Detailed Stratigraphy Research Articles

Folding, thrusting and diapirism: Competing mechanisms for shaping the structure of the north Dezful Embayment, Zagros, Iran

AbstractDifferentiating compressional growth strata from halokinetic sequences is not straightforward in foreland fold‐and‐thrust belts where compressional and diapiric processes were coeval. Although there are numerous studies on the role of salt layers in fold‐and‐thrust belts, very few focus on syntectonic evaporites where they are thick enough to develop diapirism. The tectonic structures of the northern Dezful Embayment, along the footwall of the Zagros Mountain Front Fault, show a complex evolution interpreted in this study by the concurrence of folding, thrusting and pre‐ and syn‐shortening diapirism of the lower Miocene Gachsaran evaporites. We explore this tectonic–diapiric–sedimentary interplay by combining field studies and remote‐sensing mapping, detailed stratigraphy and sedimentology, high‐quality seismic data, and step‐by‐step balanced tectono‐sedimentary restorations. Initial diapirism occurred soon after the deposition of at least 1.5 km thick Miocene Gachsaran evaporites during the sedimentation of up to 5 km thick Aghajari, Lahbari and Bakhtyari formations, which display syntectonic mixed growth strata and halokinetic sequences. These sedimentary sequences filled salt‐related minibasins, from which the Azanak Minibasin is the deepest, limited by growing salt walls and salt anticlines (Azanak thrust‐weld and the Saland–Lali anticline). Palaeocurrents and clasts compositions document fluvial diversions and exposure and erosion of Gachsaran evaporites along the active salt walls. Although, by further shortening, the precursor salt walls squeezed and reactivated as thrust‐welds structuring a duplex of overriding minibasins. During the deposition of the middle‐late Miocene Aghajari Formation, Kazhdumi and Pabdeh source rocks were buried to oil‐expulsion depths, and Sarvak and Asmari reservoirs were mildly folded in large and open anticlines. The Gachsaran system in the northern Dezful Embayment is collated with the structures of preshortening Hormuz salt and syn‐shortening Fars salt to highlight the important role of these ductile units in the tectonic evolution of the Zagros fold belt that is compared to syn‐compressional salt‐related Pyrenees, Carpathians, Sivas and Kuga fold belts.

High-resolution stratigraphy and multiple luminescence dating techniques to reveal the paleoseismic history of the central Dead Sea fault (Yammouneh fault, Lebanon)

Continuous sedimentation and detailed stratigraphy are key parameters for a complete paleo-earthquake record. Here, we present a new paleoseismological study across the main strike-slip fault branch of the Dead Sea fault in Lebanon. We aim to expand the current knowledge on local paleoseismicity and seismic behavior of strike-slip plate boundary faults and to explore the limitations of paleoseismology and dating methods. The trench, dug in the Jbab el-Homr basin, reveals a succession of remarkable, very thin (0.1 to 5 cm) palustrine and lacustrine layers, ruptured by at least 17 earthquakes. Absolute ages of 4 samples are obtained from three luminescence-dating techniques targeting fine-grain minerals. Blue-green stimulated luminescence (BGSL) on quartz and post-infrared infrared-stimulated luminescence at 225 °C on polymineral aliquots led to consistent ages, while ages from infrared-stimulated luminescence at 50 °C on polymineral aliquots appeared underestimated. The quartz BGSL ages are 26.9 ± 2.3 ka at 0.50 m depth and 30.8 ± 2.9 ka at 3.65 m depth. During this time period of 3.9 ka ([0; 9.1 ka]), 14 surface-rupturing events occurred with a mean return time of 280 years ([0; 650 years]) and probable clustering. This return time is much shorter than the 1127 ± 135 years return time previously determined at the Yammouneh site, located 30 km south. Although fault segmentation and temporal variations in the earthquake cycle remain possible causes for such different records, we argue that the high-resolution stratigraphy in Jbab is the main factor, enabling us to record small deformations related to smaller-magnitude events that may have been missed in the rougher strata of Yammouneh. Indeed, focusing only on larger events of Jbab, we obtain a mean return time of 720 years ([0; 1670 years]) that is compatible with the Yammouneh record.

