Tolting Around Pseudocraters at Lake Myvatn, Iceland

The Lake Myvatn area, located in northeast Iceland, has an amazing, and truly beautiful, volcanic landscape. This area lies within Iceland’s North Volcanic Zone, which is a part of the Mid-Atlantic Ridge – the spreading rift between the Eurasian and North American plates that slices through Iceland. Lake Myvatn is the fourth largest lake in Iceland, and is quite shallow, with the deepest part being only about 4 meters. This area is also renown for its wetlands and birdlife, with the lake’s numerous bays and its outlet to the north-flowing river Laxa being host to a multitude of birds.

Lake Myvatn, viewed from the lake’s eastern side.
Basaltic landscape in the Hofdi area, on the southeast side of Lake Myvatn. Hofdi is a rocky promontory into Lake Myvatn that affords excellent bird watching.
Lava pillars in the Kálfastrandavogar area, southeastern Lake Myvatn.

My favorite experience at Lake Myvatn was riding an Icelandic horse around the pseudocraters in the Skútustaðagígar area of Lake Myvatn (southwestern part of the lake). Pseudocraters are unusual in that they are rootless volcanic cones that formed in this area about 2300 years ago when basaltic lava flowed over the water-logged lake sediment, resulting in the cones being built from steam exploding through the lava. So -not only did I want to see pseudocraters, but I also wanted to lean how to tolt because this is a natural gait exclusive to Icelandic horses. According to Riding-Iceland.com,

“the Tölt is a natural, fluid gait of the Icelandic Horse, during which at least one foot always touches the ground. Foals often tölt in pastures at an early age. The tölt is an extraordinarily smooth four-beat gait, which allows the rider an almost bounce-free ride, even at 32 kmh (20 mph). “

I contacted Safari Horse Rental (located just off the main road in the Skútustaðagígar area) and set up a two hour ride. Gilli was my guide, and he took me through mostly private land to both look at pseudocraters and to teach me how to tolt. It did take me awhile to understand how to let my horse know it was time to break into the tolting gait, but when we both got it figured out, wow! what a way to see pseudocraters! I’d urge anyone who loves to ride horses to try this!

The start of the pseudocrater exploration ride at Safari Horse Rentals!
A pseudocrater looms ahead of us. The pseudocraters are typically composed of tephra, scoria, and splatter that resulted from basaltic lava flowing over water-logged lake sediments forming steam eruptions that blast through the lava.
The remnants of a pseudocrater becomes a watering hole for the area sheep herds.
Basalt block fences are common on Icelandic farm lands.
This photo shows midges covering a part of a pseudocrater. The midges weren’t numerous when I was at Lake Myvatn, but they periodically emerge by the billions to cover the Lake Myvatn area. In fact, Lake Myvatn means “midge lake” in Icelandic. The midge populations are very closely tied to the Lake Myvatn fishery. Unfortunately, dredging in the lake during the 1960’s for a silicon mining operation has probably caused enough fluctuation in the midge populations to result in the collapse of the fishery. See the following publication for more information on this – High-amplitude fluctuations and alternative dynamical states of midges in Lake Myvatn.

Again – I’ll highly recommend that the best way to view Lake Myvatn’s pseudocraters is by tolting on an Icelandic horse!

Iceland Geology – Snorkeling the Silfra Fissure, Thingvellir National Park

I did a snorkel tour of the Silfra fissure with Dive.is while I was in Iceland a couple weeks ago. That is a very impressive way to view part of the mid-Atlantic ridge system! Here’s what Dive.is says about Silfra that makes it so unique:

Snorkeling the Silfra Fissure in Iceland.

