Geobulletin alpha

Flying To and From a Grand Canyon Rafting Trip 

My latest river trip in the Grand Canyon included some choice perks! In advance of the trip, there were three nights at The Enchantment Resort located in Boynton Canyon near Sedona and on the back end was a night at the Vdara Hotel on the Strip in Las Vegas. That might sound cheesy I agree, but sandwiched between these two luxurious bookends was a six-day rafting trip in Grand Canyon. It was a perfect ying and yang of a trip. Additionally, there were some fantastic flight to and from the river. [...]

Six new GIGAmacro images of sedimentary rocks 

Here are some new “virtual samples” for you to check out: Dessication cracks in Tonoloway Formation (Silurian): Link Image by Callan Bentley Random conglomerate (unknown age and formation): Link Image by Robin Rohrback Skolithos trace fossils (tops) in Hampshire Formation (Devonian): Link Image by Callan Bentley Crinoid calyx fossil (unknown age and formation): Link Image by Callan Bentley Iron oxide staining in Tuscarora Formation quartzite (Silurian): Link Image by Callan

Sunny Antarctica 

Before I ever had a chance to visit the Antarctic Peninsula, a fellow naturalist said to me, "When you go, may you have a sunny day in the Lemaire Channel." I never forgot those words and in my 28 trips here I've seen a few of those. But this years trip was super special, as well as a hike to the top of a hill in Neko Harbor.High pressure beginning to set in along the Antarctic Peninsula.The visuals are outstanding. It is like seeing Alaska, New Zealand or Norway 20,000 years ago when the Ice [...]

Four new GIGAmacro images of sedimentary rocks 

It’s been a week and a half since Mountain Beltway has seen any publishing action, given the overlapping timesucks of the AGU Fall Meeting and the end of the semester. But now I’m back in the Appalachian mountain belt, and my grades are all in, and I have time to think about indulgences like blogging again. Let me make up for it now with a suite of four new macro

Considering the Spechty Kopf diamictite 

I have known for a long time about a diamictite in the latest Devonian part of the Appalachian stratigraphic sequence, since it is exposed in the lowermost part of the section (western end of the outcrop) at Sideling Hill, Maryland. When I led field trips there, I talked students through the multiple possible origins for diamictites (sedimentary rocks that are poorly sorted, with significantly “outsized” clasts “floating” in a finer-grained

Imaggeo on Mondays: Mola de Lord 

From the easterly Atlantic waters of the Bay of Biscay to the Catalan wild coast (Costa Brava) in the west, the Spanish Pyrenees stretch 430 km across the north of the country. At the foothills of the Catalan Pyrenees you’ll find the Pre-Pyrenees. Despite not reaching the soaring heights of the peaks of the Pyrenees, they nonetheless offer important insights into the geology of the range and stunning panoramas, such as the one featured as today’s Imaggeo on Mondays image. In today’s post, [...]

Fithian Illite, lllinois, US 

Fithian Illite at Salt Fork of Vermilion River near Fithian, IL Illite is one of the most frequent clay minerals and is an important constituent of many sedimentary rocks. It was named after the state of Illinois, United States, by Grim, Bray and Bradley in 1937. The type locality of the Late Pennsylvania Fithian cyclothem is also the type locality of the clay mineral illite. In October 2013

Wind River earthquake of 2013: unusually deep and in the mantle 

Scenary of the Wind River area illustrating that thesurface is covered with sedimentary rocks andsupporting the observation that there is noactive volcanism within about 200 km. From the BBCarticle by Matt Walker cited in the text.Today the BBC has a nice article  by Matt Walker pointing out an article by T.J. Craig and R. Heyburn in Earth and Planetary Science Letters (425, pp. 12-23, 2015) on a very deep earthquake in the Wind River range of Wyoming. The authors point out that while [...]