Subsurface controls on the development of the Cape Fear Slide Complex, central US Atlantic Margin

Abstract The Cape Fear Slide is one of the largest (>25 000 km 3 ) submarine slope failure complexes on the US Atlantic margin. Here we use a combination of new high-resolution multichannel seismic data (MCS) from the National Science Foundation Geodynamic Processes at Rifting and Subducting Margins (NSF GeoPRISMS) Community Seismic Experiment and legacy industry MCS to derive detailed stratigraphy of this slide and constrain the conditions that lead to slope instability. Limited outer-shelf and upper-slope accommodation space during the Neogene, combined with lowstand fluvial inputs and northwards Gulf Stream sediment transport, appears to have contributed to thick Miocene and Pliocene deposits that onlapped the lower slope. This resulted in burial of an upper-slope bypass zone developed from earlier erosional truncation of Paleogene strata. These deposits created a broad ramp that allowed accumulation of thick Quaternary strata across a low-gradient (<3.5°) upper slope. Upslope of one of the larger headwalls, undulating Quaternary strata appear to downlap onto a buried failure plane. Many of the nested headwalls of the upper-slope portion of slide complex are underlain by deformed strata, which may be the result of fluid migration associated with localized subsidence from salt migration. These new data and observations suggest that antecedent margin physiography, sediment loading and substrate fluid flow were key factors in preconditioning the Cape Fear slope for failure.

Comprehensive investigation of submarine slide zones and mass movements at the northern continental slope of South China Sea

Multi-beam bathymetry and seismic sequence surveys in the northern slope of the South China Sea reveal detailed geomorphology and seismic stratigraphy characteristics of canyons, gullies, and mass movements. Modern canyons and gullies are roughly elongated NNW–SSW with U-shaped cross sections at water depths of 400–1000 m. Mass movements include slide complexes, slide scars, and debris/turbidity flows. Slide complexes and slide scars are oriented in the NE–SW direction and cover an area of about 1790 and 926 km2, respectively. The debris/turbidity flows developed along the lower slope. A detailed facies analysis suggests that four seismic facies exist, and the late Cenozoic stratigraphy above the acoustic basement can be roughly subdivided into three sequences separated by regional unconformities in the study area. The occurrence of gas hydrates is marked by seismic velocity anomalies, bottom-simulating reflectors, gas chimneys, and pockmarks in the study area. Seismic observations suggest that modern canyons and mass movements formed around the transition between the last glacial period and the current interglacial period. The possible existence and dissociation of gas hydrates and the regional tectonic setting may trigger instability and mass movements on the seafloor. Canyons may be the final result of gas hydrate dissociation. Our study aims to contribute new information that is applicable to engineering construction required for deep-water petroleum exploration and gas hydrate surveys along any marginal sea.

Use of sedimentary megasequences to re-create pre-Flood geography

Knowledge of pre-Flood geography and the location of the Garden of Eden have eluded Bible-believing scientists and theologians. This study attempts to reconstruct the gross geography of the pre-Flood world by examining the detailed stratigraphy that was deposited during the Flood. Over 1500 stratigraphic columns were constructed across North and South America and Africa, recording the lithology and stratigraphy at each location. Sedimentary layers were examined using Sloss-type megasequences which allowed detailed analysis of the progression of the Flood in six discrete depositional segments. The three earliest megasequences, Sauk, Tippecanoe and Kaskaskia, were the most limited in areal coverage and volume and contain almost exclusively marine fossils, indicating a likely marine realm. The 4th megasequence (Absaroka) shows a dramatic increase in global coverage and volume and includes the first major plant and terrestrial animal fossils. The 5th megasequence (Zuni) appears to be the highest water point of the Flood (Day 150) as it exhibits the maximum global volume of sediment and the maximum areal coverage, compared to all earlier megasequences. The final megasequence (Tejas) exhibits fossils indicative of the highest upland areas of the pre-Flood world. Its rocks document a major shift in direction reflective of the receding water phase of the Flood. Results include the first, data-based, pre-Flood geography map for half of the world. By comparing the individual megasequences to the fossil record, patterns emerge that fit the concept of ecological zonation. The paper concludes with a new ecological zonation-megasequence model for Flood strata and the fossil record.

