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The geodynamic evolution of the South Armenian Block (SAB) within the Tethyan realm during the Palaeozoic to present-day is poorly constrained. Much of the SAB is covered by Cenozoic sediments so that the relationships between the SAB and the neighbouring terranes of Central Iran, the Pontides and Taurides are unclear. Here we present new geochronological, palaeomagnetic, and geochemical constraints to shed light on the Gondwanan and Cimmerian provenance of the SAB, timing of its rifting, and geodynamic evolution since the Permian. We report new 40Ar/39Ar and zircon U-Pb ages and compositional data on magmatic sills and dykes in the Late Devonian sedimentary cover, as well as metamorphic rocks that constitute part of the SAB basement. Zircon age distributions, ranging from ∼3.6 Ga to 100 Ma, firmly establish a Gondwanan origin for the SAB. Trondhjemite intrusions into the basement at ∼263 Ma are consistent with a SW-dipping active continental margin. Mafic intraplate intrusions at ∼246 Ma (OIB) and ∼234 Ma (P-MORB) in the sedimentary cover likely represent the incipient stages of breakup of the NE Gondwanan margin and opening of the Neotethys. Andesitic dykes at ∼117 Ma testify to the melting of subduction-modified lithosphere. In contrast to current interpretations, we show that the SAB should be considered separate from the Taurides, and that the Armenian ophiolite complexes formed chiefly in the Eurasian forearc. Based on the new constraints, we provide a geodynamic reconstruction of the SAB since the Permian, in which it started rifting from Gondwana alongside the Pontides, likely reached the Iranian margin in Early Jurassic times, and was subject to episodes of intraplate (∼189 Ma) and NE-dipping subduction-related (∼117 Ma) magmatism.

Earth's thermo-tectonic evolution determines the way the planet's interior and surface interact and shows temporal changes in both trends and periodic rhythms. By sampling the subcontinental lithospheric mantle that represents the interface between the convecting mantle and the crust, carbonatite and kimberlite should be ideal rock types for documenting this evolution. The first-order secular rise of kimberlites over time has been noted by researchers, but there is much debate over how to interpret this trend, and their second-order variability has received less attention. We compiled a comprehensive global carbonatite database and compared it with an existing kimberlite one. We find that the numbers of carbonatites and kimberlites have similar increasing secular trends, with accelerated growth after ca. 1 Ga, and show the same periodic rhythms that have been synchronized to the supercontinent cycle since ca. 2.1 Ga. We link these trends and rhythms to the long-term change of Earth and the supercontinent cycle, both of which have altered the temperature of, and the subduction-recycled volatile flux into, the subcontinental lithosphere. Such consistent records in carbonatite and kimberlite behavior provide critical evidence for the synchronous thermo-tectonic evolution of the entire subcontinental lithosphere.

The Devonian position of the South China Block (SCB) remains debated because apparently contradictory Devonian paleopoles have been documented. Here we report two characteristic remanent magnetization components from the mildly deformed Guanyang Devonian successions (Lochkovian-Famennian) within the cratonic interior of the SCB. Both components pass reversal tests and occur in different samples across the successions. Component A and associated paleopole DA (228.9°E, 37.7°N, A95 = 3.7°) are comparable with published Devonian data and were likely acquired before Permian-Triassic folding and likely reflect syn-depositional magnetization. Component B and its associated paleopole DB (204.6°E, 4.5°N, A95 = 5.5°) are distinct from published results and were probably acquired during minor tilting associated with the Late Devonian Liujiang orogeny. If paleopole DA was acquired prior to the Late Devonian Liujiang orogeny, the paleolatitude of the Guanyang successions varied little throughout the Devonian, but the azimuthal orientation of recorded declinations exhibits a 40° difference. The distinct positions of the two paleopoles are broadly consistent with existing enigmatic Devonian field records. Alternatively, given the uncertainty in the acquisition ages of both components in the Guanyang successions, a case can be made for component A being a secondary magnetization acquired during the Permian-Triassic Indosinian orogeny. Nonetheless, the similar distribution of Devonian paleopoles from Gondwana to those of cratonic interior of the SCB suggests a Devonian connection between the two continents, and adds further support for a non-uniformitarian geomagnetic field during this enigmatic time interval.

Interpretation of Earth's oldest preserved crustal archive, the Jack Hills zircon of Western Australia, has been controversial in terms of the onset of plate tectonics. We conduct time-series analysis on hafnium isotopes of the Jack Hills zircon and reveal an array of statistically significant cycles that are reminiscent of plate-tectonic subduction. At face value, such cycles may suggest early Earth conditions similar to those of today—the uniformitarian hypothesis that plate tectonics was essentially operational since “day one”. On the other hand, in the context of expected secular changes due to planetary evolution and geological observations, the cycles could instead imply that modern plate-tectonic subduction inherited mantle convective harmonics already facilitated by an early phase of stagnant-lid delamination—the “lid-to-plates” hypothesis. Either way, any model for the nature of plate tectonics must incorporate conditions operating during Hadean time, either by initiation of plate tectonics then or by later inheritance of preexisting cycles of mantle convection.

Abstract The Zagros Mountain belt in Iran comprises an extensive record of Mesozoic and Cenozoic deposits uplifted by collision of the Arabian and Iranian continental plates. This area has been shown to provide important information to decipher the climatic history of Western Asia, especially regarding the evolution of deserts in Mesopotamia and Northern Arabia. In a high-resolution geological record of 84 samples, we combine clay mineralogy and micropalaeontological observations to refine the late Neogene climate record in Northern Arabia. We investigated a 2.6-km-thick sedimentary profile from the Simply Folded Zagros Mountain belt spanning ca. 10.2 myrs from the late Middle Miocene (Serravallian) to earliest Pleistocene (Gelasian) comprising floodplain sediments and saline mudstones with a strong aeolian contribution. The clay fraction

SUMMARY We present palaeo- and rock magnetic results from a well-dated, 21 m-thick, Late Pleistocene continental sedimentary section located in southern Germany. Rock magnetic measurements reveal a complex magnetic mineralogy dominated by low coercivity minerals likely related to single domain biogenic magnetite and biogenic or early diagenetic greigite. In the lower part of the section also detrital haematite is present. The stable remanence shows predominantly normal polarity with two marked deviations at ∼1280-1200 cm and at 886 cm profile depth. Whereas the lower excursion is well established by several samples and documented also by detrital haematite, the upper one is only represented by a single sample and revealed by magnetite and greigite. Using the radiocarbon-based age model for the section, the lower excursion yields an age of 42.8–41.3 ka cal BP and is interpreted to represent the Laschamps geomagnetic excursion. The increased abundance of greigite in the upper part of the section, especially in the sample responsible for the upper anomalous direction, renders the interpretation of an actual excursion problematic due to the reducing environment necessary for the greigite formation.

