The depth extent and tectonic setting of Oroclinal Orogens

Purpose. The structure of the Sarmatia`s llithospheric plate was studied based on the latest integrated geological, geophysical, tectonophysics, aerocosmo-geological, neo-tectonic data and the gravity, magnetic, dense and seismic (GSZ, seismotomography) modeling data. The aim of the study to reveal the nature of heterogeneities of the Sarmatia Lithosphere and their influence on the nature of the process of structural and material differentiation of the Earth's continental crust. Method. A comparative geotectonic analysis of the structure, composition, and relationships of individual layers of the consolidated crust, the Moho section, and the sub-crustal mantle was performed. According to the results of the analysis, the nature of the relationship between the structure and composition of the Lithosphere component surfaces and the layers of the Earth's crust, the peculiarities of the tectonic division of the Pre-Rifean craton core of Sarmatia were clarified. Results. The relationship and regularities of the spatial distribution of individual floors of the Lithosphere, the layers of the Earth's continental crust and the core-mantle mixture, the structure of the Moho interface and the sub-crustal mantle on the territory of Ukraine have been clarified. Based on the comparison of the modern segmentation of the consolidated crust with the structure of the lithosphere layers, it was established that the modern structural and material heterogeneity of the Sarmatia plate core is determined by the original, "built-in" anisotropy of the Lithosphere, while the structure of the Earth's crust does not have an unequivocal connection with the relief of the sole of the modern seismic lithosphere. Exceptions are its rise with the formation of mantle dome structures in separate areas of the Western and Eastern micro-plates and under the Lokhvytskyi segment of the Dnipro-Donetsk Avlacogen. Scientific novelty. The nature of the impact of the heterogeneity of the Sarmatia`s lithosphere, "frozen" during the stabilization of the Pre-Rifean craton core of the East European Platform, on the modern segmentation and structural-material differentiation of the Earth's continental crust has been clarified. Scientific novelty. For the first time, a conclusion was made about the deformational nature of the structural differentiation of the continental crust of Sarmatia, which was formed against the background of the initial anisotropy of the Lithosphere under the influence of processes of mantle activation at the stages of tectonic evolution in the Phanerozoic. Practical significance. The obtained data on the geodynamic relationship between the structural surfaces of the lithosphere, the layers of the Earth's crust and the coromantium mixture can be used for geological interpretation when elucidating the geodynamic conditions of the formation and tectonic evolution of the intra-plate geostructures of Sarmatia in the Phanerozoic.

The geochemistry of Precambrian bedrocks

The distribution of iodine in the earth's crust

Effects of flat, parabolic and realistic steady flow inlet profiles on idealised and realistic stent graft fits through Abdominal Aortic Aneurysms (AAA)

Progressive growth of the Earth's continental crust and depleted mantle: Geochemical constraints

Global groundwater volumes in the upper 2 km of the Earth's continental crust—critical for water security—are well estimated. Beyond these depths, a vast body of largely saline and non‐potable groundwater exists down to at least 10 km—a volume that has not yet been quantified reliably at the global scale. Here, we estimate the amount of groundwater present in the upper 10 km of the Earth's continental crust by examining the distribution of sedimentary and crystalline rocks with depth and applying porosity‐depth relationships. We demonstrate that groundwater in the 2–10 km zone (what we call “deep groundwater”) has a volume comparable to that of groundwater in the upper 2 km of the Earth's crust. These new estimates make groundwater the largest continental reservoir of water, ahead of ice sheets, provide a basis to quantify geochemical cycles, and constrain the potential for large‐scale isolation of waste fluids.

Composition of the Earth's Crust

Annotation. The genesis of hydrocarbons has been debated for more than 300 years and continues to the present. The discussion of the problem led to the formation of organic and inorganic scientific schools. Over time, the hypothesis of polygenesis was also formed. With the development of engineering and technology, new concepts on the genesis of hydrocarbons and diamond-bearing structures were presented. One of these is the concept presented by us, according to which hydrocarbons and diamonds are formed not only at great depths of the mantle, but also at different depths of the Earth's crust in different regions of the Earth, due to the dehydration of serpentinized rocks. Dehydration of rocks occurs in both oceanic and continental crust. Under the continental slope, due to the collision of the continental and oceanic crust, the dehydration of serpentinized rocks of the 3rd layer of the oceanic crust occurs. Dehydration of rocks also occurs at various depths of the continental crust. Formed hydrocarbons and geofluids migrate to the upper horizons of the crust, differentiate and accumulate in fractured granites and sedimentary layers. Based on the proposed concept, the genesis of some giant deposits of the Earth, the Gulf of Mexico, the Caspian Depression, and Western Siberia is presented. According to laboratory studies, dehydration of rocks in the earth's crust causes ultra-high pressures. Kimberlites and explosive tubes are formed from carbon-containing components present in the medium. The proposed concept is characterized by more than 17 criteria that are set before prospecting and exploration in different regions of the Earth. The results obtained cover a wide range of issues of geology, geophysics and seismology. The results are presented to specialists for wide discussion. Further research is presented to the author in close cooperation with specialists from these fields of science from around the world.

