Irregular Topography Research Articles

Broaching Digital Twin to Predict Forces, Local Overloads, and Surface Topography Irregularities

Broaching is a key manufacturing process that directly influences the surface integrity of critical components, impacting their functional performance in sectors such as aeronautics, automotive, and energy. Such components are subjected to severe conditions, including high thermomechanical loads, fatigue, and corrosion. For this reason, the development of predictive models is essential for determining the optimal tool design and machining conditions to ensure proper in-service performance. This study, therefore, presents a broaching digital twin based on hybrid modelling, which combines analytical, numerical, and empirical approaches to provide rapid and accurate predictions of the forces per tooth, local overloads, and surface topography irregularities. The digital twin was validated with a critical industrial case study involving fir-tree broaching of turbine discs made of forged and age-hardened Inconel 718. The accuracy of the digital twin was demonstrated by the results: the average error in force predictions was below 10%, and the model effectively identified the most critical teeth and zones prone to failure. It also predicted surface topography irregularities with an error of less than 15%. Interestingly, the relationship between surface topography irregularities and surface residual stress variations across the machined surface was observed experimentally for the first time.

EXPERIMENTAL ANALYSIS OF POISSON RATIO ON METAMATERIALS MANUFACTURED FROM CRUMPLED ALUMINUM FOIL SUBJECTED TO UNIAXIAL COMPRESSION

In this work experimental results are presented concerning the auxetic behavior of a crumpled metamaterial manufactured with aluminum foil, so far such experimental evidence has not been reported by other authors. Thus, 2D digital image correlation (DIC) was used to make full field measurements of longitudinal and transverse strains on the surface of crumpled aluminum specimens under axial compression; it was no possible to use conventional methods on the measurements of strains, such as strain gages or extensometers, due to the irregular topography on the surface of the specimens. The obtained results exhibit the auxetic nature of the aluminum crumpled material, with Poisson´s ratio values that vary from ?=-0.17 to ?=-0.02 for relative densities in the range ?_r=0.07 to ?_r=0.21. Keywords: Auxetic, Digital Image Correlation, Crumpled material, Poisson, Computer vision system.

Elastic least‐squares reverse time migration from topography through anisotropic tensorial elastodynamics

AbstractLeast‐squares reverse time migration is an increasingly popular technique for subsurface imaging, especially in the presence of complex geological structures. However, elastic least‐squares reverse time migration algorithms face significant practical and numerical challenges when migrating multi‐component seismic data acquired from irregular topography. Many associated issues can be avoided by abandoning the Cartesian coordinate system and migrating the data to a generalized topographic coordinate system conformal to surface topology. We introduce a generalized anisotropic elastic least‐squares reverse time migration methodology that uses the numerical solutions of tensorial elastodynamics for propagating wavefields in computational domains influenced by free‐surface topography. We define a coordinate mapping assuming unstretched vertically translated meshes that transform an irregular physical domain to a regular computational domain on which calculating numerical elastodynamics solutions is straightforward. This allows us to obtain numerical solutions of forward and adjoint elastodynamics and generate subsurface images directly in topographic coordinates using a tensorial energy‐norm imaging condition. Numerical examples demonstrate that the proposed generalized elastic least‐squares reverse time migration algorithm is suitable for generating high‐quality images with reduced artefacts and better balanced reflectivity that can accurately explain observed data acquired from topography in a medium characterized by arbitrary heterogeneity and anisotropy. Finally, the computational cost of our method is comparable to that of an equivalent Cartesian elastic least‐squares reverse time migration numerical implementation.

