Paleogeographic Maps Research Articles

Sedimentology and New Paleogeographic Data of the Lower Eocene Chouabine Formation in the Gafsa Basin (Tunisia), Southern Tethyan Margin

Abstract Facies and paleo-environment reconstruction applied to the lower Eocene Chouabine deposits occurring in the Gafsa area in Tunisia provided important information on sediment cyclicity and paleogeographic conditions. From west to east, four sections were surveyed: Tamerza (25 m), Oued Thelja (48 m), Jebel Ong (25 m), and Jebel Chamsi (45 m). Furthermore, the facies stacking pattern allowed for the reconstruction of depositional environments in relation to sea level changes. The Chouabine Formation is formed by the succession of three sequences composed of marls, phosphorites, and carbonates. There are five main facies organized into two transgressive cycles. The gradual transition of facies from intertidal to circatidal environments unraveled the sedimentation on a homoclinal ramp, episodically swept by upwelling currents. The Chouabine Formation is made of deepening–upwards cycles. Each cycle ranges from 2 to 5 m in thickness. The proximal-distal transition of depositional environments was gradually increasing from intertidal to offshore environments. Lateral variation of thickness and facies is generated by the reactivation of inherited NW-SE extensive and/or transtensive faults, acting since the late Cretaceous during the intermediate closing phase of the Neotethys. Synsedimentary tectonics has created trap structures favouring confinement conditions in the center of the basin, permitting the accumulation and preservation of large thicknesses of phosphate deposits. Based on new litho- and biostratigraphic data, this study presents for the first time a clear and detailed regional stratigraphic correlation and paleogeographic maps.

Seals, whales and the Cenozoic decline of nautiloid cephalopods

AbstractAimNautilusandAllonautilus, last members of the once widespread nautiloid cephalopods, are today restricted to the deep central Indo‐West Pacific Ocean, for reasons that remain unclear. Cephalopod evolution is generally considered as being driven by vertebrate predation; therefore, we investigated the role of whales and seals in the decline of nautiloids through the Cenozoic.LocationGlobal.TaxonNautiloids, pinnipeds, cetaceans.MethodsDistribution data for nautiloids, pinnipeds and cetaceans through the Cenozoic were compiled and plotted on a series of paleogeographic maps. Nautiloid shell sizes were compiled and plotted against the first appearance of pinnipeds and cetaceans in key regions.ResultsFrom the Oligocene onward, nautiloids became extinct in areas where pinnipeds appeared. The exception is the agile nautiloidAturia, extinct globally at the end of the Miocene. A major role of odontocetes in the demise of nautiloids is not apparent, except for a few brevirostrine Oligocene taxa from the North American Atlantic and Pacific coasts, which appeared in these areas at the same time as nautilids disappeared. The Oligocene disappearance of nautiloids (exceptAturia) from the American Pacific coasts coincides with the development of oxygen minimum zones (OMZs) in this region.Main conclusionsWe hypothesize that the Cenozoic spread of pinnipeds drove nautiloids into their present‐day central Indo‐West Pacific refuge. Additional factors for the local extinction of nautiloids in the Oligocene include predation by short‐snouted whales and the development of OMZs, preventing nautiloids from retreating into deeper water.

Digital paleogeographic reconstruction of the eastern Tethyan tectonic domain from the Middle Permian to the Middle Triassic

