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Die Entstehung der Kontinente un Ozean
... He considered that Greenland had been fixed in position and that the surrounding lands had moved away from it. Alfred Wegener expanded Taylor's ideas in his theory of continental drift and publicised the theory widely ( Fig. 2b) (Wegener 1915(Wegener , 1922(Wegener , 1924. Movement of Greenland along Nares Strait was a very important element of Wegener's theory. ...
... The Nares Strait region and some reconstructions that have been suggested: a, present geography, representing fixist theories; b, strike-slip displacement of about 350 km(Wegener 1915(Wegener , 1922); c, strike-slip displacement of about 400 km (Carey 1958); d, oblique displacement (Bullard et al. 1965); e, strike-slip displacement of about 220 km (Keen e, al. 1972); f, no displacement, but great oblique displacement farther west (Pitman & Talwani 1972); g, about 100 km of transverse displacement taken up farther west, combined with about 90 km of strike-slip oblique to Nares Strait (Kristoffersen & Talwani 1977); h, great oblique displacement (Sclater et al. 1977); i, no displacement along the Strait, but movement northward and westward of a larger block that includes Ellesmere and Devon Islands (Le Pichon et al. 1977); j, left-lateral displacement of 250 km (Newman 1977); k, an oblique approach of Greenland toward Ellesmere Island (Srivastava 1978, Srivastava et al. 1981 ), involving two phases, the first compressive (oblique, 50 to 220 km), and the second left-lateral (250 km);/, minor strike-slip displacement, minor rotational opening and major foundering(Kerr 1967a, b, 1981a). Slightly modified from Kerr (1980a).M06 :,g ► ,. .. -c. ...
The question "Did Greenland drift along Nares Strait?" has been debated for more than 70 years. There have been five periods, each represented by a consensus on one or the other extreme, or by a conflict. At times opinions on the Strait have changed rapidly when a new global theory came in or went out. There is a possibility that at these times opinion on the Strait has been determined more by theory than by evidence. At present there is a conflict. One group of earth scientists have worked on the shores of the Strait and have correlated stratigraphic and structural features across it. They conclude that a slight movement of some kilometres, but not exceeding 25 km, may have occurred. Another group have worked in the oceanic basins surrounding Greenland and their conclusion is that there has been 220 km or more of sinistral movement along the Strait. The solution to the Nares Strait conflict appears to be clear-cut. We must determine whether displacement was a) less than 25 km orb) more than 220 km. There have been no serious suggestions about sinistral motion between these two extremes. The origin of Nares Strait has enormous implications for tectonics. The Strait is an important element in tectonics of the northern hemisphere, and it is a key to the pre-drift position of Greenland. It is thereby an important feature in the reconstruction of the North Atlantic Ocean as well as the Arctic Ocean. If there has been hundreds of kilometres of sinistral displacement of Greenland along the Strait, then much support is given to the conventional plate tectonic theory which is widely accepted today. If displacement was minor, or non-existent, then plate tectonic theory is faced with a major problem: what are the origins of Baffin Bay and Labrador Sea?
... The geological significance of the region was heavily debated during the rise of the continental drift theory and the understanding of plate tectonics (e.g. McKenzie et al., 1970;Mohr, 1967;Tazieff et al., 1972;Teilhard de Chardin, 1930;Wegener, 1929). The kinematic reconstruction of the Afar region has been at the core of this discussion for nearly a century. ...
... The kinematic reconstruction of the Afar region has been at the core of this discussion for nearly a century. Wegener (1929) argued for continental drift based on the fitting between the African and Arabian continents when removing Afar. Conversely, Mohr (1967) denied this theory based on the presence of pre-rift blocks in the Afar Depression. ...
The Afar Depression is a unique place on Earth where active rift processes can be directly observed. It is believed to be close to continental breakup. The Afar hotspot has a strong influence on the geology of the Depression. Despite the strong geological interest in the region, difficult field access slowed scientific discoveries. During the last two decades, new projects and studies resulted in a better characterization of the region. New field data and global advances in understanding rift processes call for an integrative and holistic review of the tectonostratigraphic evolution of the Afar Depression. This study compiles new geological maps and reviews the stratigraphy and the geological history of the Afar Depression and the Afro-Arabian Rift System. A new kinematic evolution model and integrative paleogeological maps are proposed. Results show that geological events are diachronous throughout the region. We consider the Afar Rift to be distinct from the Red Sea Rift, both being separated by the Arrata Microplate. The Afar Rift is propagating northwards and forms a relay structure with the Red Sea Rift, linked to the counter-clockwise rotation of the Danakil Block since the Mid- to Late Miocene. The Afar Depression can be segmented into two distinct domains, Central Afar and the Danakil Depression. Central Afar experienced significant extension, protracted and extensive magmatism and magma-compensated thinning. It is believed to be strongly influenced by the Afar hotspot. In comparison, the Danakil Depression is younger and went through less extension and less magmatic activity until Recent (∼0.6 Ma) times. The absence of magma-compensated thinning allowed the development of an evolved stage of continental breakup. The tectonostratigraphic evolution of the Afar Depression with distinct rifting styles shows the complexity of continental break-up.
... The present geographic distribution of the extant species of the side-necked turtles except Chelidae can be explained by the following five hypotheses. The breakup of Gondwana 28,29) resulted in the fragmentation of landmasses, including the Indo-Madagascar landmass, and then, the separation of Madagascar continued at roughly the same time, around 88 mya 30) . Consistent with the divergence times based on the globin phylogeny (Table 2 and Fig. 2), (1) the ancestral population of the two families, Podocnemididae and Pelomedusidae, was initially separated from the lineage of the side-necked turtles in Africa. ...
... (2) Meanwhile, the separation of the ancestral population of Erymnochelys occurred somewhere in Africa, and later, Erymnochelys might have colonized Madagascar by continental drift and/or transmarine migration. After the separation of Madagascar from the continent had completed (the end of breakup was thought to be around 65 mya 28,29) ), (3) the two genera Pelomedusa and Pelusios diversified in Africa, where they still occur. ...
Extant side-necked turtles consist of three families: Chelidae, Pelomedusidae, and Podocnemididae. The lasttwo families (the subject of this study) include five genera, three of which are endemic to Africa (Pelomedusa andPelusios) and Madagascar (Erymnochelys), while the other two (Podocnemis and Peltocephalus) are restrictedto South America. This study was undertaken to determine the molecular relationships of side-necked turtlesbased on the primary and tertiary structures of α<sup>A</sup>, α<sup>D</sup>, and β globin chains as deduced by cDNA sequencing and amachine-learning algorithm for protein structure prediction, AlphaFold2. Analyses of the globin primary structures of four species from different genera provide three major insights. (1) The genera Pelomedusa and Pelusiosmight be endemic taxa that diversified in Africa after the Gondwana separation. (2) Although the extant species ofErymnochelys and Podocnemis are restricted to Africa and South America, respectively, they are closely related toeach other, and thus, these genera apparently diversified during the breakup of Gondwana. Thus, the colonizationof the ancestral population of Podocnemis unifilis in South America might have coincided with continental drift.(3) The divergence times of the four species based on globin genealogy were estimated to have begun 120–11million years ago (mya), which generally coincides with the break-up of Gondwana 135–65 mya. In addition,tertiary structures predicted by AlphaFold2 were compared using a PyMOL overlaying technique. An in-depth examination of the four α<sup>A</sup> globin chains revealed considerable consistency among species, and a similar pattern wasobserved for α<sup>D</sup> and β globin chains. Additionally, species-specific differences were recognized among the primarystructures, and their higher-order structures (i.e., tertiary structures) were consistent, offering new information onthe molecular phylogeny of side-necked turtles.
... The first attempts at reconstructing the paleoposition of continental land masses can be traced back to Dutch map makers in the 17th century, and later to Alfred Wegener and Boris Choubert in the early 20th century (Kornprobst et al., 2018;Wrobel-Daveau and Nicoll, 2019;Wrobel-Daveau et al., 2020). These, however, were singular handdrawn snapshots illustrating the relative positions of continents with respect to each other based on observations of the similarities of their continental coastlines, or of rock and fossil types (see also Snider-Pellegrini, 1858;Wegener, 1929). It would not be until plate tectonic theory was formulated in the late 1960s (e.g., McKenzie and Parker, 1967;Le Pichon, 1968) that 'modern' plate reconstructions as we understand them today started circulating (e.g., Dewey and Bird, 1970), reflecting the developing understanding of the Earth as a dynamic planet, and attempting to reconcile plate kinematics with the geodynamic processes ruling them. ...