Topography prediction at boundaries between sub-regions in the 5-axis milling of Plexiglas based on dimension reduction method

Sub-regional milling has become an important machining method in the production of free-form surface parts. However, due to complex tool paths, irregular surface topography can occur at the region boundaries, which in turn affects the performance of the part such as the light transmission, optical distortion and mechanical strength of non-metallic transparent material etc. It is vital for manufacturers and researchers to study the forming mechanism of topography at boundaries and then to control it to get the high quality of the machined surface. Therefore, this paper thoroughly investigates the formation of surface topography at the boundary of sub-regions in the five-axis machining process. First, the boundaries of sub-regions are classified. Simultaneously, swept surfaces of the cutting edge, taking into account the process parameters and tool path, are constructed. Then, the surface topography is calculated using an improved model based on dimension reduction theory. Furthermore, through simulation and experiments, the predicted surface topographies agree well with the measured ones. Finally, some conclusions are listed and the method in this paper can provide a reliable basis for manufacturing high-quality parts.

Microzonation Approach for Analyzing Regional Seismic Response: A Case Study of the Dune Deposit in Concón, Chile

Urban areas located on complex geological formations, such as dune deposits, require detailed seismic risk assessments that extend beyond standard seismic codes. This study focuses on the city of Concón, Chile, where a significant portion of the urban area is situated on a coastal dune deposit. The research integrates seismic microzonation with a three-dimensional finite element model (3D FEM) to comprehensively evaluate the regional seismic response. Field data from 208 strategically distributed points were collected and combined with geotechnical and geomorphological information to construct a detailed 3D model of the region. This model allowed for the simulation of seismic behavior under various conditions, highlighting the limitations of general seismic codes in capturing local variations in seismic response. The results underscore the importance of considering local geological conditions in structural design, particularly in areas with irregular topography and complex subsurface conditions. This study concludes that incorporating microzonation into urban planning and seismic analysis can significantly enhance infrastructure resilience and disaster preparedness, providing a replicable approach for other cities facing similar geological challenges.

Effect of valley topography on dynamic response of arch dams

Arch dams are typically built in the mountain and gorge regions with complex terrain. In the current engineering practice, foundation models are commonly simplified as the half-space with the canyon of regular geometry. The complex topography conditions above the dam crest are neglected. This study investigates the effect of realistic valley topography on the dynamic response of arch dams. The direct finite element method is generalized and applied to the dam-reservoir-foundation system with realistic valley topography. The input ground motions are transformed into the effective earthquake loads at the truncated boundaries by performing several dynamic reaction calculations using one-dimensional (1D) and two-dimensional (2D) auxiliary finite element models. The effect of valley topography on the seismic response of the Baihetan arch dam is evaluated as a case study. Results indicate that the valley topographic irregularities significantly influence the dynamic responses of the arch dam, including relative displacement and stress distribution. Notably, the valley topography effect on the seismic response of arch dams depends on the incident ground motions and is hardly predicted in advance, demonstrating the necessity to account for the realistic topography conditions.

Influence of annealing temperature on 3D surface stereometric analysis in C-Ni films

PurposeThe purpose of this paper is to study the correlation between the thicknesses of the C–Ni films that have been prepared by RF-magnetron sputtering on quartz substrates and their three-dimensional (3D) micro morphology. In this work by AFM images, this paper studied stereo metric analysis of these films.Design/methodology/approachThe C–Ni films have been prepared by RF-magnetron sputtering on quartz substrates using a mosaic target consisting of pure graphite and strips of pure nickel approximately 2 cm2 attached to the graphite race track. The field emission scanning electronic microscopy (FESEM) images were used for the morphological characterization.FindingsThe histogram peaks are zero for all samples and the histograms are almost symmetric around zero. Temperature did not have much effect on the degree of isolation, so all four diagrams have similar results. The qualitative observations through statistical parameters of the 3D surface texture revealed that the smoothest surface has been obtained for C-Ni films annealed at 500 °C (Sa, Sq, Sz and Sv have the lower values), while the most irregular topography has been found for C-Ni films annealed at 300 °C (the fractal dimension D = 2.01 ± 0.131).Originality/valueAs shown in FESEM images, the size of the particles was increased for films deposited from 300 ºC to 800ºC; however, at 1000ºC, it decreased significantly. The histogram peaks are zero for all samples and the histograms were almost symmetric around zero. Also, the largest and lowest root mean heights (Sq) belong to films at 300 °C and 500 °C. Furthermore, the more irregular surface was found at 300 °C, and the more regular surface was found at 500 °C. As the temperature was increased to 800 °C, the values of the IAPSD function increased systematically, and then the values of the IAPSD function was decreased in the fourth sample. The surface skewness of samples annealed at 1000 °C was positive which confirms the lack of dominance of cavities on their surface with the highest amount of C-Ni films at 800 °C.