“Silfra is a fissure between the North American and Eurasian tectonic plates in Thingvellir National Park. The rift was formed in 1789 by the earthquakes accompanying the divergent movement of the two tectonic plates . The diving and snorkeling site at Silfra is right where the two continents meet and drift apart about 2 cm per year. Silfra is the only place in the world where you can dive or snorkel directly in a crack between two tectonic plates. The earthquakes of 1789 opened up several fissures in the Thingvellir area, but the Silfra fissure cut into the underground spring filled with glacial meltwater from the nearby Langjökull glacier.”

My Silfra snorkel group starting out in the fissure with our guide Jake from Dive.is.

There are 6 people to a group for the snorkel tour, with each group accompanied by a guide from Dive.is. Jake was our guide and he was great! The tour is simply snorkeling through basalt and more basalt, but with the water clarity, the colors are beautiful. There is also one place where you can stretch across the fissure and basically touch both plates.

The start of the snorkel tour where the entrance platform can be seen in the background.
The stretch between plates…
This is where basalt really looks grand!
Near the end of the snorkel tour, the fissure opens into a shallow lagoonal area.
The colors in the sandy lagoon are just as spectacular as elsewhere in the fissure. The exit platform can be seen in the distance.
The end of the snorkel tour – ours was a great weather day, so even though the fissure water is cold (we all wear dry suits with long underwear and two pairs of wool socks), I could have snorkeled around the lagoon for a long time.

I also took video while I was snorkeling, so am inserting a clip from the first part of the snorkel tour at the end of this blog. The video clip includes the time when we all get geared up, have our gear checked, and then flipper-walk down the entrance ramp, into the water. We all have to do a flip over to our back once we’re in the water, just to make sure we can maneuver once we’re in the water. The clip continues on as we snorkel through the first several minutes of exploring the fissure. At the end of the snorkel tour, we hike back to where the Dive.is vans/equipment are. After taking off our gear – which getting off the dry suit is somewhat of a challenge – we have hot chocolate and cookies. Because the weather was so nice, it was a pleasurable experience to stand around and feast. But – we were told that in the wintertime the guides take the hot water that is suppose to be used for the hot chocolate and it pour down the snorkelers’ necks so the dry suits can be pulled off. Glad I opted for late May to do this!

Yellowstone To Southwest Montana Autumn Field Photo Snaps

Montana’s autumn is my favorite time of the year to do field work. Daytime temperatures are usually cool enough to encourage one to keep moving and the lighting is simply gorgeous. It is also one of the best times to visit areas in and around Yellowstone National Park (YNP) because most of the tourists have gone home. So no huge bear traffic jams or jostling for parking spots at the better known thermal spots in YNP and surrounding environs – it’s just a wonderfully introspective time for field forays. What follows are several photos that chronicle some of my fall wanderings in the greater Yellowstone area, both in terms of wildlife and geology.

Some of my favorite sightings in YNP are bison at any time of the year. But the autumn snows bring on the bison’s technique of using its head to clear snow away from any vegetative food source. The result of their snow-clearing activity is a snow-masked face.

Snow-caked face of a bison in YNP portends the winter food retrieval.

Snow-masked bison near Soda Butte Creek, YNP.

And where the snow hasn’t stacked up much, the YNP bison calmly graze and occasionally congregate on a ridge line to watch what remains of the YNP visitor traffic.

YNP bison contemplating passing vehicles.

Geological features in YNP take on new dimensions with the golden low and slanting light of autumn. I’ve spent much time re-photographing geologic features at all scales that seem to glow in this season’s light.

Tertiary sediments and Quaternary sediments/basalts of “The Narrows” cliff face adjacent to the Yellowstone River, northern YNP. Columnar basalt capped by auto-brecciated basalt makes a morel-like image for these geological units.

An early morning at -7 F on the Lamar River with steam fog resulting from the fall’s chilled air moving over water still warmed from summer.

A rodent trackway disappears into microterracettes of Palette Springs, Mammoth Hot Springs, YNP.

Microbial growth near the proximal part of Mound Springs, Mammoth Hot Springs, YNP.

The proximal end of Mound Springs abounds in various colored microbial life. It’s hard to stop photographing these features because they are so intriguing!

