The analysis of ‘mélanges’ of various types (sedimentary, diapiric, tectonic and polygenetic) is generally difficult and depends on a variety of criteria. However, understanding the nature and origin of mélanges is crucial to deciphering the evolution of some mountain belts. The Lichi Mélange of the Taiwan Coastal Range is juxtaposed against remnant forearc basin sequences by thrust faults and is composed of exotic ophiolite and sedimentary blocks, with sizes ranging from metres to kilometres, and coherent turbidite beds, all embedded in a sheared scaly argillaceous matrix. The Lichi Mélange has been interpreted either as a subduction complex, or as an olistostrome. By separating four main deformation levels based on the degree of disruption within the Lichi Mélange and adjacent sedimentary rocks, we have made new detailed geological maps and structural profiles in two key areas of the Lichi Mélange. We paid particular attention to the original stratigraphic relationships between the mélange and the adjacent flysch formation. Our field results compared with submarine seismic profiles suggest that the present-day structure of the Lichi Mélange results mainly from the shearing of lower forearc basin sequences, rather than from a subduction complex or a mere olistostrome. In Late Miocene time, because lithospheric subduction turned into arc–continent collision in the southern Taiwan area, the site of the proto-Manila trench changed from an active plate boundary into a deformation zone with several thrusts. A new plate suture zone between the Eurasian plate (eastern Central Range) and the Philippine Sea plate (Coastal Range) was therefore formed along the Longitudinal Valley. The Longitudinal Valley originated as a submarine arc–prism boundary, an innate weak zone within the overriding plate, and has become a prominent tectonic feature of the arc–continent collision. This inference is supported by observations on the Lichi Mélange in the Coastal Range and the Huatung Ridge off southeastern Taiwan.

Nd isotopic composition has been determined for 16 igneous rocks, representing the wide geochemical, spatial and temporal range of post-collisional, late Cenozoic magmas in the Aegean area. Nd isotopes are used to further interpret previously published Pb and Sr isotope data. The overall pattern of late Cenozoic volcanism resulted from rapid extension, with thermal effects causing melting of hydrated, enriched, subcontinental lithosphere to produce widespread K-rich magmas. Slab break-off and intrusion of hot asthenosphere caused partial melting of rift-related continental margin basalts at the detachment point to generate adakitic magmas. Further outboard, mafic magma from enriched lithospheric mantle melted thickened lower crust to produce the granitoid plutons of the Cyclades. Nd isotopic variation in these varied rock types correlates with pre-Cenozoic palaeo-geography. Proterozoic subduction-related enrichment in Th and U, together with other large-ion lithophile elements, produced distinctive Pb isotope composition. This was later modified where Mesozoic subduction of terrigenous sediment was important, whereas subduction of oceanic carbonate sediments produced enrichment in radiogenic Sr and low Ce/Sr ratios. Late Cenozoic magmas sourced in eastern Pelagonian zone sub-continental lithospheric mantle have Nd model ages of about 1.0 Ga, and generally high 87Sr/86Sr and high 207Pb/204Pb (∼ 15.68) and 208Pb/204Pb (∼ 39.0) for low 206Pb/204Pb (∼ 18.6), but rocks to the west have more radiogenic Pb and higher Ce/Sr as a result of greater subduction of terrigenous sediment from the northern Pindos ocean. Magmas sourced from sub-continental lithosphere beneath the Apulian continental block were strongly influenced by subduction of oceanic crust and sediments north of the passive margin of north Africa. Subduction of Nile-derived terrigenous sediment in the east resulted in Nd model ages of 0.7 to 0.8 Ga and radiogenic Pb isotopes. Greater subduction of oceanic carbonate in the west resulted in magmas with higher 87Sr/86Sr and lower Ce/Sr. The strongly negative εNd for adakites in the central Aegean rules out a source from subducted oceanic basalt, and the adakite magma was probably derived from melting of hydrated Triassic sub-alkaline basalt of continental origin. Where trachytic rocks are succeeded by nepheline-normative basalts (e.g. Samos), Nd isotope data imply that early partial melting of the enriched subcontinental lithospheric mantle involved hydrous amphibole and phlogopite, but once these minerals were consumed, younger magmas were produced by partial melting dominated by olivine and orthopyroxene.