Usefulness of spinal unenhanced computed tomography and CT-myelography in the age of multidetector CT technology and magnetic resonance imaging - Preliminary considerations.

Over the last decade, magnetic resonance imaging (MRI) and multidetector computed tomography (MDCT) have revolutionized diagnostic potential in small animal practice, providing adequate assessment of spinal diseases at levels comparable to that achieved in human radiology. T2-weighted MRI images are extremely sensitive to intramedullary parenchymal disorders, while balanced steady-state free precession sequences provide high-quality myelographic images of the spine without the need of intrathecal contrast medium administration. Multidetector computed tomography, with its near-isotropic spatial resolution and multiplanar reformatting of the acquired datasets, provides sufficient stratigraphic details of the spinal cord and the epidural space, facilitating the detection of compressive pathologies without the need of subarachnoid opacification. Nowadays, MDCT and low-field (LF) MRI have become fairly standard and available in academic institutions and private veterinary facilities, appearing to be valuable, complementary, and non-invasive diagnostic tools for imaging the spine. In this scenario, this clinical communication provides a series of preliminary observations that may help to reconsider the usefulness of CT-myelography in the light of its invasiveness and actual diagnostic advantages compared to MRI and unenhanced MDCT for the assessment of compressive and non-compressive spinal diseases in small animals.

Aptian sedimentation in the Recôncavo-Tucano-Jatobá Rift System and its tectonic and paleogeographic significance

This study, based on detailed sedimentologic and stratigraphic analysis of the Aptian succession preserved in the Recôncavo-Tucano-Jatobá Rift System (RTJ), present new elements for biostratigraphic correlation and paleogeographic reconstruction in the mid-Cretaceous South Atlantic realm, supporting novel interpretations on the tectonic and sedimentary evolution related to the W-Gondwana breakup. The Aptian sedimentary succession in the RTJ has been referred to as Marizal Formation, and interpreted as post-rift deposits. Detailed sedimentologic and stratigraphic studies of these deposits enabled the recognition and individualization of two distinctive sedimentary units that can be traced in the entire RTJ. These units are here described and named Banzaê and Cícero Dantas members of the Marizal Formation. Their contact is locally marked by the fossiliferous successions of the here proposed Amargosa Bed, lying at the top of the Banzaê Member. Both members of the Marizal Formation record large river systems captured by the Tucano Basin with the local development of eolian dune fields and fault-bounded alluvial fans. The Amargosa Bed represents a regional-scale base level change preserved between the Aptian fluvial successions along the RTJ. Hence, the studied sedimentary record presents important implications for the timing and direction of marine ingressions affecting NE-Brazil interior basins during the Aptian. A remarkable contrast in preserved fluvial architecture between the Banzaê Member, characterized by connected channel bodies, and the Cícero Dantas Member, characterized by isolated channel bodies within overbank fines, is here reported. The main interpreted control for the observed contrast in fluvial stratigraphy is sedimentary yield variation. The interval is also subject to the interpretation of a regional shift in the mechanism responsible for the subsidence of the basins formed during the Cretaceous break-up of the Central South Atlantic. This view is challenged by our results which reveal that basin forming extension continued throughout the Aptian. As a conclusion, the detailed stratigraphy of the Marizal Formation forward alternative geodynamic interpretations for the Aptian successions in northeastern Brazil, bringing new elements to the mid-Cretaceous biogeographical, paleogeographical and tectonic reconstructions of western Gondwana.

