Understanding 21Ne inventories in Precambrian basement below the Great Unconformity in Estonia

2021 ◽  
Author(s):  
Adrian M. Hall ◽  
Fin Stuart ◽  
Kalle Kirsimae ◽  
Peeter Somelar
Keyword(s):  
Isotope Composition ◽  
Precambrian Basement ◽  
Weathering Profile ◽  
Deep Time ◽  
Late Precambrian ◽  
Cosmogenic Nuclide ◽  
The Earth ◽  
Land Surfaces ◽  
Natural Decay ◽  
Geochemical Mass Balance

<p>Stable cosmogenic Ne isotopes are widely used to determine the erosion rate of slowly-eroding land surfaces through the Cenozoic. Constraining erosion and surface exposure back in Earth history remains a challenge largely due to the presence of Ne isotopes generated by natural decay processes over the lifetime of rocks.  Prospects are best when cosmogenic nuclide production has been significant and nucleogenic Ne production is low and can be quantified.  We have explored the limits of palaeo-cosmogenic Ne in one of the Earth’s most extensive erosion surfaces, the late Precambrian Great Unconformity in Estonia. Here deep kaolinitic saprolites formed on Baltica prior to the deposition of Late Ediacaran quartz sandstones. On the basis of geochemical mass balance the duration of saprolite development is estimated to be of the order of a few Myr.</p><p>Borehole F163 samples a section through still-buried weathered unconformity that includes a saprolite surface consistent with negligible erosion during the marine transgression. Samples from the unconformity have <sup>21</sup>Ne concentrations (>10<sup>8</sup> atoms/g) that are significantly higher than shielded samples from >20 m below the unconformity. This difference is borne out by Ne isotope composition, and leads to the tanatalising prospect that Precambrian cosmogenic Ne is present in the saprolite. Using modern <sup>21</sup>Ne production rates the palaeosols appear to record a few million years irradiation. This is broadly consistent with geochemical estimates of saprolite development.  Samples from the uppermost preserved part of the weathering profile in borehole F231 have low <sup>21</sup>Ne concentrations that are indistinguishable from deeper in the rock profile. This would require profile truncation or the redeposition of weathered material.  The borehole is located on the western flank of an uplifted basement block rising ca 130 m above the typical Precambrian basement level in the area and likely that the thick regolith contains material eroded from the uplifted basement units. Clearly these are early days and quantifying surface exposure in deep time will require effort in field as well as the lab.</p>

The Earth Sciences and Creative Practice

2015 ◽  
pp. 110-140
Author(s):  
Suzette Worden
Keyword(s):  
Earth Sciences ◽  
Digital Media ◽  
Time Interval ◽  
Audience Participation ◽  
Transdisciplinary Approach ◽  
Deep Time ◽  
Environmental Care ◽  
The Earth ◽  
Geological Age ◽  
Curatorial Practice

The Anthropocene is being suggested as a new geological age replacing the Holocene and is a description of a time interval where significant conditions and processes are profoundly altered by human activity. Artists interested in the earth sciences are using digital media to provide audiences with ways of understanding the issues highlighted in discussions about the Anthropocene. These artists are harnessing data through visualisation and sonification, facilitating audience participation, and are often working in art-science collaborations. These activities demonstrate a transdisciplinary approach that is necessary for confronting the world's most pressing problems, such as climate change. After a discussion of the opportunities provided by visualisation technologies and an overview of the Anthropocene, this chapter explores the following interrelated themes through examples of creative works: (1) nanoscale, (2) geology and deep time, (3) climate, weather, and the atmosphere, (4) extreme places – beyond wilderness, and (5) curatorial practice as environmental care.