Paleogeographic reconstruction studies the evolution of the earth's surface tectonic process, the pattern of land and sea, climate, and biology in time and space in geological history. With the advent of the big data era, the accuracy of the digital paleogeographic reconstruction is essential. Although there are various global paleogeographic reconstruction models, there is still a lack of paleogeographic reconstruction integrating tectonic, lithofacies, paleontology, and paleoclimate data. In this paper, a case study of the comprehensive paleogeographic reconstruction is carried out in the Middle Permian-Middle Triassic eastern Tethyan tectonic domain, which is highly concerned and rich in geological data accumulation. The digital paleogeographic map is completed by the combination of automatic mapping with machine learning and manual correction. We use the newly upgraded paleomagnetic, geological and paleontological data to reconstruct the paleoposition of the East Asian blocks at 260, 250 and 240 Ma, which shows the Paleo-Tethys Ocean (PTO) had a wider east-west range than the previous version due to adopting the method of Torsvik et al. (2008) to reconstruct the paleolongitude of South China at 260 Ma. The new model shows the PTO was semi-closed with several narrow seaways and was divided into north and south branches at 260 Ma. Based on the updated lithofacies paleogeographic map data of China and marine fossils data, we updated the paleogeographic map of the Eastern Tethyan tectonic domain on the basis of the global paleogeographic map, combining automatic mapping with machine learning and manual revision of paleotopography and paleocoastline. Based on the new tectonic paleogeographic reconstruction, we revised the paleoclimate zonation pattern of the East Tethys ocean using climate-sensitive lithologies.

Sedimentology and New Paleo-geographic Data of the Upper Cretaceous-Lower Paleocene Haria Formation in the Gafsa Basin (Tunisia) Southern Tethyan Margin

Abstract Facies associations and environmental evolution of the late Cretaceous–lower Paleocene shallow platform of the Haria Formation (upper Maastrichtian–Danian–Selandian) have been studied from the Gafsa basin, located in southern Tunisia. Four main lithostratigraphic units have been identified. Unit 0, deposited on a restricted platform, is organized into aggradational and shallowing-upward sequences. Unit 1 is composed of shallowingand deepening-upward sequences that are deposited in externally restricted platform environments. Unit 2 is a peritidal shallowing-upward sequences deposited in shallow restricted environments ranging from the intertidal to supratidal environments. Unit 3,is composed of shallowing-upward sequences corresponding to the “muddy” type in the lower part, deposited in the proximal part of the shallow restricted external platform, and the “grainy” type in the upper part, representing wave-dominated bioclastic shoals and channel deposits. The proximal-distal transition of depositional environments gradually ranges from lagoon to offshore environments. Lateral variation of thickness and facies is generated by the reactivation of NW-SE extensive and/or transtensive faults, acting since the late Cretaceous during the intermediate closing phase of the Neotethys. These tectonic features were also expressed by changes in facies. The Haria Formation’s mixed carbonate-marls successions are classified into seven major facies associations, with carbonates considered a new facies represented by channel deposits and lumachellic limestones. This study establishes for the first time a clear and detailed regional stratigraphic correlation and paleogeographic maps based on the new litho- and biostratigraphic data.

Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China

Lower Cambrian Xiaoerblak Formation is one of the major exploration targets in Cambrian pre-salt Tarim Basin; however, the exploration breakthrough is restricted by insufficient understanding of its sedimentary evolution and reservoir genesis. In this paper, based on a systematic description of the outcrop in the Xiaoerblak section, northwestern Tarim Basin, some samples were selected for tests of stable carbon and oxygen isotopic compositions, strontium isotopic composition, order degree, trace and rare earth elements, U-Pb isotopic age and clumped isotope. It is found that the Xiaoerblak Formation mainly develops nine types of dolomites, i.e., laminated microbial dolomite, thrombolite dolomite, stromatolite dolomite, foamy microbial dolomite, grain dolomite, etc. According to the lithofacies associations, it can be divided into three members: Xi 1, Xi 2, and Xi 3, of which member Xi 2 is subdivided into three submembers. The characteristics of lithofacies assemblage formed bottom to top indicate that it can be described as a third-order sequence. The Xiaoerblak Formation was deposited in a nearshore shallow seawater environment characterized by high water salinity and temperature under a warm and humid climate during the Early Cambrian, giving rise to the sedimentary sequence of inner ramp lagoon, subtidal microbial mound shoal and tidal flat in the carbonate ramp setting from bottom to top. Its dolomitization occurred in the penecontemporaneous–shallow burial period when the temperature was relatively low and high-salinity seawater acted as the main dolomitizaiton fluid. The reservoir space mainly comprises primary microbial framework pores and vugs formed by the atmospheric freshwater dissolution. Reservoirs were controlled by lithofacies, high-frequency sequence boundary and early dolomitization. The research results are of great significance for presalt Cambrian lithofacies paleogeographic mapping and reservoir prediction.