Virtual time-lapse seismic monitoring using fully coupled flow and geomechanical simulations

SEAM Time Lapse, a collaborative technical project of SEG and the Society of Petroleum Engineers, created integrated geologic, reservoir, and geophysical models to simulate temporal changes in the geometry and physical properties of a complex reservoir with the detail and accuracy needed to explain the subtle effects seen in time-lapse surveys of real oil fields. The geologic model consisted of 2 billion grid cells, representing a region 12.5 × 12.5 km in horizontal extent and 5 km in depth and including a 420 m thick reservoir with upper and lower units separated by an impermeable shale layer and offset by faults. Deepwater clastic turbidite channels and lobes were used to create a typical shallow Gulf of Mexico reservoir that also can serve as an analogue of other turbidite fields around the world. Stratigraphic detail within the reservoir was retained in the simulation model through careful finite-element meshing. The reservoir simulation computed the fully coupled three-phase fluid flow and linear geomechanical response in a production scenario involving 11 production wells and six water-injection wells penetrating the reservoir's three compartments. Seismic surveys were simulated with isotropic elastic-wave modeling before the start of production and after 27.5 months of production at a simulated rate of about 67,500 barrels per day, with about 32,500 barrels per day of water injection. Rock properties were updated by petrophysical models calibrated to turbidite systems in the Gulf of Mexico. Analysis of the model and simulations improves understanding of the complex interaction of fluid effects, pressure changes, and rock deformation. For example, compaction in the reservoir may cancel time-lapse fluid effects, and compaction or dilation in the surrounding shales may override the observed reservoir signal in the seismic bandwidth. Strain-induced velocity changes in the shales have a much larger effect on estimated time-lapse time shifts than do strain-induced changes in path lengths. Geomechanical effects impact the interpretation of 4D seismic difference attributes and require careful consideration. The integrated, full-physics SEAM approach used for this model provides a unique data set to explore these complex production effects and the value of 4D seismic surveys. The models and data, which also include simulations of time-lapse gravity and electromagnetic surveys, are publicly available through SEAM.

Upper Homerian (Silurian) high-resolution correlation using cyclostratigraphy: an example from western Lithuania

AbstractThe Gėluva regional stage stratigraphically corresponds to the late Wenlock. This time interval witnessed significant graptolite extinctions and turnovers of conodont faunas, as well as a large positive Mulde carbon isotopic excursion. Thus, the development of a detailed stratigraphy is a necessary step in understanding the complex patterns of regional and global variations in the sediments accumulating during the time interval studied. Therefore, in this contribution we present a cyclostratigraphic analysis of gamma ray (GR) logs from four wells, which are located in the deep water facies belt of the Lithuanian part of the Silurian Baltic Basin of the Gėluva regional stage. The analysis was performed using REDFIT spectral estimation, continuous wavelet transform and signal filtering techniques. As a result two 4thorder and five 5thorder cycles were distinguished and named in all sections. The correlation of cycles between sections was calibrated with the graptolite biozones. The comparative analysis revealed that intra-basinal cyclostratigraphic correlation could achieve resolution of the order of several tens of thousands of years.

Deep-water clastic systems in the Upper Carboniferous (Upper Mississippian–Lower Pennsylvanian) Shannon Basin, western Ireland

The Upper Carboniferous Shannon Basin of western Ireland contains a more-than-2300-m-thick (7540 ft) basin-fill succession, shallowing upward from deep-water to deltaic and incised fluvial deposits. The deep-water basin floor and slope succession is world renowned as an analog for hydrocarbon-bearing deep-water sandstones on several continental margins such as the basins in East and West Africa, South America, the Gulf of Mexico, and not least offshore northwest Europe. The Shannon Basin is frequently visited by both academia and industry for research and training purposes. A series of behind-outcrop research boreholes reveals the subsurface expression of the deep-water rocks and is complemented by seismic-scale cliff exposures. The succession is interpreted as a first-order basin-scale linked sedimentary system. This system can be analyzed using the principles of source-to-sink analysis and leaves the visitor with a complete picture of the basin fill, enhanced by spectacular sedimentological and stratigraphic detail.