... For exploration-based applications the typical approach is to try and resolve the highest resolution of continental GDUs, constrained from observable geological or tectonic features, whilst maintaining consistency within a global plate tectonic framework to constrain regional reconstructions. More detailed subdivisions also facilitate the recognition of reactivation loci along inherited structures such as intra-cratonic boundaries (i.e., Paleozoic and Proterozoic belts) and more fundamentally, further constrain paleocontinent assemblies as pointed out by Alfred Wegener in the early 20th century (e.g., Wegener, 1929; in the case of Madagascar, see for instance Collins, 2006;Key et al., 2011). It is also worth highlighting that in any model, the accuracy of GDU shape, extent, and relative position will have a significant effect on modelled motion as well as accretion and extension systems. ...
The formulation of plate tectonic theory and its application to modelling the motion of lithospheric units on a sphere using Euler rotations has been a foundational advance for 20th century geosciences. Its inception has supported significant industry funded research, better understanding and visualisation of geological concepts, and underpinned exploration for resources in the energy sector since the 1970's. As a direct result of the development of modern computing infrastructure and methodology, significant progress in tectonic modelling approaches have occurred since the 1980's, today allowing for sophisticated predictions of both the time-dependent kinematics and geodynamics of the paleo Earth. For example, in an exploration context, modern coupled paleo Earth system science models combining regional geology, tectonics, elevation, bathymetric, climate, drainage systems and geophysical data are capable of predicting occurrences of specific rock facies, mineralization systems and natural resources in relation to past physio-chemical settings. Critically, these predictions minimize uncertainties, allowing for more accurate modelling and de-risking of subsurface targets, each of which are becoming increasingly important considerations in supporting the growing resource demands of the current energy transition.
The transition to an electricity-powered society supplied by low carbon energy sources is one of the changes needed to mitigate the impact of climate change. In order to deliver on these challenges that have been agreed and set by international accords (e.g., Paris agreement, COP26), there is already a significant shift of focus within hydrocarbon exploration away from oil towards both gas and geological storage. Additionally, in the coming decades there will also be a significant increase in exploration for “critical minerals” as demand grows. This, combined with a progressive decrease in the grade of ore extracted from long-operating, large mines and the decrease of new, large-scale mineral deposit discoveries at or near the surface, has created an unprecedented challenge upon the mineral industry in terms of both exploration and production. With new approaches to mineral exploration, such as mineral systems thinking, which links the formation of many mineral resources to a geodynamic setting, plate models are now more important than ever. The transfer of integrated plate tectonic and Earth system modelling mindsets, workflows and techniques which development was initiated under the influence of the hydrocarbon industry during the 20th century will likely develop further in the 21st century, incorporating a greater range of scientific data types, detailed regional knowledge and physics-based geodynamic constraints.
Here we provide an overview of how the development of global plate tectonic models over the last 50 years have been applied and integrated into predictive workflows to inform and assist natural resource exploration. The challenges faced by the energy transition will continue to drive plate model usage in exploration while also securing their continued development and evolution.
... Various hypotheses have been taken into consideration regarding the geological behavior of the whole planet Earth. The dominant one today is the plate tectonics theory that has its roots in the A. Wegener's continental drift hypothesis [2], see Figure 1. A minor one is the O. C. Hilgenberg's expanding Earth hypothesis [3], see Figure 2. Neither Wegener nor Hilgenberg had any satellite images of the Earth and no oceanic crust images existed at the time of their publications. ...
... . Wegener's idea of drifting continents[2]. ...
Plate-fixed and Earth-fixed measurement chain concepts were briefly described and explained. It was shown that the International Terrestrial Reference Frame (ITRF) contains a fundamental inconsistency, which is its alignment to plate tectonics geological models, e.g. to the NNR-NUVEL-1A in the ITRF2000. The Global Positioning System (GPS) is fundamentally an example of an Earth-fixed measurement chain concept and has enabled to detect global tectonic motions of the Earth's crust at an accuracy of a few millimeters in the last decades. Results of long-term GPS monitoring networks such as The North America Reference Frame (NAREF) provide high accuracy fields of horizontal motions in the Earth's crust. When the ITRF is put into practice, these horizontal motions radically change into a field of highly coordinated longer (plate) velocity vectors. This highly coordinated vector field is in fact created by an erroneous, fully independent and man-made plate motion model added into the ITRF by using a subroutine. A true global GPS velocity field can be obtained, paradoxically, by a removal of the ITRF plate motion model from the ITRF velocity field. This operation offers an insight into the Earth-fixed behavior of the Earth's crust and also falsifies the highly coordinated artificial plate tectonic motions.
... "As geology is essentially a historical science, the working method of the geologist resembles that of the historian. This makes the personality of the geologist of essential importance in the way he analyzes the past" Reinout Willem van Bemmelen in "The Scientific Character of Geology" (1961) In memory of my PhD supervisor and friend Bernard Pittet (26/01/1966 -08/10/2021) La théorie de la dérive des continents (Wegener, 1920) est essentielle pour comprendre le mouvement des plaques tectoniques et donc indirectement l'évolution des rifts continentaux. Cependant, ce n'est que depuis les années 1960 que l'hypothèse proposée par Alfred Wegener a été confirmée par des campagnes océanographiques de grande envergure, ainsi que sur le domaine terrestre avec le développement du GPS. ...
... It has been a century since the theory of continental drift (Wegener, 1920) was proposed by the scientist Alfred Wegener. The term "rift" is however circa two hundred years old and was first defined as a "major elongate tectonic depression bounded by normal faults" (de Beaumont, 1827(de Beaumont, , 1830Gregory, 1896;Olsen, 1995). ...
Stratigraphic rift-basin successions have promoted a tremendous amount of tectonostratigraphic studies during the last decades. However, the syn-rift to post-rift transition is still a matter of debate. This PhD thesis presents the case of the Norwegian Sea continental margin, intending to reconstruct the evolution of depositional environments during the syn-rift and post-rift stages. The Norwegian Sea has been chosen for its atypically wide terrace domain across which a tremendous amount of data has been acquired, but never comprehensively integrated. In this study, the identification of fifteen stratigraphic sequences (S1 to S15), combined with a reappraised dinoflagellate cyst zonation, enables the studied stratigraphic interval to be divided into three major periods with (i) the syn-rift period (S1 to S7, dated from the Middle Bathonian to the Middle/Late Berriasian), (ii) the transitional rift-sag period (S8, dated from the Middle/Late Berriasian to the Aptian/Albian boundary) and (iii) the post-rift period (S9 to S15, dated between the Aptian/Albian boundary and the Early Coniacian). Those three major periods fit well into the Atlantic multiphased rift evolution. The syn-rift period is marked by an intense tectonic activity during which coarse-grained deltas have conjointly developed with wave-dominated coasts. The rift-sag stage is a transitional period during which tectonic activity waned between the terrace and the platform domains while fostered the development of deep-water turbidite lobe complexes. The rift-sag phase most probably corresponds to a period of migration of the deformation from the terrace domain to the deep domain. The post-rift stage is defined by a phase of tectonic quiescence coevally with the deposition of thick offshore marine mudstone successions.
... In addition, the flat-lying fossiliferous Silurian limestones of the Hall Basin -Kennedy Channel area, the age of which had been established decades before by Meek (1865) and Etheridge (1878), were indicated as Devonian. This age designation is interesting in the context of this symposium, since it was Willis' map that formed the basis of Wegener's (1915) initial comments about the geological evidence for the displacement of Greenland along Nares Strait (Fig. 13). ...
