Contourite characterization and its discrimination from other deep‐water deposits in the Gulf of Cadiz contourite depositional system

This project was funded through the Joint Industry Project supported by BP, ENI, ExxonMobil, TOTAL, Wintershall Dea and TGS, within the framework of "The Drifters" Research Group at Royal Holloway University of London (RHUL), in conjunction with the projects CTM 2012-39599-C03, CGL2015-66835-P, CTM2016-75129C3-1-R, CGL2016-80445-R (AEI/FEDER, UE) and B-RNM-072-UGR18. This research used data and samples collected by IODP Expedition 339 aboard the Joides Resolution. Data was acquired at the XRF Core Scanner Lab at MARUM -Center for Marine Environmental Sciences, University of Bremen, Germany. Our thanks to Dr Javier Dorador (RHUL, UK) for the high-resolution core imaging treatment, to Dr David Roque (ICMAN-CSIC, Spain) for his help in the hydrographic panels from Fig. 2, and to Dr Angel Puga-Bernabeu (University of Granada, Spain) for revision that helped to improve the original version of the manuscript before submission. This study significantly benefited from discussions with all who attended the IODP Exp. 339 MOW meeting in Heidelberg (Germany) in January 2019. We would like to thank Associate Editor Dr Adam McArthur and the three reviewers, Dr Rachel Brackenridge, Dr Giancarlo Davoli and Dr Adriano Viana, for their positive and constructive comments that helped us improve the manuscript.Despite numerous efforts to properly differentiate between contourites and other deep‐water deposits in cores and outcrops, reliable diagnostic criteria are still lacking. The co‐occurrence of downslope and along‐slope sedimentary processes makes it particularly difficult to differentiate these relatively homogeneous deposits. The main aim of this paper is to identify differences in deep‐water sediments based on Principal Component Analysis of grain size and geochemistry, sedimentary facies, and reinforced by microfacies and ichnofacies. The sediments studied were obtained from two International Ocean Drilling Program Expedition 339 sites in mounded and sheeted drifts in the Gulf of Cadiz. The statistical approach led to the discernment of hemipelagites, silty contourites, sandy contourites, bottom current reworked sands, fine‐grained turbidites and debrites over a range of depositional and physiographic elements. These elements are linked to contourite drifts, the drift‐channel transition, the contourite channel and distal upper slope. When bottom currents or gravity‐driven flows are not the dominant depositional process, marine productivity and continental input settling forms the main depositional mechanism in deep‐water environments. This is reflected by a high variability of the first principal component in hemipelagic deposits. The stacked principal component variability of these deposits evidences that the contourite drift and the adjacent contourite channel were influenced by the interrelation of hemipelagic, gravitational and bottom current induced depositional processes. This interrelation questions the paradigm that a drift is made up solely of muddy sediments. The interrelation of sedimentary processes is a consequence of the precession‐driven changes in the intensity of the Mediterranean Outflow Water related to Mediterranean climate variability, which are punctuated by millennial‐scale variability. Associated vertical and lateral shifts of the Mediterranean Outflow Water, and therefore of its interface with the East North Atlantic Central Water, controlled sediment input and favoured turbulent sediment transport in the middle slope. During the interglacial precession maxima/insolation minima, a more vigorous upper core of the Mediterranean Outflow Water and the enhanced impact of the East North Atlantic Central Water – Mediterranean Outflow Water interface allowed for the development of the sandier contourite deposits.BP within the "The Drifters" Research Group at Royal Holloway University of London (RHUL)ENI within the "The Drifters" Research Group at Royal Holloway University of London (RHUL)ExxonMobil within the "The Drifters" Research Group at Royal Holloway University of London (RHUL)TOTAL within the "The Drifters" Research Group at Royal Holloway University of London (RHUL)Wintershall Dea within the "The Drifters" Research Group at Royal Holloway University of London (RHUL)TGS within the "The Drifters" Research Group at Royal Holloway University of London (RHUL)AEI/FEDER, UE CTM 2012-39599-C03 CGL2015-66835-P CTM2016-75129C3-1-R CGL2016-80445-RB-RNM-072-UGR1

Drought as a possible contributor to the Visigothic Kingdom crisis and Islamic expansion in the Iberian Peninsula

