Steno and the rock cycle

Geologists categorize the basic types of rock according to their origin – igneous, sedimentary, or metamorphic -- rather than by their physical properties. This is expressed dynamically by the fundamental concept of the rock cycle, which describes how the basic rock types are derived from one another within the Earth system as a result of ongoing cyclic geologic processes. In Nicolaus Steno’s published geological work, particularly De Solido, he takes a similar approach, outlining how a substance can be examined “to disclose the place and manner of its production”. Steno also recognizes the roles of erosion, transport, and deposition in the production of sedimentary strata from pre-existing earth materials. His description and diagrams of the geological evolution of Tuscany also show a clear cyclicity of process. While the modern concept of the rock cycle did not emerge until the 19th century, Steno’s work contains key elements of this important concept.

Application of gamma-ray spectroscopy and IR-spectroscopy methods for the purposes of ore geology in the Timan-Pechora Oil and Gas Province (the case of Ukhta Region)

Two express methods are presented in this paper. The first method is a high-resolution gamma-spectroscopic method based on a germanium detector, the second method is an IR-spectroscopic method. The applied complex of methods allows to determine the sources of uranium and thorium, identify the rhythms of uranium accumulation associated with regional events; identify areas with a high content of uranium due to the influence of local sources (faults, hydrothermal, etc.); determine the amount of authigenous uranium in the composition of total uranium; determine thermal maturity of organic matter in shales without their preliminary demineralization. To identify levels of increased uranium intensity in the high-carbon strata, a set of indicators has been proposed, which includes both applied indicators in practice of geological work and new indicators. New indicators have been tested on the collection of shale reference samples. For them, values ​​were established that characterize the processes of uranium accumulation and uranium removal. On the example of Ukhta Region according to the proposed indicators, the sections from the Vendian-Riphean to Domanic inclusive were interpreted. The performed work showed the possibility of comparing the calculated gamma-spectroscopic data with the data of other methods. This opens up a broader perspective for the use of express non-destructive gamma-spectroscopic method for detecting levels with a high content of uranium in the shale rocks, to which ore-bearing concentrations of a number of metals are also confined.

About the monograph “Collection and jewelry cassiterite”

Specialists of the Sergo Ordzhonikidze Russian State University for Geological Prospecting (MGRI), which had been training gemologists for many years, conducted an interesting and substantial study devoted to a non-traditional use of cassiterite, a mineral known to man for millennia. The monograph2 under review discusses various aspects of the use of cassiterite, as well as its accompanying minerals, for producing jewelry, collection and ornamental materials. Given the increasing popularity of natural minerals in recent decades, there is a growth of interest among collectors and manufacturers in non-traditional semi-precious stone raw materials and their use in the jewelry industry. The world trade in this area is significant and continues to demonstrate an increasing trend. In this regard, the work of D.A. Petrochenkov devoted to jewelry and ornamental cassiterites seems to be highly relevant. For the first time in world practice, the monograph comprehensively covers questions concerning cassiterite and its application, thus contributing to popularization of cassiterite jewelry and craftsmanship and laying the foundation for a new direction in the semi-precious stone industry. The author of the monograph critically reviewed the results of previous studies on the mineral and chemical composition of cassiterite and added an extensive set of his own analytical methods. The gemological and technological characteristics of cassiterite minerals were given, along with recommendations on their rational search, use and quality improvement. In term of ecological parameters, it was shown that the content of carcinogenic and radioactive elements in jewelry cassiterites does not exceed the background values. The market conditions were described, and recommendations on the organization of mining and geological work in this sphere were presented.

