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Sheared granite pegmatite layer boudinaged in two directions. Chocolate boudinage! "Caledonized" Proterozoic gneiss, Askøy, Norway.

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Ever wondered about the reliability and accuracy of your smartphone when collecting orientation data, using apps like Clino and Stereonet Mobile? A new article by Rick Allmendinger and coauthors suggests that the iPhone is reliable, while the reliability of Androids is questioned. It also gives advices about the use of such apps. Check out the paper here:
https://doi.org/10.1016/j.jsg.2017.07.011

linkinghub.elsevier.com
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Physical structural geology experiments don't have to be very sophisticated to be useful. This video shows a plaster experiment done a couple of days ago. The experiment itself only takes minutes, and the whole thing an hour or two. It is always fun to se how structures form and evolve, and to think about why things happen the way they do.
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Only some of the many interesting aspects of shear zones can be captured in a single book chapter or paper. Here is a review paper that mostly deals with meso/macroscopic aspects of shear zones, with many references to more sources of information. It goes a little further than my book chapter. Coauthored with Carolina Cavalcante.
Apparently anyone can download this paper from this link until August 25, 2017: https://authors.elsevier.com/a/1VKgr2weQXNSm

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I just created a bunch of simple gif-animations based on animations from my e-learning modules. They can easily be imported into powerpoint and used to add movements to your lectures or presentations. There are animations that relate to basically all chapters of the book, and they can be downloaded as 3 ppt files from my website. Check them out at http://folk.uib.no/nglhe/StructuralGeoBookExcel2ndEd.html

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Stereonet Mobile for the iOS (iPhone, iPad) (available from the iOS AppStore) was made by Rick Allmendinger for both collecting data in the field and analyzing data anywhere – new version just released. It is a free app that is easy to use, contours data, makes rose diagrams, rotates data, finds angles between planes, has a cool sighting function and works seamlessly with Rick's desktop Stereonet program. Well worth a try! More at http://www.geo.cornell.edu/…/RWA/prog…/stereonet-mobile.html

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Normal faults are easy to recognize where stratigraphic markers appear, as is the case with this one affecting a mudstone layer in the lower part of the Entrada Sandstone in southern Utah. Striations on slip plane indicate dip-slip movement.

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Shear zone from the Caledonian Jotun Nappe (S Norway) showing a central ultramylonitic core that represents an early or preexisting vein on which the shear zone nucleated.

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Normal faults in the Neogene-Quaternary Granada Basin, Spain.

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Well-developed S-C structure where the foliation back-rotates as shear bands develop. Top-to-toe-left, consistent with E-directed thrusting of the Passos Nappe toward the São Francisco craton. Brasilia Belt, Brazil.

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Liesegang rings, controlled by fractures (joints) during ground water percolation in cemented Aztec Sandstone in Nevada.

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Oblique section through folded mafic layer in Proterozoic gneisses near Oslo, Norway.

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It is always inspiring to see well organized field books with hand-drawn sketches of structures. Enjoy this reworked example by UFPR student Hely Cristian Branco.

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Desenho Geológico

Página de livro a ser publicado pelo Departamento de Geologia da Universidade Federal do Paraná, contendo exemplos de dados registrados em caderneta de campo.

Slickenside lineation on a slip surface. These kinds of structures are valuable as we seek to understand the kinematics of fracture populations. Primarily it enables us to separate shear fractures from extension fractures. Secondarily, populations of striated fracture surfaces may enable us to say something about the paleostrain and -stress fields. This example shows slickenlines on calcite from cemented Jurassic sandstone in southernmost Utah.

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Fault core (or fault zone if you wish) of normal fault in the shaly Green River Formation (lacustrine) near Thistle, Utah. Fault dipping to the left (hanging wall to the left, footwall to the right). Minor antithetic fault seen in the left part of the picture. Eastern expression of Basin and Range extension.

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Today is Geologist's day in Brazil. A great thing! This picture, taken in the field today, is for anyone who loves rocks and geology. The rock is a Proterozoic granulite from the Bergen area, Norway with beautiful Sveconorwegian (Grenvillian) corona structures that resulted from metamorphic reaction between olivine and plagioclase.

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Beautifully folded layers in the Pan African Ribeira Belt, Rio de Janeiro.

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