Application of active MASW study on irregular and undulated sloping terrain: a case study

ABSTRACT Multichannel Analysis of Surface Waves (MASW) is a geophysical technique used for deciphering subsurface profiling by the determination of shear wave velocity. It is increasingly utilized in sloping terrain; however, its accuracy is limited by the presence of undulating or irregular topography. The study analysed the impact of undulating topography on sloping terrain using models of depressed and elevated topography. The surface waves lose more energy as depth, width, and steepness of the undulated topography increased. The study revealed that the elevated topography had a greater influence than depressed topography. The undulating topography in close proximity to the source resulted in a decrease in resolution dispersion, however the terrain located further away did not have a substantial impact. The study aims to identify suitable configurations that must be taken into account while identifying the subsurface characterization of a sloping terrain using the MASW.

Effect of silver nanochitosan on control of seed-borne pathogens and maintaining seed quality of wheat

Seeds, considered as the foundation of agriculture, are invaded by a broad spectrum of seed-borne pathogens. The current study aimed to control seed-borne fungal pathogens of wheat, Aspergillus flavus and A. niger, by using Ag+ nanochitosan (Ag-NC) for nano-priming of seeds and enhancing seed quality. Nanochitosan (NC) and Ag-NC were synthesized using the gelation method and characterized by UV–vis spectrophotometry, FESEM, EDXS, and HRTEM. NC and Ag-NC showed irregular surface topography with an average particle size of 275 and 325 nm, respectively. Antifungal activity of both the nanoparticles at 0.1, 0.2, 0.3, 0.4, and 0.5 mg/mL revealed that Ag-NC at 0.5 mg/mL has completely terminated the mycelial growth of both pathogens. Malonaldehyde content increased to 77.77% in A. flavus and 82.66% in A. niger when exposed to 0.5 mg/mL Ag-NC. High-intensity fluorescence due to oxidative stress was observed in Ag-NC-treated pathogens. Ultra-structural changes in Ag-NC treated pathogenic spores under SEM displayed pronounced membrane damages. Wheat seeds were nano-primed with NC and Ag-NC at 0.5 mg/mL, and fungal load was examined to evaluate the mitigation of pathogenic stress and its effect on seedling growth promotion activity. Ag-NC priming reduced the fungal load and allowed successful seed germination. Ag-NC priming increased the albumin, gliadin, gluten, and glutenin content along with total phenol, reducing sugar and starch levels. Ag-NC priming increased the overall protein levels traced through SDS-PAGE. Seed priming with Ag-NC promotes seed germination, mean germination time, stress tolerance index, vigour, etc. NC and Ag-NC at 0.5 mg/mL showed no cytotoxic effect on the Human Embryonic Kidney (HEK293) cell line that ensures the nanoparticles are non-toxic. Thus, the synthesized nanoparticles exhibit a dual role in antifungal activity and plant growth promotion.

An Interpretable Multi-Model Machine Learning Approach for Spatial Mapping of Deep-Sea Polymetallic Nodule Occurrences

