Über geologische Grundtheorien. Zur Kritik der Argumentation

Ohne Zusammenfassung     

A gradual transition to plate tectonics on Earth between 3.2 to 2.7 billion years ago

Zircon crystals precipitated from granitoid magmas contain a robust record of the age and chemistry of continental magmatism spanning some 4.375 Ga of Earth history, a record that charts initiation of plate tectonics. However, constraining when exactly plate tectonics began to dominate crustal growth processes is challenging as the geochemical signatures of individual rocks may reflect local subduction processes rather than global plate tectonics. Here we apply counting statistics to a global database of coupled U–Pb and Hf isotope analyses on magmatic zircon grains from continental igneous and sedimentary rocks to quantify changes in the compositions of their source rocks. The analysis reveals a globally significant change in the sources of granitoid magmas between 3.2 and 2.7 Ga. These secular changes in zircon chemistry are driven by a coupling of the deep (depleted mantle) and shallow (crustal) Earth reservoirs, consistent with a geodynamic regime dominated by Wilson cycle style plate tectonics.     

Main Stages of Evolution of Pacific Ferromanganese Stromatolites and Oncolites

As exemplified by cobalt–bearing Fe–Mn crusts (ferromanganese stromatolite) of the Magellan Seamounts (Clarion–Clipperton Province), the main stages of the structural evolution of bacterial communities have been recognized. It has been demonstrated that the change of the stages is caused by the effect of major tectonic, volcanic, and other geological events.     

Easy method of interpreting dyke anomalies

Summary An entirely new procedure is proposed in this paper for interpreting anomalies of dykes. This reduces the ambiguity in magnetic interpretation. Measurements of the first vertical derivative simplifies the problem of interpretation and also supplies additional information concerning the parameters of a dyke. The first vertical derivative profile cuts the distance axis at two points whose separation is related to the depth and direction of magnetisation of a dyke.     

Physical Libration of the Moon: An Extended Problem

Astronomy Reports - The work is devoted to the study of the physical libration of the Moon. Interest in the traditional topic related to the rotation of the Moon is stirred up by the activity of...     

Application of a square wave potentiometry technique for electroreductive sulfur removal from a thiophenic model fuel

Thiophene-containing solutions were electroreductively desulfurized by a dynamic method. Initially, cyclic voltammetry was utilized to study thiophene electroadsorption from aqueous solution onto a platinum electrode surface and also to investigate the thiophene electroreductive behavior. Then, the solution was desulfurized via a square wave potentiometry method. The objective of this study was to find the optimal conditions. In this regard, the best adsorption potential, electroreduction potential, and square wave frequency were found to be ?0.54 V, ?0.95 V, and 1 Hz, respectively. Finally, a model fuel (containing 294 part per millions thiophene) was desulfurized by the square wave potentiometry method. Gas chromatography and Fourier transform infrared spectroscopy were used to examine the feed and product solutions. Gas chromatographic measurements revealed that sulfur content decreased to 55 part per millions. Based on the acquired results, electroreductive desulfurization could be designated as an efficient superseded for the commercial hydrodesulfurization process. However, more studies must perform to overcome technical limitations of electroreductive desulfurization technique and to guarantee its reliability.