Compilation of various geologic time scales

2001 ◽  
Author(s):  
Anna B. Wilson
Keyword(s):  
2019 ◽  
Vol 124 (8) ◽  
pp. 2056-2078 ◽  
Author(s):  
Paul R. Eizenhöfer ◽  
Nadine McQuarrie ◽  
Eitan Shelef ◽  
Todd A. Ehlers

Geology ◽  
2005 ◽  
Vol 33 (11) ◽  
pp. 909 ◽  
Author(s):  
Jon D. Pelletier ◽  
Joseph P. Cook
Keyword(s):  

2021 ◽  
Author(s):  
Matthew Ferguson

Instruments of Gaia is a thesis which interviews the role of architecture as an interface between nature and human experience. The contained argument is a critique on architecture’s reliance on climatic mitigation; whereas relationships between site and user are nullified through concealed building systems. This thesis project as a counterpoint explores new ideas of architectural design and expression as a register for and active agent in the anthropocene where the magnification and understanding of place and site plays a key role in the development of the climatic imagination needed ever more, to grapple with human impact on the very ground we rest our foundations upon. Architectural expression as an intuitive, didactic mechanism and amplifier of this relationship is explored through the collapsing of multidisciplinary research, and expression of the fragility, and enormity of Gaia as a new secular mythos of the cosmos, and the embedding of these new myths, through weathering and geologic time scales, into an architectural project. The experiential memories formed within this expanded field of architecture constitute a new body of sensible knowledge. The art of architecture offers the medium with which to collapse these assemblages into poetic space and memory, and the beginning of a new dialogue with the Gaia of the Anthropocene.


2021 ◽  
Author(s):  
Cari Johnson ◽  
Julia Mulhern ◽  
Andrew Green

<p>Existing depositional and facies models for ancient barrier island systems are primarily based on modern observations. This approach overlooks processes tied to geologic time scales, such as multi-directional motion, erosion, and reworking, and their resulting expressions in preserved strata. We have investigated these and other challenges of linking modern and ancient barrier islands through outcrop studies and through data compilation from the rock record compared to modern barrier island dimensions. Results emphasize key depositional and preservation processes, and the dimensional differences between deposits formed over geologic versus modern time scales. For example, when comparing deposits from individual barrier islands, thickness measurement comparisons between modern and ancient examples do not vary systematically, suggesting that local accommodation and reworking dictate barrier island thickness preservation. A complementary outcrop study focusing on paralic strata from the Upper Cretaceous Straight Cliffs Formation in southern Utah (USA) is used to update models for barrier island motion and preservation to include geologic time-scale processes. Barrier island deposits are described using four facies associations (FA): backbarrier fill (FA1), lower and upper shoreface (FA2), proximal upper shoreface (FA3), and tidal channel facies (FA4). Three main architectural elements (barrier island shorefaces, shoreface-dominated inlet fill, and channel-dominated inlet fill) occur independently or in combination to create stacked barrier island deposits. Barrier island shorefaces record progradation, while shoreface-dominated inlet fill records lateral migration, and channel-dominated inlet fill records aggradation within the tidal inlet. Barrier islands are bound by lagoons or estuaries and are distinguished from other shoreface deposits by their internal facies and outcrop geometry, association with backbarrier facies, and position within transgressive successions. Tidal processes, in particular, tidal inlet migration and reworking of the upper shoreface, also distinguish barrier island successions. In sum, these datasets demonstrate that improved depositional and facies models must consider multidirectional island motion, ravinement, erosion, inlet migration, and reworking when describing processes and predicting barrier island dimensions.</p>


2016 ◽  
Vol 2 (10) ◽  
pp. e1600204 ◽  
Author(s):  
Vamsi Ganti ◽  
Christoph von Hagke ◽  
Dirk Scherler ◽  
Michael P. Lamb ◽  
Woodward W. Fischer ◽  
...  

Deciphering erosion rates over geologic time is fundamental for understanding the interplay between climate, tectonic, and erosional processes. Existing techniques integrate erosion over different time scales, and direct comparison of such rates is routinely done in earth science. On the basis of a global compilation, we show that erosion rate estimates in glaciated landscapes may be affected by a systematic averaging bias that produces higher estimated erosion rates toward the present, which do not reflect straightforward changes in erosion rates through time. This trend can result from a heavy-tailed distribution of erosional hiatuses (that is, time periods where no or relatively slow erosion occurs). We argue that such a distribution can result from the intermittency of erosional processes in glaciated landscapes that are tightly coupled to climate variability from decadal to millennial time scales. In contrast, we find no evidence for a time scale bias in spatially averaged erosion rates of landscapes dominated by river incision. We discuss the implications of our findings in the context of the proposed coupling between climate and tectonics, and interpreting erosion rate estimates with different averaging time scales through geologic time.


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