May 7th - Numerical modelling of sedimentary systems 

Bath Geological Society - May lectureNumbers, models and layered rocks: what can we learn from numerical modelling of sedimentary systems?Professor Peter Burgess, Head of Department of Earth Sciences, Royal Holloway, University of LondonWhile many other areas of science, for example physics and chemistry, can use experiments to help understand how physical systems work, sedimentary geology has for most of its history been limited to observation of natural systems recorded in outcrop and beneath [...]

Into the Third Dimension: using Google Maps to know what’s underground 

Much of the earth’s surface is covered by sedimentary rocks. These form as sediment settles on the surface. As the types of sediment change – sand to mud to sand again – different layers are formed, some hard some soft. The … Continue reading

Imaggeo on Mondays: Retreating Glacier 

The Svalbard archipelago is considered to be one of the best places to study the geological history of the Earth because its rocks represent every geological period. This image shows a view from the peak of Fugleberget (569 m a. s. l.; 77º 00’ N, 15º 30’ E) on the south-western coast of the island of Spitsbergen. Glaciation of this geologically diverse area gave rise to a variety of geomorphic features. The most prominent of them, depicted in the picture, is the Hornsund Fjord that cuts [...]

New York State Paleontologist 

Os adjuntamos información de un puesto de trabajo de paleontólogo en Nueva York, Os la adjuntamosI am sending this informal announcement of an anticipated job opportunity to make it more widely known. The forthcoming official announcement may appear only on the NY State Civil Service web site and that of the Geological Society of America. It is not expected to appear on the NYS Museum page nor on that of the State Education Department. Moreover, the window of opportunity is expected to be [...]

Bundenbach fossil display 

The name Bundenbach is one which excites me because it is the name of a town that is near a layer of rock, called the Hunsruck Slate, that preserves some extraordinary fossils. It's what is called a Lagerstätte which are sedimentary rocks that have exceptional preservation of fossils, sometimes including soft parts which usually rot away before being fossilized. The Burgess Shale outcrop in Yoho National Park, BC, Canada is the perhaps the ultimate example of this type of fossil treasure trove [...]

Cross bedding and ancient currents 

Today's new ELI is the last in our current series of sedimentary structures. It is 'Cross bedding and ancient currents; using cross-bedding to find the directions of ancient currents' Cross-bedding is a common feature of sedimentary rocks. The formation of cross-bedding can be seen in modern depositional environments and then related to similar structures in sedimentary rocks – an example

Cross-bedding and way-up structures 

Today's new ELI is another in our series about sedimentary structures. This one 'Cross-bedding' uses cross bedding to determine the way-up of a bed of sedimentary rock. It gives an introduction to the types of evidence which can be obtained from cross-bedding in sediments and in sedimentary rocks. Other activities to show sedimentary structures can be found in the link to Teaching

Monday Geology Picture(s): Two Views from the Top of Table Mountain 

My two American geologist friends, with whom I went ziplining amidst some sedimentary rocks a little over a week ago, left on Saturday. Before they left on their evening flight, we decided to go up Cape Town’s beautiful Table Mountain. We took the cable car up the mountain, hiked around on the top for a couple of hours, and then took the cable car back down. Saturday was a beautiful

Emeralds 

Emeralds are gem-quality specimens of the beryl mineral family with a rich, distinctly-green color. They are found in igneous, metamorphic and sedimentary rocks in a small number of locations

Glad You Asked: July 3, 2014 

We reflect on our American heritage with July 4th on the horizon and our weekend adventures coming up. How about a little Utah history to go with it? Sedimentary rocks are telling teachers in piecing together Utah’s geologic history. Check it out in our “Glad You Asked” article

All good things come to an end 

We are heading the last part of the 349 Expedition, just 4 days left!. It seems that the South China Sea had a very last surprise for us; more than 200 meters of sediments and sedimentary rocks coming up in the cores that we expected to be basalts, according to the seismic profiles. read

Density of Geological Materials 

The density of a rock is closely tied to its mineralogy. Sedimentary rocks have a lower density than igneous rocks, with most sandstones having a density close to the density of quartz (ρ = 2.65 g/cm3), suggesting that they are … Continue reading