Subsurface Exploration Research Articles

Design and verification of flexible penetrometer for planetary subsurface exploration

In-situ extraction of geological information from planetary subsurfaces is of great importance. To achieve this goal with low power consumption and deep penetration, a novel subsurface sounding system for planetary regolith exploration is proposed based on the operating principle of tape measures. Penetration model analysis and validation were conducted. The penetration mechanics of the penetrator head and body were modeled separately, and static penetration tests were performed to verify the feasibility of the penetrator and modify the penetration load model. As the structural design of the penetrator was completed, a cam-based impact clamping scheme was proposed. The impact system dynamics model was established to analyze the effect of pene-tration resistance and kinetic parameters on the penetration capability of the penetrator. The principle prototype of the penetrator was developed, and a load-free simulated planetary regolith penetration test system was built to verify the correctness of the design. This study may provide technical support for the future application of flexible detectors in planetary exploration.

Detecting geothermal anomalies using Landsat 8 thermal infrared remote sensing data in the Ruili Basin, Southwest China.

With the recent increase in global focus on green energy, the application of thermal infrared remote sensing data for the detection of geothermal anomalies has attracted wide attention as it can overcome the difficulty of using only ground surveying. This study aimed to highlight areas of geothermal anomalies with land surface temperature (LST) time series data in winter derived from thermal infrared remote sensing. To extract LST anomaly areas in the Ruili Basin for geothermal prospecting, nine types of data on the study area in winter during 2014 ~ 2021 from Landsat 8 were analyzed. Landsat 8 LST inversion data based on the mono-window algorithm (MWA) can be used to identify hot springs, volcanoes, and other heat-related phenomena. Superimposing LST anomalies for each cycle through drilling data, excluding the heat island effect, geothermal anomaly regions could be plotted. The results show that the accuracy of MWA LST varied within 2K, which is acceptable for geothermal energy and higher than those of the radiative transfer equation (RTE) algorithm and MODIS LST products. Three high-LST regions in the southeast of the study area were identified as geothermal anomaly areas (A, B, and C), and region B was further verified through a comprehensive field investigation of geothermal wells, supplemented by the temperature gradient (TG) method. The findings reveal that the distribution of geothermal anomaly areas and high-LST areas are highly consistent with the northeast trending fault structure; faults act as thermal channels and help in accurately detecting local LST anomalies. Overall, the infrared remote sensing method proved to be a valid technique for detecting LST anomalies. Considering the synergy between thermal infrared surface detection and subsurface exploration methods, the identification of known geothermal fields (B) and other possible areas (A and C) has significance in the upscaling of local geologic information to regional prospecting, thus providing a direction for future geothermal research.

INFRASOUND SOURCE AND CALIBRATION METHODS IN SEISMIC INTERPRETATION

Worldwide research and recordings discovered that low-frequency acoustic waves are inaudible sound, travels around the globe up to four times with modernization of data analytics and infrasound sensor network systems. Seismic interpretation is a critical process in subsurface exploration with infrasound sensor network systems. The evolution aims at identifying structures or environments of significant importance in various applications. Study in this paper attempts to understand behaviour of infrasounds and determine measurable procedures with digital microbarometer . Furthermore, this will be a key practice for understanding and calibration mechanisms , characterization of the infrasound sensors.

Efficient source-independent full waveform dual-parameter inversion of common-offset GPR data

Full waveform inversion (FWI) of common-offset ground penetrating radar (GPR) data can make up for the defects of the traditional prospecting technology such as destructive, cumbersome, and low efficiency, which also provides a robust and high-precision tool for quantitative assessment of subsurface prospecting. Nonetheless, conventional GPR-FWI is of limited practicality since the deficiency of accurate source wavelet and tremendous computational cost. We develop an efficient source-independent inversion algorithm based on the convolution method to eliminate the influence of source wavelet and enhance the algorithm efficiency to inverse field data. To suppress the noises induced by the convolution and cross-correlation operations, the time window is introduced in the reference trace which is selected automatically by singular value decomposition (SVD). The stochastic strategy reduces the computational cost by source subsampling. The synthetic model of a complex lens body demonstrates that source-independent FWI with time window has more tolerant to the initial model and noise, and the stochastic strategy improves the efficiency with ensured inversion accuracy. In the field GPR data of a sand trough containing two anomalous bodies, our algorithm has good adaptability and can accurately reconstruct the distribution of the permittivity and conductivity of the subsurface media without accurate estimation of the source wavelet. The results above indicate that the proposed algorithm in this study is valid for common-offset GPR data and improves the inversion efficiency by 1.24 to 3.10 times, which shows great potential to promote qualitative assessment in real-time subsurface exploration.

