Source‐to‐Sink: Regional Grain Size Trends to Reconstruct Sediment Budgets and Catchment Areas

2021 ◽  
Author(s):  
Nikolaos A. Michael ◽  
Rainer Zühlke
Keyword(s):  
Grain Size ◽  
Sediment Budgets ◽  
Source To Sink ◽  
Catchment Areas

“Grain-size bookkeeping,” a new aid for siliciclastic systems with examples from paralic environments

2019 ◽  
Vol 89 (10) ◽  
pp. 976-1016
Author(s):  
Tony Reynolds
Keyword(s):  
Grain Size ◽  
Large Scale ◽  
Sedimentary Facies ◽  
Fine Sand ◽  
Temporal Variations ◽  
Digital Data ◽  
Overbank Sediments ◽  
Sediment Routing ◽  
Depositional Processes ◽  
Catchment Areas

ABSTRACT Sedimentary logs form the foundation of many studies of ancient and modern sedimentary successions. In siliciclastic settings in particular, vertical grain-size trends are important records of past depositional processes and environments, so that they are recorded with care and are often central to final interpretations. It is rare for the actual grain size to play a similar role. Yet there is significant value in (i) digitizing sedimentary logs to produce statistical grain-size data and (ii) the deliberate study of grain size, a process described here as “grain-size bookkeeping.” To illustrate this, over 5.9 km of sedimentary logs have been digitized from the Miocene to Pliocene paleo–Orinoco delta, the Cretaceous Ferron Last Chance and Notom deltas, and the Jurassic Ravenscar Group. The digital data reveal how grain size partitions into distinct sedimentary facies, proximal-to-distal changes, changes related to stratigraphy and base level, and the overall grain size of paralic systems. It emerges that fluvio-distributary channels are the coarsest-grained sediment bodies in each of the studied systems. The coarsest material does not reach the shoreline, though the grain sizes of fluvio-distributary channels and shoreline sand bodies overlap, in accordance with the concept that the former feeds the later. By contrast, overbank sediments are relatively fine-grained, suggesting that, with the exception of channel belts, coarse sediment can largely bypass the delta plain. Grain-size changes occur across some key stratigraphic surfaces, but not consistently so. Channels in valleys are, on average, coarser than similar channels in unconfined systems, but, in the presented datasets, valleys do not contain the coarsest channels. The data have also allowed the analysis of down-system fining rates in ancient, sandy fluvio-distributary systems, with grain size being measured to decrease at rates ranging from 0.7 to 7.7 μm/km—values that compare favorably with modern rivers. Such large-scale trends are ornamented by, and link to, smaller-scale spatial changes associated with, for example, channel bars, crevasses, and mouth bars, and an initial dataset of associated fining rates has been collected. In general, very large systems (rivers) have low fining rates because of their great size, whereas the converse is true for small systems, especially if the grain size range is large. Consideration of downstream fining rates has led to the insight that avulsion initiates an unequal race to the shoreline. Suspended very fine sand and silt is likely to reach the shoreline with the avulsion flood waters, but bedload will advance far more slowly, perhaps too slowly to reach the shoreline before the river avulses again. Some avulsions may lead to notable temporal variations in the caliber of sediment supplied to shorelines. As expected, the largest system, the paleo-Orinoco, is the finest grained. The Ferron deltas have catchment areas 12 and 22 times smaller than the Orinoco, and are the coarsest grained. Remarkably, though their catchment areas differ by a factor of two, they have almost identical sand grain-size distributions. The data have also proved powerful in refining paleogeographic reconstructions, in particular suggesting “missing” depositional elements needed to complete local sediment routing systems. Careful tracking of grain size is also beneficial in that it is a key control on permeability, the description of which is crucial to the prediction of subsurface fluid flow.

