Ever wonder why beach sand is so well sorted and beautiful? Shoreface depositional environments are the regions of the beach and the near-shore region of the continental shelf where beach sand is deposited, weathered, rounded, and sorted. In this video, I go over shoreface, or shoreline, depositional systems, including wave and current processes, the zones of the shoreface (upper, middle, and lower), and the sedimentary structures and stratigraphy in each of these zones. Over geologic time, the movement of the sand along the beach and shoreface environments leads to sedimentary structures, such as trough cross bedding, hummocky and swaley stratification, ripple marks, and laminations, but these structures form in different regions of the shoreface environment. The upper shorface, middle shoreface, and lower shoreface lead to distinct sedimentary structure sequences due to the difference in the wave strength that hits the seafloor at each depth. What does wave strength at the seafloor mean? Well waves have a base, the rotation of the water molecules in waves becomes less strong with depth and ends at a certain depth, this is the wave base. The wave base is deeper during storms because the stronger winds form larger waves. For this reason, stratified layers of rock form in the deeper parts of the shoreface during storms than they normally would. I also go over how to recognize these shoreface environments in the rock record and certain trace fossils that will help you distinguish which zone of the shoreface you are looking at. Hope you enjoy the video! ;)
References:
Depositional Sedimentary Environments: amzn.to/3kutTso
Facies models 4: amzn.to/3Fp5v3B
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0:00 What/where are shoreline environments?
0:14 Wave processes (how waves work)
2:33 Currents (currents are different than waves!)
3:22 Shoreface environmental facies
4:39 Shoreface deposition & stratigraphy
5:26 Beach/foreshore stratigraphy
5:41 Breaker zone/upper shoreface stratigraphy
5:50 Lower shoreface stratigraphy
6:38 Ripples, & hummocky vs. trough cross stratification
8:25 transgressive vs. regressive sequences
10:40 Ichnofacies (trace fossils) in shoreface environments
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Non-textbook books I recommend:
Oxygen by D. Canfield: amzn.to/3gffbCL
Brief history of Earth by A. Knoll: amzn.to/3w3hC1I
Life on young planet by A. Knoll: amzn.to/2RBMpny
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Your inner fish by N. Shubin: amzn.to/3cpw3Wb
Oxygen by N. Lane: amzn.to/3z4FgwZ
Alien Oceans by K. Hand: amzn.to/3clMx1l
Life's Engines: amzn.to/3w1Nhke
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Geology field notebook: amzn.to/3lb6dJf
Geology rock hammer: amzn.to/3DZw8MA
Geological compass: amzn.to/3hfbdLu
Geological hand lens: amzn.to/3jXysM5
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Image sources:
www.greecetravel.com/thessalo...
geology.isu.edu/Alamo/rocks/li...
web.arc.losrios.edu/~borougt/S...
sepmstrata.org/page.aspx?pagei...
www.geocaching.com/geocache/G...
www.amazon.ca/Facies-Models-R...
www.flickr.com/photos/1358217...
www.geocaching.com/geocache/G...
/ 157485318203242721
geologypics.com/hummocky-cros...
basdargeophysics.wordpress.co...
commons.wikimedia.org/wiki/Fi...
geologylearn.blogspot.com/201...
speedstar71.blogspot.com/2014/12/
www.geol.umd.edu/~jmerck/geol...
www.schursastrophotography.com...
www.geol.umd.edu/~tholtz/G331...
www.hayesandjarvis.co.uk/holi...
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Негізгі бет Ғылым және технология Shoreface Depositional Environments & Stratigraphy | GEO GIRL
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