The Variscides of southeast England are buried beneath post-Carboniferous cover. Interpretations of the basement are based mainly on deep boreholes. Geophysical signatures from the basement are contained within the regional gravity and magnetic data. A gravity stripping exercise has been undertaken to remove the gravitational effect of the post-Variscan cover to generate a residual gravity map. This map is interpreted along with integrated potential field modelling along four long interconnected profiles and compared with a revised pre-Permian subcrop map. The magnetic evidence suggests that Precambrian magnetic basement of the Midlands Microcraton has been buried southwards by north-vergent Variscan thusting over the foreland. North of the Variscan Front, short-wavelength anomalies superimposed upon this deep Precambrian source are due to shallower Silurian and Carboniferous volcanic rocks. Many residual gravity lows within the Rhenohercynian zone may be related to thick, low-density Devonian basins. In the English Channel a change in geophysical signature occurs north of the Portland–Wight Fault, coinciding with phyllites in the basement. Models are presented in which the English Channel magnetic anomalies originate within the pre-Permian basement. Comparisons with anomalies in the Southwestern Approaches suggest that the Portland–Wight Thrust is a terrane boundary, possibly a subduction-related suture, implying southerly directed Variscan subduction.

Kronprins Christian Land lies at the northernmost limit of the East Greenland Caledonides, and may be divided into four main tracts: foreland, parautochthon, thin-skinned thrust sheets containing Neoproterozoic sediments, and thick-skinned thrust sheets of crystalline basement. The eastern part of the foreland and the parautochthon are composed of Ordovician–Silurian shelf carbonates overlain by Llandovery–lower Wenlock turbidites deposited at the southern margin of the Franklinian Basin. Deformation of the parautochthon occurred beneath a major detachment, the Vandredalen thrust, with Neoproterozoic sediments of the Rivieradal Group lying in the hanging wall. The Rivieradal Group was deposited in an E-facing half-graben and was displaced westwards across its rift shoulders during Caledonian thrusting. Extensive sampling for conodonts has been carried out within the Lower Palaeozoic rocks of the foreland and parautochthon in order to increase the precision of structural interpretations and to provide data on maximum burial temperature and, in turn, the thickness of overburden. In contrast to earlier studies, conodont colour alteration indices (CAI) show a gradual and continuous increase from CAI 3 in the eastern part of the foreland to CAI 5+ in the easternmost parts of the parautochthon. The isopleths are not disrupted or truncated by thrusting, as previously suspected, indicating that the heating is not attributable to pre-thrusting stratigraphic overburden. Furthermore, considerations of the regional geology indicate that there was no significant accumulation of sedimentary overburden in post-Caledonian time; the predominant component is thus considered to be loading by thrust sheets. Modelling of the overburden thickness suggests that, prior to erosion, it increased from 3.9 km (CAI 3) in the easternmost foreland to a maximum of 12.5 km beneath the Vandredalen thrust sheet in the easternmost part of the area, providing constraints for restoring cross-sections across the orogen.

The Mäekalda section presents a c. 12 m thick succession of mainly limestones, dolomites and siltstones of late Tremadoc to late Llanvirn age, exposed on the eastern outskirts of Tallinn, northern Estonia. The condensed sequence is rich in well-preserved conodont elements that provide the basis for detailed biozonation. In the Baltoscandian zonation, beds from the upper Varangu Paltodus deltifer Zone up to the lower Aseri Eoplacognathus foliaceus Subzone have been identified. In all, the conodont faunas exhibit a close resemblance to Swedish faunas. Many intervals can also be compared with coeval strata in western Russia. The presence at some levels of representatives of Laurentian conodont lineages provides an unusual opportunity for correlating Baltoscandian sequences with sequences in North America, especially in the lower Arenig part of the succession. The middle Volkhov (upper middle Arenig) Paroistodus originalis Zone at Mäekalda is remarkably complete bearing in mind the highly condensed nature of the section as a whole. The details of this zone can be correlated with the equivalent intervals in Swedish sections. In the upper Volkhov–lower Kunda beds there is a considerable stratigraphic gap in the section, but the upper Kunda has provided an excellent series of successive populations of Eoplacognathus, indicating that in this part the section is virtually complete.

The northernmost exposures of rocks formed during the Late Neoproterozoic Cadomian orogeny in the Channel Islands–northern France region occur on Alderney. The island mainly comprises foliated quartz diorite, once considered to be 2 Ga, pre-Cadomian basement, and an undeformed basic to intermediate plutonic complex. A precise age of 610±2 Ma, based on U–Pb analyses of single and small groups of zircons, for the foliated Fort Tourgis quartz diorite demonstrates that the oldest rocks were emplaced and deformed during a Cadomian magmatic event. The age is virtually identical to ages from similar, foliated syntectonic quartz diorite bodies on the islands of Guernsey and Sark and at La Hague (north Normandy), indicating that this magmatic and deformational event was regional in extent. Discordant zircon xenocrysts define an upper intercept age of c. 2 Ga indicating the presence of Palaeoproterozoic basement at depth. Single zircons from the undeformed Bibette Head granodiorite give a precise U–Pb age of 572±1 Ma. This age is closely similar to that for the emplacement of the Northern Igneous Complex of Guernsey. The emerging data indicate that Cadomian magmatism in the northern Channel Islands region was not a protracted continuum, but occurred during two distinct, short-lived events separated by c. 30–40 my.