Earth’s clay mineral inventory and its climate interaction: A quantitative assessment

Reply [to “Comment on ‘The petrologic case for a dry lower crust’ by Bruce W. D. Yardley and John W. Valley”

Although there is evidence for periodic geological perturbations driven by regular or semi-regular extra-terrestrial bombardment, the production of Earth's continental crust is generally regarded as a function of planetary differentiation driven by internal processes. We report time series analysis of the Hf isotopic composition of zircon grains from the North Atlantic and Pilbara cratons, the archetypes of Archean plate tectonic and non-plate tectonic settings, respectively. An ~170–200 m.y. frequency is recognized in both cratons that matches the transit of the solar system through the galactic spiral arms, where the density of stars is high. An increase in stellar density is consistent with an enhanced rate of Earth bombardment by comets, the larger of which would have initiated crustal nuclei production via impact-driven decompression melting of the mantle. Hence, the production and preservation of continental crust on the early Earth may have been fundamentally influenced by exogenous processes. A test of this model using oxygen isotopes in zircon from the Pilbara craton reveals correlations between crust with anomalously light isotopic signatures and exit from the Perseus spiral arm and entry into the Norma spiral arm, the latter of which matches the known age of terrestrial spherule beds. Our data support bolide impact, which promoted the growth of crustal nuclei, on solar system transit into and out of the galactic spiral arms.

Basic principles of the geosynclinal theory

Although Earth's continental crust is thought to have been derived from the mantle, the timing and mode of crust formation have proven to be elusive issues. The area of preserved crust diminishes markedly with age, and this can be interpreted as being the result of either the progressive accumulation of new crust or the tectonic recycling of old crust. However, there is a disproportionate amount of crust of certain ages, with the main peaks being 1.2, 1.9, 2.7 and 3.3 billion years old; this has led to a third model in which the crust has grown through time in pulses, although peaks in continental crust ages could also record preferential preservation. The 187Re-187Os decay system is unique in its ability to track melt depletion events within the mantle and could therefore potentially link the crust and mantle differentiation records. Here we employ a laser ablation technique to analyse large numbers of osmium alloy grains to quantify the distribution of depletion ages in the Earth's upper mantle. Statistical analysis of these data, combined with other samples of the upper mantle, show that depletion ages are not evenly distributed but cluster in distinct periods, around 1.2, 1.9 and 2.7 billion years. These mantle depletion events coincide with peaks in the generation of continental crust and so provide evidence of coupled, global and pulsed mantle-crust differentiation, lending strong support to pulsed models of continental growth by means of large-scale mantle melting events.

Even though surface water is essential for Earth's habitability, the estimates of total amount of water (at the surface and in the deep interior) throughout Earth's evolution vary from 5-15 ocean masses (OM) based on magma ocean solidification models [Hamano et al., 2013] to 1.2-3.3 OM based on petrological studies [Hirschmann, 2006]. Previous numerical models of coupled surface-mantle system have estimated a lower bound of 9-12 OM [Nakagawa et al., 2018]. Experiments have shown that water lowers the melting temperature, density and viscosity of rocks and it is also required for the generation of felsic magmas. In this work, we use global convection models [Tackley, 2008] spanning the age of the Earth to elucidate the effect of water on mantle dynamics in terms of planetary cooling, surface mobility and production of continental crust.Our models self-consistently generate oceanic and continental (Archean TTGs) crust while considering both plutonic and volcanic magmatism and incorporate a composite rheology for the upper mantle. Pressure-, temperature-, and composition-dependent water solubility maps calculated with Perple_X [Connolly, 2009] control the ingassing and outgassing of water between the mantle and the surface [Jain et al., 2022]. Irrespective of the initial water content used, our models exhibit mobile-lid regime (high surface mobility with subduction) throughout the 4.5 Gyr with episodes of short-lived plutonic-squishy-lid regime (low surface mobility with delamination or dripping) in the Hadean. These models are also consistent with the cooling history of the Earth inferred from petrological observations [Herzberg et al., 2010]. A strong positive correlation is observed between continental crust production and the total amount of water available, with the former's cumulative mass increasing by roughly three times when water in the planetary system is raised from 1 OM to 10 OM.Models that consider a reduction in the density of crustal and mantle materials in the presence of water exhibit mobile-lid regime for the initial 200 Myr. Afterwards, the mobility stays low as the hydrated oceanic crust is less dense and does not subduct. It thickens over time and eventually collapses as global resurfacing events. Mantle stays comparatively warm and a much lower amount of continental crust is produced. This motivated us to make the following improvements to achieve more realistic models. First, mantle minerals only in the top 5 km of the computational domain (as opposed to 10 km considered previously) are ingassed with water. Second, instead of fully saturating the rocks based on their solubility maps, they are partially saturated to control the input of surface water into the lithosphere. Third, different partition coefficients for water are considered: 0.01 for pyrolite to basalt melting and 0.25 for basalt to TTG melting. These changes help in increasing the surface mobility, cooling down the planet and producing more continental crust. These trends are further amplified in models that additionally consider a viscosity reduction of mantle materials in the presence of water.

Analogue modelling of continental extension: a review focused on the relations between the patterns of deformation and the presence of magma