The Australia-Laurentia connection in the Paleoproterozoic to Mesoproterozoic supercontinent Nuna is thought to have initiated by ca. 1.6 Ga when both continents were locked in a proto-SWEAT (southwestern U.S.–East Antarctic) configuration. However, the longevity of that configuration is poorly constrained. Here, we present a new high-quality paleomagnetic pole from the ca. 1.3 Ga Derim Derim sills of northern Australia that suggests Australia and Laurentia were in the same configuration at that time. This new paleopole also supports a connection between Australia and North China and, in conjunction with previously reported data from all continents, indicates that the breakup of Nuna largely occurred between ca. 1.3 and 1.2 Ga. The Australia-Laurentia connection in the Paleoproterozoic to Mesoproterozoic supercontinent Nuna is thought to have initiated by ca. 1.6 Ga when both continents were locked in a proto-SWEAT (southwestern U.S.-East Antarctic) configuration. However, the longevity of that configuration is poorly constrained. Here, we present a new high-quality paleomagnetic pole from the ca. 1.3 Ga Derim Derim sills of northern Australia that suggests Australia and Laurentia were in the same configuration at that time. This new paleopole also supports a connection between Australia and North China and, in conjunction with previously reported data from all continents, indicates that the breakup of Nuna largely occurred between ca. 1.3 and 1.2 Ga.

The ca. 1.4 Ga Velkerri and Xiamaling Formations, in Australia and the north China craton, respectively, are both carbonaceous shale deposits that record a prominent euxinic interval and were intruded by ca. 1.3 Ga dolerite sills. These similarities raise the possibility that these two units correlate, which would suggest the occurrence of widespread euxinia, organic carbon burial, and source rock deposition. Paleomagnetic data are consistent with Australia and the north China craton being neighbors in the supercontinent Nuna and thus permit deposition in a single large basin, and the putative stratigraphic correlation. However, lack of geochronological data has precluded definitive testing. The Xiamaling Formation has been shown to exhibit depositional control by orbital cycles. Here, we tested the putative correlation with the Velkerri Formation by cyclostratigraphic analysis. The Velkerri Formation exhibits sedimentological cycles that can be interpreted to represent the entire hierarchy of orbital cycles, according to a sedimentation rate that is consistent with Re-Os ages. Comparison of the inferred durations of the euxinic intervals preserved in both the Xiamaling and Velkerri Formations reveals a nearly identical ∼10-m.y.-long oceanic euxinic event. This permits the interpretation that the two hydrocarbon-rich units were deposited and matured in the same basin of Nuna, similar to the Gulf of Mexico during the breakup of Pangea.

Many ideas have been proposed to explain the origin of bipedalism in hominins and suspension in great apes (hominids); however, fossil evidence has been lacking. It has been suggested that bipedalism in hominins evolved from an ancestor that was a palmigrade quadruped (which would have moved similarly to living monkeys), or from a more suspensory quadruped (most similar to extant chimpanzees)1. Here we describe the fossil ape Danuvius guggenmosi (from the Allgau region of Bavaria) for which complete limb bones are preserved, which provides evidence of a newly identified form of positional behaviour-extended limb clambering. The 11.62-million-year-old Danuvius is a great ape that is dentally most similar to Dryopithecus and other European late Miocene apes. With a broad thorax, long lumbar spine and extended hips and knees, as in bipeds, and elongated and fully extended forelimbs, as in all apes (hominoids), Danuvius combines the adaptations of bipeds and suspensory apes, and provides a model for the common ancestor of great apes and humans.

We present new paleo- and rock magnetic results from the ca. 1792 Ma Hart Dolerite sills that intrude the strata of the Kimberley craton, Western Australia. From 24 sites sampled, 23 are directionally clustered and the site mean directions were used to calculate a grand mean direction. Ten of the 23 sites have 95% confidence intervals ( α 95 ) less than 16°. A positive reversal test, dissimilarity of the corresponding paleopole from known younger Australian poles, and a previously reported positive baked contact test, indicate that our paleomagnetic results are of primary origin, and the results are consistent with the geologic interpretation that the Hart Dolerite sills represent a multiphase magmatic emplacement over the duration of several million years. The new ca. 1792 Ma paleopole for the Kimberley craton is applicable to the entire North Australian Craton. A comparison of Paleoproterozoic poles from the North and West Australian cratons supports the occurrence of a previously proposed 40° intracontinental rotation between the two cratons during latest Neoproterozoic time. Furthermore, comparing these Australian poles with similar aged Laurentian poles shows that the apparent polar wander paths of the two continents have a similar history between ca. 1800 and 1730 Ma and between ca. 1650 and 1400 Ma. To achieve a fit within uncertainty limits, an additional relative latitudinal motion is necessary during the transition interval (1730–1650 Ma). We suggest that a two-stage evolution occurred between Laurentia and Australia during the assembly of the supercontinent Nuna. Australia and Laurentia traveled together between ca. 1800 Ma until ca. 1730 Ma in a semi-stable configuration. During 1730–1650 Ma, they underwent a net relative latitudinal motion, leading to the final assembly of Nuna after ca. 1650 Ma.

