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We discuss the tectonic structure, seismic stratigraphy and evolution of the NW Sulu Sea using reprocessed 2D reflection profiles. The NW Sulu Sea is located between the Palawan continental shelf and the Cagayan Ridge and represents the northern part of the Sulu Sea, a marginal sea resulting from Paleogene extension and subsequent Neogene contraction due to convergence between the Palawan and the Philippine blocks. The basin consists of six seismo‐stratigraphic units overlying crystalline basement. Syn‐orogenic depocenters contain calibrated Middle Miocene to, possibly, Lower Miocene units, while rift‐related depocenters consist of uncalibrated but tentatively dated Paleogene to Lower Miocene units. Thickness and depth maps of the main units and bounding horizons differentiate the Piedra‐Blanca and the Rasa domains, separated by the NW‐Sulu‐Break major tectonic structure. Fault‐bounded rift‐related depocenters are strongly segmented. We interpret that NW‐SE and NE‐SW trending zones accommodate shape and trend variations of these depocenters. We suggest that these zones may link rift segments, recording different extensional deformation. Miocene thrusting and folding in the Piedra‐Blanca Domain and mudflow with associated gravitational structures in the Rasa Domain influenced the deposition of syn‐orogenic units. Rift structures inherited from rift segmentation may have conditioned the style and distribution of contractional deformation during the subsequent incipient reactivation during contraction. In the context of SE Asia, our results support that the timing of rifting of the NW Sulu Sea overlaps with the opening of the South China Sea and the North Palawan margin, which may indicate a common geodynamic driving force triggering extension. Plain Language Summary: The SE Asia region includes several basins partially floored by oceanic crust, frequently containing or bounded by volcanic island arcs. These basins are known marginal seas and, although it is critical to decipher the geodynamic evolution of the entire region, the structure and tectonic history of most of these marginal seas are still insufficiently known. The Sulu marginal sea lies between the Sulu Archipelago and the Palawan, Mindanao, Negros and Panay islands. The Cagayan Ridge separates the NW and SE Sulu seas, which show a contrasting seafloor morphology, resulting from Paleogene extension and subsequent Neogene contraction. In this work, we study the structure and tectonic evolution of the NW Sulu Sea based on the re‐processing and interpretation of seismic reflection profiles acquired in 1982 and 1987. We analyzed and calibrated the seismo‐stratigraphy of the sediment infill, determined the main tectonic and gravitational structures and the geometry and spatial distribution of depocenters. Our results show for the first time the basin‐wide overall structure and constrain tectonic models, describing the opening and, particularly, the contractional deformation of the NW Sulu Sea. This provides further information to understand the formation of the Sulu Sea and the evolution of convergent systems in SE Asia. Key Points: A multi‐stage tectonic evolution shaped the Piedra‐Blanca and Rasa structural domains separated by the gentle NW‐Sulu‐Break structureNW‐SE and NE‐SW trending accommodation zones define the geometry and location of the rift‐related oldest basin depocentersThrusts and associated folds deformed the Piedra‐Blanca and mudflows affected the Rasa domain during the contractional basin reactivation [ABSTRACT FROM AUTHOR]

Rifting and continental break-up is a key research topic within geosciences, and a thorough understanding of the processes involved, as well as of the associated natural hazard and natural resources is of great importance to both science and society. As a result, a large body of knowledge is available in the literature, yet most of previous research focuses on tectonic and geodynamic processes and their links to the evolution of rift systems. However, we believe that the key challenge for researchers is to make our knowledge of rift systems available and applicable to face new societal challenges. In particular, we should embrace a system analysis approach, and aim to apply our knowledge to better understand the links between rift processes, natural hazards, and the geo-resources that are of critical importance to realize the energy transition and a sustainable future. The aim of this paper is therefore to provide a first-order framework for such an approach, by providing an up-to-date summary of rifting processes, hazards, and geo-resources, followed by an assessment of future challenges and opportunities for research. We address the varied terminology used to characterise rifting in the scientific literature, followed by a description of rifting processes with a focus on the impact of (1) rheology and stain rates, (2) inheritance in three dimensions, (3) magmatism, and (4) surface processes. Subsequently, we address the considerable natural hazards and risks that occur in rift settings, which are linked to (I) seismicity, (II) magmatism, and (III) mass wasting, and provide some insights in how the impacts of these hazards can be mitigated. Moreover, we classify and describe the geo-resources occurring in rift environments as (a) non-energy resources, (b) geo-energy resources, (c) water and soils, and (d) opportunities for geological storage. Finally, we discuss the key challenges for the future linked to the aforementioned themes, and identify numerous opportunities for follow-up research and knowledge application. In particular, we see great potential in systematic knowledge transfer and collaboration between researchers, industry partners and government bodies, which may be the key to future successes and advancements. [ABSTRACT FROM AUTHOR]