AbstractHigh-resolution mapping of deep-sea polymetallic nodules is needed (a) to understand the reasons behind their patchy distribution, (b) to associate nodule coverage with benthic fauna occurrences, and (c) to enable an accurate resource estimation and mining path planning. This study used an autonomous underwater vehicle to map 37 km2 of a geomorphologically complex site in the Eastern Clarion–Clipperton Fracture Zone. A multibeam echosounder system (MBES) at 400 kHz and a side scan sonar at 230 kHz were used to investigate the nodule backscatter response. More than 30,000 seafloor images were analyzed to obtain the nodule coverage and train five machine learning (ML) algorithms: generalized linear models, generalized additive models, support vector machines, random forests (RFs) and neural networks (NNs). All models ML yielded similar maps of nodule coverage with differences occurring in the range of predicted values, particularly at parts with irregular topography. RFs had the best fit and NNs had the worst spatial transferability. Attention was given to the interpretability of model outputs using variable importance ranking across all models, partial dependence plots and domain knowledge. The nodule coverage is higher on relatively flat seafloor ( < 3°) with eastward-facing slopes. The most important predictor was the MBES backscatter, particularly from incident angles between 25 and 55°. Bathymetry, slope, and slope orientation were important geomorphological predictors. For the first time, at a water depth of 4500 m, orthophoto-mosaics and image-derived digital elevation models with 2-mm and 5-mm spatial resolutions supported the geomorphological analysis, interpretation of polymetallic nodules occurrences, and backscatter response.

Statement of the Risk Level for Gliding in the Cooperative San Marcos del Cantón el Empalme, Provincia del Guayas, Equador

Objective: The purpose of this study is to investigate the risk of slipping of the San Marcos cooperative in the canton of El Empalme, with the aim of making the correct assessment of the existing level of risk. Theoretical Framework: It is important to take into account that, from the year 2014 every construction process must compulsorily comply with the Ecuadorian construction standards that the governing body in the area of habitat and human settlements will issue for the purpose (Ecuador, 2014). And in the canton of El Empalme has a completely irregular topography, increasing the level of risk of sliding in several sectors, Taking into account the conditioning factors, and adding to this the triggering factors that might occur, such as heavy rainfall or seismic events, would increase the likelihood of the risk materializing and collapse occurring. (Empalme, 2020). Method: For the realization of this research project field visits will be made to the cooperative San Marcos to be able to take samples of slopes in various sectors, where the method of direct observation of the study area will be used and the topography of the terrain will be visible. Therefore, the calculation of the slope will be carried out with the help of the Apparatus “A”, which is a fundamental tool that allows us to know the level of a terrain with respect to a horizontal plane, (“Apparatus A” distance to 2 meters), and thus to be able to determine the distance between lines depending on the slopes inclination; therefore, once having the relief and slope later will include some additional factors such as lithology, humidity, vegetation cover, rain intensity, type of relief. To subsequently carry out the slide risk assessment. Results and Discussion: The results obtained determined that the presence of several conditioning factors in the study area has contributed to the increased risk of sliding in several sectors, having already classified by polygons a zoning of areas of greater susceptibility and represented with maps the existing risk levels. In this process, it can be said that there are areas that are less vulnerable, due to proper territorial planning and the provision of public and mitigation works. Implications of the research: This research has important social, economic and environmental implications. Early risk assessment and mitigation can prevent major impacts on the population. In addition, results can influence public policy formulation and implementation and thus increase community resilience. Originality/Value: This study contributes to the literature by highlighting the originality of the research, having more detailed information about the risk of sliding that exists in the San Marcos cooperative of the canton El Empalme. The relevance and value of this research is demonstrated by explaining in a more detailed way the level of risk existing in the study area.

Simulate the elastic wavefields in media with an irregular surface topography based on staggered grid finite difference

Abstract Wave equation forward modeling is a useful method to study the propagation regulation of seismic wavefields. Finite difference (FD) is one of the most extensively employed numerical approaches for computing wavefields in earthquake and exploration seismology. However, the FD approach relying on regular grids often struggles to calculate wavefields in regions featuring surface topographies. The elastic wave equation can more accurately describe the propagation of seismic wavefields in elastic media compared to the acoustic wave equation. We introduce a new FD scheme to calculate the elastic wavefields in an isotropic model with a surface topography. The novel approach can use a conventional staggered grid FD (SGFD) approach based on regular grids. A new elastic model with a horizontal surface is first obtained from the nearby surface's elastic properties and the undulating terrain elevation. We subsequently employ a topography-related strategy to eliminate the effects of surface topographies on the seismic wavefields in models with irregular surface topographies. The merits of our proposed scheme lie in its ability to stable numerically compute wavefields in models with irregular surface topographies without altering the conventional SGFD relying on regular grids. To validate the effectiveness and practicality of our method, we utilize elastic models featuring complex surface topographies. Numerical experiments demonstrate that our approach efficiently calculates elastic wavefields in isotropic media with irregular topographies based on conventional SGFD.

