Shallow water corrugates as it flows over the curved surface of Brown Mountain granite in Wilson Creek, North Carolina. Crests in the flow act like lenses creating many suns between many vales.
Many Suns and Vales
Sun Haloes at Morrow Mountain State Park in Central North Carolina
Under propitious conditions, at sunset you might see something amazing. These images were captured from Morrow Mountain State Park in the central Piedmont of North Carolina. This is a rhyolite ridge in the Uwharrie Mountains. The volcanic rocks formed several hundred million years ago as part of a volcanic arc …
Meander and Point Bar in Flat Creek, SC
Flat Creek southeasterly through Lancaster County, South Carolina. The stream feeds into Lynches River, that farther southeast joins the Great Pee Dee River. The Pee Dee joins the Waccama River at Georgetown on the SC Atlantic Coast.
Flat Creek carries a heavy load of sediment. Where this image was made, the stream crosses the Pageland granite, a pluton that is about 300 million years old. The granite is coarse-grained and sheds considerable quartz and feldspar grains as it weathers and erodes.
This image is a 180° panorama around a meander bend in Flat Creek. Lower water velocity on the inside of the meander causes the coarser sediment load to drop out to form a sandy point bar. The near bank of the river is being undercut by erosion on the outside of the meander where water velocity is greater. In time, the stream channel will migrate toward this cut bank.
It’s difficult to see in the shadows, but in the lower left corner of the photograph a tributary trickles into the main channel, and there are abundant beaver tracks there. Beavers use the tributary mouth as a slide.
In the lower right corner of the photograph you can see a boulder of Pageland granite. It’s rounded shape is characteristic of spheroidal weathering of a larger mass of granite bedrock.
Not far to the southeast, Flat Creek crosses from Piedmont igneous and metamorphic rocks into sedimentary rocks of the Sandhills.
This image was made late on a Spring afternoon under a brilliant blue sky reflecting off the water’s surface and under the long shadows of hardwood trees yet to put out theire leaves.
This image is ©Andy R. Bobyarchick
Images from the Nace Brock Photographic Collection
Ignatius Watsworth Brock (1866-1950) was a photographer, artist, and poet who worked out of New Bern and Asheville, NC. Images that he made roughly between 1889 and 1934 are collected at the North Carolina Collection Photographic Archives at the University of North Carolina at Chapel Hill.
Nace Brock made photographs (and drawings) of people and places in North Carolina. Some of the photographic materials in the archive are from glass plates, others from photographic prints.
Some of his portraiture is stunning in how he captured his subjects’ personalities in stillness. Most of the character photographs in the collection are from 1889-1938. During most of that time period, people did not smile for portraits by convention, although in some of the photographs you can see a hint of a smile on the subject’s lips or in her eyes.
Here are a few images extracted from the collection. It’s impossible to view these images without wondering who these people were, what they were thinking, and where they went for the rest of their lives. You can almost reach out and touch them.
Happy Valentine’s Day 2018
Happy Valentine’s Day from me and my friends in the Underworld!
Love, Andy.
Morrow Mountain State Park, NC. Image ©Andy Bobyarchick.
Invasive Gastropods in High Rock Lake, NC
High Rock Lake is one of several impoundments on the Yadkin-Pee Dee river system in the North Carolina Piedmont. Flat Swamp Creek is, or was, a tributary to the Pee Dee River. After the High Rock reservoir filled Flat Swamp Creek became a narrow, northeast-trending arm to the larger lake. …
Sand and Ripples in the Pee Dee River
Ripples are periodic waveforms throughout the natural environment. These subaqueous asymmetrical wave ripples in sand under the Pee Dee River in North Carolina are created by oscillatory wave motions normal or slightly oblique to the shoreline.
Needle Ice: A Gallery
Needle ice forms in porous, wet soil or sediment when the soil temperature is above freezing and the surface atmosphere temperature is below freezing. Permeability is important. Capillary action pulls water up toward the surface where the water freezes at the bases of growing ice crystals. The growing crystals are capable of lifting small particles and vegetation above the normal soil surface. This differential motion can thoroughly disaggregate and disrupt the upper several centimeters of the soil profile in temperate climates.
The images in this gallery were made in an elementary school yard where patches of bare soil are exposed. By the time I walked over the yard, the sun had melted most of the crystals except for those protected by shadows. Most of the single, larger grains on top of the crystals are coarse sand, perhaps around 2 mm (millimeters) in diameter.
All photographs in this post ©Andy R. Bobyarchick.
Bibliography
Carter, J. R., 2013, Flowers and ribbons of ice: American Scientist, v. 101, p. 360-369.
Li, A., Matsuoka, N., and Niu, F., 2017, Frost sorting on slopes by needle ice: A laboratory simulation on the effect of slope gradient: Earth Surface Processes and Landforms, p. <xocs:firstpage xmlns:xocs=””/>. 10.1002/esp.4276
Li, A., Matsuoka, N., and Niu, F., 2018, Frost sorting on slopes by needle ice: A laboratory simulation on the effect of slope gradient: Earth Surface Processes and Landforms, p. n/a-n/a. 10.1002/esp.4276
Soons, J. M., and Greenland, D. E., 1970, Observations on the Growth of Needle Ice: Water Resources Research, v. 6, no. 2, p. 579-593. 10.1029/WR006i002p00579
Yamagishi, C., and Matsuoka, N., 2015, Laboratory frost sorting by needle ice: a pilot experiment on the effects of stone size and extent of surface stone cover: Earth Surface Processes and Landforms, v. 40, no. 4, p. 502-511. 10.1002/esp.3653
Needle Ice in a Loamy Soil
Needle ice in a loamy soil in a schoolyard near Salisbury, NC. The individual particles on top of the needles are coarse sand in size. Needle ice forms when soil water moves upward under capillary pressure and freezing when it contacts cold air. I will be posting a gallery of images with context on my blog soon. (The server is having intermittent problems right now.)
Tectonic Architecture
“Tectonic” as an adjective or “tectonics” as a noun refers to the large-scale structure of Earth’s crust and lithosphere. Outside of geology, the word tectonic may refer to a building or construction. The concept arrived in geological sciences prior to “plate tectonics”, mainly with application to mountain building. The word …