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This variant of the geological compass is used to measure the dip angle and orientation of an inclined plane simultaneously.. What that means is that during a geological survey you can measure precisely by how much a rock surface is inclined, and towards which direction. The strike (intersection of inclined and horizontal planes can be computed by adding or subtracting 90 degrees to/from the dip orientation.
It was made by Freiberger Präzisionsmechanik in Freiberg in the German Democratic Republic starting in 1954. Freiberg in Saxony is the seat of Germany's oldest university of mining and geology, so it's not a coincidence that this device was made there.
My university has a number of these compasses and I have used them on field trips, but theirs look more modern than this one. I found this on ebay and I originally thought it was an early (i.e., mid-1950s) model, but after checking back with the maker found out it was made between 1982 and 1990.
I wanted to have an early one because I am really into vintage technology, especially, when it's solidly and lovingly crafted to last. It's in perfect working order.
Shot with a Canon EOS600D, a Leica Bellows R and a Leica 100mm f/4 Macro-Elmar-R.
One of the things i´m supposed to do when i finish my studies will be exploring and camping in the mountaims searching for minerals and geological structures that can give us some clues about the location of mineral deposits of economical interest.
I will probably spend weeks in these explorations without having a shower and eating just a few things. AWESOME.
In the photo is my mate Cristopher who posed for me on this capture. There is a similar version of this that won the national photo contest of my college. I was the winner. This image will be used for publicity and will probably appear in buses and many other ways of advertising.
So... cool eh! I´m happy in this moment.
Here's a wider and slightly more colorful view of the checkerboard-patterned bedrock photographed earlier. This is a steep slope... While I didn't try to walk on it, I did make a (foolish) attempt at Checkerboard Mesa in Zion National Park many years ago. Didn't take more than a few steps for me to realize it was a bad idea, and I'm sure the result would have been the same here.
Seen in Grand-Staircase Escalante National Monument, Utah.
Folks on the left are following the trail to the Fire Wave.
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Lake of the Clouds on a cloudy day. The lake occupies a glaciated valley that runs parallel to the strike of the Precambrian rocks that comprise the area. The cliff is basalt. The view is northeasterly, parallel to the length of the lake and the strike of the rocks. Porcupine Mountain Wilderness State Park in Michigan's Upper Peninsula.
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Calcite. The mineral is calcium carbonate. Crystals are scalenohedrons (dogtooth spar). Many exhibit rhombohedral modification of the termination. Under shortwave ultraviolet light, this specimen fluoresces red. Carbonate Canyon. Supai, Coconino Co., Arizona.
I photographed Reed's Beach to capture the artistic designs that the soil, silt & clay create every day. I find the designs fascinating. Some days they remind me of the veins and arteries of the body.
Description (1964) Dr. E. Dale Jackson, U.S. Survey Geologist, with Astronauts Neil Armstrong, Richard Gordon and Don F. Eisele during Geological Training Grand Canyon, Arizona
Credit: NASA
Image Number: S64-13727
Date: March 5, 1964
Now a favorite spot for playing children, the Devil's Den was on 2 July 1863 the scene of a fiercely contested action between Federal and Confederate soldiers. Both forces suffered heavy losses from their inability to entrench on this exposed, stony ground.
While the Southern troops eventually drove their enemy from this location, they were unable to secure the heights of Little Round Top nearby and thereby failed to turn the Union army's left. Had they done so, they could have gone on to stage a surprise attack from the rear that might have profoundly changed the course of American history.
As it was, the battle was decided the following day when General Robert E. Lee's massive frontal attack on the Union center ("Pickett's Charge") failed disastrously.
Approximately 200 Ma before, near the beginning of the Jurassic period, the Gettysburg area was part of a great rift system created by the breakup of the supercontinent Pangaea. As the crust was stretched, bodies of magma rose—some reaching the surface as volcanic eruptions, and others being emplaced at shallow depth as sills. The rock here, the York Haven Diabase, was part of the latter, and only later was exposed by the forces of erosion.
To see the other photos and descriptions of this series, visit
Another view across the Chinaman Creek Dam in Cloncurry. As different from the vast grass plains of Outback Queensland as you can get, (and they are only 50 kilometres or so down the road), these hills signify the change in geology around Cloncurry and west towards Mt. Isa. Them tha hills are full of rich mineral deposits, in fact, there is a mine about a kilometre away. Copper, silver, lead, zinc, uranium, gold and more have been or are mined in this massively rich area.
That is Black Mountain on the other side of the dam and the Black Mountain Hotel was once a stopover for bullockies (drovers driving cattle) and travellers coming in from the mining communities to the west. Water is pumped from the nearby Cloncurry River into the dam which was constructed in 1994 to keep it topped up.
An intimate capture of the warm and cool tones of light reflected on the textures of this old bristlecone near 14,000 feet in elevation.
The entire gorge of Watkins Glen State Park is full of geological wonders. For ages the rock has been carved down to what we see now. Its truly spectacular.
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this formation is at the western end of Barlings Beach, at Tomakin NSW. It's 2 - 3 metres across, and looks like a quartz-filled swiss roll.
