indicate strata equivalent to major portions of the Australian sequence are either absent or are restricted to highly condensed intervals. These intervals are correlative with regressive sea level events identified in Australia and western North America, suggesting regional or eustatic sea level changes strongly influenced deposition of the Xiaoyangqiao sequence. These results also suggest the Xiaoyangqiao section is unfavourable as the site of the Cambrian-Ordovician Boundary Global Stratotype Section and Point.

Feldspathoidal and quartz-bearing syenite xenoliths in c. 235 to 155 ka tuffs surrounding the Latera caldera have textures and mineral assemblages that indicate an origin from the crystalline margins of a shallow magma chamber. This lithic suite exhibits a diversity of plutonic fabrics; unaltered, glass-bearing nodules with undeformed sanidine frameworks coexist with completely crystallized clasts, many of which show evidence of subsolidus modification. The syenites comprise eutectic mineral assemblages with high percentages of titanite, apatite, and melanite garnet as accessory minerals. Ubiquitous reaction textures in syenite accompany progressive changes in mineral assemblages, and they show the decreasing influence of limestone contamination with distance from the contact of syenite and skarn wallrock. Diagnostic mineral assemblages include nepheline rich in calcite inclusions, coexisting titanite and metamorphic perovskite, zircon with baddeleyite inclusions, fluorapatite mantled by a possible carbonate-bearing apatite (francolite), melanite garnet intergrown with clinopyroxene, and interstitial haüyne rich in pyrrhotite inclusions.

At Latera, pumice fragments in the same deposit can exhibit up to ten-fold differences in vesicularity and crystal content (from < 5 to > 50 vol. % phenocrysts). These clasts, in conjunction with glass-bearing syenite and skarn xenoliths, may represent a range of progressively crystallized magmas that were quenched at the instant of their eruptive entrainment. The major element abundances of pumices and syenite reflect the fractionation of plagioclase and sanidine, with lesser amounts of fassaitic diopside, leucite, biotite, apatite, and alkali amphibole. Trace element ratios (e.g. Rb/Sr, Nb/Ta, Zr/Hf, LREE/HREE), on the other hand, are highly variable for crystalline and pumiceous ejecta, and some element variations (e.g. Li, Ta, Nb, Th) cannot be entirely reconciled with simple crystal-liquid fractionation. The syenite clasts span a range of compositions from strongly fractionated assemblages rich in accessory minerals to compositions that more closely approximate quenched reservoir liquids. These features reflect processes that range from pure fractional crystallization to in situ crystallization where fractionated liquid was trapped in the pores of sidewall cumulates along the chamber roof and walls.

The Bångonåive basement culmination, a doubly plunging antiform trending SW-NE in its southern part and SSW-NNE in the north, is part of a major Caledonian antiform in north-central Scandinavia. Crystalline, Proterozoic basement rocks (mainly syenite) are unconformably overlain by a sedimentary cover including tillites at the base, passing up into arkoses, quartzites and shales, capped by black phyllites. This sequence is correlated with the Varangian to Cambrian succession of the Baltoscandian platform farther east. Detailed mapping revealed a succession of five basement-cover horses, which represent the accessible part of an antiformal stack exposed beneath the Middle and Upper Allochthons and taken here as the Lower Allochthon structural level.

Caledonian deformation varies in intensity from penetrative near thrusts and in pelitic rocks to very weak in the more internal parts of the horses. A penetrative foliation is associated with the growth of white mica and rare biotite. This early fabric is overprinted by a mylonitic foliation related to localized shear zones, which separate the structural units within the Lower Allochthon. Stretching and mineral lineations trend WNW-ESE and related shear-sense criteria indicate transport (top) towards the ESE. Structural units (horses) are thrust into an antiformal stack and folded around the lowermost horse exposed, which is itself folded into an anticlinal lift-off fold. Towards the northeast, the antiformal stack is overprinted by a pop-up and an out-of-sequence thrust. The latter breached the roof of the Lower Allochthon and transported part of it over the Middle and Upper Allochthons. Further folds are associated with lateral and oblique ramps in the Lower Allochthon. These structures relate very well with the complex fold pattern previously observed in the higher structural units and thrust tectonics provides a straightforward genetic explanation for these folds. Therefore, earlier genetic models of the Bångonåive basement culmination as a simple imbrication of basement into higher units, as a buckling structure or as a gravitational dome structure are rejected here. The structural information, supported by gravimetric data, is consistent with an essentially flat regional detachment surface (2° dip) extending from the present external Caledonian margin to the base of the Bångonåive antiformal stack.