Power from Geothermal Resources as a Co-product of the Oil and Gas Industry: A Review.

The increase in the global demand for energy and fossil fuel dependency is hindering efforts to reduce greenhouse gas (GHG) emissions. Geothermal resources supplement this increase in energy demand with reduced emissions because of their availability, base-load production profile, and climatic independence. Despite these advantages, the development of geothermal energy is limited because of different reasons such as subsurface exploration risk and high upfront capital cost for drilling and facility construction. However, similarities in infrastructure and operations between the oil and gas industry and the geothermal industry can optimize expense and development when exploiting geothermal resources. Thus, in this review, we present recent advances and applications of geothermal power systems in the oil and gas industry starting from the fundamentals and basic principles of geothermal energy and the organic Rankine cycle (ORC). These applications include the use of geothermal resources via abandoned wells, active wells, and paired thermal enhanced oil recovery processes with injection for fluid heating and energy production. Abandoned wells are alternatives that reduce costs in geothermal energy-use projects. The use of geothermal resources via active wells allows the valorization of a resource, such as the production of water, which is considered a byproduct of production activities in an oilfield. The use of thermally enhanced oil recovery processes enhances the energy conditions of fluids produced in the field, improving geothermal systems with fluids at higher temperatures. Finally, an overview is presented of the challenges and opportunities of geothermal energy in the oil industry where the requirement to improve the usage of technologies, such as the ORCs, with the working fluids used in the cycles, is highlighted. Furthermore, the importance of environmental studies and use of novel tools, such as nanotechnology, to improve the efficiency of geothermal energy usage is highlighted.

A niching particle swarm optimization strategy for the multimodal inversion of surface waves

SUMMARY In practice, near-surface structures with shear wave velocity inversions or strong shear wave velocity contrasts may cause the phase velocity spectra of surface waves to be complex. Hence, it is sometimes difficult to identify mode numbers in the phase velocity spectrum. To avoid numbering different modes, the determinant misfit function has been applied to invert multimodal dispersion curves with a very limited computational cost due to the absence of the root-seeking procedure. However, this function presents a complicated relation with modal parameters and thus has multiple minima, resulting in an increase in model ambiguity. Therefore, it is more appropriate to adopt a multimodal optimization algorithm to find multiple minima instead of obtaining one optimal solution. In this study, we use a niching particle swarm optimization to find multiple minima with an enhanced fine search ability. Subsequently, we performed cluster analysis to distinguish different clusters in the inverted solutions and find the best-fitting profiles from multiple minima based on the Euclidean distance between the measured and inverted dispersion curves. Moreover, a modified Thomson–Haskell transfer matrix method is used to calculate the determinant misfit function for a better constraint on inversion because it can only resolve the surface wave modes possessing energy at the free surface, where both the sources and geophones are commonly deployed for active and passive surface wave exploration. Tests of synthetic and field data demonstrate that our inversion method is both effective and robust and emphasize its great potential in urban subsurface exploration and geotechnical characterization applications.

An overview of GPR subsurface exploration of planets and moons

Geophysical techniques were first tested beyond Earth during the Apollo program. Of those examined, radio-wave propagation methods appeared to be the most suitable for the moon and other solar system bodies. This was due to the electromagnetic characteristics of planetary subsurfaces and the possibility to remotely perform measurements on board spacecrafts and rovers. After the first successful experiment on the moon, more than 20 years passed before ground-penetrating radar (GPR) was included in the payload of a planetary mission. Technological advancements in GPR design and successful results of radio echo sounding measurements for the detection of basal water below terrestrial ice sheets paved the way for the application of similar techniques to search for liquid water in the Martian subsurface. Since deployment of the first two subsurface radar sounders above Mars, the number of proposed planetary missions relying on GPR for surveying the subsurface of planets, moons, and other objects has grown progressively. Six orbiting radar sounders and five GPRs mounted on rovers/landers have been employed so far to explore the moon, Mars, and comet 67P/GC. Some of these are in full operation and some are just starting to operate. Planned missions to the icy moons of Jupiter will also depend heavily on radar sounders to detect evidence of an internal ocean on Europa and to understand the habitability conditions on Europa, Ganymede, and Callisto. Finally, planetary missions to Earth's twin, the planet Venus, could take advantage of GPR to understand the cause of its drastic change in climatic conditions and the geologic phenomena that contributed to changing a watery and hospitable surface into a hot and asphyxiating inhabitable planet.