Rifting and continental break-up is a key research topic within geosciences, and a thorough understanding of the processes involved, as well as of the associated natural hazard and natural resources is of great importance to both science and society. As a result, a large body of knowledge is available in the literature, yet most of previous research focuses on tectonic and geodynamic processes and their links to the evolution of rift systems. However, we believe that the key challenge for researchers is to make our knowledge of rift systems available and applicable to face new societal challenges. In particular, 5 we should embrace a system analysis approach, and aim to apply our knowledge to better understand the links between rift processes, natural hazards, and the geo-resources that are of critical importance to realize the energy transition and a sustainable future. The aim of this paper is therefore to provide a first-order framework for such an approach, by providing an up-to-date summary of rifting processes, hazards, and geo-resources, followed by an assessment of future challenges and opportunities for research. We address the varied terminology used to characterise rifting in the scientific literature, followed by a description of 10 rifting processes with a focus on the impact of (1) rheology and stain rates, (2) inheritance in three dimensions, (3) magmatism, and (4) surface processes. Subsequently, we address the considerable natural hazards and risks that occur in rift settings, which are linked to (I) seismicity, (II) magmatism, and (III) mass wasting, and provide some insights in how the impacts of these hazards can be mitigated. Moreover, we classify and describe the geo-resources occurring in rift environments as (a) non-energy resources, (b) geo-energy resources, (c) water and soils, and (d) opportunities for geological storage. Finally, we discuss the 15 key challenges for the future linked to the aforementioned themes, and identify numerous opportunities for follow-up research and knowledge application. In particular, we see great potential in systematic knowledge transfer and collaboration between researchers, industry partners and government bodies, which may be the key to future successes and advancements. [ABSTRACT FROM AUTHOR]

Crustal roots are identified in collision chains worldwide. Frequently mirroring the summits of mountain systems, they elegantly encapsulate the concept of isostasy. The rugged topography of northern Iberia results from convergence with the European plate during the Alpine orogeny that formed the Pyrenean-Cantabrian mountain range. From east to west, the range comprises three distinct parts: the Pyrenees, the Basque Cantabrian region, and the Cantabrian Mountains. The identification of the Pyrenean root in the 1980s and the observation of a similar geometry beneath the Cantabrian range in the 1990s gave place to the current view of crustal thickening as a continuous feature, resulting from the northward subduction of Iberian crust. Recent developments in rift architecture have delivered a complex rifting template for the area prior to convergence, and contrasting views based on two-dimensional restorations have led to a debate over its evolution. A crucial geophysical constraint is Moho topography. Using two different data sets and techniques, we present the most accurate Moho surface to date, evidencing abrupt changes throughout the orogen. The complexity of hyperextended margins underlies the current Moho topography, and this is ultimately transferred to the nonuniform orogenic pattern found in northern Iberia. [ABSTRACT FROM AUTHOR]

Despite considerable progress in restoring rifted margins, none of the current kinematic models can restore the Mesozoic motion of the Iberian block in full agreement with the circum‐Iberian geology. This conflict requires a revision of the kinematic description at the onset of divergence. The circum‐Iberian region has a unique geological dataset that allows calibration and testing of kinematic reconstructions and therefore it is an ideal candidate for testing intracontinental restoration approaches. Here we define intracontinental deforming regions, referred to as strike‐slip corridors, based on alignments of Mesozoic rift basins and/or transfer zones bordering rigid continental blocks. We use these strike‐slip corridors and data from the southern N‐Atlantic and Tethys to define the motion path of the Flemish Cap, Ebro and Iberia continental blocks. The resulting Mesozoic kinematic model for the Iberian block is compatible with recently published data and interpretations describing the Mesozoic circum‐Iberian geology. Large‐scale intracontinental strike‐slip corridors may offer a valid boundary condition for reconstructing continental block motion at the onset of divergence in intracontinental settings. [ABSTRACT FROM AUTHOR]

This contribution investigates the role of a hyperextended rift system in the formation of the Basque–Cantabrian Pyrenees by discussing their present‐day architecture as well as the inherited rift template. Moreover, this work attempts to decipher the onset of reactivation of a hyperextended system and to discuss the related processes during collision. To carry out this study, two regional, crustal‐scale cross‐sections are presented that provide geological and geophysical information and interpretations across the Central and Western Basque–Cantabrian Pyrenees. Moreover, the two sections are restored back to the Cenomanian and Barremian, corresponding to the end of two independent rift stages respectively. The two sections document different structural styles observed along the orogenic belt. The Central section, involving the Iberian and European plates, shows a thin‐skinned structural style, where the Upper Triassic salt acted as a decoupling level between the sedimentary cover and the underlying basement during both extension and reactivation. The Western section, by contrast, crosses only the Iberian plate (i.e., intra‐plate section) and displays a hybrid situation showing both thin‐ and thick‐skinned structural styles that were conditioned by the irregular distribution of Triassic salt. Extensional deformation was localised in the north (i.e., Bay of Biscay) and less important in the south. Despite compressional reactivation, the northern part of the Western section preserves its rift template, which provides key insights to restore the internal part of the Central section. In contrast to the Western section, the Central section shows stacked depocenters, resulting from overprinted Mesozoic rift events that had a first order control on the subsequent reactivation. This study corroborates the importance of rift inheritance during the onset of convergence by reactivating the most distal and weak part of the rift system (i.e., serpentinised mantle) before starting the collision phase. A key learning is that the understanding of the nature and distribution of decoupling levels at a crustal scale is fundamental to reconstruct the structural evolution during the formation and reactivation of a hyperextended rift system. [ABSTRACT FROM AUTHOR]