The Muslim expansion in the Mediterranean basin was one the most relevant and rapid cultural changes in human history. This expansion reached the Iberian Peninsula with the replacement of the Visigothic Kingdom by the Muslim Umayyad Caliphate and the Muslim Emirate of Córdoba during the 8th century CE. In this study we made a compilation of western Mediterranean pollen records to gain insight about past climate conditions when this expansion took place. The pollen stack results, together with other paleohydrological records, archaeological data and historical sources, indicate that the statistically significant strongest droughts between the mid-5th and mid-10th centuries CE (450–950 CE) occurred at 545–570, 695–725, 755–770 and 900–935 CE, which could have contributed to the instability of the Visigothic and Muslim reigns in the Iberian Peninsula. Our study supports the great sensitivity of the agriculture-based economy and socio-political unrest of Early Medieval kingdoms to climatic variationsMinistry of Science and Innovation of the Government of Spain, Agencia Estatal de Investigación /10.13039/501100011033/ and Fondo Europeo de Desarrollo Regional - A way ofmaking Europe, in particular the grant numbers FJC2020-044215- IThe grant number Retos P20_00059The action Proyectos I + D + i del Programa Operativo FEDER 2018 (grant number A-RNM-336-UGR20Research group RNM-190 from the Junta de Andalucía (Regional Government of Andalusia)The project SBPLY/21/ 180501/000205Scientific Research and Technology Transfer Projects of the Junta deComunidades de Castilla-La Mancha (Regional Government of Castilla-La Mancha

Orbital Forcing and Evolution of the Southern African Monsoon From Late Miocene to Early Pliocene

This research used samples provided by the International Ocean Discovery Program (IODP). The authors thank to Editor Dr. Ursula Röhl, Dr. Christian Zeeden, and the anonymous reviewer for improving the quality of our study providing critical review of it. The authors thank to the Operational Oceanography and Paleoceanography Laboratory (LOOP—Brazil), the Andalusian Earth Sciences Institute (IACT—Spain), the University of Granada (UGR—Spain), and the University of Salamanca (USAL—Spain) for all infrastructure and support. The first author thanks to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—CAPES for Ph.D. fellowship (process 88887.372122/2019‐00). FJJE and CE has been supported by the Spanish Ministry of Science and Innovation (Grant CTM2017‐89711‐C2‐1‐P), cofunded by the European Union through FEDER funds.The late Miocene-early Pliocene (7.4-4.5 Ma) is a key interval in Earth's history where intense reorganization of atmospheric and ocean circulation occurred within a global cooling scenario. The Southern African monsoon (SAFM) potentially played an important role in climate systems variability during this interval. However, the dynamics of this important atmospheric system is poorly understood due to the scarcity of continuous records. Here, we present an exceptional continuous late Miocene to early Pliocene reconstruction of SAFM based on elemental geochemistry (Ca/Ti and Si/K ratios), stable isotope geochemistry (δ18O and δ13C recorded in the planktonic foraminifera Orbulina universa), and marine sediment grain size data from the International Ocean Discovery Program (IODP) Site U1476 located at the entrance of the Mozambique Channel. Spectral characteristics of the Si/K ratio (fluvial input) was used to identify the main orbital forcing controlling SAFM. Precession cycles governed precipitation from 7.4 to ∼6.9 Ma and during the early Pliocene. From ∼6.9 to ∼5.9 Ma, the precession and long eccentricity cycles drove the SAFM. The major Antarctic ice sheet expansion across this interval appear to influence the isotopic records of O. universa imprinting its long-term variability signal as a response to the ocean and atmospheric reorganization. Precession cycles markedly weakened from 5.9 to 5.3 Ma, almost the same period when the Mediterranean Outflow Water ceased. These findings highlight important teleconnections among the SAFM, Mediterranean Sea, and other tropical regions.Andalusian Earth Sciences InstituteIACTInternational Ocean Discovery ProgramUniversity of SalamancaEuropean Commission ECCoordenação de Aperfeiçoamento de Pessoal de Nível Superior 88887.372122/2019-00 CAPESFEDERMinisterio de Ciencia e Innovación CTM2017‐89711‐C2‐1‐P MICINNUniversidad de Granada UGRUniversidad de Salamanca USA

Programmable retinal dynamics in a CMOS mixed-signal array processor chip

The low-level image processing that takes place in the retina is intended to compress the relevant visual information to a manageable size. The behavior of the external layers of the biological retina has been successfully modelled by a Cellular Neural Network, whose evolution can be described by a set of coupled nonlinear differential equations. A mixed-signal VLSI implementation of the focal-plane low-level image processing based upon this biological model constitutes a feasible and cost effective alternative to conventional digital processing in real-time applications. For these reasons, a programmable array processor prototype chip has been designed and fabricated in a standard 0.5μm CMOS technology. The integrated system consists of a network of two coupled layers, containing 32 × 32 elementary processors, running at different time constants. Involved image processing algorithms can be programmed on this chip by tuning the appropriate interconnections weights. Propagative, active wave phenomena and retina-like effects can be observed in this chip. Design challenges, trade-offs, the buildings blocks and some test results are presented in this paper.Office of Naval Research (USA) N00014-00-10429European Community IST-1999-19007Ministerio de Ciencia y Tecnología TIC1999-082

