Lithospheric thinning occurred in the North China Craton (NCC) that resulted in extensive Mesozoic magmatism, which has provided the opportunity to explore the mechanism of the destruction of the NCC. In this study, new zircon U–Pb ages, geochemical and Lu–Hf isotopic data are presented for Early Cretaceous adakitic rocks in the Liaodong Peninsula, with the aim of establishing their origin as well as the thinning mechanism of the NCC. The zircon U–Pb data show that crystallization occurred during 127–120 Ma (i.e. Early Cretaceous). These rocks are characterized by high Sr (294–711 ppm) content and Sr/Y ratio (38.5–108), low Yb (0.54–1.24 ppm) and Y (4.9–16.4 ppm) contents, and with no obvious Eu anomalies, implying that they are adakitic rocks. They are enriched in large-ion lithophile elements (e.g. Ba, K, Pb and Sr) and depleted in high-field-strength elements (e.g. Nb, Ta, P and Ti). These adakitic rocks have negative zircon ϵ Hf(t) contents (−28.9 to −15.0) with two-stage Hf model ages (T DM2) of 3004–2131 Ma. Based on the geochemical features, such as low TiO2 and MgO contents, and high La/Yb and K2O/Na2O ratios, these adakites originated from the partial melting of thickened eclogitic lower crust. They were in an extensional setting associated with the slab rollback of the Palaeo-Pacific Ocean. In combination with previous studies, as a result of the rapid retracting of the Palaeo-Pacific Ocean during 130–120 Ma, the asthenosphere upwelled and modified the thickened lithospheric mantle, which lost its stability, resulting in the lithospheric delamination and thinning of the NCC.

The subduction model of the Neo-Tethys during the Early Cretaceous has always been a controversial topic, and the scarcity of Early Cretaceous magmatic rocks in the southern part of the Gangdese batholith is the main cause of this debate. To address this issue, this article presents new zircon U–Pb chronology, zircon Hf isotope, whole-rock geochemistry and Sr–Nd isotope data for the Early Cretaceous quartz diorite dykes with adakite affinity in Liuqiong, Gongga. Zircon U–Pb dating of three samples yielded ages of c. 141–137 Ma, indicating that the Liuqiong quartz diorite was emplaced in the Early Cretaceous. The whole-rock geochemical analysis shows that the Liuqiong quartz diorite is enriched in large-ion lithophile elements (LILEs) and light rare-earth elements (LREEs) and is depleted in high-field-strength elements (HFSEs), which are related to slab subduction. Additionally, the Liuqiong quartz diorite has high SiO2, Al2O3 and Sr contents, high Sr/Y ratios and low heavy rare-earth element (HREE) and Y contents, which are compatible with typical adakite signatures. The initial 87Sr/86Sr values of the Liuqiong adakite range from 0.705617 to 0.705853, and the whole-rock ϵNd(t) values vary between +5.78 and +6.24. The zircon ϵHf(t) values vary from +11.5 to +16.4. Our results show that the Liuqiong adakite magma was derived from partial melting of the Neo-Tethyan oceanic plate (mid-ocean ridge basalt (MORB) + sediment + fluid), with some degree of subsequent peridotite interaction within the overlying mantle wedge. Combining regional data, we favour the interpretation that the Neo-Tethyan oceanic crust was subducted at a low angle beneath the Gangdese during the Early Cretaceous.

The study of the petrogenesis of some magmatic rocks with special geochemical attributes provides effective information for us to explore the deep geodynamic background of their formation. A series of granitic porphyry dykes have been found in the mélange zone of the Asa region in southern Tibet, whose genesis may be closely related to the evolution of the Meso-Tethyan Ocean. Regional geodynamic evolution is investigated by whole-rock geochemical analysis, zircon U–Pb dating and Lu–Hf isotopic analysis of two porphyritic granites. The Asa porphyritic granites have high SiO2 (74.29–78.65 wt %) and alkalis (Na2O + K2O = 6.51–9.35 wt %) contents, and low Al2O3 (11.60–14.51 wt %), CaO (0.04–0.19 wt MgO (0.01–0.10 wt %) contents. They are enriched in Zr, Nb, Ce, Y and Hf and depleted in Ti, Ba, Sr and P, consistent with A-type granites. The samples are relatively rich in LREEs, with LREE/HREE ratios of 1.73–3.04. They display negative Eu anomalies (Eu/Eu* = 0.24–0.28) and obvious Ce anomalies in some samples. Zircon U–Pb analyses show that the porphyritic granites formed in late Early Cretaceous time, 107.4 to 105.5 Ma. Zircon εHf(t) values are in the range of 6.9 to 12.0. These data indicate that the porphyritic granites were sourced from interaction between mantle-derived and juvenile lower crust-derived melts, with the addition of oceanic sediment-derived melts. This occurred when the subducting Bangong–Nujiang oceanic crust split to create a slab window. Rising asthenosphere triggered re-melting of lower crust basalts, resulting in the formation of the late Early Cretaceous A-type granites around Asa.