A palaeomagnetic study was carried out on the newly identified 1888 ± 9 Ma Boonadgin dyke swarm of the Yilgarn Craton in Western Australia. The Bonnadgin dykes yield a mean direction of magnetisation of D = 143°, I = 13°, k = 37 and α95 = 8°, based on samples from 10 diabase dykes, with a corresponding palaeopole at 47° S, 235° E, A95 = 6°. A positive baked contact test establishes the primary nature of the magnetisation. The ca. 1.89 Ga palaeopole suggests that the Yilgarn Craton was near the equator at this time, and the Boonadgin dyke swarm can be interpreted to represent an arm of a radiating dyke swarm that shared the same plume centre with coeval mafic dykes in the Dharwar and Bastar cratons of southern India. We therefore propose that the West Australian Craton (WAC, consisting of the Yilgarn and Pilbara cratons) and the South Indian Block (SIB, consisting of the Dharwar, Bastar, and Singhbhum cratons) were connected ca. 1.89 Ga. Globally, available high-quality palaeopoles of similar age allow the West Australian Craton to be placed northwest of proto-Laurentia during the assembly of the supercontinent Nuna.

The supercontinent cycle of episodic assembly and breakup of almost all continents on Earth is commonly considered the longest period variation to affect mantle convection. However, global zircon Hf isotopic signatures and seawater Sr isotope ratios suggest the existence of a longer-term variation trend that is twice the duration of the supercontinent cycle. Here we propose that since ∼2 billion years ago the superocean surrounding a supercontinent, as well as the circum-supercontinent subduction girdle, survive every second supercontinent cycle. This interpretation is in agreement with global palaeogeography and is supported by variations in passive margin, orogen, and mineral deposit records that each exhibits both ∼500–700 million years periodic signal and a 1000–1500 million years variation trend. We suggest that the supercontinent cycle is modulated by an assembly that alternates between dominantly extroversion after a more complete breakup, and dominantly introversion after an incomplete breakup of the previous supercontinent.

Many Archean cratons exhibit Paleoproterozoic rifted margins, implying they were pieces of some ancestral landmass(es). The idea that such an ancient continental assembly represents an Archean supercontinent has been proposed but remains to be justified. Starkly contrasting geological records between different clans of cratons have inspired an alternative hypothesis where cratons were clustered in multiple, separate “supercratons.” A new ca. 2.62 Ga paleomagnetic pole from the Yilgarn craton of Australia is compatible with either two successive but ephemeral supercontinents or two long-lived supercratons across the Archean-Proterozoic transition. Neither interpretation supports the existence of a single, long-lived supercontinent, suggesting that Archean geodynamics were fundamentally different from subsequent times (Proterozoic to present), which were influenced largely by supercontinent cycles.

Materials and methods, five supplemental figures, seven supplemental tables, and references providing further detail on paleomagnetic and rock-magnetic results, sampling descriptions, performed analysis, and reconstruction data.

Seismic imaging of Earth’s crust shows signs that subduction became a global phenomenon about 2 billion years ago., The earliest evidence for subduction, which could have been localized, does not signify when plate tectonics became a global phenomenon. To test the antiquity of global subduction, we investigated Paleoproterozoic time, for which seismic evidence is available from multiple continents. We used a new high-density seismic array in North China to image the crustal structure that exhibits a dipping Moho bearing close resemblance to that of the modern Himalaya. The relict collisional zone is Paleoproterozoic in age and implies subduction operating at least as early as ~2 billion years (Ga) ago. Seismic evidence of subduction from six continents at this age is interpreted as the oldest evidence of global plate tectonics. The sutures identified can be linked in a plate network that resulted in the assembly of Nuna, likely Earth’s first supercontinent. Global subduction by ~2 Ga ago can explain why secular planetary cooling was not appreciable until Proterozoic time.

For Oligocene and Miocene sediments of the Central Paratethys realm, regional chronostratigraphic stages have been defined on the basis of characteristic faunal assemblages, often containing abundant endemic elements. Although considerable progress has been made in correlating Paratethyan stages with the Global Time Scale (GTS), the task remains incomplete, especially for the Early Miocene period. The present study focuses on Lower Miocene deposits of the Central Paratethys in southeastern Germany, i.e. the Upper Marine Molasse (OMM) and Upper Brackish Molasse (OBM) of the North Alpine Foreland Basin (NAFB, Molasse Basin). The sediments concerned are assigned to the regional Ottnangian stage of the Central Paratethys, which corresponds to the middle Burdigalian in the GTS. We present a formal lithostratigraphic definition of the Untersimbach and Neuhofen Formations (both OMM), combined with litho-, bio- and magnetostratigraphic investigations, which together provide an improved chronology for the middle Burdigalian interval in the NAFB. The base of the Ottnangian stage is shown to correlate with polarity chron C5En, and we consider an absolute age of around 18.2 Ma to be most plausible. As the OMM in the southeast German part of the NAFB represents a single transgressive-regressive sequence, our new data suggest that the Ottnangian transgression began during chron C5En (similar to 18.2 Ma), whereas the onset of the regressive phase lies within chron C5Dr.2r (similar to 18 Ma). The uppermost marine deposits (top OMM/"Glaukonitsande & Blattermergel") and the lowermost brackish sediments (OBM/Oncophora Formation) are correlated with polarity chron C5Dn (similar to 17.4 Ma). Moreover, our results clearly demonstrate that the lower Oncophora Formation (normal polarity) is not time-equivalent to the OBM/Kirchberg Formation in the southwest German sector of the NAFB (largely reverse polarity) as has hitherto been assumed. The lower Oncophora Formation is most probably contemporaneous with the lowermost OBM sediments (Grimmelfingen Formation) in the southwest German Molasse Basin.

