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The paper by Schito et al. (2017) contains many misquotations of the regional literature on the Holy Cross Mountains, that may confuse the reader. Present comment suggests more appropriate references related to the stratigraphic, tectonic and palaeothermal aspects of the commented paper. The burial-thermal history as interpreted by Schito et al. is based on doubtful, poorly documented or even unsubstantiated thermal maturity and stratigraphical data, ignoring important regional evidence, such as Caledonian (sub-Devonian) unconformity and Permian thermal anomaly. The 1-D modeling study performed by Schito et al. (2017) did not consider published alternative concepts of the temporal and spatial heat flow patterns. The resulting models, assuming uniformly low heat flow between the Ordovician and the earliest Cretaceous, are inconsistent with independent regional data pointing to a hotter Variscan (Carboniferous-Permian) thermal regime.

The Tarim Craton of NW China hosts abundant hydrocarbon resources within clastic reservoirs characterized by a complex entrapment and fill history. In this paper, we review the processes of hydrocarbon accumulation in typical clastic reservoirs from the literature, and combine this with new research from six hydrocarbon-bearing regions (the Yakela Faulted-Uplift, the southern slope of the Tabei Uplift, the Tazhong Uplift, the northern slope of the Tazhong Uplift, the southern margin of the Bachu Uplift, and volcanic reservoirs) to identify the key controls on hydrocarbon accumulation and distribution in reservoirs of the Tarim Craton. Favorable reservoir–trap configurations exist on structural highs created during the evolution of paleo-uplifts and paleo-slopes in the region, with hydrocarbons accumulating in both structural (fault, salt dome, and thrust-fault anticline) and combined structural-primary stratigraphic traps. Vertical hydrocarbon migration occurred via deep–shallow superposed faults, and (rarely interpreted) fault textures in volcanic conduits. Unconformity surfaces and sand bodies provided pathways for both limited lateral redistribution and significant long-distance (>100 km) migration of hydrocarbons. The prospectivity of upper Paleozoic sandstone facies and paleogeography was controlled by denudation of the paleo-uplifts, and these reservoirs are most likely to host giant oil and gas fields in the region.

The Central Uplift region of the Tarim Basin contains a series of thick Ordovician carbonates that form fractured-vuggy hydrocarbon-rich reservoirs along an unconformity. These fractured-vuggy reservoirs are difficult to characterize using traditional well logging and seismic interpretation methods because these carbonates feature complex and heterogeneous lithologies and variations in scale, geometry and spatial distribution. In this paper, a series of deeply buried fractured-vuggy carbonate reservoirs are characterized on micro-, macro- and mega-scales. These characterizations are based on previous studies detailing the carbonate sedimentation, diagenesis, and tectonic processes in the study area and abundant geological and geophysical data, including core samples, thin sections, and well logging and seismic datasets, which have been obtained and upscaled using the “choosing-classification-evaluation- generalizing-upscaling” (CCEGU) method. In this area, different facies can be identified at different scales: (1) Detailed core and thin section observations performed based on the Dunham classification demonstrate that 7 lithofacies and 19 rock types are present at the micro-scale (0.01 m); (2) logging data and assorted reservoir characteristics indicate that these 19 different rock types consist of 9 different electro facies at the macro-scale (0.1 m–1 m), and the presence of electro facies in individual wells can be recognized; and (3) these 9 different electro facies comprise 6 distinct seismic facies at the mega-scale (10 m), and can be used to delineate the spatial outlines of potential reservoirs and evaluate their properties. The targets of particular interest in the study area are a series of partially dissolved dolomites located near large faults and a series of vuggy soluble limestones located near NE-trending strike-slip faults. This study combines geological and geophysical response data from fractured-vuggy carbonate reservoirs to achieve seamless connections among micro-scale, macro-scale and mega-scale observations to effectively characterize a series of strongly heterogeneous fractured-vuggy reservoirs. This method can also be applied to characterize other deeply buried paleokarst reservoirs in the Tarim Basin, as well as other strongly heterogeneous reservoirs.