Application of Geoportal’s Web-Technologies in GIS, Case Study: Interactive Geology Atlas

Abstract: A unique geoinformation service “The Interactive Geology Atlas” has been created and launched based on the data obtained by the Authors during years of research and evaluation of integrated biostratigraphic, paleomagnetic and sedimentological data as well as published references materials. The Interactive Atlas includes geological sections comprehensively studied, described and mapped. Contrary to analogous services, the Atlas covers more territory of Paratethys and time laps and allows to add various content depending on the user requirements. All maps (basemaps) are available for study both individually and joint for comprehensive analysis through the compiling the unified legend to all layers and maps. The combination of different data allows to track how the paleogeographic conditions of the Paratethys territory have evolved and to highlight the main events associated with fluctuations in climate, salinity, etc. Besides being scientifically interesting, the Atlas can become useful in geologic exploration with a view to evaluate the potential areas of mineral resources. For instance, paleogeographic maps are crucial in this regard. FAIR principles have become the reference criteria for improving datasets: Findability, Accessibility, Interoperability, and Reusability.

Stratigraphy, Paleogeography and Depositional Setting of the K–Mg Salts in the Zechstein Group of Netherlands—Implications for the Development of Salt Caverns

The 1 km thick evaporitic Permian Zechstein group in the Netherlands is subdivided into 5 halite rich evaporitic sequences including K–Mg salts (polyhalite, kieserite, sylvite, carnallite and bischofite) for which the position in the Zechstein stratigraphy is still poorly constrained. Understanding the repartition of K–Mg salts is especially important for the development of salt caverns which require a salt as pure as possible in halite. By compiling well log and seismic data in the offshore and onshore domains of the Netherlands, regional cross-sections and isopach maps were performed in order to update the lithostratigraphy of the Zechstein group by including the K–Mg salts. Results enable (i) to propose paleogeographic maps representing the spatial repartition and the thickness variations of one to two K–Mg rich intervals in each evaporite cycle, (ii) to constrain the depositional setting of the different type of salts and the hydrological conditions which influenced the Zechstein stratigraphic architecture and (iii) to develop over the Netherlands risking maps assessing the risk of encountering K–Mg salts in salt pillows or salt diapirs eligible in term of depth and thickness for the development of salt caverns.

Characteristics of Cambrian tectonic-lithofacies paleogeography in China and the controls on hydrocarbons

In early Cambrian, the earth was in a state of active super-continental disintegration, ocean basin expansion, and seawater transgression. It was a critical period for hydrocarbons source rocks development on a global scale. In China for example, hydrocarbons reservoirs, including conventional and unconventional, have been discovered in the Cambrian rocks. By using regional tectonic analysis, stratigraphic correlation, and lithofacies comparison, we compiled a tectonic-lithofacies paleogeographic map and determined the lithofacies paleogeographic characteristics of the main plates of the early Cambrian period in China. Our results show that although the North China Plate was deposited in shallow-water shore facies, it was later uplifted and exposed to long-term denudation; and thus, lacked the depositional conditions necessary to form hydrocarbon source rocks. In contrast, both the South China and the Tarim Plates contain the complete platform-slope-basin facies sequence, which is the required depositional conditions to promote the formation of hydrocarbon source rocks. Furthermore, our results demonstrate that, during the period of Meishucun and Qiongzhusi formations, South China Plate was composed of deep-water sediments. Correspondingly, during the sedimentation of the Yuertusi Formation, several areas such as the Kalpin, Tabei, and Taxinan in the Tarim Basin, formed a gentle-sloping continental shelf sedimentary sequence of phosphorous siliceous rocks, muddy shales, marlstones, and doloarenite. In addition, we demonstrate that (1) abundant nutrients provided by the hydrothermal and coastal upwelling events, combined with the “periodic anoxic” bottom water conditions, resulted in the formation of high-quality hydrocarbon source rocks in the Yuertus Formation in the Tarim Basin; and (2) the intracratonic sag and continental shelf edge slope settings controlled the deposition of hydrocarbon source rocks in the Sichuan Basin.