Source to sink studies between the Shaleitian uplift and surrounding sags: Perspectives on the importance of hinterland relief and catchment area for sediment budget, Western Bohai Bay Basin, China

2017 ◽  
Vol 5 (4) ◽  
pp. ST65-ST84 ◽  
Author(s):  
Xiaomin Zhu ◽  
Shunli Li ◽  
Qianghu Liu ◽  
Zili Zhang ◽  
Changgui Xu ◽  
...  
Keyword(s):  
Physical Properties ◽  
Seismic Data ◽  
Catchment Area ◽  
Coarse Grained ◽  
Bohai Bay ◽  
Tectonic Zone ◽  
Clastic Rocks ◽  
Source To Sink ◽  
Coupling System ◽  
Catchment Areas

Source-to-sink system analysis, a cutting-edge topic in the field of earth science, encompasses the whole system, from erosion and transportation to sediment accumulation on the earth’s surface, and involves multidisciplinary collaboration. This current analysis, based on high-precision 3D seismic data, well logs, and other drilling data, using quantitative characterization of the source-to-sink elements, documents that Archean-Proterozoic migmatitic granite, Cambrian-Ordovician carbonate and clastic rocks, and Mesozoic volcaniclastic rocks are developed in the Shaleitian uplift from south to north across large relief differences (up to 2300 m). The relief and size of the catchment in the source area were calculated by denudation recovery, time-depth conversion and high-resolution interpretation on seismic data. Three types of sediment-transporting channel system and 20 catchment areas ([Formula: see text]) were documented around the edges of the uplift: paleovalley channels, fault-controlled channels, and fault-transfer channels. The Paleogene sink is dominated by near-source coarse-grained depositional systems, with the lithofacies characteristics of low lake level (sand rich), lake transgressive (mud rich), and uplift period (sand rich). Three types of boundary conditions developed in the region of the Shaleitian uplift: fault-related steep-slopes (single or multiple), fault ramps, and slope patterns. The bedrock composition, catchment area, channel systems, and fault-border patterns in the Shaleitian uplift jointly controlled the types and scales of sedimentary sandbodies. The south Shaleitian tectonic zone functioned as a high-efficiency coupling system in which reservoir sandbodies were developed (extensive length distance, with well-sorted and round-grained sediments, but weak physical properties). The coupling system for the southwest and west Shaleitian tectonic zones is subordinate (near source and sand rich, sand and mud interbedded, and weak physical properties). The coupling system of the northeast Shaleitian tectonic zone is lowest in efficiency (relatively mud rich).

Effect of Shock Loading on the Microstructure of Uniloy 326

1974 ◽  
Vol 32 ◽  
pp. 504-505
Author(s):  
K. P. Staudhammer ◽  
L. E. Murr
Keyword(s):  
Grain Size ◽  
Shock Loading ◽  
Current Investigation ◽  
Two Phase ◽  
05 C ◽  
Shock Deformation ◽  
Heat Treated

The effect of shock loading on a variety of steels has been reviewed recently by Leslie. It is generally observed that significant changes in microstructure and microhardness are produced by explosive shock deformation. While the effect of shock loading on austenitic, ferritic, martensitic, and pearlitic structures has been investigated, there have been no systematic studies of the shock-loading of microduplex structures.In the current investigation, the shock-loading response of millrolled and heat-treated Uniloy 326 (thickness 60 mil) having a residual grain size of 1 to 2μ before shock loading was studied. Uniloy 326 is a two phase (microduplex) alloy consisting of 30% austenite (γ) in a ferrite (α) matrix; with the composition.3% Ti, 1% Mn, .6% Si,.05% C, 6% Ni, 26% Cr, balance Fe.

Aspects of microanalysis in a transmission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 510-511
Author(s):  
R. Sinclair ◽  
B.E. Jacobson
Keyword(s):  
Grain Size ◽  
Electron Beam ◽  
Electron Microscope ◽  
Chemical Analysis ◽  
Transmission Electron Microscope ◽  
Vapor Deposition ◽  
Critical Currents ◽  
X Ray ◽  
Fine Grain ◽  
Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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