P08 阿蘇火山、Aso-4火砕流堆積物中の弁利スコリア流堆積物の層序的特徴と、斑晶鉱物および石基ガラスの化学組成について(ポスターセッション,日本火山学会2007年秋季大会)

P08 阿蘇火山、Aso-4火砕流堆積物中の弁利スコリア流堆積物の層序的特徴と、斑晶鉱物および石基ガラスの化学組成について(ポスターセッション,日本火山学会2007年秋季大会)

Complexity of Quaternary aeolian dynamics (Canary Islands)

Carbonate aeolianites are important Quaternary archives at the point of intersection between marine and terrestrial systems. Since they are composed of alternating aeolian sediments and several paleosol units, these sequences are highly suitable to reconstruct palaeoenvironmental conditions. In northern Fuerteventura, at least five different areas are characterised by successions of different dune generations and paleosols. Few studies have addressed the stratigraphic order of individual dune areas. Therefore, a comprehensive consideration spanning several dune fields is needed. Here, we aim to present a detailed stratigraphy of two different dune areas and to identify the contribution of different materials (shelf origin, dust origin, volcanic origin) along with processes (accumulation, soil formation, erosion/preservation) that build up these archives. Four key sections were selected and sampled for laboratory analyses (texture, elemental composition, CaCO3 content, palaeoenvironmental magnetics, luminescence dating, and gastropod assemblages). Based on main stratigraphic features, five major sedimentary sequences were identified indicating differences in prevailing sediment supply, humidity, and volcanic activity. First luminescence dating (IRSL) of the sequences revealed sedimentation ages between 360ka and 15ka. Finally, we are able to demonstrate that different dune areas show comparable stratigraphic patterns, but each studied site is defined by certain characteristics depending on the respective features of the closer surrounding. The knowledge of these peculiarities and the underlying background is essential in order to correlate different sites and to attempt an appropriate environmental interpretation of the sedimentary sequences.

Римские республиканские монеты из археологических раскопок святилища у перевала Гурзуфское Седло в горном Крыму

The article describes the characteristics of 35 Roman republican and Roman provincial silver coins II-I cent BC found during archaeological excavations of the sanctuary near the pass Gurzufskoe Sedlo in 1981–1993 at Mountain Crimea. Coins refer to the chronological periods of the Mithridates' Wars, the first triumvirate, the dictatorship of Julius Caesar, the second triumvirate, the reign of Octavian. In view of the rarity of the discovery of Roman republican coins in the cultural layers of archaeological sites of the Northern Black Sea region, the detailed stratigraphy data of Roman coins are provided.

Shoot first, ask questions later: application of seismic reflection to a greenfields zinc exploration project

As exposed portions of premier Zn belts reach exploration maturity, targets become deeper and more challenging to explore. Explorationists are faced with having limited methods for effective deep exploration. Seismic reflection is one method which can be used effectively to characterise geological targets at depth. Teck has applied seismic reflection at an early stage on several zinc exploration projects, including the greenfields Yalco Zn project. Geophysical methods have been used to assess the structural architecture of the remote Yalco area, located within the highly prospective Emu Fault corridor. 2D Seismic reflection lines have been used in addition to potential field methods and magnetotellurics. The superior resolution of seismic reflection has allowed us to characterise the stratigraphy and map key structures in detail in order to validate a conceptual geological target. The preliminary interpretation of the seismic sections has confirmed favourable depths to host, and resulted in a re-evaluation of target locations. Use of seismic reflection surveys at an early stage has the potential to reduce technical risk and increase the effectiveness of target testing.

Evolution of magma chambers generating the phonolitic Cão Grande Formation on Santo Antão, Cape Verde Archipelago

The Cão Grande Formation (CGF) on the western plateau of Santo Antão is a sequence of four phonolitic tephras (Canudo Tephra, Cão Grande I Tephra, Cão Grande II Tephra and Furninha Tephra) produced by highly explosive eruptions that alternatingly originated from a basanitic - phonolitic and a nephelinitic - phonolitic magmatic system. Detailed stratigraphy and petrological investigations of each unit are used to demonstrate the unusual situation that two distinct highly evolved magmas differentiated contemporaneously in separate magmatic systems. Chemical thermobarometry suggests that both magmatic systems not only temporally co-existed, but also that their magma chambers resided close to each other at 7 to 16km depth, beneath the western plateau of Santo Antão. However, the distinct melt and magma compositions indicate that both systems evolved independently. The only interaction between both magmatic systems was an injection of magma from the nephelinitic - phonolitic magmatic system into the Cão Grande II Tephra (CG II) phonolitic reservoir, which is associated to the basanitic - phonolitic magmatic system. Compositional zonations in the tephra deposits indicate that the eruptions of the CGF tapped stratified magma reservoirs that mainly resulted from crystal accumulation generating downward increasing magma density. However, the CG II tephras also show a significant gradient in melt (glass) compositions. Magmas of the Canudo Tephra (CT) and the Cão Grande I Tephra (CG I) were H2O-saturated and their eruptions were probably triggered by fluid overpressure in the magma chamber. On the other hand, the CG II magma was H2O-undersaturated; we therefore assume that the injection of the hot nephelinitic - phonolitic magma system-type melt/magma triggered the eruption. The zoned deposit of the Furninha Tephra (FT) indicates mafic magma replenishment into a phonolitic reservoir directly prior to the eruption, thus providing a probable triggering mechanism. The new magma chamber models and thermobarometric results for the four CGF units provide constraints for hazard assessments, because similar events may occur in the future considering the longevity of the CGF magma systems.