Exploration in the Nares Strait region in the late 19th and early 20th centuries was connected with the seaway's position as a principal route of geographic discovery. Few of the early expeditions were directed towards obtaining data for the young science of geology. At the turn of the century, with the passing of the main era of geographical discovery, including the race for the North Pole and the establishment of Greenland's insularity, geological understanding of the region advanced rapidly and geologists more or less became 'standard' members of expeditions to this part of the Arctic. Systematic geological studies in the Nares Strait region began when Lauge Koch mapped the Greenland side of the Strait in the period 1916-23; such investigations on the Canadian side by the Geological Survey of Canada took place in the 1950s and later. Early private expeditions and later work by university and petroleum and mineral enterprises have also contributed many geological data, as have several 'military operations' centred on Thule Air Base in Greenland. Regional geological mapping in Greenland was renewed by the Geological Survey of Greenland in the 1970s and continues today. Cooperative Danish-Canadian projects, initiated by "Operation Grant Land" in 1965-66 in northern Nares Strait, have aimed at coordinating field studies in order to better assess correlation of stratigraphy and structure across the Strait. Greenland and Nares Strait held important positions in the early ideas about the horizontal mass movements of the continents, and both Frank B. Taylor and Alfred Wegener featured the narrow linear channel between Ellesmere Island and Greenland in their respective theories of continental drift. These two creative theorists built on the immense global knowledge assembled by Eduard Suess, who published one of the earliest appraisals of the region. Early geological maps of the Nares Strait region by Bailey Willis and Lauge Koch were used by Wegener in support of his theory of continental drift.
... Since the supercontinent Pangaea was defined for the first time (Wegener 1915), its configuration and outer shape were improved and perfected over the last decades, mainly by making use of a combination of palaeomagnetic, geochronologic, palaeoclimatic and palaeontological data (e.g. McKerrow and Scotese 1990;Torsvik and Cocks 2017). ...
U-Pb ages of detrital (n = 2391) and magmatic (n = 170) zircon grains from the Harz Mountains were obtained by LA-ICP-MS for provenance studies and absolute age dating. Results point to a complete closure of the Rheic Ocean at c. 419 Ma. A narrow Rhenish Seaway then re-opened in Emsian to mid-Devonian time (c. 390–400 Ma). Devonian sedimentary rocks of the Harz Mountains were deposited on the northwestern (Rheno-Hercynian) and on the southeastern (Saxo-Thuringian) margins of the Rhenish Seaway. A new U-Pb zircon age from a plagiogranite (329 ± 2) Ma within a harzburgite makes the existence of oceanic lithosphere in the Rhenish Seaway probable. The Rhenish Seaway was completely closed by Serpukhovian time (c. 328 Ma). Existence of a terrane in the seaway is not supported by the new data. Provenance studies and spatial arrangement allow reconstruction of the thin- to thick skinned obduction style of the Harz Mountains onto the southeastern margin of East Avalonia (Rheno-Hercynian Zone) during the Variscan orogeny. Detrital zircon populations define Rheno-Hercynian and Saxo-Thuringian nappes. Intrusion of the granitoid plutons of the Harz Mountains occurred in a time window of c. 300 to 295 Ma and constrained the termination of Variscan deformation.
Supplementary material at https://doi.org/10.6084/m9.figshare.c.6873591
... Roberts & Bally 2012). A striking example is the continental drift hypothesis (Wegener 1915), supported by the regional distribution of rocks and fossils while contradicting earth physics paradigms of that epoch. Similarly, large thrust sheets had been recognised (Bertrand 1884), mapped and their existence accepted long before their mechanics were understood (Hubbert & Rubey 1959;Chapple 1978). ...
Regional geology is an essential cornerstone in geosciences and combines concepts and data from multiple geological and other Earth science disciplines to study important geological features of a region and understand its history. The size and borders of each region are usually defined by distinct geological boundaries and by the occurrence of a specific suite of rocks. Regional geology is used to solve a wide range of questions in geosciences and is essential for resource management, hazard mitigation, urban planning, and sustainable development, among others. Here, we aim to present some historical accounts of regional geology, highlighting the importance of geological mapping that is essentially founded on thorough fieldwork. Finally, the contributions of this special issue dedicated to regional geology are briefly introduced. Some of these originate from presentations at the annual conference of the DGGV (Deutsche Geologische Gesellschaft – Geologische Vereinigung e. V.) GeoKarlsruhe2021 “Sustainable Earth – from processes to resources”.
... South Africa's Karoo Basin has been a golden spike for the Permian and Triassic since Alex Du Toit, a Cape Town-born mining engineer and geologist employed to map the Cape Province, published his book Our Wandering Continents (Du Toit, 1937). Du Toit noticed similarities between South African rocks and those of other southern hemisphere continents (Gondwana) and, thus, provided supporting evidence for Continental Drift (Wegener, 1915). Evidence for Wegener's "hypothesis, " the basis for modern plate tectonic theory, comes from various disciplines. ...
Terrestrial fossil assemblages preserved in the upper Permian–Lower Triassic strata of the Karoo Basin, South Africa, have played a central role in the interpretation of ecosystem patterns and end-Permian extinction models. However, these models need to be carefully reconsidered because of the limitations of the rock record. Four lessons learned from a multidisciplinary approach to the rocks, lithology, stratigraphy, and dating are relevant to other paleofloras in large continental basins. In reality, the Karoo paleofloral record is very sparse. Hence, reports of a near continuous fossil record in this basin should be considered as the near continuous record of erosion and time lost with sporadic plant-fossil assemblages.
A review of the debate over the rate and timing of the Permian–Triassic in the Karoo Basin reinforces the need for extensive stratigraphic mapping, the analysis of depositional environments of the plants, as well as the application of a variety of dating methods. First, Late Permian to Early Triassic paleobotanical assemblages are extremely rare in the basin with only a handful of sites in the Free State and Eastern Cape Provinces. These fossil
data originate from >3750 m of total measured section wherein megafloral remains are preserved in <1% of the available rock record (0.9% all megafloral elements; permineralized wood = 0.1%, adpressions = 0.8%), with spore-and-pollen assemblages only slightly more frequently encountered at 1.3%. This low occurrence is comparable with other basins. Thus, any continental fossil assemblage represents a very short temporal window into
the paleobiosphere because of taphonomic effects of the soils, pedogenesis, and controls on depositional environments.
Second, geochronometric and rock magnetic data, developed in a sequence stratigraphic context, are critical to constrain time and biological trends in continental successions. The missing time, diastems and hiatuses, are critically important. Third, the spatial relationships of plant-fossil assemblages are not easily correlated
across the basin without an extensive dataset of the paleolandscape. In general, the Late Permian Beaufort rocks
represent channels, floodplains, and braided streams rather than lakes and oxbows that are conducive to the preservation of plant parts. Finally, the temporal distribution of paleobotanical assemblages is complicated by the missing time (sediments) that has resulted in the apparent scarcity of vegetation before and after the end Permian extinction. The reported uncharacteristic diversity and abundance of plants in the Carnian–Norian
Molteno Formation is most likely due to an environment conducive to preserving fossil-plant assemblages combined with a record of intensive collecting. Overall, the large inland Karoo Basin, without any marine influence or extensive volcanic deposits, has favored the preservation of vertebrate assemblages.
... Since the first space probes in the 1960s, the pace of space-crafts sent to Mars has continued to increase significantly. Since the Red Planet lacks plate tectonics as found on the Earth, geological features persist for a long time and can be used to gather information on the planet's history [4][5][6] , The Noachian period coinciding with the Late Heavy Bombardment about 4.1-3.7 billion years ago and was characterized by high impact rates. As such, Noachian landscapes exhibited a worn and eroded appearance, with sediment-filled craters and valley networks 7,8 . ...