The Lower Cretaceous Wealden sideritic ironstones have a wide occurrence and great potential to aid the reconstruction of the depositional environments of the Weald Basin in SE England. However, mineralogical and geochemical datasets on the ironstones are scarce in the literature. Geochemical and mineralogical data on the sideritic ironstones are presented from the Wadhurst Clay Formation within the Weald Basin. The mineralogy of the ironstones was examined using a PANalytical X'Pert Pro X-ray diffractometer and PANalytical's HighScore Plus software. Elemental composition of the ironstones was measured using a PANalytical MiniPal2 ED-XRF (benchtop X-ray spectrometer). The examination of the mineralogy of the Wealden ironstones confirms the presence of early diagenetic siderites. The trace-element assemblage shows that the sideritic ironstones are chemically pure pointing to a freshwater origin. The sideritic ironstones reveal anoxic conditions and palaeo-salinity in the basin. More generally, it is suggested that the composition of the host rocks has significant controls on the composition of sideritic ironstones in sedimentary basins. This work reinforces the importance of the composition of sideritic ironstones as useful non-traditional data for understanding the depositional settings of sedimentary basins, especially when traditional datasets are not readily available or insufficient.

New evidence of the extinct tree fern of the genus Tempskya Corda from Albian deposits in western Eurasia (northeastern Spain) is presented. These plant fossil remains consist of several silicified false trunks measuring up to 1.20m long, some of which still preserve the apex. Rhizomes and petioles are more abundant in the apical zone of the false trunk. Some false trunks preserve charcoalified tissues that can be interpreted as evidence that palaeo-wildfires affected the false trunks several times from mostly the same direction. Sedimentological evidence suggests that the fern habitat was close to coastal, tidally influenced environments. These new fossils from the Albian of Spain fill the chronological and distributional gap of Tempskya that existed in Eurasia during the Early Cretaceous. Temporal and spatial changes in Tempskya distributions are proposed on several palaeogeographical maps.

This study is focused on slide blocks including oceanic lavas associated with pelagic sediments within the eastern part of the Ankara Mélange. A detailed petrological characterization of the volcanic rocks and a detailed biochronological investigation of the associated radiolarian cherts in eight sections (east of Ankara) was carried out. The volcanic rocks are largely represented by basalts and minor ferrobasalts and trachytes. They show different geochemical affinities and overlapping ages including: (a) Late Jurassic – Early Cretaceous garnet-influenced MORB (middle late Oxfordian to late Kimmeridgian–early Tithonian and early–early late Tithonian; late Valanginian–early Barremian); (b) Early Cretaceous enriched-MORB (middle late Barremian–early early Aptian; Valanginian to middle Aptian–early Albian); (c) Middle Jurassic plume-type MORB (early–middle Bajocian to late Bathonian–early Callovian); (d) Late Jurassic – Early Cretaceous alkaline basalts (middle–late Oxfordian to late Kimmeridgian–early Tithonian; late Valanginian to late Hauterivian). All rock types show a clear garnet signature, as testified to by their high MREE/HREE (middle rare earth element/heavy rare earth element) ratios. The coexistence of chemically different rock types from Middle Jurassic to Early Cretaceous times suggests that they were formed in a mid-ocean ridge setting from partial melting of a highly heterogeneous mantle characterized by the extensive occurrence of OIB-metasomatized portions, which were likely inherited from Triassic mantle plume activity associated with the continental rift and opening of the Neotethys branch.

The vertebrate assemblage from the Early Cretaceous non-marine Xinlong Formation of the Napai Basin, in the south-western part of Guangxi Zhuang Autonomous Region (southern China), is reviewed. The assemblage includes chondrichthyans (at least six species of hybodont sharks including Hybodus, Thaiodus, Heteroptychodus and Acrorhizodus), actinopterygians (Halecomorphi and Ginglymodi), turtles (the adocid Shachemys and the carettochelyid Kizylkumemys), crocodilians (cf. Theriosuchus) and dinosaurs (the sauropods Fusuisaurus and Liubangosaurus, carcharodontosaurid and spinosaurid theropods, iguanodontians and a possible psittacosaurid). This assemblage shows many similarities to those from non-marine formations of the Khorat Group of north-eastern Thailand. It seems to be particularly close to that from the Khok Kruat Formation, considered as Aptian in age, as shown especially by sharks and turtles and by the presence of iguanodontians. An Aptian age is therefore proposed for the Xinlong Formation. A study of the stable oxygen and carbon isotope compositions of reptile apatite suggests that this part of South China experienced subtropical arid conditions during the deposition of the Xinlong Formation. In its composition, the vertebrate fauna from the Xinlong Formation seems to be more similar to coeval faunas from SE Asia than to assemblages from northern China (including the Jehol Biota). Although this may partly reflect different depositional and taphonomic environments (fluvial for the Xinlong Formation versus lacustrine for the Jehol Biota) it seems likely that, during Early Cretaceous time, southern China and SE Asia were part of a distinct zoogeographical province, different from that corresponding to northern China. This may be the result of both climatic differences (with relatively cool climates in northern China versus a subtropical climate in the south) and geographical barriers such as mountain chains.