Elastic reverse time migration without wavefield decomposition

In this paper, we provide a clear definition represented by a concise expression for seismic data migration that is a linear inversion of subsurface exploration targets using primary waves given a smooth migration model with accurate wave kinematics. Combining the definition with noncurl characteristic of P-wave and nondivergence characteristic of S-wave, we propose an elastic reverse-time migration approach without wavefield decomposition applied to heterogeneous isotropic media, in which decoupled P- and S-wave propagators independent of each other are derived. We obtain ideal imaging results when we apply the proposed migration approach to elastic synthetic seismic data of a simple four-layered model and the complex Marmousi2 model with pure P- or S-wave source exciting, demonstrating the validity of our method. Because the proposed method does not include wavefield decomposition in the backward extrapolation of recorded wavefield and demand less spatial derivative numbers in the forward extrapolation of source wavefield, it is capable of achieving high-efficiency computing. In the case of P/S composite source exciting, we suggest that although the recorded wavefield can be divided into P- and S-wave component, the P-wave component consists of primarily reflected waves PP plus primarily converted waves SP and the S-wave component consists of primarily reflected waves SS plus primarily converted waves PS. Because PP and SP or SS and PS cannot be further separated from each other by current decoupling methods, the crosstalk artifacts are unavoidable, which is verified by the migration imaging results of a two-layered model.

Spatial Ensemble Anomaly Detection Method for Exhaustive Map-Based Datasets

Spatial anomaly detection is an essential part of subsurface data quality control and modeling for resources, e.g., groundwater aquifer, hydrocarbon resources, and mining mineral grades, along with environmental remediation. Efficiently identifying spatial local anomalous regions is important for detecting changes in subsurface population and data acquisition artifacts. Advanced data analytics and machine learning methods may be applied, but often omit essential spatial context with the additional cost of reduced interpretability. Considering the high cost of the risk in subsurface resource exploration, it is essential to maximize the integration of domain expertise. Our proposed method is an ensemble anomaly detection method that calculates the local anomaly probability based on the joint probability density space derived from the semivariogram model. The ensemble approach of our proposed method utilizes multiple local anomaly classifications calculated over a moving search window around each grid of a 2D map or 3D model. The anomalous regions are eventually decided based on the majority rule of the ensemble anomaly classifiers. We demonstrate the proposed method with 3 synthetic exhaustive, map-based, spatial datasets to cover different scenarios for spatial anomaly applications. The proposed ensemble anomaly detection method integrates domain expertise, spatial continuity, and scale of interest. We suggest using the proposed method as an automated tool to effectively identify the spatial local anomalies, based on the rigorous use of spatial continuity and volume variance from geostatistics, to focus professional time.

The pulse-elevator: A pump for granular materials

Granular materials include fuels, foods, feedstocks, and raw materials, and they are frequently created in drilling, exploration, and comminution. However, despite this ubiquity, they can be much more difficult to transport than other materials. Screw conveyors can be used, as can bailing, gas-blowing, and vibro-conveyors, but all have issues related to some combination of complexity, inclination, differential friction, and torque reaction. We propose an entirely new concept: a combination of the vibro-conveyor and the Tesla valve. This ‘pulse-elevator’ is a single piece of inert material, it can operate vertically, it does not depend upon frictional interactions, and it is effectively torqueless. This paper describes the mechanism in analytical, numerical, and experimental terms, and then illustrates two successful experimental use cases: powder uplift from a hopper, and the replacement of augering in a rock-drilling application. These cases are particularly relevant for the facilitation of ISRU and subsurface exploration in space.