Understanding the habitability of both past and present Mars continues to evoke scientific interest, particularly now that there is growing evidence of previous, vastly available liquid water and a warmer Martian climate. While today the surface of the Red Planet is barren and dry, the presence of hydrated minerals like phyllosilicates and sulphate minerals may indicate that the planet was once much more conducive to the emergence of life. These observations are the driving force behind investigations into possible biomarkers and signs of extinct life in the context of Mars. While Mars orbiters, landers and rovers have significantly improved our understanding of the planet’s past, Earth-based experiments are necessary to support those missions technically and scientifically. Simulation facilities replicating the Mars climate are used to test instruments before flight and investigate interactions of biomarkers with the Martian environment. Here, we review some exemplary, modern ground-based facilities with a focus on sample species relevant to astrochemistry and astrobiology. The presented Mars simulation facilities utilize a variety of technical implementations and thus are capable of simulating all of the major environmental parameters on the Martian surface: atmosphere, temperature and electromagnetic solar radiation. Depending on the subject-specific requirements of each investigation, these setups integrate various simulation features and different measurement techniques. A few examples of particularly remarkable simulation facilities include: the Planetary Atmospheres and Surfaces Chamber and the MARTE Simulation Chamber at INTA's Centro de Astrobiologia, Spain, which are unique in terms of integrated measurement techniques and Martian dust simulation; the Mars Simulation Facility, one of several planetary simulation chambers based at the German aerospace center DLR, Germany, is specialized in humidity measurements and sample analysis using PAM fluorometry; the Mars Simulation Chamber/Planetary Atmosphere Chamber at the Kennedy Space Center, USA, integrates an optical filter system to simulate ultraviolet-light attenuation by Martian dust; the Mars Environmental Simulation Chamber at Aarhus University, Denmark, provides atmospheric cooling and the possibility to extract samples mid-experiment. Many state-of-the-art technologies used in Mars simulation chambers are also integral to space-based experimental platforms, such as the planned OREOcube/Exocube experiment on the International Space Station. In-situ space experiments are highly complementary to Martian simulations, particularly in providing supplementary knowledge about the influence of broad-range radiation exposure and the true solar spectrum.
... Panthalassa (Figs. 1, 2, 5, 6, 9) also referred to as the Panthalassic Ocean was originally defined as a vast ocean that surrounded Wegener (1915) Pangea (Torsvik et al., 2021). Later, this term was used for the Neoproterozoic-Early Palaeozoic ocean that surrounded Pannotia and, subsequently, Gondwana, Laurentia, Baltica, Siberia and the Asiatic plates (Ross et al., 1992;Jiedong et al., 1999;Colpron and Nelson, 2009;Golonka, 2009;Torsvik and Cocks, 2017;Kroner et al., 2022;Scotese, 2021). ...
This paper discusses the paleogeography and plate tectonics of the Silurian using five global and twelve regional scale maps. These maps illustrate the distribution of major
tectonic elements such as subduction zones, spreading centres, transform faults and main volcanic areas 435 and 425 Ma ago. The regional maps show the global paleogeographic configuration combined with palaeoenvironmental and palaeolithofacies distribution. The paleogeographic analysis shows that the continents of Gondwana, Laurentia, Laurussia, Siberia, South China and North China were separated by the Iapetus, Rheic, Paleoasian (Prototethys), Paleotethys, Panthalassa and Mongol-Okhotsk oceans. Spreading of the Rheic and Paleotethys oceans constituted the main Silurian extensional event. The Scythian-Turan-South Kazakhstan-Junggar-Tarim-North China chain of continents moved north-westwards, and this led to a gradual narrowing of the Paleoasian ocean. The Caledonian-Scandian orogeny that resulted from the collision of Baltica, Avalonia and Laurentia constituted the main convergent event during Silurian times.
... While Snider-Pellegrini did not have a compelling scientific theory to explain it, this was a bold statement, suggesting that large portions of the planet's surface have moved thousands of kilometers. Yet, it was only a few decades later that Alfred Wegener put together evidence to sustain this hypothesis, which became known as the continental drift theory (Wegener, 1929). Probably Wegener was not aware of it, but this was the first revolution in the solid earth sciences. ...
In this book, I have asked experts to write perspective papers on plate tectonics and mantle convection. Over the last century, our understanding of the solid Earth has completely revolutionized. It began with the continental drift theory of Wegener. Then everything changed with the discovery of ocean spreading and the formalization of the theory of plate tectonics. Now, we are developing an integrated theory of plate tectonics and mantle convection. This book is about the last step of this journey.
... This question was already addressed in the very first reconstructions by Köppen and Wegener [1924]. They used paleoclimatic proxies such as the presence of tillites, evaporites or coal to test the reliability of Wegener's reconstructions [Wegener, 1912[Wegener, , 1924[Wegener, , 1929 on a globe where the present latitudinal zonation of climates would not change. One powerful tool to determine the paleolatitudinal position of a given plate is through paleomagnetic constraints. ...
... This can be interpreted to have resulted from the widespread distribution of the Tethyan shallow water and also the opening of the equatorial Atlantic gateway during the late Albian. The connection between the Tethyan Ocean with both northern and southern Atlantic oceans has been approved during the late Albian time, where similarities of the shallow marine fossils have been noted from different continents (Wegener, 1929;Wiedmann and Neugebauer, 1978;Friedrich and Erbacher, 2006;Nagm and Boualem, 2019). ...
Albian rocks of northwest Algeria are commonly clastic deposits with poor dating markers. This study records two late Albian ammonites from northwest Algeria for the first time. They are Elobiceras (Elobiceras) sp. and Pervinquieria (Pervinquieria) pricei (Spath). These ammonites are collected from the Mcharref Formation interpreted here to be deposited south of Tiaret city
under a lagoonal carbonate ramp setting based on facies analysis.
The recognition of the well-known early late Albian ammonite Pervinquieria (Pervinquieria) pricei biozone from the study
area highly improves the assigned age for the studied sections.
The unconformity surface separates the lower and upper members of the Mcharref Formation coincides with the upper boundary of this biozone.
The correlation of this boundary with the global sequence
boundaries in the frame of ammonite biozones reveals that it equivalent to the SB KAl 6 (~103.8 my ago) that marks the end of the identified biozone everywhere.
Therefore, the recorded biozone shows an excellent correlation between the study area and that of Tethyan, European, American, and Asian biozones. Paleobiogeography of the recognized biozone indicates a cosmopolitan distribution that is interpreted here as a response to the widespread distribution of the Tethyan shallow water that reached to form a connection with the northern and southern Atlantic oceans during the late Albian time.
... W. Uhlig proponował przyjęcie autochtonizmu procesów fałdowych, tak dla Tatr jak i dla Fig. 6. Activity of Polish Carpathian geologists and foreign geologists in the Polish Carpathians -including the dates of their birth and death -in the context of historical events: field trip (July 11-18, 1903) to the Pieniny and Tatra Mountains of the IX International Geological Congress in Vienna; 2 -Alfred Wegener's first presentation of the theory of the break-up of continents and their drift in a lecture entitled "Die Entstehung der Kontinente" in 1912 in Frankfurt am Main, later discussed in detail in the monograph (Wegener 1912(Wegener , 1915Jurewicz 2015); 3 -World War I (July 28, 1914-November 11, 1918; 4 -Poland regained independence (November 11, 1918) and the establishment of the Polish Geological Institute in 1919: April 3 -Submission of an Emergency Request to the Parlament, May 7 -opening of the PGI, May 30 -obtained legal grounds for its activity by a resolution of the Legislative Parlament (Graniczny et al. 2003(Graniczny et al. , 2004Skoczylas 2009;Urban, Graniczny 2009;Wołkowicz 2020), although the necessity to establish a state geological survey was discussed decades earlier (Czarniecki 1970, Skoczylas 2009); 5 -World War II ( September 1, 1939-September 2, 1945; 6 -flourishing of lithospheric plate tectonics, which began with the works of Wilson (1965), McKenzie and Parker (1967) as well as Morgan (1968) and Le Pichon (1968); 7 -first Polish publications (1970s) applying the lithospheric plate tectonics to explain the origins of the Carpathians. Explanation of colors and symbols: yellow stars -"Pieniny" publications and their number (in parentheses after the surname), green -foreign geologists, red -"old guard" of the University of Lausanne -M. ...