This paper presents brief sedimentological inventory of the Misaki and the overlying Hasse Formation (constituting the Miura Group) based on observations made at Jogashima Island, Miura Peninsula and infers the nature of the stratigraphic transition from tectonic viewpoint. The lower part of the Misaki Formation is made of very coarse to coarse-grained scoriaceous, normally graded sandstones, fine-grained sandstones/siltstones, and mudstones and indicates a deep sea submarine canyon depositional setting. There is no evidence of storm reworking (shallow marine processes) in the lower parts of the Misaki Formation at least in the Jogashima Island as suggested by Stow et al. (1998). However, the upper part of the Misaki succession formed in a shallow marine depositional setting. The overlying Hasse Formation characterized by brownish coloured, very coarse to coarse-grained large-scale trough cross stratified, very poorly sorted sandstones, very poorly sorted polymictic and matrix dominated mass flow conglomerates with siltstone/fine-grained sandstone clasts derived from the underlying Misaki Formation and occasional reverse grading. In significant contrast to the underlying Misaki Formation the Hasse Formation lacks very fine-grained sandstone/siltstone/mudstone facies. Unlike the tholeiitic basalt composition of the lapilli and pebbles of the Misaki sandstone beds, the scoriaceous lapilli and pumiceous beds of the Hasse Formation are of calc-alkaline composition. The Hasse sedimentation probably took place in much shallower paleogeography compared to the underlying Misaki Formation, most probably in an alluvial fan-braided fluvial setting. The Misaki-Hasse stratigraphic contact is very sharp and erosional, and represents a subaerial unconformity (i.e., depositional sequence boundary). Our sedimentological data from the Jogashima Island clearly indicate progressive shallowing of the depositional setting during the terminal phase of the Misaki sedimentation and much abrupt shallowing across the Misaki-Hasse transition possibly as a consequence of ongoing collision between the Izu-Bonin and Honshu arcs.

The Volgian–Ryazanian shale interval in the Norwegian Central Graben, North Sea, is assigned to the Mandal Formation. Despite shales with similar lithological and log characteristics are being present in the Danish Central Graben, the formation is not defined for this part of the Central Graben. This paper presents a new lithostratigraphic subdivision of the Upper Volgian–Upper Ryazanian interval in the Danish Central Graben, where the Mandal Formation is defined and replaces the uppermost part of the Farsund Formation in the ‘old’ lithostratigraphy. The Mandal Formation is recognized from its log character and is correlatable across the Danish Central Graben. The formation typically has high gamma-ray (GR) and resistivity readings accompanied by low velocity and density values. In basin centres it normally consists of a lower part showing an upward increase in GR readings (‘warming-up’ interval), an overlying interval with conspicuous high GR readings (Bo Member), and an upper heterogeneous shale interval. The base of the Mandal Formation can be seismically mapped in most of the Danish Central Graben. The upper boundary of the formation, corresponding to the Base Cretaceous Unconformity (BCU) at the transition to the Lower Cretaceous, can likewise be seismically mapped throughout the basin. The Mandal Formation is developed with thick successions in basin depocentres, while it is thin or absent along inversion structures and on structural highs. The organic-rich shales of the Mandal Formation were deposited in a restricted, low-energy, oxygen-deficient/anoxic marine environment distal from any significant terrestrial influence. Along the eastern Coffee Soil Fault in the Danish Central Graben, siliciclastic deposits constituting the gravity-flow sandstones of the Poul Member interfinger with the Mandal Formation. Gravity-flow deposits formed by turbidite currents are also common throughout the Mandal Formation in basin centres. The Mandal Formation and particularly the Bo Member are highly oil-prone and contain the best source rock quality of the entire Upper Jurassic – lowermost Cretaceous shale succession in the Danish Central Graben. Interbedded potential reservoir sandstones suggest the Mandal Formation may in places be considered as an interval with hydrocarbon prospectivity, especially along the Coffee Soil Fault.