Thorium Metallogeny in U-Cu-REE bearing Singhbhum Shear Zone, Eastern India

Abstract The long arcuate Singhbhum Shear Zone (SSZ) of around 160 km length having roughly an E-W trend hosts many uranium deposits and working uranium mines viz., Mohuldih, Bandhuhurang, Turamdih, Narwapahar, Bhatin, Jaduguda and Bagjata from west to east in addition to Cu deposits viz., Rakha, Mosabani etc. REE is well known from Kanyaluka area. Recent sub-surface exploration for uranium by AMD unravelled occurrence of thorite (ThSiO4)-bearing bands in a number of locations in western, central and eastern sectors of uranium mineralisation in SSZ, spanning over the entire shear zone. Thorite is observed in various host rocks involving metapelites of Dhanjori and Singhbhum Group and also in the Soda Granite/ feldspathic schist unit emplaced along the shear zone at the contact between the two groups. The individual lithounits that host thorite-bearing bands are restricted along the Singhbhum Shear Zone and include feldspathic schists (possible derivative of Soda Granite), albite veins, quartz-chlorite schists, quartz-biotite schists and sericite/muscovite-quartz schists. The thorite bearing zones transgresses lithology, stratigraphy as well as uraniferous zones along the shear zone evidently placing them as epigenetic hydrothermal mineralisation possibly later to major uranium metallogeny. Thorite occurs as discrete, rounded as well as subhedral to euhedral grains in various metapelites. They also form veins of their own besides occurring as phases within veins of albite and magnetite-apatite along the shear zone. Such multiple modes of occurrence and varied associated mineralogy suggest hitherto unknown thorium related hydrothermal mineralisation in SSZ. Presence of secondary thorium phases such as brockite (Ca-Th-phosphate) as well as post tectonic vein-type occurrence, points towards the mobility of thorium under a hydrothermal regime as well. However, present study thus, for the first time, establish the occurrence of thorite along with REE-Th minerals showing definite evidences of thorium mobilisation in several sectors of the well know U-Cu province of Singhbhum Shear Zone. Thorium-REE mobility is a widely understudied domain and the present findings place the SSZ as an ideal ground for exploring the concept with more understanding of this metal.

Eavesdropping at the Speed of Light: Distributed Acoustic Sensing of Baleen Whales in the Arctic

In a post-industrial whaling world, flagship and charismatic baleen whale species are indicators of the health of our oceans. However, traditional monitoring methods provide spatially and temporally undersampled data to evaluate and mitigate the impacts of increasing climatic and anthropogenic pressures for conservation. Here we present the first case of wildlife monitoring using distributed acoustic sensing (DAS). By repurposing the globally-available infrastructure of sub-sea telecommunication fiber optic (FO) cables, DAS can (1) record vocalizing baleen whales along a 120 km FO cable with a sensing point every 4 m, from a protected fjord area out to the open ocean; (2) estimate the 3D position of a vocalizing whale for animal density estimation; and (3) exploit whale non-stereotyped vocalizations to provide fully-passive conventional seismic records for subsurface exploration. This first example’s success in the Arctic suggests DAS’s potential for real-time and low-cost monitoring of whales worldwide with unprecedented coverage and spatial resolution.

Sequential Value of Information for Subsurface Exploration Drilling

Sequential Value of Information for Subsurface Exploration Drilling

The Paleo-Mesoarchaean Gondpipri Mafic-Ultramafic Intrusions, Western Bastar Archaean Craton, Central India: Insights from Bulk-Rock Geochemistry and Sm-Nd and S Isotope Studies on the Formation of Ni-Cu-PGE Mineralization

Abstract Magmatic Ni-Cu-platinum group element (PGE)-Te mineralization in the Gondpipri mafic-ultramafic layered intrusion of ca. 3323 ± 74 Ma age, western Bastar craton, central India, is one of the most prospective exploration targets for magmatic sulfides in India. The Gondpipri layered intrusion is divided into two distinct groups of rocks based on their mineralization potential, which include (1) mineralized layered gabbro and pyroxenite and (2) a barren olivine gabbro intrusion. The host rocks show Cu + Ni concentrations up to 5,000 ppm with a Cu/Ni ratio <1 and all PGE values between 0.1 and 1.1 ppm. Mineralization occurs in two modes: type I mineralization occurring as blebs, specks, and dissemination and type II mineralization occurring as stringers and minor veins. The geochemical data suggest that the parental magma of the host rock was generated at depths between spinel and garnet peridotite mantle source regions and subsequently modified by assimilation fractional crystallization (AFC) of the continental crust. High large ion lithophile elements, Th/Yb ratios of the studied rocks, and Sm-Nd isotope studies are consistent with a depleted mantle source. The geochemical proxies such as Th versus Ba/Th and (Ta/La)PM versus (Hf/Sm)PM and higher Sr/Nd (2.21–82.58) ratios indicate involvement of fluid-related subduction metasomatism and enrichment processes in an island-arc tectonic setting. Mineral assemblages and textural relationships between platinum group minerals (PGMs) and base metal sulfides suggest that sulfide-silicate liquid immiscibility was brought about by the precipitation of magnetite/Cr magnetite resulting in sulfide saturation in the melt by decreasing S solubility. Sulfur isotope compositions (δ34S: 1.61–3.30‰) and Sm-Nd geochemistry suggest that the sulfur was added in the tholeiitic magma by magmatic process. Crustal contamination played a significant role in sulfide saturation and in bringing about PGE and Te, As, Bi, Sb, Se (TABS) mineralization. PGM-NiTeBi developed at relatively low temperatures, whereas moncheite (PtPd)Te2 and merenskyite (PdTe) were formed at 650°C. The identification of Ni-Cu-PGM-Te in the margin of the western Bastar craton boosts deeper subsurface exploration.