Late Neogene dinoflagellate cyst and acritarch biostratigraphy for Ocean Drilling Program Hole 642B, Norwegian Sea

The Arctic is a critical region in the current and past global climate system. One major challenge for investigating the geological history of the Arctic is the establishment of a rigorous chronology. To get better insights into the late Neogene history of oceanographic and climatic change in the region, well-calibrated ocean drill cores are essential. Nevertheless, detailed stratigraphy from (sub)Arctic ocean drill sites remains problematic due to the generally poor preservation of calcareous microfossils in high northern-latitude oceans. Here, organic-walled palynomorphs (dinoflagellate cysts and acritarchs) can compensate for the lack of calcareous microfossils because diverse and rich palynological assemblages can be recovered. We defined three magnetostratigraphically-calibrated dinoflagellate cyst and acritarch biozones in the Upper Miocene to Upper Pliocene of Norwegian Sea Ocean Drilling Program Hole 642B (Vøring Plateau) that show potential for correlation within the Nordic Seas. It is also noted that several bioevents in the Nordic Seas are strongly diachronous with the North Atlantic, highlighting the limitations of applying North Atlantic bioevents directly to the Nordic Seas. For each of the three interval biozones (VP1 to VP3) we use the highest occurrences of acritarch and dinoflagellate cyst species (“Veriplicidium franklinii” of Anstey 1992, Reticulatosphaera actinocoronata, and Invertocysta lacrymosa) that are relatively synchronous across the Nordic Seas and North Atlantic and thus show potential for a North Atlantic–Arctic reference stratigraphy.

3D geological modeling of the transboundary Berzdorf–Radomierzyce basin in Upper Lusatia (Germany/Poland)

The management of natural resources has to follow the principles of sustainable development. Therefore, before starting new mining activities, it should be checked, whether existing deposits have been completely exploited. In this study, a three-dimensional (3D) cross-border geologic model was created to generalize the existing data of the Neogene Berzdorf–Radomierzyce basin, located in Upper Lusatia on the Polish–German border south of the city of Gorlitz–Zgorzelec. The model based on boreholes and cross sections of abandoned and planned lignite fields was extended to the Bernstadt and Neisse-Reczyn Graben, an important tectonic structure at the southern rim of the basin. The partly detailed stratigraphy of Neogene sequences was combined to five stratigraphic units, considering the lithological variations and the main tectonic structures. The model was used to check the ability of a further utilization of the Bernstadt and Neisse-Reczyn Graben, containing lignite deposits. Moreover, it will serve as a basis for the construction of a 3D cross-border groundwater model, to investigate the groundwater flow and transport in the Miocene and Quaternary aquifer systems. The large amount of data and compatibility with other software favored the application of the 3D geo-modeling software Paradigm GOCAD. The results demonstrate a very good fit between model and real geological boundaries. This is particularly evident by matching the modeled surfaces to the implemented geological cross sections. The created model can be used for planning of full-scale mining operations in the eastern part of the basin (Radomierzyce).