A three-dimensional immersed boundary method for accurate simulation of acoustic wavefields with complex surface topography

Abstract Irregular topography of the free surface significantly affects seismic wavefield modelling, especially when employing finite-difference methods on rectangular grids. These methods represent the free surface as discrete points, resulting in a boundary that resembles a ‘staircase’. This approximation inaccurately represents surface topography, introducing errors in surface reflection traveltimes and generating artificial diffractions in wavefield simulation. We introduce a stable three-dimensional immersed boundary method (3DIBM) employing Cartesian coordinates to address these challenges. The 3DIBM enables the simulation of acoustic waves in media with complex topography through standard finite difference, extending the two-dimensional immersed boundary approach to compute spatial coordinates for ghost and mirror points in a three-dimensional space. Wavefield values at these points are obtained by three-dimensional spatial iterative symmetric interpolation, specifically through the Kaiser-windowed sinc method. By implicitly implementing the free surface boundary condition in three dimensions, this method effectively reduces artificial diffractions and enhances the accuracy of reflection traveltime. The effectiveness and accuracy of 3DIBM are validated through numerical tests and pre-stack depth migration imaging with simulated data, demonstrating its superiority as a modelling engine for migration imaging and waveform inversion in three-dimensional land seismic analysis.

Semi-analytical method for calculating ground vibrations from a tunnel in a homogeneous half-space with an irregular surface

This paper proposes a novel two-dimensional (2D) semi-analytical method for calculating ground vibrations from a tunnel situated in a homogeneous half-space with an irregular surface. The circular tunnel is conceptualized as an elastic solid, while the soil is modelled as an elastic, isotropic, and homogeneous half-space with an irregular surface. A virtual horizontal interface is introduced to divide the soil domain into an irregular region with an arbitrary-shaped surface and a half-space with a circular hollow. The wavefield scattered by the irregular surface is simulated by the boundary integral equation. Through the application of the discrete wavenumber approach and expansion of wavefield on the irregular surface, the boundary integral equation is transformed into a set of simultaneous matrix equations containing unknown expansion coefficients. By utilizing the transformation between cylindrical and plane waves, the boundary conditions on soil-tunnel interface are satisfied, yielding a solution for a harmonic point load acting on the tunnel in a half-space with an irregular surface. The proposed method can simulate topographies with arbitrary shapes and only requires the discretization of the irregular part of the ground surface, which provides a highly efficient tool to investigate the propagation characteristics of train-induced vibrations in complex topographies. The proposed method is verified through comparisons with the existing analytical methods and the finite element method. The dynamic responses of a tunnel embedded in a half-space with a Gaussian-shaped surface are meticulously investigated. A case study involving a site for the Shenzhen metro line 5 is performed. The numerical results demonstrate that the presence of irregular topography alters the distribution of ground vibrations, leading to significant differences in responses within the irregular region and certain disparities in the regular region. The effect of the location, size, and undulating direction of the irregular topography on ground vibrations is frequency-dependent.

Odor-Cued Grab Air Sampling for Improved Investigative Odorant Prioritization Assessment of Transient Downwind Environmental Odor Events.