Facies belts exhibit a back-stepping trend towards the London Brabant/ Rhenish Massif through the Early Cretaceous. The overall eustatic sea-level rise was punctuated by short-term tectonic events identified either as localised or North Sea wide in extent. The biostratigraphically constrained sequences have, for the first time, allowed a detailed calibration of tectonic and eustatic events on a North Sea scale. The most extensive database available to any North Sea Cretaceous study was available to the authors together with a comprehensive suite of new high-resolution biostratigraphy and sedimentology. This has allowed unique insights into provenance, depositional environment, extent of sequence stratigraphical events and the degree to which unconformities have been tectonically accentuated.

Lower Cretaceous pedogenic carbonates exposed in SE China have been dated by U–Pb isotope measurements on single zircons taken from intercalated volcanic rocks, and the ages integrated with existing stratigraphy. δ13C values of calcretes range from –7.0‰ to –3.0‰ and can be grouped into five episodes of increasing–decreasing values. The carbon isotope proxy derived from these palaeosol carbonates suggests pCO2 mostly in the range 1000–2000 parts per million by volume (ppmV) at S(z) (CO2 contributed by soil respiration) = 2500 ppmV and 25°C during the Hauterivian–Albian interval (c. 30 Ma duration). Such atmospheric CO2 levels are 4–8 times pre-industrial values, almost double those estimated by geochemical modelling and much higher than those established from stomatal indices in fossil plants. Rapid rises in pCO2 are identified for early Hauterivian, middle Barremian, late Aptian, early Albian and middle Albian time, and rapid falls for intervening periods. These episodic cyclic changes in pCO2 are not attributed to local tectonism and volcanism but rather to global changes. The relationship between reconstructed pCO2 and the development of large igneous provinces (LIPs) remains unclear, although large-scale extrusion of basalt may well be responsible for relatively high atmospheric levels of this greenhouse gas. Suggested levels of relatively low pCO2 correspond in timing to intervals of regional to global enrichment of marine carbon in sediments and negative carbon isotope (δ13C) excursions characteristic of the oceanic anoxic events OAE1a (Selli Event), Kilian and Paquier events (constituting part of the OAE 1b cluster) and OAE1d. Short-term episodes of high pCO2 coincide with negligible carbon isotope excursions associated with the Faraoni Event and the Jacob Event. Given that episodes of regional organic carbon burial would draw down CO2 and negative δ13C excursions indicate the addition of isotopically light carbon to the ocean–atmosphere system, controls on the carbon cycle in controlling pCO2 during Early Cretaceous time were clearly complex and made more so by atmospheric composition also being affected by changes in silicate weathering intensity.

The sauropod Aragosaurus ischiaticus Sanz, Buscalioni, Casanovas & Santafé, 1987 was the first dinosaur to be described in Spain. The holotype was recovered from the site of Las Zabacheras (Galve, Teruel province). This site has traditionally been situated in the El Castellar Formation (in the lower part of the Wealden facies). Recently, it has been proposed that the remains of Aragosaurus stem from the Villar del Arzobispo Formation (late Tithonian–upper part of the early Berriasian), which would mean that the sauropod was almost 15 million years older than previously thought. Detailed field work has been carried out, making it possible to pinpoint the position of the low-angle unconformity between the Villar del Arzobispo Formation and the El Castellar Formation. This unconformity originated as a result of block tilting that occurred during the early stages of the Early Cretaceous rifting episode. The upper levels of the Jurassic sequence (i.e. the Villar del Arzobispo Formation) were exposed to erosion and karstification, leading to the formation of a discontinuous conglomeratic level. This level has been locally preserved at the bottom of the Wealden syn-rift sequence (i.e. the El Castellar Formation). The results of our detailed mapping demonstrate that the Aragosaurus holotype was found in the lower part of the El Castellar Formation. Moreover, our revision of the existing datings suggests that the El Castellar Formation as a whole is Valanginian?–early Barremian in age. Given that Aragosaurus was located in its lower part, it is probably Valanginian?–Hauterivian in age.