The Rhenodanubian Flysch zone (RDF) is a Lower Cretaceous-lower Palaeocene turbidite succession extending for similar to 500 km from the Danube at Vienna to the Rhine Valley (Eastern Alps). It consists of calcareous and siliciclastic turbidite systems deposited in a trench abyssal plain. The age of deposition has been estimated through micropalaeontologic dating. However, palaeomagnetic studies constraining the age and the palaeolatitude of deposition of the RDF are still missing. Here, we present palaeomagnetic data from the Early Cretaceous Tristel and Rehbreingraben Formations of the RDF from two localities in the Bavarian Alps (Rehbrein Creek and Lainbach Valley, southern Germany), and from the stratigraphic equivalent of the Falknis Nappe (Liechtenstein). The quality of the palaeomagnetic signal has been assessed by either fold test (FT) or reversal test (RT). Sediments from the Falknis Nappe are characterized by a pervasive syntectonic magnetic overprint as tested by negative FT, and are thus excluded from the study. The sediments of the Rehbreingraben Formation at Rehbrein Creek, with positive RT, straddle magnetic polarity Chron M0r and the younger M'-1r' reverse event, with an age of similar to 127-123 Ma (late Barremian-early Aptian). At Lainbach Valley, no polarity reversals have been observed, but a positive FT gives confidence on the reliability of the data. The primary palaeomagnetic directions, after correction for inclination shallowing, allow to precisely constrain the depositional palaeolatitude of the Tristel and Rehbreingraben Formations around similar to 28 degrees N. In a palaeogeographic reconstruction of the Alpine Tethys at the Barremian/Aptian boundary, the RDF is located on the western margin of the Brianconnais terrain, which was separated from the European continent by the narrow Valais Ocean.

While it is well established that the Earth's magnetic field is generated by a self sustaining dynamo that reversed its polarity at irregular intervals in the geological past, the very mechanisms causing field reversals remain obscure. Paleomagnetic reconstructions of polarity transitions have been essential for physically constraining the underlying mechanisms in terms of time scale, but thus far remain ambiguous with regard to the transitional field geometry. Here we present new paleomagnetic records from a rapidly deposited lacustrine sediment sequence with extraordinarily stable paleomagnetic signals, which has captured in unprecedented detail the bottom (reverse to normal: R–N) and top (normal to reverse: N–R) transitions of the Jaramillo subchron (at 1.072 Ma and at 0.988 Ma). The obtained virtual geomagnetic pole (VGP) path indicates an oscillatory transitional field behavior with four abrupt transequatorial precursory jumps across the Pacific. The distribution of VGP positions indicates regions of preferred occurrence. Our results are in agreement with previously proposed bands of transitional VGP occurrence over the Americas and Australia/northwest Pacific. Additionally, our VGP positions seem to avoid large low shear velocity provinces (LLSVPs) above the core mantle boundary (CMB). Thus, our data supports the idea that the transitional field geometry is controlled by heat flux heterogeneities at the CMB linked to LLSVPs.

The Central European Basin is very suitable for high-resolution multistratigraphy of Late Permian to Early Triassic continental deposits. Here the well exposed continuous transition of the lithostratigraphic Zechstein and Buntsandstein Groups of Central Germany was studied for isotope-chemostratigraphy (δ13Corg, δ13Ccarb, δ18Ocarb), major and trace element geochemistry, magnetostratigraphy, palynology, and conchostracan biostratigraphy. The analysed material was obtained from both classical key sections (abandoned Nelben clay pit, Caaschwitz quarries, Thale railway cut, abandoned Heinebach clay pit) and a recent drill core section (Caaschwitz 6/2012) spanning the Permian-Triassic boundary. The Zechstein–Buntsandstein transition of Central Germany consists of a complex sedimentary facies comprising sabkha, playa lake, aeolian, and fluvial deposits of predominantly red-coloured siliciclastics and intercalations of lacustrine oolitic limestones. The new data on δ13Corg range from − 28.7 to − 21.7 ‰ showing multiple excursions. Most prominent negative shifts correlate with intercalations of oolites and grey-coloured clayey siltstones, while higher δ13Corg values correspond to an onset of palaeosol overprint. The δ13Ccarb values range from − 9.7 to − 1.3 ‰ with largest variations recorded in dolomitic nodules from the Zechstein Group. In contrast to sedimentary facies shifts across the Zechstein-Buntsandstein boundary, major element values used as a proxy (CIA, CIA*, CIA-K) for weathering conditions indicate climatic stability. Trace element data used for a geochemical characterization of the Late Permian to Early Triassic transition in Central Germany indicate a decrease in Rb contents at the Zechstein-Buntsandstein boundary.New palynological data obtained from the Caaschwitz quarry section reveal occurrences of Late Permian palynomorphs in the Lower Fulda Formation, while Early Triassic elements were recorded in the upper part of the Upper Fulda Formation. The present study confirms an onset of a normal-polarized magnetozone in the Upper Fulda Formation of the Caaschwitz quarry section supporting an interregional correlation of this crucial stratigraphic interval with the normal magnetic polarity of the basal Early Triassic known from marine sections in other regions. Based on a synthesis of the multistratigraphic data, the Permian-Triassic boundary is proposed to be placed in the lower part of the Upper Fulda Formation, which is biostratigraphically confirmed by the first occurrence date of the Early Triassic Euestheria gutta-Palaeolimnadiopsis vilujensis conchostracan fauna. Rare records of conchostracans reported from the siliciclastic deposits of the lower to middle Zechstein Group may point to its potential for further biostratigraphic subdivision of the Late Permian continental deposits.

Earth’s oldest preserved crustal archive, the Jack Hills zircon of Western Australia, has been controversial to interpret in terms of the onset of plate tectonics. Here we conduct time series analysis on hafnium isotopes of the Jack Hills zircon and reveal an array of statistically significant cycles that are reminiscent of plate tectonics, i.e., subduction. At face value, such cycles may suggest early Earth conditions similar to today—the uniformitarian “day one” hypothesis. On the other hand, in the context of expected secular changes due to planetary evolution and geological observations, the cycles could instead imply that modern plate tectonic subduction inherited convective harmonics already facilitated by an early phase of stagnant-lid delamination—the “lid-to-plates” hypothesis. Either way, any model for the initiation of plate tectonics must begin in Hadean time.