Seismic geomorphological analysis of the oligocene-neogene sediments in the north-eastern part of the Black Sea

The evolution of the deep-sea sedimentation system in the north-eastern part of the Black Sea during the Oligocene-Pliocene is considered mainly on the basis of seismic data. The fans and erosion canyons formation time is presumably related to the regressive-transgressive stages in the history of the Eastern Paratethys. The source areas of detrital sediments in the Tuapse Trough are identified. The sedimentation model of the Tuapse Trough and the changes in the Trough’s morphology since the Oligocene were reconstructed based on the analysis of the thickness maps and the onlap surfaces on the northern side of the Shatsky Swell. Paleogeographic maps were compiled for the Late Oligocene-Early Miocene (Maikop), Middle Miocene, and Pliocene.

Quantifying the relative contributions of Miocene rivers to the deep Gulf of Mexico using detrital zircon geochronology: Implications for the evolution of Gulf Basin circulation and regional drainage

AbstractSediment routing from hinterland to the deep sea is complicated because it involves evolution of river drainage from source areas to coastal plains and sediment mixing on the shelf and slope by marine currents. Previous regional paleogeographic mapping in the Gulf of Mexico (GOM) has observed a >150 km offset between the middle Miocene paleo‐Tennessee fluvial axis and the associated deep‐sea fan depositional axis, indicating a complicated sediment pathway. We integrate new and published detrital zircon (DZ) U‐Pb age data from fluvial, shelf and deep‐sea deposits to examine the complex Miocene sediment routing system in the northern GOM. These data suggest an increase in sediment load derived from western North America (increased Western Cordillera terranes; <300 Ma zircon age component) from the early to middle Miocene in the deep‐water Green Canyon protraction area. The early Miocene Green Canyon area received sediments mainly from fluvial axes located directly updip: the paleo‐Mississippi River (44%–56%; characterized by Yavapai‐Mazatzal, Mid‐Continent and Western Cordillera sourced 1800–1600 Ma, 1500–1300 Ma and <300 Ma, respectively, and Grenville‐Appalachian sourced 1300–950 Ma and 500–300 Ma age components) and smaller rivers and tributaries draining the Appalachian Mountains (e.g. paleo‐Tennessee River, 18%–43%; mainly Grenville‐Appalachian sourced 1300–9500 Ma and 500–300 Ma age components). In contrast, the middle Miocene Green Canyon deep‐sea fan shows a strong DZ signal from the paleo‐Red River (38%; increased <300 Ma zircon age component), which requires input of additional sediment sources from west of the paleo‐Mississippi system. In addition, the paleo‐Tennessee River, which was a major middle‐Miocene sediment source for the central‐eastern GOM due to uplift and increased erosion of the Appalachian Mountains, is underrepresented (34%; decreased 1300–950 Ma zircon age component) in the middle Miocene Green Canyon fan. We suggest that two mechanisms combined to produce the increased middle Miocene input from western sediment sources and restriction of locally up‐dip Tennessee River sources: (1) regional drainage changes involving middle Miocene capture of the paleo‐Red River and its tributaries by the paleo‐Mississippi River, which at the same time lost some of its eastern tributaries owing to expansion of the paleo‐Tennessee and (2) eastward (clockwise) marine transport of western‐sourced sediment along the shelf or slope, which deflected the paleo‐Tennessee signal >150 km eastward to feed the deep‐sea fan further east, perhaps reflecting intensification of a precursor to the GOM Loop Current.