... Though these studies share the same goal, the methods and data that they have employed differed. These investigations can be grouped into one modelling and two proxy-based categories: 1) computer simulations of global paleoclimate (e.g., Huber, 2012;Valdes et al., 2017;Haywood et al., 2019;Valdes et al., 2021), 2) quantitative reconstructions of climate parameters using various isotopic and molecular systems (e.g., δ 18 O, clumped isotopes, and TEX 86 ; Royer et al., 2004;Grossman, 2012aGrossman, , 2012bVeizer and Prokoph, 2015;O'Brien et al., 2017;Song et al., 2019;Vérard and Veizer, 2019;Grossman andJoachimski, 2020, 2022), and 3) censored climate estimates from geological and paleontological proxies (Wegener, 1912a(Wegener, , 1912b(Wegener, , 1915Du Toit, 1937;Frakes, 1979;Habicht, 1979;Frakes et al., 1992;Parrish et al., 1982;Sellwood and Price, 1994;Parrish, 1998;Ziegler et al., 1985;Boucot et al., 2013;Cao et al., 2019). Here the term "censored" refers to truncated or limited observations where the value is only partially known (e.g., "greater than 30 • C" or "<500 mm yr − 1 ). ...
... Early in the last century Wegener (1980) invoked polflucht as a mechanism to move continents from the poles toward the equator (Epstein, 1921;Lambert 1921;Krause, 2007). Although this acceleration and its attendendent forces have been subsequently neglected, they influence Coulomb failure conditions on plate boundaries. ...
Three quarters of all Mw ≥ 6.6 earthquakes and volcanic eruptions surrounding the Caribbean plate occur preferentially during periods of decadal minima in Earth’s angular spin velocity. This correlation is revealed most clearly as a 4–6 years phase lag following the first derivative of the length of the day (LOD), Earth’s angular deceleration. We show that local strains and displacements resulting from oblateness changes, or plate boundary stresses associated with changes in tropical rotation rates are orders of magnitude lower than those typically associated with earthquake or volcano triggering. Notwithstanding the absence of a satisfactory causal physical mechanism, the relationship permits decadal trends in Caribbean tectonic hazards to be anticipated many years before their occurrence. The next period of increased tectonic activity in the Caribbean, corresponding to a probable slowing in Earth’s spin rate, will occur in the decade starting on or about 2030.
... Almost a half century was taken to develop the paradigm of plate tectonics from the hypothesis of continental drift (Wegener, 1912(Wegener, , 1922DuToit, 1937) through the observation of seafloor spreading (Dietz, 1961;Hess, 1962;Vine and Matthews, 1963;Pitman and Heirtzler, 1966) to the interpretation of lithospheric subduction (Dickinson and Hatherton, 1967;Hamilton, 1969;Dewey and Bird, 1970;Ernst, 1970;White et al., 1970). The integration of observations and interpretations available at that time led to the birth of the new global tectonics, as it was termed by a series of classic papers published in the mid-late 1960s (Bullard et al., 1965;Wilson, 1965aWilson, , 1966Vine, 1966;McKenzie and Parker, 1967;Heirtzler et al., 1968;Isacks et al., 1968;Morgan, 1968;McKenzie, 1969;Dickinson, 1970a). ...
Plate tectonics was originally established as a kinematic theory of global tectonics, in which the Earth’s rigid outer layer, the lithosphere, consists of different size plates that move relative to each other along divergent, convergent or transform boundaries overlying the ductile asthenosphere. It comprises three elements: rigid lithosphere plates, ductile asthenosphere, and coupled movement systems. It operates through the interlinked processes of continental drift, seafloor spreading and lithospheric subduction, resulting in the generation, modification and demise of lithospheres throughout geological time. The system of lithospheric plates in horizontal and vertical movements forms the spatiotemporal linkages of matter and energy between the surface and interior of Earth, advancing the kinematic theory with a dynamic explanation. While top-down tectonics through lithospheric subduction plays a key role in the operation of plate tectonics, it is balanced for the conservation of both mass and momentum on the spherical Earth by bottom-up tectonics through asthenospheric upwelling to yield seafloor spreading after continental breakup. The gravity-driven subduction of cool lithosphere proceeds through convergence between two plates on one side, and rollback of the subducting slab makes the vacancy for upwelling of the hotter asthenosphere to form active rifting in backarc sites. Plate convergence is coupled with plate divergence between two plates along mid-ocean ridges on the other side, inducing passive rifting for seafloor spreading as a remote effect. Thus, plate tectonics is recognizable in rock records produced by tectonic processes along divergent and convergent plate margins. Although the asthenospheric upwelling along fossil suture zones may result in continental breakup, seafloor spreading is only induced by gravitational pull of the subducting oceanic slab on the remote side. Therefore, the onset and operation of plate tectonics are associated with a series of plate divergent-convergent coupling systems, and they are critically dependent on whether both construction and destruction of plates would have achieved and maintained the conservation of both mass and momentum on the spherical Earth. Plate margins experience different types of deformation, metamorphism and magmatism during their divergence, convergence or strike-slip, leaving various geological records in the interior of continental plates. After plate convergence, the thickened lithosphere along fossil suture zones in intracontinental regions may be thinned by foundering. This causes the asthenospheric upwelling to reactivate the thinned lithosphere, resulting in superimposition and modification of the geological record at previous plate margins. The operation of plate tectonics, likely since the Eoarchean, has led to heat loss at plate margins and secular cooling of the mantle, resulting in the decrease of geothermal gradients and the increase of rheological strength at convergent plate margins. Modern plate tectonics is characterized by the predominance of rigid plate margins for cold subduction, and it has prevailed through the Phanerozoic. In contrast, ancient plate tectonics, that prevailed in the Archean and Proterozoic, is dominated by relatively ductile plate margins for collisional thickening at forearc depths and then warm subduction to subarc depths. In either period, the plate divergence after lithospheric breakup must be coupled with the plate convergence in both time and space, otherwise it is impossible for the operation of plate tectonics. In this context, the creation and maintenance of plate divergent-convergent coupling systems are responsible for the onset and operation of plate tectonics, respectively. Although a global network of mobile belts is common between major plates on modern Earth, it is difficult to find its geological record on early Earth if microplates would prevail at that time. In either case, it is important to identify different types of the geological record on Earth in order to discriminate between the different styles of plate tectonics in different periods of geological history.
... T he South Atlantic Ocean has been a research hotspot for the geodynamics of continental drift and seafloor spreading [1][2][3][4][5][6][7][8] . Since the Early Cretaceous 3,4 , the South Atlantic has experienced the latest rift-drift cycle of the West Gondwana supercontinent without major tectonic overprinting. ...
South Atlantic opening has been typically modelled as being related to symmetric and static thermal upwelling and seafloor spreading that drive divergent continental drift of South America and Africa. Comparative analyses, however, show that South Atlantic opening is asymmetric and non-uniform. For neither asymmetric nor non-uniform opening are the underlying mechanisms clear. Here I use geological and geophysical data to inform analytical modelling, revealing that westward drifting and southward tapering of the South American continent have controlled the asymmetry and the non-uniformity in South Atlantic opening. I interpret that the asymmetric non-uniform seafloor spreading caused the ridge and hotspots to migrate, leaving behind non-linear seamount trails that are indicative of the speed of hotspot migration rather than direction of plate movement. The findings point towards a chain reaction from continental drifting, through seafloor spreading to ridge-hotspot interaction, which is instrumental in understanding the geodynamics for global plate tectonics.
... Meanwhile, Alfred Wegener (1880-1930) learned of Keidel's work at the international congress from Steinmann's publication and contacted Keidel, who sent him his latest papers. It is due to this exchange that Wegener modified from his 1920 edition of his Die Entstehung der Kontinente und Ozeane the justification of the geological evidence (Wegener 1915. Wegener claimed: ...
This work presents research that we intended to publish jointly with Maarten de Wit on the importance of Hans Keidel in the definition of the Gondwanides and in his pioneering proposal of correlation between the Sierras de la Ventana mountain system in the province of Buenos Aires, Argentina, and its counterpart in the Cape System in South Africa. Keidel's proposals were used by Wegener in the 1920 second edition of his Theory on Continental Drift. Keidel's role and his ideas of correlation were recognized and strengthened by du Toit's field work in 1923 in the Sierras de la Ventana and which he left behind in his field notebook. Du Toit has the credit of being the first to carry out fieldwork on both continents. His observations and his precise correlations confirmed Keidel's hypotheses through his 1927 publication and his book on The Wandering Continents. It is noteworthy that after Wegener's death in 1930, du Toit defended the Theory of Continental Drift for years almost alone. The work is documented with photographs from du Toit's trip to South America, the originals of which have been lost in the devastating 2021 fire at the Jagger Library at the University of Cape Town.