The paleogeography and chronology of the Paleoproterozoic supercontinent Nuna are highly debated. To further test the paleogeography of Australian cratons in the leadup to Nuna formation, we present new paleomagnetic results from two Paleoproterozoic rock formations in North Australia. First, we obtained paleomagnetic directions from the 1825±4 Ma, bimodal Plum Tree Creek Volcanics sequence located within the Pine Creek Inlier of the North Australian Craton. Second, we studied the 1855±2 Ma layered mafic-ultramafic ‘Toby’ intrusion from the Kimberley Craton (KC). Samples from both study areas reveal high quality, stable, magnetite related characteristic remanent magnetization directions. Combining within-site clustered mean directions, we obtained two paleopoles, which plot proximal to each other in the present day central Pacific Ocean, off the east coast of Australia. These results agree with previous interpretation that the Kimberly Craton was amalgamated with the rest of the North Australian Craton (NAC) prior to ca. 1.85 Ga. Comparing these new results with slightly younger poles from the NAC and slightly older, rotated poles form the West Australian Craton (WAC) reveal a high degree of clustering suggesting very minimal absolute plate motion between ca. 1.9-1.85 and 1.6 Ga before the final amalgamation of Nuna. All available paleomagnetic poles agree with an assembly, or close juxtaposition, of the two major Australian cratons (NAC and WAC) before 1.8 Ga. Furthermore, the individual virtual geomagnetic poles from the potentially slow cooled Toby intrusion show a non-fisherian distribution along a great circle. This spread might be related to previously interpreted major true polar wander events based on Laurentian data, which would be global if such an interpretation is correct. The assembly of proto-Australia prior to ca. 1.85 Ga roughly 250 to 300 Myr before the final stage of supercontinent Nuna’s amalgamation ca. 1.6 Ga suggests that assembling of major building blocks, such as Australia and Laurentia for the supercontinent Nuna and Gondwana for the supercontinent Pangea, is an important step in the formation of supercontinents.

The most dominant features in the present-day lower mantle are the two antipodal African and Pacific large low-shear-velocity provinces (LLSVPs). How and when these two structures formed, and whether they are fixed and long lived through Earth history or dynamic and linked to the supercontinent cycles, remain first-order geodynamic questions. Hotspots and large igneous provinces (LIPs) are mostly generated above LLSVPs, and it is widely accepted that the African LLSVP existed by at least ca. 200 Ma beneath the supercontinent Pangea. Whereas the continental LIP record has been used to decipher the spatial and temporal variations of plume activity under the continents, plume records of the oceanic realm before ca. 170 Ma are mostly missing due to oceanic subduction. Here, we present the first compilation of an Oceanic Large Igneous Provinces database (O-LIPdb), which represents the preserved oceanic LIP and oceanic island basalt occurrences preserved in ophiolites. Using this database, we are able to reconstruct and compare the record of mantle plume activity in both the continental and oceanic realms for the past 2 b.y., spanning three supercontinent cycles. Time-series analysis reveals hints of similar cyclicity of the plume activity in the continent and oceanic realms, both exhibiting a periodicity of ∼500 m.y. that is comparable to the supercontinent cycle, albeit with a slight phase delay. Our results argue for dynamic LLSVPs where the supercontinent cycle and global subduction geometry control the formation and locations of the plumes.

Many ideas have been proposed to explain the origin of bipedalism in hominins and suspension in great apes (hominids); however, fossil evidence has been lacking. It has been suggested that bipedalism in hominins evolved from an ancestor that was a palmigrade quadruped (which would have moved similarly to living monkeys), or from a more suspensory quadruped (most similar to extant chimpanzees)

The precise Eurasian chronostratigraphy of the Neogene-Quaternary period is still hampered by the existence of numerous regional stages often lacking independent and absolute age constraints. Therefore, detailed paleoclimatic reconstructions of areas like the Caucasus are still poorly constrained and the influence of climate variability on faunal interchange between Africa and Eurasia in the late Neogene-Quaternary is still difficult to address. During the last decades, Quaternary sections from western Georgia have produced a wealth of paleoclimatic proxy data. Unfortunately, these sections do not have a robust age control. This is especially true for the Gurian stage which has been vaguely defined as being coeval with the lower Pleistocene on the basis of poorly documented bio- and magnetostratigraphic data. In order to constrain the age of the Gurian stage, a detailed magnetostratigraphic study has been carried out. All major sections with known Gurian sediments in the former Rioni bay (a marine restricted area to the southeast of the Major Caucasus) have been studied. Our results confirm for the first time the strict correlation between the Gurian succession and the Calabrian stage. In addition, our data provides further information on the tectonic setting of the Rioni bay during the Calabrian in this region: (1) in the north, Gurian sediments were unconformably deposited on older Meotian sediments in a piggy back basin, (2) in the south, Gurian sediments are conformably overlying Kujalnician (Plio-Pleistocene) strata, (3) magnetostratigraphic correlation among sections indicate drastic changes in sediment accumulation rates within the basin, (4) rock magnetic experiments reveal significant magnetomineralogical differences between Gurian and the underlying Miocene sediments likely documenting a transition related to changes in oxic conditions, supply of terrigenous material and sedimentation rate close to the Miocene-Pliocene boundary. These results provide a robust basis for further tectonic and paleoclimatic investigations of this region.