An Artful Planet

2020 ◽  
pp. 128-145
Author(s):  
Adam Pryor
Keyword(s):  
Biogeochemical Cycles ◽  
Imago Dei ◽  
Shared Responsibility ◽  
Human Beings ◽  
Deep Time ◽  
The Earth

This chapter offers a constructive account of interpreting the Anthropocene and the imago Dei as corroborative symbols interpreted in an astrobiological context of engagement by weaving the crucial themes of intra-action, refraction, planetarity, and deep time together. It proposes that to be the imago Dei is not a property of individuals or even a species but describes a categorical shift in planetary flows of energy and matter. This is a shift from biogeochemical cycles to technobiogeochemical cycles. If human beings live into our shared responsibility for being the imago Dei, then the Earth should be understood as not only a living planet, but an artful one.

scholarly journals Deep-time organizations: Learning institutional longevity from history

2019 ◽  
Vol 7 (1) ◽  
pp. 19-41 ◽  
Author(s):  
Frederic Hanusch ◽  
Frank Biermann
Keyword(s):  
Empirical Research ◽  
Design Principles ◽  
Earth System ◽  
Political Organizations ◽  
Deep Time ◽  
Initial Design ◽  
Earth System Governance ◽  
The Earth ◽  
Temporal Interdependencies

The Anthropocene as a new planetary epoch has brought to the foreground the deep-time interconnections of human agency with the earth system. Yet despite this recognition of strong temporal interdependencies, we still lack understanding of how societal and political organizations can manage interconnections that span several centuries and dozens of generations. This study pioneers the analysis of what we call “deep-time organizations.” We provide detailed comparative historical analyses of some of the oldest existing organizations worldwide from a variety of sectors, from the world’s oldest bank (Sveriges Riksbank) to the world’s oldest university (University of Al Quaraouiyine) and the world’s oldest dynasty (Imperial House of Japan). Based on our analysis, we formulate 12 initial design principles that could lay, if supported by further empirical research along similar lines, the basis for the construction and design of “deep-time organizations” for long-term challenges of earth system governance and planetary stewardship.

Clumped Isotope Paleothermometry: Principles, Applications, and Challenges

2012 ◽  
Vol 18 ◽  
pp. 101-114 ◽  
Author(s):  
Hagit P. Affek
Keyword(s):  
Isotope Composition ◽  
Isotope Analysis ◽  
Atomic Scale ◽  
Clumped Isotopes ◽  
Temperature Dependent ◽  
Deep Time ◽  
Diagenetic Alteration ◽  
Carbonate Formation ◽  
Rare Isotopes ◽  
Clumped Isotope

Clumped isotopes geochemistry measures the thermodynamic preference of two heavy, rare, isotopes to bind with each other. This preference is temperature dependent, and is more pronounced at low temperatures. Carbonate clumped isotope values are independent of the carbonate δ13C and δ18O, making them independent of the carbon or oxygen composition of the solution from which the carbonate precipitated. At equilibrium, it is therefore a direct proxy for the temperature in which the carbonate mineral formed. In most cases, carbonate clumped isotopes record the temperature of carbonate formation, irrespective of the mineral form (calcite, aragonite, or bioapatite) or the organism making it. The carbonate formation temperatures obtained from carbonate clumped isotope analysis can be used in conjunction with the δ18O of the same carbonate, to constrain the oxygen isotope composition of the water from which the carbonate has precipitated. There are, however, cases of deviation from thermodynamic equilibrium, where both clumped and oxygen isotopes are offset from the expected values. Such carbonates must be characterized and calibrated separately. For deep-time applications, special care must be paid to the preservation of the original signal, in particular with respect to diagenetic alteration associated with atomic scale diffusion that may be undetectable by common tests for diagenesis.

On the position of the Variscan front in southern New Brunswick and its relation to Precambrian basement

1976 ◽  
Vol 13 (1) ◽  
pp. 194-196 ◽  
Author(s):  
N. Rast ◽  
K. L. Currie
Keyword(s):  
New Brunswick ◽  
Precambrian Basement ◽  
Precambrian Rocks ◽  
Late Precambrian ◽  
Mylonite Zone

The Variscan front is marked by a zone of cataclasis that generally follows an older and larger mylonite zone, but locally cuts across relatively undeformed Precambrian rocks. The older mylonite zone probably developed in Late Precambrian (Avalonian) time. Correlative Precambrian rocks extend across both the Variscan front, and the Bellisle fault to the northwest.