Cretaceous Rift‐Drift Tectonics Then Paleogene Prearc Subsidence Related to Subduction Initiation: Aotea Basin, Zealandia, Southwest Pacific

AbstractStratal stacking patterns and termination relationships of Upper Cretaceous and Paleogene strata of Aotea Basin, which is at the southern end of New Caledonia Trough and adjacent to Taranaki Basin, are used to infer vertical movements before, during, and after Tonga‐Kermadec subduction initiation. Regional 2D seismic‐stratigraphic units are tied to petroleum exploration wells, including recently drilled Romney‐1. We identify: (a) an uppermost Cretaceous to Paleocene (70–56 Ma) aggradational shelf sequence, with at least two regressional events linked to eustatic sea‐level falls; (b) a diachronous deepening of the basin from shelfal to bathyal environments, that progressed northwest to southeast during the early to middle Eocene (53–46 Ma); (c) that was contemporaneous with small‐scale volcanism; (d) a brief phase of middle to late Eocene (46–35 Ma) delta development at the western basin margin (Challenger Plateau) that is evidence for local uplift; and (e) an onlapping sequence deposited since the latest Eocene (35–0 Ma) that requires ∼1,300 m of subsidence at the western margin. Paleogeographic maps and a generalized stratigraphic chart summarize our observations. The Eocene phase of tectonic subsidence, uplift, and diffuse volcanism (53–46 Ma) was a precursor to plate motion at the Cenozoic plate boundary through New Zealand and suggests a causal relationship between prearc subsidence, Tonga‐Kermadec subduction initiation, and plate motion change. Delamination of lower crust beneath Aotea Basin during initial subducted slab formation might explain our observations.

Lithofacies paleogeography and characteristics of large-scale reservoirs of the Middle Triassic Leikoupo Formation in Sichuan Basin, China

Material exploration discoveries have been achieved in the Middle Triassic Leikoupo Formation in the Sichuan Basin in recent years, and a large-scale reservoir is one of the key factors controlling reservoir formation. In this paper, the lithofacies paleogeographic map of the Leikoupo Formation is prepared based on field outcrops, exploratory wells, well logs, and seismic data. The characteristics of large-scale reservoirs have been analyzed, which resulted in three new summarized understandings: (1) At the Leikoupo stage, the Sichuan Basin was relatively closed in the south, east and north, and the seawater entered through the west side, so it was a relatively closed carbonate platform; during the sedimentary stage of Lei I and Lei II members, it was a weakly fringed carbonate platform. In the sedimentary period of Lei III (T2l3) and Lei IV (T2l4) members, it was a rimmed carbonate platform. (2) The sedimentary facies including the platform margin, open platform, restricted platform, and evaporative platform were developed in the Leikoupo Formation; these were mainly the restricted platform facies covering the subfacies of the lagoon, intra-platform shoal, and tidal flat. Two types of hydrocarbon reservoirs, namely the platform-margin shoal and intra-platform shoal reservoirs, were developed in this period. (3) Two sets of large-scale reef beach facies reservoirs were developed in the Leikoupo Formation, one is the platform margin reef beach facies of Lei III (T2l3) and Lei IV (T2l4) members in northwestern Sichuan with a large thickness (generally larger than 50 m); the other one is the intra-platform shoal facies in the lower part of Lei I Member (T2l1) in Central Sichuan with a small thickness, stable distribution, and a large area (larger than 20,000 km2) forming large-scale reservoirs. The two types of large-scale reservoirs experienced multi-stage karstification transformation to become reservoirs with a good quality, laying the material basis for large-scale oil & gas reservoir formation. The research results have important theoretical and practical significance to improve the understanding on the sedimentation and reservoirs of the Leikoupo Formation in the Sichuan Basin, and to provide guidance for the oil and gas exploration in this region.

