Landscape Response to Lateral Advection in Convergent Orogens Over Geologic Time Scales

2019 ◽  
Vol 124 (8) ◽  
pp. 2056-2078 ◽  
Author(s):  
Paul R. Eizenhöfer ◽  
Nadine McQuarrie ◽  
Eitan Shelef ◽  
Todd A. Ehlers
Keyword(s):  
Time Scales ◽  
Geologic Time ◽  
Landscape Response ◽  
Lateral Advection

Deposition of playa windblown dust over geologic time scales

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

scholarly journals Instruments of Gaia

2021 ◽  
Author(s):  
Matthew Ferguson
Keyword(s):  
Human Impact ◽  
Time Scales ◽  
Architectural Design ◽  
Active Agent ◽  
Human Experience ◽  
Multidisciplinary Research ◽  
Geologic Time ◽  
Building Systems ◽  
New Ideas

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.

scholarly journals Controlling factors of the oxygen balance in the Arabian Sea's OMZ

2012 ◽  
Vol 9 (12) ◽  
pp. 5095-5109 ◽  
Author(s):  
L. Resplandy ◽  
M. Lévy ◽  
L. Bopp ◽  
V. Echevin ◽  
S. Pous ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Time Scales ◽  
Arabian Sea ◽  
Eastern Coast ◽  
Western Coast ◽  
Oxygen Balance ◽  
Ekman Pumping ◽  
The South ◽  
Sources And Sinks ◽  
Lateral Advection

Abstract. The expansion of OMZs (oxygen minimum zones) due to climate change and their possible evolution and impacts on the ecosystems and the atmosphere are still debated, mostly because of the unability of global climate models to adequatly reproduce the processes governing OMZs. In this study, we examine the factors controlling the oxygen budget, i.e. the equilibrium between oxygen sources and sinks in the northern Arabian Sea OMZ using an eddy-resolving biophysical model. Our model confirms that the biological consumption of oxygen is most intense below the region of highest productivity in the western Arabian Sea. The oxygen drawdown in this region is counterbalanced by the large supply of oxygenated waters originated from the south and advected horizontally by the western boundary current. Although the biological sink and the dynamical sources of oxygen compensate on annual average, we find that the seasonality of the dynamical transport of oxygen is 3 to 5 times larger than the seasonality of the biological sink. In agreement with previous findings, the resulting seasonality of oxygen concentration in the OMZ is relatively weak, with a variability of the order of 15% of the annual mean oxygen concentration in the oxycline and 5% elsewhere. This seasonality primarily arises from the vertical displacement of the OMZ forced by the monsoonal reversal of Ekman pumping across the basin. In coastal areas, the oxygen concentration is also modulated seasonally by lateral advection. Along the western coast of the Arabian Sea, the Somali Current transports oxygen-rich waters originated from the south during summer and oxygen-poor waters from the northeast during winter. Along the eastern coast of the Arabian Sea, we find that the main contributor to lateral advection in the OMZ is the Indian coastal undercurrent that advects southern oxygenated waters during summer and northern low-oxygen waters during winter. In this region, our model indicates that oxygen concentrations are modulated seasonally by coastal Kelvin waves and westward-propagating Rossby waves. Whereas on seasonal time scales the sources and sinks of oxygen are dominated by the mean vertical and lateral advection (Ekman pumping and monsoonal currents), on annual time scales we find that the biological sink is counterbalanced by the supply of oxygen sustained by mesoscale structures (eddies and filaments). Eddy-driven advection hence promotes the vertical supply of oxygen along the western coast of the Arabian Sea and the lateral transport of ventilated waters offshore the coast of Oman and southwest India.

How to link modern and ancient barrier island systems: Dimensional comparisons and updated sedimentary facies models 

2021 ◽  
Author(s):  
Cari Johnson ◽  
Julia Mulhern ◽  
Andrew Green
Keyword(s):  
Time Scales ◽  
Barrier Island ◽  
Barrier Islands ◽  
Sedimentary Facies ◽  
Thickness Measurement ◽  
Tidal Inlet ◽  
Lateral Migration ◽  
Geologic Time ◽  
Facies Associations ◽  
Facies Models

<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>

scholarly journals Time scale bias in erosion rates of glaciated landscapes

2016 ◽  
Vol 2 (10) ◽  
pp. e1600204 ◽  
Author(s):  
Vamsi Ganti ◽  
Christoph von Hagke ◽  
Dirk Scherler ◽  
Michael P. Lamb ◽  
Woodward W. Fischer ◽  
...  
Keyword(s):  
Time Scales ◽  
Time Scale ◽  
Erosion Rate ◽  
Earth Science ◽  
Geologic Time ◽  
Erosion Rates ◽  
River Incision ◽  
Tightly Coupled ◽  
Heavy Tailed ◽  
Averaging Time

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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