The present paper highlights the sequence development within the Mesoproterozoic Koldaha Shale Member of the Kheinjua Formation, Vindhyan Supergroup which records the occurrence of a forced regressive wedge and associated discontinuity surfaces at the base of the wedge. Nine lithofacies have been identified within the study area that are grouped into three lithofacies associations varying in depositional setting from outer shelf, through shoreface-foreshore-beach to continental braidplain. The outer shelf sediments are aggradational to slightly progradational representing highstand systems tract. The rapidly progradational, wedge-shaped shoreface to foreshore-beach succession occurs sharply or erosively above the outer shelf sediments and is bounded by a regressive surface of marine erosion (RSME) at the base and by a subaerial unconformity at the top. This, along with its downstepping trajectory, supports deposition of this sedimentary wedge during falling sea level. A laterally extensive soft sediment deformation zone occurs at the base of the wedge. The forced regressive wedge is incised by fluvial braidplain deposits that rest on an erosive surface representing a sequence boundary. The thin braidplain deposits are the product of aggradation during a subsequent early rise in relative sea level, and thus, they are inferred to represent a lowstand systems tract. The constituent architectural elements that characterize the braidplain deposits are downstream accretion elements and small channel elements. Further landward, the base and top of the shoreface wedge merge to form an unconformity across deposits that rest directly on the outer shelf sediments. The identification of forced regressive wedges has significant economic importance in view of the potential occurrence of hydrocarbons within the Proterozoic formations.

In order to capture the general tectono-stratigraphic framework of a magma-poor conjugate rifted margin, two examples have been analysed and compared, the seismically imaged and drilled Iberia–Newfoundland rifted margins ( e.g. seismic sections SCREECH1-ISE1) and the fossil distal Tethys rifted margins exposed in the Alps. The Lower Austroalpine and the Ligurian Brianconnais units exposed in SE Switzerland and NW Italy respectively, are here considered and described for the first time as conjugate margins. They form, like the Iberia–Newfoundland rifted margins, conjugate upper and lower plate margin. Both pairs of margins show a similar first-order morpho-tectonic arrangement. Using the Top of Pre-Rift Succession (TPRS) and the Base of Post-Rift Successions (BPRS) as stratigraphic marker levels and two Syn-Tectonic Sequences (STS 1&2 ) three major rift domains can be identified, which experienced different evolutions and preserved different stratigraphic architectures: i) The proximal margin, soled by normal, 30 ± 5 km thick continental crust. It is characterized by widespread fault-bounded graben/half graben basins filled by the STS 1 showing growth structures followed by a succession (time-equivalent unit to STS 2 ) that does not show any evidence for syn depositional tectonic activity. ii) The upper plate distal margin, floored by thinned to ultra-thinned continental crust. It can be subdivided into a distal “high” and a distal “low” separated by a major fault system. The “high” is characterized by the occurrence of a marked syn-rift unconformity leading to the erosion and/or non deposition of the whole syn-tectonic sequence (STS 1 + STS 2 ); the “low” displays complete stratigraphic successions in which the STS 2 becomes very characteristic and exclusive of this part of the margin. iii) The lower plate distal margin, floored by hyper-extended crust, exhumed crust and subcontinental mantle. The pre-tectonic sequence and the STS 1 are only present inside extensional allochthons that are excised from the upper plate and passively transported on top of major exhumation faults. The STS 2 , deposited during the formation of the most distal domain, is mostly formed by clasts derived from the dismantling of the extensional allochthons and of the surrounding exhumed basement. It is overlain by deep marine turbidites and hemi-pelagic sediments. The nature of basement (serpentinized mantle and hydrated upper or lower continental crust) will selectively condition the composition of the STS 2 in the distal lower plate margin. The recognition of a complex rift stratigraphy in the two conjugate pairs of margins shows that simple stratigraphic models are unable to describe the complete evolution of rifted margins from their initial stage, preserved in the proximal margins to the final evolution leading to upper and lower plate margins in the conjugate distal margins. This paper describes for the first time the stratigraphic relationships at distal conjugate rifted margins, which is a key to understand the rift evolution and architecture of these yet little investigated systems.