Paleogeography of the West Siberian Sedimentary Basin in the Late Bajocian–Bathonian

Abstract —The paper presents results of regional paleogeographic reconstructions of the West Siberian sedimentary basin in the Late Bajocian–Bathonian. Regional paleogeographic maps of the Yu4, Yu3 and upper part of the Yu2 reservoir units were constructed and described for the first time ever. The implemented approach provided insights into the evolution of paleolandscapes and highlighted the deposition features of the Upper Tyumen Subformation and Malyshev Formation in the different parts of the West Siberian basin. The compilation of paleogeographic maps was based on the electrofacies analysis performed for individual parts of the Malyshev stratigraphic horizon, with regard to the core description materials, paleontological, sedimentological, geochemical data and other. The paleogeographic control of the reservoir’s formation in the Bathonian regional reservoir is discussed.

Biostratigraphy and depositional architecture of the Kazhdumi formation (Aptian-Albian) in the Izeh zone, Zagros mountains, SW Iran

In the easternmost part of the Izeh Zone of the Zagros Mountains, the Kazhdumi Formation of upper Aptian-middle Albian interval is superbly exposed in three-main exposures as argillaceous carbonate facies. The main bioclastic components of the Kazhdumi Formation are Orbitolinid and other larger benthic foraminifers, planktonic foraminifera and calcareous algae. The depositional system in the study area during the upper Aptian-middle Albian corresponds to a shaly carbonate ramp. Two depositional sequences are determined, as prograding system from west to east. Comparison of the proposed depositional sequences with those reported in the Arabian Plate and adjacent areas suggests a correlation with the global sea-level curve. The Lower Cretaceous, Aptian carbonates of Kazhdumi Formation contain nine microfacies, which were deposited on a ramp system deepened in both directions (west and east). Stratigraphic sequence led to recognize two third-order sequences. On the other hand, rudstone and boundstone lithofacies of the studied formation have higher reservoir potential and were deposited during Apt 3 and Apt 5 sequences of the Arabian Plate. The Kazhdumi Formation in the study area was deposited in an intrashelf basin that should be classified as an independent basin in the future paleogeographic maps of the southwest Iran. We interpret the Kazerun Fault, as a crustal warping of basement faults of the Arabian Plate boundary, which were responsible for the creation of the intrashelf basin in the study area.

On the discovery of Gilboaphyton (Lycopsida) from the Upper Devonian of East Junggar, Xinjiang, and its global distribution

Protolepidodendralean lycopsid Gilboaphyton is firstly described from the Upper Devonian Kaxiweng Formation of Fuyun, East Junngar, Xinjiang, northwest China as a new species. G. fuyunensis sp. nov. is characterized by flat-hexagonal to fusiform leaf base and hastate leaf with two lateral upturned segments. In Gilboaphyton species, two types of leaf base with longitudinal- and flat-hexagonal shapes, are recognized. Spores are obtained from plant fossil-bearing rocks and help determining the Late Devonian age of the present plant. The spatio-temporal distribution of Gilboaphyton and Archaeosigillaria are reconstructed onto Devonian and Carboniferous paleogeographic maps using global occurrence data of the two genera. Gilboaphyton and Archaeosigillaria were probably originated from southeastern Laurentia in the Early-Middle Devonian and had similar dispersal patterns. It is suggested that the two genera might belong to one plant based on their global occurrence records.

Late Paleozoic (Late Mississippian–Middle Permian) sediment provenance and dispersal in western equatorial Pangea