Deep time and compressed time in the Anthropocene: The new timescape and the value of cosmic storytelling

2020 ◽  
Vol 7 (2) ◽  
pp. 125-137
Author(s):  
Boris Shoshitaishvili
Keyword(s):  
Technological Change ◽  
Scientific Discovery ◽  
The Other ◽  
Earth System ◽  
Human Beings ◽  
Geologic History ◽  
Deep Time ◽  
The Earth ◽  
The One

The scientific discovery of our universe’s immense cosmological history and Earth’s vast geologic history has radically altered common perceptions of time, prompting us to think in terms of millions and billions of years rather than hundreds and thousands. Meanwhile human societies impact the Earth System at accelerating rates and more comprehensively than ever before, leading scientists to propose the new geological epoch of the Anthropocene. These two contrasting temporal transformations have mostly been considered separately: the expanding awareness of cosmological and geologic duration, on the one hand, and the acute sense of swift technological change, on the other. However, their contrast and coexistence are important to recognize. The challenge of understanding the Anthropocene’s complex timescales is partly due to the inability of human institutions to reconcile this twofold disruption whereby time has both expanded (into deep time) and compressed (in techno-social acceleration). After theorizing this transformation, I evaluate the current cosmic stories helping human beings reconceptualize the new timescape.

‘HUMBOLDTIAN SCIENCE’ AND BEYOND. THE HUMBOLDTIAN WAY OF SEEING AND KNOWING IN VIENNA AND IN FRANZ UNGER’S AND FRIEDRICH SIMONY’S EARTH SCIENCES

2020 ◽  
Vol 39 (2) ◽  
pp. 228-245
Author(s):  
MARIANNE KLEMUN
Keyword(s):  
Earth Sciences ◽  
Academic Disciplines ◽  
Cultivated Plants ◽  
Deep Time ◽  
Everyday Activities ◽  
The Earth ◽  
Victorian Period ◽  
American Historian ◽  
The Impact ◽  
Different Levels

ABSTRACT This contribution builds on the notion of ‘Humboldtian Science’, coined by the American historian of science Susan F. Cannon who, in her book Science in Culture: The Early Victorian Period (1978), identifed a constellation of practices, strategies and ideas as typical of the research style of British naturalists during the nineteenth century. Cannon’s explanatory model has been widely accepted and for many different reasons. It became attractive as it seemed to break the deadlock of the ambivalence between idealism and empiricism, leading beyond the narrow perspective of academic disciplines. At the same time, it focused on practices and has become a useful tool to analyze the seemingly everyday activities of naturalists in the field. This contribution discusses the potential of this concept at different levels and will also show its limits; insofar as it runs the risk of idealizing Humboldt as an already epigonal figure. It will also analyze Humboldt’s connections to Vienna and his influences on natural sciences by focusing on two examples from the earth sciences, the contributions of the palaeontologist and biologist Franz Unger and the geologist and geographer Friedrich Simony. In so doing, it will widen understanding of the impact of Humboldt’s work in Vienna, detecting not only ‘Humboldtian Science’ but also the Humboldtian way of seeing and knowing where it is not expected: in Unger’s Atlantis theory, his visualization of origins of cultivated plants, and his visualization of deep time, as well as Friedrich Simony’s concept of scientific landscape drawings.

scholarly journals Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

2018 ◽  
Author(s):  
Marcus P. S. Badger ◽  
Thomas B. Chalk ◽  
Gavin L. Foster ◽  
Paul R. Bown ◽  
Samantha J. Gibbs ◽  
...  
Keyword(s):  
Isotope Fractionation ◽  
Isotope Composition ◽  
Ice Core ◽  
Co2 Uptake ◽  
Geological Time ◽  
Time Intervals ◽  
The Past ◽  
The Earth ◽  
Global Carbon ◽  
Carbon System

Abstract. Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present and future climate. Accurate and precise reconstructions of its concentration through geological time are, therefore, crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyrs, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Plio-Pleistocene at ODP Site 999 across a glacial-interglacial cycle. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2.

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