Interpretations of subsurface data and computer simulations of basin-fill history in the late Neogene Pannonian Basin of eastern Hungary established a regional stratigraphic model presented in this paper. Three fluvial systems overfilled the basin: a large system from the NE, another from the NW and a third smaller system transported sediments from the territory of Romania, from the SE. Large part of the basin had been filled by Messinian time (late Miocene); the remaining lake was located in southeastern Hungary and neighboring countries. In the Tortonian stage, the three fluvial systems advanced concomitantly (with small-scale, high-frequency cycles), toward the basin center. A significant relative lake-level drop occurred in the Messinian, which induced large-scale erosion and fluvial incision and generated an unconformity surface that provides a major division in the Pannonian strata; it appears as a significant stratigraphic divide that separates two different stages in the history of the Pannonian Basin. In the upper Messinian-Pliocene stage, the basin underwent a tectonic inversion; the shallow lake was filled up rapidly by lowstand turbidites and prograding delta-slope sediments. The inversion continues up to the present day. Turbidites and lowstand prograding wedges associated with the Messinian event may be targets for hydrocarbon exploration. Four main stages can be identified in the Upper Miocene–Pliocene basin fill history: (1) Tortonian highstand regression with several low-rank relative lake-level cycles; (2) Messinian lake-level drop, accompanied by the formation of the “Messinian unconformity” and the deposition of a falling-stage systems tract (FST). The “Messinian unconformity” is a composite surface, represented by a subaerial unconformity at the margins, and a basal surface of forced regression in the depocenters; (3) relative rise of lake level, when the FST turned to a lowstand systems tract (LST); (4) tectonic inversion (basinward tilt and marginal uplift) during or at the beginning of the LST.

This paper presents a detailed seismic analysis of a hitherto undescribed Permian succession interpreted to consist of interbedded anhydrite and carbonate from the northern flank of the Loppa High, western Barents Sea. The Fafner succession forms a locally restricted transgressive unit down-dip on the rotated Loppa High. It is subdivided into four seismic sequences each interpreted to be composed of a basal transgressive anhydrite overlain by highstand carbonates. Fafner seismic sequences 2 and 3 include well-developed buildup complexes which in map view form polygonal patterns. Analysis of attribute maps indicates that the Fafner succession is overprinted by two dissolution systems related to two prominent events of subaerial exposure, creating numerous paleo-sinkholes, breccia-pipes, and collapsed composite cavern systems. The stratigraphical position of the Fafner succession, below the Mid Sakmarian – Artinskian Bjarmeland Group and above the Top Orn unconformity, resembles that of the Lower Permian Gipshuken Formation on Spitsbergen, and the Fafner succession is thus regarded as its offshore equivalent.

The New Siberian Islands divide the Laptev Sea from the East Siberian Sea. The Archipelago comprises three island groups: De Long Islands, Anjou Islands, and Lyakhov Islands. The regional structural ensemble comprises De Long, Kotel'nyi, Faddeya and Lyakhov tectonic Domains. Aptian–Albian, Late Cretaceous, Palaeocene–Eocene, Oligocene–Miocene, and Pliocene–Eopleistocene tectono-stratigraphic and igneous sequences have been identified on the Islands. The succession of these sequences and their structural and compositional characters provide to distinguish specific stages in the tectonic history of the region showing alteration of regional tectonic environment through the middle Cretaceous and the Tertiary correlative to major North-East Eurasia, Arctic, and Global events. LS1, LS2, and LS3 major regional unconformities have been identified offshore by German geoscientists based on MCS data in the New Siberian Islands area. It is hypothesized in this paper that three offshore sedimentary cover units bounded by the unconformities correlate to the onshore sequences the following way: Unit I comprises Aptian–Albian and late Cretaceous Sequences, Unit II, Palaeocene–Eocene and Oligocene–Miocene Sequences, and Unit III comprises Pliocene–Eopleistocene Sequence and overlying Quaternary sediments.