Late Mississippian to middle Permian sediment-dispersal networks of regional to continental scale in western equatorial Pangea, depicted here in a series of paleogeographic maps, developed in response to temporally and spatially changing influences of climate, eustasy, and a continent-wide late Paleozoic orogenic system. The orogenic system included linked Alleghanian, Ouachita-Marathon-Sonora collisional belts and associated foreland basin systems on Laurentia and magmatic arcs on Gondwana, intracratonic basement uplifts and basins of the Ancestral Rocky Mountains, flexural arches and intracratonic basins of the US midcontinent region, and basins and uplifts of the southwestern Laurentian transcurrent continental margin. Consideration of new and published U-Pb detrital-zircon datasets permits delineation of Laurentian sediment-dispersal networks of the developing supercontinent. The Transcontinental Arch deflected Late Mississippian transcontinental rivers with Alleghanian headwaters toward the southern midcontinent and nascent, deep-marine foreland basins along the Ouachita collision orogen. Pennsylvanian rivers likewise headed in the Alleghanian Orogen, transporting sediment southwest across the midcontinent and along the Alleghanian foreland basin to empty into the Arkoma Basin and Fort Worth Basin, which also received voluminous sediment from Gondwana and the Ouachita Orogen. Concomitantly, major growth of Ancestral Rocky Mountains uplifts yielded basement-derived sediment, much of which was retained in local flexural basins. Increased aridity drove ascendant eolian transport in early Permian (Artinskian) time, just as lowstand desiccation of a midcontinent seaway exposed unconsolidated silt and sand derived from eastern, western, and southern sources in an extensive interior desert sink. Eolian transport within the interior desert further mixed and deflated the already-cosmopolitan sediment, pushing it southwest toward the Permian Basin and westward beyond the Ancestral Rocky Mountains. Intercepted by newly developed monsoonal circulation, the deflated sediment came to reside in erg systems along the western marine margin of Pangea. Subtropical Pennsylvanian transcontinental fluvial networks were similar to those of modern big river systems of the eastern and midcontinent United States that drain toward the Gulf of Mexico. In contrast, Permian drainage networks yielding sediment to a continental desert more resembled Pleistocene sediment routes of the Arabian Plate; there, intermittent wadis draining western rift highlands and big rivers of the Mesopotamian foreland contribute sediment to Arabian eolian sands via zonal and monsoonal surface winds to create widespread sand seas of mixed Eurasian and Arabian provenance.

An Atlas of Phanerozoic Paleogeographic Maps: The Seas Come In and the Seas Go Out

Paleogeography is the study of the changing surface of Earth through time. Driven by plate tectonics, the configuration of the continents and ocean basins has been in constant flux. Plate tectonics pushes the land surface upward or pulls it apart, causing its collapse. All the while, the unrelenting forces of climate and weather slowly reduce mountains to sand and mud and redistribute these sediments to the sea. This article reviews the changing paleogeography of the past 750 million years. It describes the broad patterns of Phanerozoic paleogeography as well as many of the specific paleogeographic events that have shaped the modern continents and ocean basins. The focus is on the changing latitudinal distribution of the continents, fluctuations in sea level, the opening and closing of oceanic seaways, mountain building, and how these paleogeographic changes have affected global climate, ocean circulation, and the evolution of life. This review presents an atlas of 114 paleogeographic maps that illustrate how Earth's surface has evolved during the past 750 million years. During that time interval, Earth has witnessed the formation and breakup of two supercontinents: Pannotia and Pangea. The continents have been transformed from low-lying flooded platforms to high-standing land areas crisscrossed by the scars of past continental collisions. Oceans have opened and closed, and then opened again in a seemingly never-ending cycle. ▪ The changing configuration of the continents and ocean basins during the past 750 million years is illustrated in 114 paleogeographic maps. ▪ These maps describe how the surface of Earth has been continually modified by mountain building and erosion. ▪ The changing paleogeography has affected global climate, ocean circulation, and the evolution of life. ▪ The data and methods used to produce the maps are described in detail.