CMOS realization of a 2-layer CNN universal machine chip

Some of the features of the biological retina can be modelled by a cellular neural network (CNN) composed of two dynamically coupled layers of locally connected elementary nonlinear processors. In order to explore the possibilities of these complex spatio-temporal dynamics in image processing, a prototype chip has been developed by implementing this CNN model with analog signal processing blocks. This chip has been designed in a 0.5/spl mu/m CMOS technology. Design challenges, trade-offs and the building blocks of such a high-complexity system (0.5 /spl times/ 10/sup 6/ transistors, most of them operating in analog mode) are presented in this paper.Office of Naval Research (USA) N-00014-00-1-0429Comisión Interministerial de Ciencia y Tecnología TIC-1999-082

Bio-inspired analog parallel array processor chip with programmable spatio-temporal dynamics

A bio-inspired model for an analog parallel array processor (APAP), based on studies on the vertebrate retina, permits the realization of complex spatio-temporal dynamics in VLSI. This model mimics the way in which images are processed in the natural visual pathway which renders a feasible alternative for the implementation of early vision tasks in standard technologies. A prototype chip has been designed and fabricated in 0.5 /spl mu/m CMOS. Design challenges, trade-offs and the building blocks of such a high-complexity system (0.5/spl times/10/sup 6/ transistors, most of them operating in analog mode) are presented in this paper.Comisión Interministerial de Ciencia y Tecnología TIC1999-082

ACE 16k based stand-alone system for real-time pre-processing tasks

This paper describes the design of a programmable stand-alone system for real time vision pre-processing tasks. The system's architecture has been implemented and tested using an ACE16k chip and a Xilinx xc4028xl FPGA. The ACE16k chip consists basically of an array of 128×128 identical mixed-signal processing units, locally interacting, which operate in accordance with single instruction multiple data (SIMD) computing architectures and has been designed for high speed image pre-processing tasks requiring moderate accuracy levels (7 bits). The input images are acquired using the optical input capabilities of the ACE16k chip, and after being processed according to a programmed algorithm, the images are represented at real time on a TFT screen. The system is designed to store and run different algorithms and to allow changes and improvements. Its main board includes a digital core, implemented on a Xilinx 4028 Series FPGA, which comprises a custom programmable Control Unit, a digital monochrome PAL video generator and an image memory selector. Video SRAM chips are included to store and access images processed by the ACE16k. Two daughter boards hold the program SRAM and a video DAC-mixer card is used to generate composite analog video signal.European Commission IST2001 – 38097Ministerio de Ciencia y Tecnología TIC2003 – 09817- C02 – 01Office of Naval Research (USA) N00014021088

Second-order neural core for bioinspired focal-plane dynamic image processing in CMOS

Based on studies of the mammalian retina, a bioinspired model for mixed-signal array processing has been implemented on silicon. This model mimics the way in which images are processed at the front-end of natural visual pathways, by means of programmable complex spatio-temporal dynamic. When embedded into a focal-plane processing chip, such a model allows for online parallel filtering of the captured image; the outcome of such processing can be used to develop control feedback actions to adapt the response of photoreceptors to local image features. Beyond simple resistive grid filtering, it is possible to program other spatio-temporal processing operators into the model core, such as nonlinear and anisotropic diffusion, among others. This paper presents analog and mixed-signal very large-scale integration building blocks to implement this model, and illustrates their operation through experimental results taken from a prototype chip fabricated in a 0.5-μm CMOS technology.European Union IST 2001 38097Ministerio de Ciencia y Tecnología TIC 2003 09817 C02 01Office of Naval Research (USA) N00014021088

A Bio-Inspired Two-Layer Mixed-Signal Flexible Programmable Chip for Early Vision

A bio-inspired model for an analog programmable array processor (APAP), based on studies on the vertebrate retina, has permitted the realization of complex programmable spatio-temporal dynamics in VLSI. This model mimics the way in which images are processed in the visual pathway, what renders a feasible alternative for the implementation of early vision tasks in standard technologies. A prototype chip has been designed and fabricated in 0.5 μm CMOS. It renders a computing power per silicon area and power consumption that is amongst the highest reported for a single chip. The details of the bio-inspired network model, the analog building block design challenges and trade-offs and some functional tests results are presented in this paper.Office of Naval Research (USA) N-000140210884European Commission IST-1999-19007Ministerio de Ciencia y Tecnología TIC1999-082