The lipped margin of Mound Spring’s pond facies, Mammoth Hot Springs, YNP.

The fall staging areas of sandhill cranes in southwestern Montana are mesmerizing. Staging areas are those locations where cranes annually congregate during late September into October, spend several days foraging through fields for food, and eventually continue on their migration southward from Montana to Colorado and the southwestern U.S.. The staging area that I usually go to is near Dillon, Montana, where hundreds of cranes can be viewed.

Sandhill crane interaction during their fall staging near Dillon, Montana.

Sandhill cranes doing a dance routine in the Dillon, Montana staging area.

As I said initially, it’s hard to surpass a Montana/YNP autumn!

Tertiary geology and paleontology of the central Gravelly Range – a project update

The 2017 field crew working at Lazyman Hill. The strata are late Eocene (probably 34-36 million years in age) tufa deposits.

It’s time for our yearly update talk on field work and data compilation for the Tertiary geology and paleontology of the central Gravelly Range project in southwestern Montana. The Madison Ranger District in Ennis, Montana (5 Forest Service Road) will be hosting my talk on Monday, April 2nd at 10am in the Madison Ranger District conference room. We have a project permit from the US Forest Service because our project area lies within the Madison Ranger District – and the USFS District people have been really helpful with our project logistics. Thus, this is the perfect way to let them know what we did this past field season and how the whole project is coming together. The Madison District just sent their public announcement for the talk:

Dr. Hanneman and Dr. Don Lofgren, PhD (Director, Raymond M. Alf Museum of Paleontology, Claremont, CA 91711) and their team have been executing a multiyear study in the Gravelly Range near Black Butte resulting in many interesting paleontological findings right here in our own back yard.  Please join Dr. Hanneman and the Madison Ranger District for an update on this project and what they hope to unearth this year!

It’s a very intriguing project on high-elevation, mainly Eocene-Oligocene Tertiary geology and paleontology (mostly vertebrate and floral). So – anyone with an interest in this and who is in the geographic area, is welcome at the talk!

Cuban Geology – An Updated Resource List

Vinales Valley in Cuba was designated a UNESCO World Heritage Site in 1999.

Within the last few weeks I’ve had several requests for available resources on Cuban geology. The requests, of course, have come from individuals outside of the U.S.A. Guess that they sense opportunities for working with and understanding Cuba’s geology that we are backing away from. In any case, I’ve sent the requests on to Manuel Iturralde-Vinet, the person who has worked and published an immense amount of information regarding Cuba’s geology. Manuel has now sent me back an updated list of resources and said:

You can advertise to all your friends and colleagues that a large
percentage of the geology, geography, paleontology, geophysics and
mining papers are free to be visited at
http://www.redciencia.cu/geobiblio/inicioEN.html

Other resources that are available include: http://www.redciencia.cu/cdorigen/arca/iturra.html

Field Trip Guides to Cuban Geology: 2001, IV Cuban Geological and Mining Congress: K-T Boundary of Western Cuba

— 2001, IV Cuban Geological and Mining Congress: Former Caribbean Plate Boundary, Camaguey, central Cuba

Compendio de Geología de Cuba y del Caribe. Segunda Edición 2012:
http://www.editorialcitmatel.cu/producto.php?producto=128

Videos de Viajes: http://www.youtube.com/user/IturraldeVinent2011#grid/user/A43949937C36E7BC

Videos de Geología y Naturaleza: http://www.youtube.com/user/IturraldeVinent2011#grid/user/DE8FDB5CE5960C19

Geological Society of America: The Geological Society’s (GSA) annual meeting in Denver, 2016, hosted a special session on the Geologic Evolution of Cuba. A link to session abstracts is: GSA Geologic Evolution of Cuba. The GSA Today October 2016 issue also highlighted Cuba Geology with the article “The geology of Cuba: A brief overview and synthesisauthored by Manuel Iturralde-Vinet and others.