... During the turn of the 20th century, Alfred Wegener become obsessed with this problem and collected a series of evidence to sustain his mobilist ideas. He presented the concept of continental drift in 1912, at the annual meeting of the German Geological Society, and compiled evidence in a book published in 1915, titled "The Origin of Continents and Oceans" (Wegener, 1929). While this was the keystone for the basis of a new theory of the Earth, Wegener always recognized that it did not come as an epiphany. ...
Plate tectonics is the unifying theory of solid earth sciences. It describes that the surface of the Earth is divided into several lithospheric tectonic plates that move in relation to each other and over the less viscous asthenosphere. Many of the fundamental geological phenomena occur along the plate's boundaries, such as earthquakes and volcanoes, and the plates’ movement gives rise to a number of fundamental geological processes that include mountain building and the supercontinent cycle itself. The idea of surface mobility was first solidly proposed by Alfred Wegener in the start of the 20th century, but it took another 50 years for a unified theory of the solid earth to emerge. Plate tectonics dictates how the surface of the planet changes, how supercontinents break and come together, and how new oceans form and old ones close. As we will see in this book, plate tectonics is intertwined with ocean tides in unexpected ways. This chapter provides a brief introduction to the history and the workings of plate tectonics.
... While this activity was going on, the American petrologist Harry Hammond Hess (1906Hess ( -1963 came up in 1959 with the idea of sea-floor spreading (he was unaware of the earlier similar suggestions by the Dutch geologist Gustaaf Adolf Frederik Molengraaf 1916Molengraaf , 1928, and the Austrian geologist Otto Ampferer 1941) and coupled it with the previous knowledge that deep-sea trenches were surface expressions of giant thrust faults along which ocean floors descended along inclined seismic surfaces beneath magmatic arcs (e.g. Benioff 1949Benioff , 1954; Benioff in turn remained ignorant of the Dutch papers describing the inclined seismic surfaces with their isobath representations under the magmatic arcs in the Netherlands East Indies {present-day Indonesia} interpreted as giant thrust faults by Hendrik Petrus Berlage Jr. 1937 andGerard Leonard Smit Sibinga 1937) to be able to reconcile Wegener's continental drift (Wegener 1915) with Sir Harold Jeffrey's (1891-1989) demonstration in 1924 that the strength of ocean floors would not allow continental rafts to plough through them (Hess 1962). Hess thus postulated that the ocean floors were moving with the continents. ...
The fame of Alexander von Humboldt has declined in the measure that observational sciences lost prestige as against theoretical sciences. This state of affairs is a result of the mistaken view that theoretical sciences deal with ‘predictable generalities’ while observational sciences study ‘contingent particulars’, whereas any scientific statement checked against an insufficient number of observations, be it about the entire universe or, say, about biological evolution on one planet, or even about the history of development of one mountain belt, has precisely the same logical structure. The mistaken view has stemmed in part from the inapposite proposal on the ‘hierarchy of sciences’ by Auguste Comte in his Cours de Philosophie Positive. Popular opinion has long contrasted the way Alexander von Humboldt did science in a ‘Baconian’ way with Einstein’s way of doing science in an almost ‘Cartesian’ way. When examined closely, it is seen that this dichotomy is unreal and that both men were trying to solve different problems, both ultimately a part of the larger human project of understanding Nature, and both used essentially the same approach to do it (albeit in different languages: von Humboldt’s natural, Einstein’s formal), namely putting forward hypotheses and testing them with observation statements with a view to formulating ever better and more comprehensive models of the world around us, including ourselves. This unrealistic polarity assumed to be present in the character of science has had a negative influence on the policies of funding agencies and scientific journals, especially since the collapse, in the twentieth century, of the European colonial empires that had immensely furthered the observational sciences, to the detriment of our understanding of the natural world.KeywordsAlexander von HumboldtAlbert EinsteinSouth AmericaAsiaPhilosophy of scienceHistory of science
... Since this review is supposed to have a personal flavor, I (B.S.) will focus on those papers that most influenced me, often by those people I interacted with along my path through the field, and I will discuss them while describing this personal path. By 1967, Wegener's (1915 continental drift theory had been developed into plate tectonics (McKenzie & Parker, 1967;Morgan, 1968) building onto the intermediate step of sea floor spreading (Dietz, 1961; Vine and Matthews, 1963;Pitman and Heirtzler, 1966). Unlike subduction zones, spreading ridges and transform faults, seamount chains such as the exemplary Hawaii-Emperor chain are not a feature that is required in plate tectonics. ...
Hotspots are regions of intraplate volcanism or especially strong volcanism along plateboundaries, and many of them are likely caused by underlying mantle plumes – localizedhot upwellings from deep inside the Earth. It is still uncertain, whether all plumes or justsome of them rise from the lowermost mantle, and to what extent and where theyentrain chemically different materials. Also, large uncertainties exist regarding their size.Some plumes (such as Hawaii) create linear hotspot tracks, as the plate moves overthem and can therefore serve as reference frames for plate motions, whereas others(such as Iceland) show a more complicated distribution of volcanic rocks due to variablelithosphere thickness and plume-ridge interaction. Plumes may also weaken plateboundaries and hence influence plate motions. They may influence surface features suchas ice sheets, and therefore climate, but we are just beginning to study and understandprocesses jointly involving solid earth, hydrosphere and atmosphere.
... With the advent of plate tectonics theory in the 1960s, which is a modernized version of Wagener's continental drift theory [6,7], mountain formation was assumed to occur by plate collisions driven by mantle-convection and augmented by plate subduction [8]. But there are problems. ...
Earth's mountain ranges, characterized by folding and unique among Terrestrial planets, are inexplicable in plate tectonics, but are consequences of Earth's initial formation as a Jupiter-like gas giant, as described by Whole-Earth Decompression Dynamics. The violent T-Tauri outbursts from thermonuclear ignition of the sun stripped away the primordial gases and ices leaving behind a cold, compressed rocky Earth, entirely covered by continental crust without ocean basins, but containing within it two powerful energy sources, the stored energy of protoplanetary compression and a nuclear fission georeactor. Over time heat added by nuclear fission and radioactive decay energy replaced the lost heat of protoplanetary compression making possible Earth's decompression. As Earth decompresses two surface phenomena must necessarily occur: (1) more surface area is produced by the formation of and in-filling of decompression cracks, and (2) continental surface areas adjust to new surface curvature primarily by the surface buckling, breaking and falling over (thereby forming mountain ranges characterized by folding) and secondarily by tension tears at continental edges (thereby forming fjords and submarine canyons). The present continental surface area plus continental shelves provides a "first guess" estimate of the juvenile crustal surface area, but it is an underestimate due to not considering the surface area that had buckled, broken and fallen over to form mountains. Preliminary calculations provide relative estimates of the "excess" surface area during whole-Earth decompression that would form mountains. Currently, there is a dearth of reliable data on the ages of fold-mountain formation and on the amount of surface matter they contain, as well as on the initial time of decompression crack formation, especially those cracks that ultimately became ocean Short Communication Herndon; JGEESI, 26(3): 52-59, 2022; Article no.JGEESI.86810 53 basins. The absence of fold-mountains on other Terrestrial planets may be understood as a consequence of their not having been compressed by massive shells of protoplanetary gases and ices.
... During the past decades, it has become increasingly clear that several earlier supercontinents existed prior to the Phanerozoic supercontinent Pangea, first proposed by Wegener (1912Wegener ( , 1915. Leaving aside the question of the existence of any late Archean supercontinent or supercraton (e.g. ...