The Giant's Bathtub is more-or-less circular enclosure in the Matthiessen Dells canyon complex. It's walled with weakly cemented Ordovician-period St. Peter Sandstone. This relatively soft rock tends to be eroded into rounded cliff forms.
In contrast, the big deposit of alluvium and colluvium at center contains quite a collection of subrounded erratics (glacially transported boulders) that have found their way down from the upland surface nearby.
Erratics, a common sight in Illinois woodlands, streams, and farm fields in areas covered by the latest, Wisconsin icesheet, include exotic igneous and metamorphic rock types carried hundreds of kilometers from the Canadian Shield. Some of these rocks are five times as old as the St. Peter beds next to them.
Before Louis Agassiz and other nineteenth-century geologists demonstrated that erratics were hefted and later dropped by Pleistocene glaciers, many Earth scientists believed that they were dropstones from icebergs adrift in Noah's Flood.
The other photos and descriptions of this series can be found in my Exploring the Upper Illinois River Region album.
A fragment of Dead Sea mud reveals embedded salt crystals with raw, natural edges. These small formations appear spontaneously beneath the cracked and mineral-rich surface.
This portion of Mycenae's walls is set in more-or-less regularly coursed ashlar blocks—albeit gigantic ones. And though the bedrock directly beneath is gray Triassic-to-Jurassic limestone, the builders here utilized the much younger, Pliocene-to-Pleistocene conglomerate found in the valley below. However, the limestone was used a great deal elsewhere on site, especially where the conglomerate's greater strength and ornamental appeal wasn't deemed necessary.
According to current definition, most of the masonry visible here isn't cyclopean—a term that now refers to unworked boulders and other massive rock fragments set in what seems to be a random fashion. That said, there is some cyclopean stonework visible on top of the walls.
To see the other photos and descriptions of this series, visit my
When we had a chat about xenoliths in the frankly otherwise drab Eugowra Granite in which our temple of democracy is clad I promised to show you some geology down the way because the denizens in this place don't trust me with a camera. I have delivered.
There's less of it than there was. The politicians in the Parliament House have fewer connections to the outside world, or so it seems, than the House itself. One of those connections is a bridge flying over State Circle from Commonwealth Avenue. I'm sure it wasn't necessary but in building that bridge they scraped away a big chunk above what you see here. Still, it remains impressive.
At the bottom of the frame is the State Circle Shale, Early Silurian in age and deposited in deep water. On top of this was the conformably deposited Black Mountain Sandstone. The whole lot lifted up by orogenic forces so that deposition ceased and erosion cut down into these rocks. Up the hill a bit, some of the Black Mountain Sandstone remained. Down here it was all eroded away.
When this part of the world found itself beneath the sea again, the Camp Hill Sandstone was deposited unconformably on top. That's it at the top of this frame. You can see by the tilting and faulting obvious in this shot that this wasn't the end of the story. But it's enough for me to feel comfortable that my promise has been kept.
Taken at the mouth of Purgatory Chasm, on the rocky western coast of Sachuest Bay.
Another in a series featuring one of my all-time-favorite rock types, the Pennsylvanian (Upper Carboniferous) Purgatory Conglomerate.
Here its predominantly cobble-sized clasts, which have been elongated by the process of pressure solution, are oriented parallel to the cliff's edge. Beyond them lies the blue water of the North Atlantic Ocean.
The Chasm's trenchlike gap is the result of a stream widing a joint in the rock. Joints, geologically speaking at least, are fractures in rock where there has been no significant displacement on either side.
To see the other photos and descriptions in this set, visit my my Rocks of Little Rhody album.
These red, white, and purplish formations provide drama in the backdrop behind the Wind River along US highway 26 between Dubois and Riverton, WY
Fluorite on Quartz. Fluorite is calcium fluoride. Blanchard Mine. Bingham, Socorro Co., New Mexico. (On loan to the Colorado School of Mines Geology Museum. Golden, Colo.)
Taken atop Pole Steeple, the trail to which starts in Pine Grove Furnace State Park and ends here, in Michaux State Forest.
It may be called South Mountain, but it's the northernmost part of the Blue Ridge physiographic province that runs all the way down to Georgia. Here, where tilted strata of Montalto Member metaquartzite form the heights just southeast of the state park's Laurel Lake, we're only some 13 miles from where this great physiographic province ends.
In addition to being an area of endless geologic interest, South Mountain has played an important role in US history. In the American Civil War, for instance, its presence profoundly affected the movement of both Federal and Confederate armies, and influenced where they met to do battle in such famous locales as Antietam and Gettysburg.
The white Montalto quartzite, a member of the Cambrian Harpers Formation, was originally deposited unconformably atop Neoproterozoic rhyolite. Both units were thrust up to a much higher level and metamorphosed when northwestern Africa collided with what is now the eastern side of North America, during the Alleghenian Orogeny and formation of the supercontinent Pangaea.
One of the most interesting aspects of the quartzite is that it still contains abundant boring tubes of the ichnofossil genus Skolithos even though it was metamorphosed. These tubes were excavated in the sandy Cambrian sea bottom by some marine animal. Part 2 of this series will show one example of these interesting features.
You'll find the other photos and descriptions of this series in my Integrative Natural History of the Blue Ridge Province album.