Non-hadrosaurid iguanodontians were the most diverse and abundant group of large-bodied herbivorous dinosaurs during the Early Cretaceous, and were a particularly important component of Laurasian ecosystems. Recent years have seen a dramatic increase in our knowledge of the diversity of this group, with multiple new taxa being described from northeast China. The most complete of these Chinese non-hadrosaurid iguanodontians is Jinzhousaurus yangi, from the middle part of the Yixian Formation (Lower Cretaceous: lower Aptian) of Liaoning Province. Here, we provide the first description of the relatively complete and partially articulated postcranial skeleton of the holotype of Jinzhousaurus, and provide detailed comparisons to closely related taxa. We document additional autapomorphies of Jinzhousaurus that provide strong support for the validity of this taxon.

Fossil vertebrates from the Cabao Formation discovered in the area of Nalut in northwestern Libya include the hybodont shark Priohybodus, the crocodilian Sarcosuchus, an abelisaurid, a baryonichine spinosaurid and a large sauropod with spatulate teeth. The Cabao Formation may be Hauterivian to Barremian in age, although an earlier Berriasian to Valanginian age cannot be excluded. Its dinosaur assemblage is reminiscent of that of the El Rhaz and Tiouraren formations of Niger and strongly differs from both the Cenomanian assemblages of Morocco and Egypt and the Late Aptian to Albian fauna of Tunisia. Fossil vertebrates may be an important tool to establish the stratigraphical framework of the poorly dated Early Cretaceous continental deposits of Africa.

Zavitokichnus fusiformis n. igen. et n. isp. occurs in Lower Cretaceous (Valanginian to Hauterivian) limestones of the Fatric Superunit in the Western Carpathians. Typical cross sections of this more or less spiral trace fossil are sometimes U–O–C–S-shaped. In cross-section the trace fossil passes from a simple linear form, and spreads to a wider rolled-up or rolled-out form and then it returns to a linear trace. Spreite-like lamellae are distinguishable on several cross-section examples. The trace fossil was produced by a deposit feeder and it might be classified as a fodinichnion. Z. fusiformis co-occurs with trace fossil associations of Zoophycos, Chondrites, Planolites, Hormosiroidea and Palaeophycus in carbonate sediments of a deep-seated ramp along the margin of the Fatric intrashelf basin.

New material of dsungaripterid pterosaurs from the Early Cretaceous of Tatal, western Mongolia, allows the diagnoses of Dsungaripteridae and Noripterus to be amended. All pterosaurs found at Tatal belong to Dsungaripteridae (either Dsungaripterus or Noripterus). The name Phobetor is a junior synonym of Noripterus. The differing shapes of the anterior tips of skulls, differing tooth morphologies and the coexistence of both Dsungaripterus and Noripterus may imply that they occupied distinct ecological niches.

Proprionoglarisguyoti gen. nov., sp. nov., Parapsyllipsocus vergereaui gen. nov., sp. nov., and Prospeleketoralbianensis gen. nov., sp. nov. are described from the Early Cretaceous amber of Archingeay (SW France). Libanoglarismouawadi gen. nov., sp. nov. is described from the Early Cretaceous amber of Lebanon. They are all placed into the suborder Trogiomorpha, incertae familiae. The discovery of these new taxa together with a first phylogenetic analysis of the trogiomorphan families demonstrate the necessity of a cladistic redefinition of the currently admitted major subdivisions of this suborder.

Most zoned plutons described in the geological literature have mafic rims and felsic cores and are referred to as “normally zoned”, whereas relatively few “reversely zoned” intrusions (felsic rims and mafic cores) have been described. That unusual zonation pattern has been variously attributed to in situ processes or to the reordering of an underlying, vertically stratified, magma chamber either by intrusion through an orifice or by emplacement of composite diapirs. The Turtle Pluton is an early Cretaceous, reversely zoned, intrusion that is divided into four facies: a Rim Sequence that is graditionally zoned from bt + ilm + muse monzogranite to hb + bt + mt + sph granodiorite; a Core Facies of more homogeneous hb + bt + mt + sph granodiorite to quartz monzodiorite; between these two facies, a structural discontinuity termed the Schlieren Zone; and an Eastern Facies of monzogranite to granodiorite. Field relationships, distribution of strain, and geochemical and isotopic studies (including a range of initial87Sr/86Sr from 0·7085–0·7065) suggest that the reverse zonation of the Turtle Pluton is the result of sequential emplacement of two diapirs each derived from the same underlying, vertically stratified, magma chamber, and that the Rim Sequence zonation is chiefly the result of mixing of intermediate and felsic magmas from distinct sources accompanied by minor fractional crystallisation.