A total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia (central South America, n = 625), Kalahari
(southern Africa and Dronning Maud Land in East Antarctica, n = 386), and western Australia (n = 199). Laurentia, Baltica, and Amazonia (and possibly other cratons) most likely formed a ca. 10 000-km-long external active continental margin of Columbia from its assembly at ca. 1800 Ma until its dispersal at ca. 1260 Ma, after which all cratons studied were involved in the Rodinia-forming Grenvillian orogeny. However, the magmatic
record is not smooth and even but highly irregular, with marked peaks and troughs, both for individual cratons and the combined data set. Magmatic peaks typically range in duration from a few tens of million years up to around hundred million years, with intervening troughs of comparable length. Some magmatic peaks are observed on multiple cratons, either by coincidence or because of paleogeographic proximity and common tectonic setting, while others are not. The best overall correlation, 0.617, is observed between Baltica and Amazonia, consistent with (but not definitive proof of) their being close neighbours in a SAMBA-like configuration at least in Columbia, and perhaps
having shared the same peri-Columbian subduction system for a considerable time. Correlation factors between Laurentia and Baltica, or Laurentia and Amazonia, are below 0.14. Comparison between the Grenville Province in northeastern Laurentia and the Sveconorwegian Province in southwestern Fennoscandia (Baltica) shows some striking similarities, especially in the Mesoproterozoic, but also exhibits differences in the timing of events, especially during the final Grenville-Sveconorwegian collision, when the Sveconorwegian evolution seems to lag behind by some tens of million years. Between the other cratons, the evolution before and during the final Grenvillian collision is also largely diachronous. After 900 Ma, magmatic activity had ceased in all areas investigated, attesting to the position of most of them within the stable interior of Rodinia.
... During the past decades, it has become increasingly clear that several earlier supercontinents existed prior to the Phanerozoic supercontinent Pangea, first proposed by Wegener (1912Wegener ( , 1915. Leaving aside the question of the existence of any late Archean supercontinent or supercraton (e.g. ...
A total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia (central South America, n = 625), Kalahari (southern Africa and Dronning Maud Land in East Antarctica, n = 386), and western Australia (n = 199). Laurentia, Baltica, and Amazonia (and possibly other cratons) most likely formed a ca. 10 000-km-long external active continental margin of Columbia from its assembly at ca. 1800 Ma until its dispersal at ca. 1260 Ma, after which all cratons studied were involved in the Rodinia-forming Grenvillian orogeny. However, the magmatic record is not smooth and even but highly irregular, with marked peaks and troughs, both for individual cratons and the combined data set.
Magmatic peaks typically range in duration from a few tens of million years up to around hundred million years, with intervening troughs of comparable length. Some magmatic peaks are observed on multiple cratons, either by coincidence or because of paleogeographic proximity and common tectonic setting, while others are not. The best overall correlation, 0.617, is observed between Baltica and Amazonia, consistent with (but not definitive proof of) their being close neighbours in a SAMBA-like configuration at least in Columbia, and perhaps having shared the same peri-Columbian subduction system for a considerable time. Correlation factors between Laurentia and Baltica, or Laurentia and Amazonia, are below 0.14. Comparison between the Grenville Province in northeastern Laurentia and the Sveconorwegian Province in southwestern Fennoscandia (Baltica) shows some striking similarities, especially in the Mesoproterozoic, but also exhibits differences in the timing of events, especially during the final Grenville-Sveconorwegian collision, when the Sveconorwegian evolution seems to lag behind by some tens of million years. Between the other cratons, the evolution before and during the final Grenvillian collision is also largely diachronous. After 900 Ma, magmatic activity had ceased in all areas investigated, attesting to the position of most of them within the stable interior of Rodinia.
Increasing mobility of people and goods, as well as the rapid growth of users of mobile devices with positioning services expands constantly the need for geospatial information. Today, the challenge for suppliers and users or sellers and buyers is how to use this information to identify and accelerate profitable measures in public and private affairs like security, environment, resource, disaster and transportation or risk assessment for industry and insurers. In this context, georeferencing of geoinformation is the key instrument to visualise the location of events of interest. This paper deals with the background of spatial reference for precise positioning on the dynamic Earth and focuses on the ETRS89 regarding applications in real-estate cadaster and similar services provided by the official authorities.
We begin with a few words about the geological history of the Bergell for non-experts. Apologies to geologists: we have simplified some aspects to make it easier to understand for laymen. And a warning for all, geology is a complicated science with many names, chemical formulas and speculations. For some strange names you may want to consult the Glossary at the end of the book. In the Bergell Alps, as is true everywhere in the world, many geological aspects are still not resolved and require further studies.
Background The Svalbard Archipelago is commonly believed to have been located at comparable latitude and, possibly, to have been attached to Laurentia in the early Paleozoic (500–420 Ma) based on trilobite assemblage similarities. Trilobite assemblage differences and lack of mixing between Laurentia–Svalbard and Baltica were further used to propose that these continents were separated by the Iapetus Ocean at that time. However, recent structural correlation of Timanian (650–550 Ma) thrust systems throughout the Barents Sea show that Svalbard was already attached to Baltica in the latest Neoproterozoic and remained so during the Phanerozoic. Methods The present study presents a new interpretation of seismic reflection data from the DISKOS database, which were tied to nearby exploration wells. The study uses recently acquired knowledge of the seismic facies of intensely deformed pre-Caledonian rocks and principles of sequence stratigraphy to interpret the data. Results The present study reconciles the proximity of Svalbard and Laurentia with the early accretion of Svalbard to Baltica in the latest Neoproterozoic. It also describes the influence of Timanian thrust systems on paleoenvironments and possible effects on trilobite assemblages, e.g. , the lack of mixing between those of Laurentia–Svalbard and Baltica. Conclusions The results suggest that paleontological constraints are robust markers to discuss continent amalgamation but should be considered with greater care when discussing continent separation since other factors, such as major thrust systems, may create major, linear, topographical boundaries, which may act as major faunal barriers within a single tectonic plate. Other factors to consider include paleoclimatic belts.
In March 1833 Charles Darwin discovered Devonian fossils in the Falkland Islands. He was excited by his find but could have had little premonition of the long-running geological controversy that he was initiating. Darwin's fossils matched a coeval South African fauna, and as further collections were made the association was apparently strengthened. A particularly important contribution arose around 1910 through collaborations between a local collector, Constance Allardyce, and professional palaeontologists: Ernest Schwarz in South Africa and John Clarke in the USA. The accumulating evidence was seized upon by the early proponents of ‘displacement theory’ - continental drift - notably Alexander Du Toit, who relocated the Falkland Islands northward for his 1927 South Atlantic reconstruction. A more radical, but geologically sounder proposal arose in 1952 when Ray Adie suggested that the Falkland Islands, rotated through 180°, had originated as the eastward culmination of the Cape Fold Belt and Karoo Basin. In effect, Adie had presciently described a rotated microplate, perhaps the first on record. An opposing view saw the Falkland Islands as part of a fixed, South American promontory, and argument around these two contrasting interpretations of South Atlantic geology continues to the present day.
Évolution des Pyrénées au cours du cycle varisque et du cycle alpin présente l’évolution des connaissances géologiques pyrénéennes découlant de grands programmes de recherche scientifique du début du XXIe siècle.Cet ouvrage, consacré au cycle varisque et au rifting crétacé, retrace l’évolution du domaine pyrénéen entre 340 Ma et 90 Ma. Il analyse, dans un premier temps, l’état des connaissances du socle des Pyrénées dont la structuration est héritée de l’évolution varisque de ce domaine. Puis il retrace l’évolution cinématique, depuis le Paléozoïque, du domaine méditerranéen occidental. Il traite enfin de l’évolution des connaissances sur le rifting crétacé et les processus sédimentaires et métasomatiques associés à l’individualisation de la limite de plaque Ibérie-Eurasie.
Hotspots are regions of intraplate volcanism or especially strong volcanism along plate boundaries, and many of them are likely caused by underlying mantle plumes – localized hot upwellings from deep inside the Earth. It is still uncertain, whether all plumes or just some of them rise from the lowermost mantle, and to what extent and where they entrain chemically different materials. Also, large uncertainties exist regarding their size. Some plumes (such as Hawaii) create linear hotspot tracks, as the plate moves over them and can therefore serve as reference frames for plate motions, whereas others (such as Iceland) show a more complicated distribution of volcanic rocks due to variable lithosphere thickness and plume-ridge interaction. Plumes may also weaken plate boundaries and hence influence plate motions. They may influence surface features such as ice sheets, and therefore climate, but we are just beginning to study and understand processes jointly involving solid earth, hydrosphere and atmosphere.