Chronostratigraphic correlation and dating of terrestrial, especially mammal bearing, sediments of the European Neogene are still problematic and highly debated. In particular, absolute ages for important vertebrate assemblages are often not available making correlation during the continental Miocene across Europe so ambiguous. Here we present a detailed magnetostratigraphic study on a paleontological key section of the Middle to Late Miocene transition in the North Alpine Foreland Basin (NAFB) in Bavaria (Hammerschmiede) and a neighboring drill core, which has a total length of 150.4 m and includes, stratigraphically, the fossil site. We identify three complete normal polarity intervals, which have been correlated based on biochronologic constraints to chrons C5An.1n, C5r.2n and C5r.2r-1n. At least two major hiatuses probably occurred within the interjacent reversed chrons, for which geological indications are present and might be relatable to isochronic features in the Vienna basin. Inferred upper limits of the accumulation rate vary between 10 and 30 cm/kyr. This correlation determines the age of the Hammerschmiede vertebrate level HAM 5 to be about 11.62 Ma, making it an ideal biochronologic tie-point for the base of the Tortonian and Pannonian stages in terrestrial settings. Additionally, we date the youngest freshwater molasse lithostratigraphic unit of the Bavarian part of the NAFB, the Obere Serie, to between 13.8 and 11.1 Ma. Following our correlation, the lack of hipparion horses in the Bavarian part of the NAFB has stratigraphic rather than ecologic reasons and the Ilipparion datum' seems to be a single bio-event at 11.1 Ma in Western Eurasia.

Voluminous early to middle Pleistocene pyroclastic flow deposits were generated from Mount Aragats (Aragats Volcanic Province, AVP), one of the largest volcanoes in the Arabia-Eurasia continental collision zone. Here we report paleomagnetic results, in combination with anisotropy of magnetic susceptibility (AMS) analysis, from 31 outcrops belonging to six ignimbrite units of the western part of the AVP (covering an area of more than 5000 km2). Paleomagnetic directions analysis of samples from 26 outcrops of the three younger ignimbrite units yields a well-defined normal polarity direction of D = 339.2°, I = 55.7°, k = 278.4 and α95 = 1.7°. The virtual coincidence of the paleomagnetic directions seems to point to an emplacement of the units within a restricted time of similar geomagnetic secular variation (i.e., few hundred years). However, new isotope 40Ar/39Ar ages of the three units suggest two separated events at ~0.65 and ~ 0.75 Ma. We cannot fully exclude the possibility of similar paleomagnetic directions at 0.65 and 0.75 Ma or the occurrence of a widespread remagnetization event at 0.65 Ma, but both scenarios are highly unlikely. In contrast to that, five sites from the three older units all show reversed magnetic polarity, which implies an age of emplacement older than the last magnetic polarity reversal at ~780 ka. This agrees with recent 40Ar/39Ar ages of the three older units at ~0.93 Ma. The paleomagnetic scatter of the older units is high compared to the younger ones. Even if paleomagnetic directions and radiometric age are similar, available data cannot unequivocally indicate if the three older units were generated from the same or three different eruptions. The high quality AMS data result in three different types of fabric (lineated, foliated and undetermined) that are all commonly observed in the studied pyroclastic deposits. Accordingly, we use lineation, tilt of foliation, or both for the determination of paleoflow direction. Results reveal a radial flow pattern surrounding Mt. Aragats, which is, however, highly influenced by topographic features, such as valleys, even in proximity of the eruption center.

Multidimensional scaling (MDS) has become an important tool in detrital zircon geochronology for discriminating and comparing multiple samples, especially where large datasets are concerned. However, the non-parametric test statistics used in MDS (e.g., Kolmogorov–Smirnov [K-S] or Kuiper) to calculate differences between detrital zircon samples are sensitive to differences in grain age uncertainty, for example, when comparing compilations of U-Pb data produced via different analytical techniques. We illustrate the effect of different age uncertainties on comparison metrics and MDS analysis using synthetic populations. Additionally, we introduce two methods that reduce these limitations: an error resampling MDS (ERM) technique and bootstrap resampling with Procrustes rotation (BoPR) technique. These new resampling techniques reduce limitations associated with MDS. We demonstrate the utility of these new tools by comparing detrital zircon samples from the Mesoproterozoic Roper Group of Northern Australia with nearby potential source regions. Mitigating the limitations of MDS, and the underlying statistics by employing resampling techniques makes MDSa more potent means of addressing source to sink relationships in detrital zircon studies.

A pilot palaeomagnetic study was conducted on the recently dated with in situ SHRIMP U-Pb method at 1134 ± 9 Ma (U-Pb, zircon and baddeleyite) Bunger Hills dykes of the Mawson Craton (East Antarctica). Of the six dykes sampled, three revealed meaningful results providing the first well-dated Mesoproterozoic palaeopole at 40.5°S, 150.1°E (A95 = 20°) for the Mawson Craton. Discordance between this new pole and two roughly coeval poles from Dronning Maud Land and Coats Land (East Antarctica) demonstrates that these two terranes were not rigidly connected to the Mawson Craton ca. 1134 Ma. Comparison between the new pole and that of the broadly coeval Lakeview dolerite from the North Australian Craton supports the putative ~40° late Neoproterozoic relative rotation between the North Australian Craton and the combined South and West Australian cratons. A mean ca. 1134 Ma pole for the Proto-Australia Craton is calculated by combining our new pole and that of the Lakeview dolerite after restoring the 40° intracontinental rotation. A comparison of this mean pole with the roughly coeval Abitibi dykes pole from Laurentia confirms that the SWEAT reconstruction of Australia and Laurentia was not viable for ca. 1134 Ma.