Development of a multi-sample acquisition technique for efficient planetary subsurface exploration

Improving the efficiency of a subsurface sample acquisition process provides operational benefits such as reduced bit wear and power consumption, and may increase the sample fidelity by minimising alterations caused by the drilling operation to the surrounding substrate. This could be achieved by acquiring multiple samples during a single drilling procedure. Although some recent planetary drills have incorporated a hybrid cored and cuttings sampling technique, there are currently no systems that have been designed to obtain and separately store multiple comparable samples. The Internal Actuation Mechanism, developed as part of the latest generation of the Dual-Reciprocating Drill, will incorporate a rotating shutter mechanism capable of acquiring up to four samples. In the first demonstration of the fully-integrated prototype using layers of differently-coloured sand, the shutter mechanism was shown to be able to take multiple samples in a single drilling operation. These experiments also confirmed the observations of numerical simulations, which showed that the drill’s teethed design results in regolith from the surface layer being dragged down with the descending drill and collected by the sampling system. By optimising the geometrical design to increase sample value and refining the shutter mechanism to improve reliability, a multi-sample acquisition system for planetary subsurface exploration could become a viable technology.

Detection and Classification of Potential Caves on the Flank of Elysium Mons, Mars

Martian caves have revived interest in the field of subsurface exploration because they are the potential destinations for future human habitats and astrobiological research. There are many pits on Mars, but some of them look like collapsed cave roofs. These special pits are formed by the collapse of surface materials into the subsurface void spaces. The signature of life is probable in a subsurface cave on Mars as the subsurface environment can protect life from the harsh and dangerous radiation environment of the surface. In a cave, there may be an abundance of minerals, fluids, and other key resources. Therefore, locating the access point of the subsurface cave is essential and crucial for formulating plans for robotic/human explorations of the Red Planet, Mars. We have used remote sensing data from Mars Reconnaissance Orbiter (MRO; NASA), Mars Global Surveyor (MGS; NASA), and Mars Odyssey (NASA) for identifying, mapping, and classifying selected special pit candidates on the flank of Elysium Mons, Mars. A total of 32 special pit candidates has been identified and classified based upon morphology and geological context. Out of these, 26 are newly discovered ones. The thermal behavior of 23 special pit candidates confirms that the special pits are radiating heat energy at nighttime, similar to potential caves. Also, cave entrances have been detected in nine candidates using data from the HiRISE camera onboard MRO. These sites could be important destinations for future robotic/human exploration and the search for life on Mars.

Application of machine learning in the identification of fluvial-lacustrine lithofacies from well logs: A case study from Sichuan Basin, China

The lithofacies identification is critical for forecasting sweet spots of hydrocarbon explorations. Well logs are widely used in lithofacies identifications because they are petrophysical measurements of subsurface stratigraphy which reflect lithological successions and depositional processes. The traditional lithofacies identification from well logs is a manual work that is time-consuming and bias-prone. An automated and bias-free method is in demand. To this end, we created a lithofacies dataset of eleven wells with well log records and lithofacies descriptions that were interpreted manually based on facies analysis of drilling cutting descriptions and well logs. Then we developed machine learning models that were trained using the lithofacies dataset of the fluvial-lacustrine Upper Triassic Xujiahe and Lower Jurassic Ziliujing formations in Yuanba Area, northern Sichuan Basin of southwestern China. By employing extreme gradient boosting and resampling algorithms, this machine learning model is efficient and outperforms support vector machine and multiple-layer perceptron, as indicated by its highest accuracy and F1-score of 0.90, the highest AUC of 0.94, as well as the shortest training time. Moreover, the result suggests that resampling is necessary for lithofacies identification with the imbalanced dataset. A combined method of oversampling and undersampling is better than a single resampling method. This study presents a successful application of machine learning in fluvial-lacustrine lithofacies identification from well logs and suggests the great potentiality of machine learning in subsurface hydrocarbon explorations.