I started thinking about the concept of Earth expansion in 1987. I’m one of several individuals who “discovered” the concept for themselves, only to find that many others had discovered it long before me.
This is my chapter from the book, The Hidden History of Earth Expansion. An eBook version is also available from Google Books: https://www.google.co.uk/books/edition/The_Hidden_History_of_Earth_Expansion/kzUmEAAAQBAJ
In the present paper all possible convincing evidences have been given on the phenomenon of Earth expansion.
Birbal Sahni (1891-1949) was well known as the first Indian palaeobotanist, and he established the Institute that was named after him, now the Birbal Sahni Institute of Palaeosciences. Alexander L. du Toit (1878-1948) was the most famous South African geologist, known internationally for advocating the idea of Continental Drift, and for his work on Gondwana geology and palaeobotany. Du Toit was introduced to Sahni by Albert Seward, who was Sahni’s mentor at Cambridge University. They started a correspondence in 1925, involving the exchange of papers, books, and samples, which lasted at least until 1944. Du Toit and Sahni met in 1938 at the Indian Science Congress in Calcutta. Their preserved letters deal with the palaeobotany, correlations, and age of the Rajmahal beds, and later with the palynological investigations of Karoo Dwyka samples sent by du Toit to Sahni, which were worked on by D. D. Pant, who had been a student of Sahni. This correspondence reveals in detail just how these geoscientists involved with problems of Gondwana palaeogeography tackled these questions in spite of the long distances, and slow communications of the time. Information, especially that published in local journals, was disseminated by means of sending reprints, proof copies, and sometimes by handwritten lists of fossils. Although, initially, Sahni had obtained South African and Australian fossil material through the British Museum in London, he later obtained South African samples specially collected for him by du Toit. Samples were also exchanged between South Africa, England, India and Australia.
A Teoria dos Supercontinentes teve como seu instaurador principal Alfred Wegener, nos seus clássicos trabalhos nas primeiras décadas do século XX. Deve ser destacada a frente de contestação que lhe foi imposta de geocientistas dos dois mundos (então, todos “geossinclinalistas”). A retomada (e o crédito) só veio com Harry Hess, em 1962, quando este mostrou que os grandes empecilhos (fatores desconhecidos da deriva continental, não explicados devidamente), inibidores da teoria, passaram a ser cientificamente demonstráveis. Isso com suas pesquisas, com o conceito de convecção mantélica e mais ainda com proveito do ímpeto do surgimento da Tectônica de Placas (e o combate ao fixismo sensu lato). Seguindo Hess, alguns trabalhos foram acrescentados, com novas proposições, adendos, revisões, principalmente entre 1992 e 2005. Desde então, instalou-se fase notável de contribuições, publicações, livros e capítulos, todos com novos dados científicos. Temos que admitir que esse ramo das geociências ainda está em estágio de fluxo. A aplicação desses conceitos e conhecimentos, merecedora de um projeto internacional específico, foi estendida do Arqueano (no caso mais problemático de todos erátemas) até o fim do Mesoproterozoico (e.g. projetos “Gondwana”, “Rodínia” etc.). Concomitantemente a esses trabalhos e dados, já surgiram várias questões pendentes, para todos os casos de supercontinentes. Catalogamos uma série de problemas que queremos expor e as soluções que são demandadas. O conclusivo hoje é que o supercontinente Pangea, pelos seus dados geológicos gerais, geocronológicos e paleomagnéticos, é o único que pode ser colocado no status de fato científico. Todas as demais configurações propostas anteriores à Pangea são boas hipóteses de trabalho, a serem investigadas/exploradas de forma multidisciplinar.
O debate sobre ciclos tectônicos apresenta uma longa história de contribuições de diferentes escolas de pensamento, como os modelos mobilistas vs. fixistas. Este artigo traça um breve resumo da complexa história e, a partir da revisão, focaliza uma questão marcante da geologia regional do embasamento da Plataforma Sul-Americana: o problema da adoção do termo Ciclo Transamazônico. Ao ser introduzido na história do continente há quase 60 anos, o conceito baseou-se em alguns grupos de idades geocronológicas paleoproterozoicas, em escala de reconhecimento (principalmente dados K-Ar e Rb-Sr). Na época, o número de idades geocronológicas era inferior a mil para toda a plataforma. Hoje em dia, com base em um conjunto de novos e bons fatos geológicos e um melhor conhecimento das províncias estruturais, com melhor suporte geocronológico, sugerimos que o Ciclo Transamazônico, como originalmente proposto, deva ser descartado da literatura geológica brasileira.
The archetype of a cycle has played an essential role in explaining
observations of nature over thousands of years. At present, this perception
significantly influences the worldview of modern societies, including
several areas of science. In the Earth sciences, the concept of cyclicity offers simple analytical solutions in the face of complex events and their respective products, in both time and space. Current stratigraphic research integrates several methods to identify repetitive patterns in the
stratigraphic record and to interpret oscillatory geological processes. This
essay proposes a historical review of the cyclic conceptions from the
earliest phases in the Earth sciences to their subsequent evolution into current stratigraphic principles and practices, contributing to identifying opportunities in integrating methodologies and developing future research
mainly associated with quantitative approaches.
Neste artigo, objetivou-se destacar a contribuição de vários autores para o conhecimento e a nomenclatura das unidades geocronológicas. Revisou-se sucintamente a história da Geologia e da Paleontologia desde a Antiguidade Clássica até o século XIX, no qual houve as contribuições relevantes relacionadas às unidades de tempo geológico e seus respectivos nomes. Neste trabalho são fornecidas informações gerais a respeito dos eventos que ocorreram em cada um desses momentos da história geológica do planeta. Além disso, procurou-se realizar uma análise dos nomes dessas unidades, bem como de seus elementos de composição, mencionados por autores clássicos. Para isso, foram incluídas informações históricas, além das etimológicas e semânticas relacionadas aos termos considerados, por meio de consulta a dicionários linguísticos e especializados nas áreas geológicas, paleontológicas e biológicas, assim como de livros e artigos científicos pertinentes ao tema. Além disso, vários termos correlatos utilizados na literatura científica foram analisados sucintamente com a finalidade de se demonstrar que esses nomes clássicos e os seus derivados são ainda empregados na onomatologia científica dos dias atuais.
An introductory chapter describing the early science innovators researching Earth expansion, mainly during the second half of the 20th century. The chapter presents the work of: Carey, Creer, Egyed, Fairbridge, Heezen, Hilgenberg, Holmes, Irving, Jordan, King, Meservey, Runcorn, Tharp and several others. The chapter begins the book, The Hidden History of Earth Expansion, which continues with specially written chapters by some of the most well-known current researchers into Earth expansion: Hugh G. Owen, Cliff Ollier, Karl-Heinz Jacob, James Maxlow, Jan Koziar, Stefan Cwojdziñski, Carl Strutinski, Stephen W. Hurrell, John B. Eichler, William C. Erickson, David Noel, Zahid A. Khan, Ram Chandra Tewari, Vedat Shehu and Richard Guy, who recount their own personal histories. The book is widely available from most good bookshops in both hardback and paperback editions. Details available at publisher's website: http://www.oneoffpublishing.com/historyee.html
Deciphering the physical causes of evolution of the biosphere as we know it today, as well as in the past, from the phylogenetic and fossil archive, within the not-so-serene geological history, is the overarching objective of geophysical biogeography. Interactions between the physical environment and the biosphere are reflected in the common classifications used by biogeographers and conservationists: realms, biomes and ecoregions. The biota responds to the current physical environment, as well as to the precursor conditions: the current biota, at a given location, can be viewed as the time integral of the interactions between the biosphere and its geophysical environment. Like the horizontal displacement of continents, regional ups and downs of the Earth's surface not only reshape the physiography on which biota evolve, but also its continental scale decorum, that is, the climate, which may facilitate or hamper dispersal routes.
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