Biostratigraphic study and re-examination of 22 late Eocene to early Oligocene sections provides data in support of three and possibly a fourth late Eocene impact events in the G. index Zone during a period of about 1 Ma of the middle Priabonian between 34.7 and 35.7 Ma. No major species extinctions or significant species abundance changes directly coincide with these impact events. Species extinctions are gradual and selective, affecting primarily cool-temperature-intolerant surface dwellers. These extinctions began with the onset of global cooling during the early middle Eocene and culminated near the Eocene/Oligocene boundary. The global cooling was associated with the isolation of Antarctica as Australia moved northward, the development of a circum-Antarctic circulation, growth of Antarctic ice sheet beginning by late middle Eocene time and a change from a thermospheric to thermohaline circulation. We find no evidence that the multiple late Eocene impact events directly contributed to the climatic deterioration already in progress.

This paper examines the potential use of the variation of the co parameter of graphite with temperature for geothermometric estimations. Two examples are presented in which graphite geothermometry, at low-and high-temperature conditions, is tested against other widely used geothermometers. The results obtained indicate that, at low-grade metamorphic conditions, the co parameter of graphite is affected by other factors besides the temperature, so graphite geothermometry (based on co) can only be used in such rocks for qualitative estimations. For temperatures above 500 °C, when the fully ordered graphite appears, there is a close correlation between the temperature estimations based on the structural ordering of graphite and from mineral-exchange geothermometry. The temperature calculations based on the co parameter of graphite are not influenced by factors (such as pressure or retrometamorphism) that clearly affect the exchange equilibria. Thus, graphite thermometry is a useful tool, for temperatures above 500 °C.

The 170 Ma Straumsvola nepheline syenite complex in western Dronning Maud Land, Antarctica, is located on the eastern edge of the Penck-Jutul Trough, a major tectonic feature which may be a Palaeozoic-Mesozoic rift system. The 5 km diameter pluton consists entirely of nepheline syenite and can be divided into two volumetrically important units: a relatively structureless outer zone which is overlain by a layered zone. The latter exhibits continuous rhythmic alternations of layers containing different proportions of alkali feldspar to amphibole+Na-rich pyroxene+biotite+nepheline throughout its 350 m thickness. The mafic zone is a volumetrically minor unit which unconformably overlies the layered zone and consists almost entirely of mafic minerals and nepheline. The layered zone shows no systematic stratigraphic variation in major or trace composition or mineral chemistry which is interpreted as being due to a combination of migration of intercumulus liquid and action of deuteric fluids. The remarkably constant thickness of successive layers throughout the layered zone suggests that layering resulted from an internally self-regulating process(es). The layering is defined by changing proportions of alkali feldspar to mafic minerals+nepheline which is consistent with layering being caused by differences in nucleation rate during eutectic crystallization. Dykes associated with the complex show wide-ranging compositions and include both over-and undersaturated types. Low σ18O values of the nepheline syenites (mean 5.9%, n = 9) suggest that the magma from which the nepheline syenites crystallized was mantlederived. Peralkaline microgranite dykes have higher σ18O values (mean 7.3%, n = 4) and it is suggested that they are either undersaturated liquids contaminated by siliceous crust, or derived by partial melting of partly fenitized gneiss. Oxygen isotope ratios of the surrounding gneiss indicate that the intrusion of the nepheline syenite did not cause extensive circulation of meteoric or magmatic hydrothermal fluids.

The biostratigraphic significance of the bivalves Buchia and Aucellina in northeast China is assessed. Buchia is abundant in four assemblages of the Dong'anzhen Formation, spanning the Jurassic-Cretaceous boundary: B. russiensis-B. fischeriana (Middle Volgian), B. fischeriana-B. unschensis (Upper Volgian), B. volgensis-B. cf. subokensis-B. cf. okensis-B. unschensis (Berriasian), and B. pacifica (Lower Valanginian). Aucellina is common in two Middle Barremian-Aptian assemblages: A. caucasica-A. aptiensis-A. jeletzkii in the lower part of the Upper Yunshan Formation, Longzhaogou Group, and in the lower part of the Chengzihe Formation, Jixi Group; A. cf. caucasica-A. cf. aptiensis in the upper part of the Upper Yunshan Formation. These assemblages can be correlated on a global scale and are particularly significant in dating the Early Cretaceous coalbearing measures of eastern Heilongjiang.