Prospectivity of the Triassic successions of the North West Shelf of Australia: New insights from a regional integrated geoscience study

The North West Shelf (NWS) of Australia is a prolific hydrocarbon province hosting significant volumes of hydrocarbons, primarily derived from Jurassic and Cretaceous targets. A new regional, integrated geoscience study has been undertaken to develop insights into the paleogeography and petroleum systems of Late Permian to Triassic successions, which have been underexplored historically in favor of Jurassic to Cretaceous targets. Within the NWS study area, graben and half-graben depocenters developed in response to intracratonic rifting that preceded later fragmentation and northward rifting of small continental blocks. This, coupled with contemporaneous cycles of rising sea levels, brought about the development of large embayments and shallow, epeiric seas between the Australian continental landmass and outlying continental fragments in the early stages of divergence. Key elements of the study results discussed herein include the study methodology, the paleogeographic and gross depositional environment mapping, and the reservoir and source kitchen modeling. The study results highlight the presence of depocenters that developed within oblique rift zones due to regional Permo-Triassic strike-slip tectonics that bear compelling similarities to modern-day analogues. These intracratonic rift zones are well-known and prominent tectonic features resulting from mantle upwelling and weakening of overlying lithospheric crust, initiating the development of divergent intraplate depocenters. The comprehensive analysis of these depocenters from a paleogeographic and petroleum system perspective provides a basin evaluation tool for Triassic prospectivity.

Paleotectonic and paleogeographic history of the Arctic region

Paleogeographic maps represent the ultimate synthesis of complex and extensive geologic data and express pictorially the hypothetical landscape of some region during a given time-slice of deep geologic time. Such maps, presented as paired paleogeographic and paleotectonic reconstructions, have been developed to portray the geologic history of the greater Arctic region over the past 400 million years. Collectively they depict four major episodes in the development of the Arctic region. The first episode witnessed early and middle Paleozoic terrane assembly and accretion during the Caledonian and Ellesmerian orogenies, which brought together many pieces of the Arctic collage along the northern margin of Laurussia. During the second phase, the assembly of Pangea in the late Paleozoic joined Siberia to Laurussia, an entity that became Laurasia during the subsequent break-up of Pangea. Then, Mesozoic subduction and terrane accretion constructed the Cordilleran margin and opened the Canada Basin. Finally, Cenozoic North Atlantic sea-floor spreading fully opened the Arctic Ocean.

Review of the syn-rift to early post-rift depositional systems of the Cretaceous Mauléon rift: sedimentary record of continental crust hyperextension and mantle denudation (Western Pyrenees)

The Mauléon Basin, in the northwestern Pyrenean Belt, is related to Early Cretaceous rifting and mantle denudation. Here we review the evolution of depositional systems in the Mauléon Rift Basin during Albian and Cenomanian time. This review includes the lithostratigraphy, regional distribution, boundaries, age and facies sedimentology of the basin’s syn-rift formations and their members. We construct paleogeographic maps to elucidate (1) the 3D distribution of sedimentary facies and depositional systems during the Albian and Cenomanian from the Iberian proximal margin to the hyperextended domain and (2) the link between major extensional structures and sedimentation during rifting and mantle denudation. The Mauléon Rift was supplied during most of the Albian by sediments from the Iberian proximal margin. The southern margin had a steep and abrupt topographic boundary related to a northward crustal rollover along the south-dipping Saint-Palais detachment. This feature controlled the deposition of coarse-grained turbidites at the base of the margin that abruptly gave way to low-density turbidites, then deep-basin deposits in the hyperextended domain. During uppermost Albian to Early Cenomanian time, mantle denudation occurred in the eastern Mauléon Basin and the vergence of the detachment systems reversed. Minor debris-flow deposits formed at the foot of fault scarps associated with the newly formed north-dipping detachments. Elsewhere, sediment from deltaic systems to the west in the Saint-Jean-de-Luz area deposited low-density turbidites in the hyperextended domain. During the post-rift stage, the flux of coarse sediment from the detachment footwall gradually declined as deformation waned, and low-density turbidites expanded onto the hyperextended domain from the European Upper Cretaceous carbonate platform. These paleogeographic reconstructions, in addition to offering a synthetic view of the evolution of sedimentary environments during rifting, offer new insight into the post-rifting exhumation of the lower crust and mantle.