Natural Field Airborne Electromagnetics—History of Development and Current Exploration Capabilities

The mineral resources exploration industry continuously expands the efficiency requirements for geophysical technologies. Due to their relatively inexpensive nature, coupled with the ability to rapidly acquire data over large areas, airborne electromagnetic technologies have been used for decades in subsurface exploration. Limitations on the depth of investigation of airborne platforms with controlled primary field sources is the main obstacle for using these systems in many geoelectrical conditions and geographical terrains. In addition, systems based on the time-domain principle are limited in applications requiring differentiations in a high resistivity range of the mapping parameter and suffer from parasitic electromagnetic non inductive natural effects in specific near surface conditions. Methods exploiting natural electromagnetic fields in the audio frequency range significantly increase depth of investigation and sensitivity to a wide range of resistivity contrasts including in the range of thousands of ohm-ms. A brief history of the development of the natural field airborne technology is provided accompanied by a comparison of the systems technical specifications. Field examples from the latest development in the airborne electromagnetic natural fields’ domain, MobileMT, demonstrate its exploration capabilities in both conductive and resistive environments, sensitivity to any direction of geoelectrical boundary, and detectability of near-surface discrete targets along with deeper structures.

Two Improved Acquisition Systems for Deep Subsurface Exploration

Present land seismic surveys mainly focus on acquiring reflection data. The maximum offset is usually 1–1.5 times the depth of targets. Limited offset results in that the acquired diving waves only penetrate the shallow parts of the Earth model, far from targets. Thus, the reflection data are used to build the deep part of the velocity model with migration velocity analysis. However, two issues challenge the success of velocity model building. First, incomplete information. Limited offsets lead to a narrow aperture of observation, which results in an under-determined inversion system. One manifestation is the trade-off between the depth of interfaces/reflectors and the average velocity above them. Second, low signal-to-noise (S/N) ratios. Complex near-surface conditions and geologic structures lead to low S/N ratios for reflection data, which fails to build velocity with reflection data. The fundamental solution to these two issues is to acquire better data with an improved acquisition system. In this work, we propose two types of modified geometries to enhance the penetration depth of the diving waves, especially the first arrivals, which can be used to build a deeper velocity model effectively. Type-I geometry adds extra sparse sources on the extension line of the normal acquisition geometry, whereas Type-II geometry deploys extra sparse receivers on the extension line. Consequently, the new acquisition system includes ultra-large offsets, which acquire diving waves from the deep subsurface. These diving waves, including waveform and first-break time, are particularly useful for recovering deeper velocity, which has paramount significance for the exploration of deep and ultra-deep hydrocarbon reservoirs. Synthetic and field data examples preliminarily demonstrate the feasibility of this improved acquisition system.

Investigating the role of differential biotic production on carbonate geometries through stratigraphic forward modelling and sensitivity analysis: the Llucmajor example

The geometry of carbonate platforms reflects the interaction of several factors. However, the impact of carbonate-producing organisms has been poorly investigated so far. This study applies stratigraphic forward modelling (SFM) and sensitivity analysis to examine, referenced to the Miocene Llucmajor Platform, the effect of changes of dominant biotic production in the oligophotic and euphotic zones on platform geometry. Our results show that the complex interplay of carbonate production rates, bathymetry and variations in accommodation space control the platform geometry. The main driver of progradation is the oligophotic production of rhodalgal sediments during the lowstands. This study demonstrates that platform geometry and internal architecture varies significantly according to the interaction of the predominant carbonate-producing biotas. The input parameters for this study are based on well-understood Miocene carbonate biotas with characteristic euphotic, oligophotic and photo-independent carbonate production in which it is crucial that each carbonate-producing class is modelled explicitly within the simulation run and not averaged with a single carbonate production–depth profile. This is important in subsurface exploration studies based on stratigraphic forward models where the overall platform geometry may be approximated through calibration runs, and constrained by seismic surveys and wellbores. However, the internal architecture is likely to be oversimplified without an in-depth understanding of the target carbonate system and a transfer to forward modelling parameters.