The late Miocene hominoid-bearing site in the Maragheh Formation, Northwest Iran

After a long period of inactivity, recent excavations at the late Miocene Maragheh Formation unexpectedly resulted in the discovery of the first fossil hominoid and second Mesopithecus remains from this area. The discovery motivated a new international initiative to conduct research in these rich fossil sites. These studies focused on the fossil hominoid and its locality, aiming to reveal more about the context of this fossil discovery. Detailed stratigraphy, sedimentology and magnetostratigraphy studies were conducted. New samples from volcaniclastic key horizons (pumice beds) in Dareh Gorg, where the hominoid fossil site is located, were dated by radiometric methods. The radiometric age determinations provide a firm tie-point for the geochronology. The polarity pattern in the palaeomagnetically investigated section corroborates the K-Ar results. The preliminary magnetostratigraphic results suggest that the hominoid locality can be correlated to the normal polarity chron C4n.2n (8.108–7.695 Ma), C4n.1n (7.642–7.528 Ma) or C3Br.1n (7.285–7.251 Ma), placing it at intervals corresponding to the mammal units MN11 or possibly early MN12. The study of fossil hominoid indicates broad affinities with a number of contemporaneous taxa from the Balkan-Iranian palaeoprovince, as well as Siwaliks and southeast Asia. A preliminary analysis of the accompanying (in situ) fauna at the hominoid site indicates the highest similarity of this level to Turolian hominoid- and Mesopithecus-bearing localities in Turkey, Greece and Bulgaria. However, some environmental differences are observed among these localities, based on their faunal structure and taxon properties, as well as in the different masticatory adaptations of their hominoids.

New drilling of the early Aptian OAE1a: the Cau core (Prebetic Zone, south-eastern Spain)

Abstract. The Cretaceous was punctuated by several episodes of accelerated global change, defined as Oceanic Anoxic Events (OAEs), that reflect abrupt changes in global carbon cycling. The Aptian Oceanic Anoxic Event (OAE1a; 120 Ma) represents an excellent example, recorded in all major ocean basins, and associated with massive burial of organic matter in marine sediments. The OAE1a is concomitant with the "nannoconid crisis", which is characterized by a major biotic turnover, and a widespread demise of carbonate platforms. Many studies have been published over the last decades on OAE1a's from different sections in the world, and provide a detailed C-isotope stratigraphy for the event. Nevertheless, new high-resolution studies across the event are essential to shed light on the precise timing and rates of the multiple environmental and biotic changes that occurred during this critical period of Earth history. Here we present a new drill core recovering an Aptian section spanning the OAE1a in southern Spain. The so-called Cau section was drilled in the last quarter of 2015. The Cau section is located in the easternmost part of the Prebetic Zone (Betic Cordillera), which represents platform deposits of the southern Iberian palaeomargin. The lower Aptian deposits of the Cau section belong to a hemipelagic unit (Almadich Formation), deposited in a highly subsident sector of the distal parts of the Prebetic Platform. Previous work on the early Aptian of the Cau succession has focused on stratigraphy, bioevents, C-isotope stratigraphy, and organic and elemental geochemistry. A more recent study based on biomarkers has presented a detailed record of the pCO2 evolution across the OAE1a (Naafs et al., 2016). All these studies reveal that the Cau section represents an excellent site to further investigate the OAE1a, based on its unusually high sedimentation rate and stratigraphic continuity, the quality and preservation of fossils, and the well-expressed geochemical signatures.

Cold surges and dust events: Establishing the link between the East Asian Winter Monsoon and the Chinese loess record

Abstract The Chinese loess/palaeosol succession is one of the most comprehensive and intensively studied archives of Neogene and Quaternary global palaeoclimate events. Its stratigraphic details are widely recognised to indicate close links to the history and function of the East Asian Winter Monsoon (EAWM) – one of the most active components of the Earth's climate system. But the formal meteorological links between the EAWM and dust emission, both in the present day and in the past, have not been established and with it, the veracity of the loess record as an indicator of the EAWM questioned. Here we show that present day major dust events over northern China, while largely occurring during spring, are nevertheless ‘conditioned’ by the strength of the preceding EAWM. We also demonstrate, for the first time, a close link between the occurrence of dust events and the strength of the EAWM. From these findings, linked to global-scale climate model simulations, we conclude that the Chinese loess succession provides a convincing proxy record of the strength of the East Asian Winter Monsoon.