A critical prelude to any community odor assessment should be the prioritization of specific chemical odorants that are most responsible for targeted downwind odors. Unfortunately, and historically, this is a step that has often been bypassed or overlooked. However, correct understanding of the specific impactful volatile organic compounds (VOCs) can inform the follow-on sampling, analytical, and remediation strategies that are most appropriate and efficient, based upon the chemistry behind the issue. With this understanding, the techniques and sampling strategies presented herein should be viewed as a qualitative prelude rather than an addendum to a follow-up routine, automated downwind odor monitoring. Downwind odor characteristics can vary depending upon the size of the upwind source, interim topography, and wind conditions. At one extreme, the downwind odor plume from a relatively large source located on a flat open plain and under stable, near-straight line wind conditions can be rather broad, sustained, and predictable. In contrast, the plume from a small point source (e.g., a roof vent stack) located on irregular topography and under rapidly shifting wind conditions can be intermittent and fleeting ("spikes" or "bursts"). These transient odor events can be surprisingly intense and offensive, despite their fleeting occurrence and perception. This work reports on improving and optimizing an environmental sampling strategy for odorant prioritization from such transient downwind odor conditions. This optimization addresses the challenges of (1) sampling of transient odor "spikes" and (2) prioritizing odors/odorants from multiple, closely colocated point sources under transient event conditions. Prioritizing is defined as identifying the key impactful odorants downwind. Grab air sampling protocol refinement has emerged from actual community environmental odor assessment projects. The challenge of assessing transient odor events has been mitigated by utilizing (a) rapid, odor-cued whole-air grab sampling (i.e., activated by and synchronous with the perceived sensory spikes) into metalized fluorinated ethylene polymer (m-FEP) gas sampling bags; (b) immediate transfer from bags onto solid-phase microextraction (SPME) fibers or sorbent tubes; and (c) maintaining refrigerated storage and shipment conditions between field collection and in-laboratory analysis. Results demonstrated approximately 11-fold increases in target odorant yields for 900 mL air sample capture on sorbent tube transfers from 2 to 3 s "burst" odor event bag captures compared to equivalent direct collections (with sorbent tubes) at the same downwind receptor location but during perceived (stable) odor "lull" periods. An application targeting general odor sampling and point-source differentiation utilizing tracer gases is also presented.

Full-Waveform Modeling of Complex Media Seismic Waves for Irregular Topography and Its Application in Metal Ore Exploration

Full-Waveform Modeling of Complex Media Seismic Waves for Irregular Topography and Its Application in Metal Ore Exploration

A novel immersed boundary approach for irregular topography with acoustic wave equations

Irregular terrain has a pronounced effect on the propagation of seismic and acoustic wavefields but is not straightforwardly reconciled with structured finite-difference (FD) methods used to model such phenomena. Accurate wavefield simulation is paramount in subsurface imaging applications such as reverse time migration and full-waveform inversion, requiring suitable topography handling. Methods currently detailed in the literature generally are limited in scope application-wise or nontrivial to apply to real-world geometries. A general immersed boundary treatment capable of imposing a range of boundary conditions in a relatively equation-agnostic manner has been developed, alongside a framework implementing this approach to complement emerging code-generation paradigms. The approach is distinguished by the use of N-dimensional Taylor-series extrapolants constrained by boundary conditions imposed at some suitably distributed set of surface points. The extrapolation process is encapsulated in modified derivative stencils applied in the vicinity of the boundary, using hyperspherical support regions. This method ensures boundary representation is consistent with the FD discretization. Furthermore, high-dimensional and vector boundary conditions can be applied without approximation prior to discretization. A consistent methodology can thus be applied across free and rigid surfaces with first- and second-order acoustic wave equation formulations. Application to both equations is demonstrated, and numerical examples based on analytic and real-world topography implementing free and rigid surfaces in 2D and 3D are presented. Numerical examples and convergence tests demonstrate the accuracy of boundary treatments devised by the prescribed approach, their suitability to practical applications, and the feasibility of automatically generating treatments to suit each case.