The Transantarctic mountains predominantly consist of Jurassic continental flood basalts (Kirkpatrick) and sills (Ferrar) emplaced during the earliest phase of the break-up of Pangea. Published ages, based on a variety of geochronological methods all agree rather well and cluster around 180 Ma suggesting emplacement during a rather short time interval of not more than 3 Myr. Paleomagnetic studies, mostly carried out between the 60s and 90s of the last century, however, yield two well defined but significantly different groups of paleomagnetic pole positions plotting either in intermediate latitudes (A) or at latitudes exceeding 60 degrees S (B). Pole positions belonging to group A are generally interpreted to be of primary origin whereas the significance of group B poles remains unclear. Here we report new data from the Kirkpatrick basalts of Northern Victoria Land, Antarctica, where 157 oriented paleomagnetic samples were taken, covering about 800 m of stratigraphy and 23 volcanic flows in Gair Mesa (73.4666 degrees S;162.8666 degrees E). After removal of a steep magnetic overprint with rather low coercivities straight linear segments of exclusively normal polarity trending toward the origin of projection are identified in 151 samples from 22 sites. Maximum unblocking temperatures do not exceed 580 degrees C and maximum coercivities not 60 mT. The resulting mean virtual geomagnetic pole (VGP) for the Gair Mesa plots at 66.4 degrees S;227.7 degrees E (alpha(95) of 6.2 degrees, k = 25.7) comparable to group B poles. Reflecting light microscopy reveals that the magnetic inventory of all samples analyzed is dominated by magnetite showing shrinking cracks and broad ilmenite lamellae, the latter being diagnostic for high temperature oxidation. Analysis of the distribution of the 22 pole positions obtained here shows that secular variation has successfully been averaged (S-b = 15.9 degrees) suggesting that the rocks studied here have recorded the time averaged geomagnetic field during early mid Jurassic times. Based on these new results we postulate that both clusters A and B of pole positions reflect primary magnetizations and that the Kirkpatrick basalts of Gair Mesa have been emplaced in a rather short normal polarity time interval of 3 Myr. If our reasoning is correct, the apparent polar wander path for the latest early Jurassic might be more complex than previously thought. Whether this complexity is evidence for massif True Polar Wander remains speculative. (C) 2015 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

The Hellenides fold-and-thrust range comprises two subparallel ophiolite belts of Triassic to Jurassic age - the external ophiolite belt (e.g., Mirdita, Pindos, Argolis) in the west, and the internal ophiolite belt in the east - broadly separated by the continental crust units of the Korabi-Pelagonian Zone. It is still a matter of debate whether these ophiolites derived from a single ocean (Meliata-Maliac-Vardar) or mark the suture of two distinct oceanic seaways (Pindos and Meliata-Maliac-Vardar). We contribute to the resolution of this controversy by studying the Migdalitsa Ophiolitic Complex in Argolis (Greece), which contains Triassic oceanic basalts and pertains to the external (western) ophiolite belt. Three key areas were mapped and several sites were targeted for structural, biostratigraphic, and paleomagnetic analyses. Radiolarian cherts in primary or tectonic contact with oceanic basalts were dated to the Late Triassic (Camian-Norian) using radiolarians, and provided paleomagnetic directions of primary origin carried by magnetite and hematite. The derived mean direction was corrected for sedimentary inclination shallowing and yielded a paleolatitude of similar to 22 degrees N that was placed in a broader paleogeographic context by reconstructing Pangea at similar to 225 +/- 5 Ma using a recent apparent polar wander path corrected for sedimentary inclination shallowing. The Late Triassic paleogeography of the Tethys Ocean was constrained using additional paleolatitude estimates from the literature, which we checked and corrected (when possible) for sedimentary inclination shallowing. According to our reconstruction, the Meliata-Maliac-Vardar Ocean between Adria - the promontory of Africa - and Europe represents the locus of origin of the Late Triassic Argolis ophiolitic rocks of the external ophiolite belt, presently resting in tectonic contact on the Pindos-Subpelagonian zones, which represent a deep-water trough with no substantial evidence of in situ oceanization in the Triassic. (C) 2014 Elsevier B.V. All rights reserved.

In the northern Alpine region only a few lacustrine sediment sequences are known from the period of the last glacial, regionally assigned as Würmian. Even less is known about Alpine palaeoenvironments prior to the last glacial maximum (LGM). The recently discovered sediment sections at the Nesseltalgraben site (northern Alps, southern Germany) presented here, comprise an approximately 27-m-high, predominantly lacustrine composite profile below coarse clastic sediments assigned to the LGM and underlain by Permian–Triassic evaporitic and sandy clayey sediments of the Haselgebirge and Werfen-Formation. The Würmian lake sediments consist of carbonate mud layers representing cooler phases, and organic rich layers (compressed peat, organic mud), that were deposited during warmer periods. Bulk organic geochemical analyses suggest that predominantly algal organic matter was deposited during the cooler periods, while higher fractions of terrestrial vascular plants were admixed during warmer phases. A diamict represents an erosional unconformity and cuts the sediment sequence into a lower and an upper part. Paleomagnetic, palynostratigraphic and radiocarbon analyses place the lower part into the Marine Isotope Stage (MIS) 5c (Lower Würmian), while the upper part covers at least the period from 45 to 31 ka cal BP (MIS 3, Middle Würmian). Different explanations for the origin and spatiotemporal extent of the palaeolake are discussed. The most plausible sedimentary deposition is the formation of the small-scaled lake in a sinkhole in the evaporitic Haselgebirge Formation. The results highlight the significance of the Nesseltalgraben site as a new reference section of the last glacial period in the Northern Calcareous Alps and call for the necessity of further geochronological and paleoenvironmental studies at that site.

SUMMARY High-quality palaeomagnetic data for the early Carboniferous of Central Asia are scarce and the palaeogeographic evolution of this area prior to final amalgamation of the region east of the Ural mountains is still rather obscure. Here, we present palaeomagnetic data for early Carboniferous deposits from two areas in the Kyrgyz North Tianshan (NTS). Detailed rockmagnetic analysis indicates the presence of magnetite and haematite as magnetic carriers in these red sediments. In the Kazakh basin section (KEL), we identify a high-temperature component (HTC) of magnetization during stepwise thermal demagnetization at temperatures of up to ∼680 ◦ C yielding a site mean direction of D = 176.2 ◦ , I =− 36.4 ◦ , k = 57.4 and α95 = 8.9 ◦ after tilt correction. Two HTCs of magnetization were identified in samples from the Sonkul Basin (DUN) with maximum blocking temperatures of ∼600 ◦ C (magnetite) and ∼680 ◦ C (haematite). The magnetite component was also identified with alternating field demagnetization. The resulting site mean directions for these two components identified in 16 and 14 sites, respectively, are D = 149.3 ◦ , I =− 50.3 ◦ , k = 73.6 and α95 = 4.3 ◦ for the magnetite and D = 139.6 ◦ , I =− 35.1 ◦ , k = 71.6 and α95 = 4.7 ◦ for the haematite component. All three mean directions show a significant increase of the precision parameter k after tilt correction indicating acquisition of the high-temperature magnetization prior to the main folding event in the Jurassic. We explain the difference of the two components of DUN by a process of inclination bias due to compaction to which the platy haematite particles are more susceptible. Applying the elongation-inclination (E/I) method to directional data from over 100 individual samples from location DUN results in a negligible correction for the magnetite component (