Alternative viewpoints on the nature and importance of a prominent syncline at the northeastern edge of Wyoming’s Hanna Basin

ABSTRACT The geologic history of Wyoming’s Hanna Basin is still being written. Surprisingly, here appeared an opportunity to share insights from previously accomplished work with that conducted anew by other scholars. The area of study was in the southeastern quadrant of Wyoming, which exhibits the state’s most complex history with respect to the Laramide orogeny. Especially important for present purposes were the tectonic conditions of the late Paleocene and earliest Eocene, recorded within the Hanna Formation. Of central focus is the 2020 publication by Dechesne and her six co-authors. Geographically, the landscape they covered was a thin, synclinal slice of the northeastern margin of the Hanna Basin. Key goals for the present publication have been to illustrate positive linkages and to highlight discrepancies between Dechesne et al. (2020) and relevant prior geological work. A concern that permeates all facets of this approach is the ability to verify viability of brand-new geologic descriptions, data, and resulting conclusions. Essential graphical elements were introduced first into this present publication. Once that package of background information was available, more focused analyses were rigorously pursued on diverse issues within the Dechesne et al. (2020) publication. Dechesne’s team presented a significantly modified but adequately defended approximation of the Paleocene–Eocene boundary. Data from fossil plants (macro- and palynofloras), continental mollusks, and bulk organic-carbon isotopes all agree within one measured section (of five sections studied) with an approximated Paleocene–Eocene boundary along with a ‘carbon isotope excursion’ (CIE). Strength of available evidence seems questionable, however, in that the inordinately high variability in bulk organic carbon (characteristic of a CIE) has been demonstrated only in the Hanna Draw Section. Although fluvial, paludal, and lacustrine facies are considered in several contexts, in no sense does the publication’s organizational form provide a ‘detailed stratigraphic framework.’ One zircon-based U–Pb depositional date (54.42 ± 0.27 Ma) came from this study that matched early Wasatchian time. Participants in the Dechesne et al. (2020) project are to be commended in that their resulting paper ranged broadly across the geologic setting, stratigraphy, paleocurrents, paleobotany, continental mollusks, zircon geochronology, associated lithofacies, and paleogeography. Despite that breadth, there exists a plethora of unexpected and wholly avoidable inconsistencies, strong contradictions within what should be homogeneous datasets, and seemingly inexplicable omissions of obviously necessary and sometimes clearly existing but unutilized data, one must question the reliability of much of the information presented in their paper.

Robert McCormick's geological collections from Antarctica and the Southern Ocean, 1839–1843

Robert McCormick (1800–1890) took part in three mid-nineteenth-century British Polar expeditions, two to the Arctic and one to the Antarctic. The latter, from 1839 to 1843 and led by James Clark Ross, is the best known. McCormick served as senior surgeon on HMS Erebus and was responsible for the collection of zoological and geological specimens. Despite the novelty and potential scientific importance of these early geological collections from Antarctica and remote islands in the Southern Ocean, they received surprisingly little attention at the time. Ross deposited an official collection with the British Museum in 1844, soon after the expedition's return, and this was supplemented by McCormick's personal collection, bequeathed in 1890. McCormick had contributed brief and idiosyncratic geological notes to the expedition report published by Ross in 1847, but it was not until 1899 that an informed description of the Antarctic rocks was published, and only in 1921 were McCormick's palaeobotanical specimens from Kerguelen examined. His material from other Southern Ocean islands received even less attention; had it been utilized at the time it would have supplemented the better-known collections made by the likes of Charles Darwin. In later life, McCormick became increasingly embittered over the lack of recognition afforded to him for his work in the Polar regions. Despite that contemporary neglect, his collections from the Ross Antarctic expedition provide unique insight into the geological work of nineteenth-century British naval surgeons.

TECTONICS AND MAGMATISM

Tectonics and magmatism are inextricably interconnected phenomena of the single tectonic-magmatic process. Their scales must be a priori commensurate. However, in practice of geological work, small magmatic complexes often do not correspond to extended magma-controlling structures, due to the notorious complex creation that distorts the geological history, leads to genetic misconceptions and errors in forecasting and searching for mineralization. The urgency of the problem of correct identification of magmatic complexes is illustrated by examples on the materials of large tectonic structures of the Urals, Siberia and the Far East of Russia.