Smoothness: The key factor in well-log information-assisted PINNtomo

Seismic traveltime tomography is popularly used to provide a smooth background model for subsequent depth migration or full waveform inversion (FWI). The core of the traveltime tomography process requires an eikonal solver for seismic traveltime calculation. Most of the conventional eikonal solvers, suffer from first-order convergence errors and difficulties in dealing with irregular topography, which will lead to inaccurate seismic tomography results. To solve these issues, physics-informed neural networks (PINNs) have been developed and demonstrated remarkable success in simultaneous traveltime calculation and velocity construction, which is referred to as PINNtomo. It combines the physics constraint (eikonal equation) and data constraint (traveltime fitting) to form the loss function of the networks. Though PINNtomo can manage to recover a smooth background velocity, it will fail in the inversion for a complicated high-resolution velocity model. We take advantage of the well-log velocity as a prior information to provide an additional model constraint in the loss function to improve the performance of PINNtomo. We found that the well-log information will provide high-resolution components in the inverted velocity model. However, it will destroy the lateral structure of the true model. We propose to use a smoothed version of the well-log velocity as the prior model constraint in PINNtomo. As a result, the accuracy of the inverted background velocity will be improved, which will be beneficial to the subsequent FWI.

Effect of surface topography and roughness on the leakage of static seals

Static seal is widely used in modern machinery. Leakage of static seals would shorten the mechanical system’s service life and affect the environment. To understand the leakage characteristics of static seals, in this work, an experimental apparatus for leakage quantization was built. The effects of surface topography and roughness on the leakage performance of static seals subject to elevated pressure were highlighted. It was found that the leakage rate is negatively correlated with contact pressure. Orientation of surface topography affects the leakage, where the grinding scar parallel to the leakage direction contributes to the leakage, and the perpendicular grinding scar has an inhibiting effect. The leakage rate of irregular and discontinuous surface topography is lower than that of regular ones, and it increases with increasing surface roughness. Furthermore, the leakage mechanism of surface topography and roughness was revealed. This work provides general guidance for the parameters design of static seals.

Linked evolution of Paleocene sea floor relief and deep marine currents in the Subbetic Zone, southern Spain

Paleocene deposits of the Subbetic Zone (southern Spain) provide outstanding evidence of the influence of sea mountains on deep marine currents. This part of the Betic Cordillera External Zones corresponds to the distal and deepest area of the original basin, where hemipelagic sedimentation prevailed during most of the Turonian-early Lutetian interval. This sedimentation is recorded by the so-called Capas Rojas and Quipar-Jorquera formations, units up to 250 m and 425 m thick, respectively, predominantly consisting of marls and marl/limestone alternations. These units draped and smoothed an irregular submarine topography of fault-bounded Mesozoic carbonate blocks. Some of these blocks became uplifted and subaerially exposed after a mid-Danian tectonic episode, transforming the Subbetic Zone in an archipelago during the late Danian-early Selandian interval. The emerged blocks were colonized by Microcodium-producing terrestrial plants, Microcodium consisting of aggregates of submilimetric monocrystalline calcite grains. Massive resedimentation of these grains into depressed zones of the archipelago resulted in discrete accumulations up to 100 m thick but of comparatively modest extent (≤150 km2) of calcarenites rich in Microcodium remains. The study of one of these calcarenite units, the Olivares Formation, demonstrates that most of its constituent Microcodium remains were brought to the deep sea by turbidity currents, but were subsequently reworked by oscillatory and unidirectional bottom-currents. The analysis of the Capas Rojas Formation in its type section and surrounding areas, where Microcodium-rich calcarenites are absent, demonstrates that the Danian-Selandian succession is riddled with hiatuses, which resulted in a drastic thickness reduction of the interval. Clearly, the rugged sea floor topography resulting from the mid-Danian tectonic event enhanced the sedimentary transport capacity of bottom-currents that, in addition to piling-up Microcodium-rich calcarenites in restricted zones, disturbed the hemipelagic sedimentation elsewhere in the Subbetic Zone. From late Thanetian times onwards the background hemipelagic sedimentation typical of the Capas Rojas progressively resumed throughout the Subbetic Zone, recording the gradual abatement of the sea floor relief by protracted erosion and/or subsidence.