[1] The paleogeography of the Altaids and its kinematic and tectonic evolution during the final collision and amalgamation of Eurasia is still poorly known. Addressing this problem, a paleomagnetic study has been undertaken on Paleozoic sedimentary rocks from the Karatau, Southern Kazakhstan. Stepwise thermal demagnetization reveals the presence of a high-temperature component of magnetization in most samples. Fold tests indicate a syn-folding age of magnetic remanence acquisition at three of the five areas studied. Directional data of Devonian and Permian rocks yield a positive fold test, implying a primary magnetization. Resulting prefolding paleolatitudes for Permian and Devonian rocks show the proximity of the Karatau to Baltica during those times. Syn- and post-folding magnetizations result in paleolatitudes for Karatau, which intersect the paleolatitude curve based on the Baltica apparent polar wander path (APWP), at times, which can be correlated to major deformational events at ~280 Ma, ~260 Ma, and ~230 Ma, respectively. We interpret this with complicated pattern of remagnetization events accompanying deformation, which can include syn-folding remagnetization events and areas of primary magnetic signals. Additionally, the differences between reference declinations based on the APWP for Baltica and observed declinations suggest successive counterclockwise rotational reorganization of the Karatau during the late Paleozoic to Early Mesozoic, with maximal rotation values of ~65° with respect to Baltica. The remagnetization events are correlated with latest intracontinental stages of orogenic evolution in the Ural mountains and thus the Paleozoic amalgamation of the Eurasian continent and suggest synchronous and coherent tectonic evolution in the Urals and Karatau mountains.

Over the last decade, important progress has been made in the study of the mammal successions from Hungary and Romania. A critical review of the taxonomy of the published small mammals is provided herein, as well as some new data and an overview of the accompanying vertebrate fauna (excluding fishes) in their stratigraphic context. In addition, the first data regarding the ruminants from Matraszőlős and Felsőtarkany are presented. This contribution aims to characterize the middle to earliest late Miocene fossil record from these countries, and provide important data for the chrono(bio)stratigraphic and palaeoenvironmental studies at the European scale.

We present new palaeomagnetic data for Cambrian and Ordovician volcanic and sedimentary rocks from the Kyrgyz North Tianshan (NTS) and review available data from the southwestern Central Asian Orogenic Belt (CAOB) to elucidate the tectonic history and evolution of this region during the early Palaeozoic. We observed a coherent evolution of the NTS and the Kazakhstan continent (or Kazakhstania) with a constant northwards movement between the Cambrian and Devonian at ∼5 cm/a. After the northwards movement ceased in the Devonian, the accreted terrane assemblage of Kazakhstania occupied a stable latitudinal position at ∼30°N until the final amalgamation of Eurasia occurred in the late Carboniferous to early Permian. Amalgamation of the Tarim and Turan blocks caused a counterclockwise bending within the southwestern segment of the CAOB, which occurred in an inconsistent way by a brittle-like response of the upper crust with a large variety of rotational movement. We suggest an evolution of the Kyrgyz CAOB terranes by steady migration away from Gondwana and subsequent capture in a zone of global downwelling at ~30°N, where accretion and subsequent amalgamation of Eurasia occurred with the CAOB terranes in its centre.

[1] Several paleomagnetic studies on Carboniferous and Permian sedimentary and volcanic rocks from Sardinia and Corsica have recently demonstrated (1) the tectonic coherence between southern Corsica and northern Sardinia and (2) significant rotations between individual crustal blocks within Sardinia itself. The geodynamic significance of these rotations, however, is not clearly understood mainly because of uncertainties in defining their timing and causes. In order to contribute to these issues, a pioneering paleomagnetic study on Jurassic carbonates from the Baronie-Supramonte region of eastern-central Sardinia has been extended regionally and stratigraphically. A total of 280 oriented drill cores were taken from 44 sites of Middle and Late Jurassic age in the Nurra, Baronie-Supramonte, Barbagia-Sarcidano, and Sulcis regions. Despite generally weak remanent magnetization intensities, on the order of less than 1 mA/m, thermal and alternating field demagnetizations were successfully applied to define a characteristic remanent magnetization component in about 60% of the samples. Site mean directions show rather good agreement after correction for bedding tilt and yield Middle and Late Jurassic overall mean directions of D = 269.7° and I = 45.0° (α95 = 8.0°, k = 14, and n = 25 sites) and D = 275.5° and I = 50.7° (α95 = 7.2°, k = 45.3, and n = 10 sites). Positive regional and local fold and reversal tests demonstrate the primary character of the natural magnetic remanence, which is carried by magnetite. These results indicate only insignificant amounts (±10°) of post-Jurassic rotations within the island of Sardinia. The resulting Middle and Late Jurassic paleopoles (latitude (Lat) = 16.5°, longitude (Long) = 299.1°, dp = 6.4°, and dm = 10.1° and Lat = 23.4°, Long = 301.2°, dp = 6.5°, and dm = 9.7°), corrected for the opening of (1) the Liguro-Provencal Basin and (2) the Bay of Biscay using rotation parameters from the literature, fall near the coeval segment of the European apparent polar wander path. These results constrain the timing of large differential block rotations found in Late Carboniferous-Permian rocks to a pre–Middle Jurassic age and lead us to exclude tectonics related to the Alpine orogeny for such rotations.