Earth Magazine: Travels in Geology: Journeying Through Cuba’s Geology and Culture.

 

Siccar Point: A Day In The Field At Hutton’s Unconformity

Siccar Point – In June, 1778, James Hutton, John Playfair, and James Hall gazed on the rocks at Siccar Point and understood that an immense amount of geologic time was needed to produce the juxtaposition of underlying vertically-oriented (Silurian graywacke) bedded rocks with overlying near-horizontal (Devonian, Old Red Sandstone) rocks.

Siccar Point is unquestionably one of the most important geological sites in the understanding of geological time. It was here in 1778 that James Hutton, John Playfair, and James Hall contemplated the immensity of time needed to produce vertically oriented rocks overlain by gently-dipping rocks. The concept of geological time is so fundamental to the science of geology that I really wanted to explore the locality that gave rise to the idea of geological time. So I finally made the trip to Scotland and Siccar Point a couple weeks ago. Wow – what an amazing country! It was a fantastic trip, but for this blog, I’ll just post a few photos of Siccar Point – just enough, perhaps, to encourage geologic time enthusiasts to also make the trip.

Siccar Point is located  on Scotland’s Berwickshire coast, about 40 km southeast of Edinburgh. It is not difficult to get there from Edinburgh if you’re willing to drive a few back roads, and also drive on the left side of the road – which for me was somewhat of an initial challenge (going left on the roundabouts was mind boggling to begin with!). The best directions that I found for getting to Siccar Point are given by Angus Miller, who also runs field trips there. Angus’s directions to Siccar Point and his contact information are found at his Geowalks website.

The gate into the fields for the hike to Siccar Point.

The pull-off for the hike to Siccar Point is well marked by signage. All that one needs to do is walk through the gate and then follow the fence lines south to the Siccar Point locality. There is a small sign on the entrance gate that advises you to beware of the bull. We happened to meet up with a local person while we were hiking through the fields to Siccar Point and she told us that the land owner posted the sign mainly because he’s at war with the hordes of people that tromp through his fields to get to Siccar Point (in Scotland there is the “right to roam”, so one can hike across private property). She also assured us that at the time we were there, the cows were off in another field, so not to worry about the bull. We then just followed the hiking instructions on the sign at the gate entrance, and found that it’s an easy walk to Siccar Point.

The entrance sign to Siccar Point with hiking instructions.

The ruins of the St. Helen’s Chapel are found near the start of the hike to Siccar Point.

Much of the hike to Siccar Point is at field edges, near the sea cliffs.

The fence lines finally give way to the rock promontory that is Siccar Point.

Once one arrives at the rock promontory that is Siccar Point, it is an amazing view looking down the cliff face. The vertical beds of Silurian graywacke outcrop beautifully below Devonian Old Red Sandstone. The “Hutton Unconformity” here marks an approximately 80 million year hiatus. Again, there is also good signage present at the promontory for an explanation of the unconformity.

Siccar Point – the rock promontory that contains Hutton’s Unconformity.

Signage at Siccar Point well explains Hutton’s Unconformity.

A view to the south of Siccar Point where the underlying vertical beds of Silurian graywacke snake along the coast line, under the more gently dipping beds of the Devonian Old Red Sandstone.

 

 

 

 

 

A rope is attached to the fence at the promontory to help the climber down the cliff face. As it was a muddy and slick climb down to the North Sea, I was very glad to use the rope! Much thanks to whoever put the rope there!

Roping down the cliff face was a welcome way to get to the rocks below.

The rope climb back up Siccar Point – once again, I was very appreciative of the rope being there!

It was fun to investigate the unconformity at the sea’s edge. The base of the Old Red Sandstone contained lags from the graywacke, some of which are cobble size.

A closer view of Hutton’s Unconformity with the Old Red Sandstone atop the Silurian graywacke.

A layer of lag clasts at the base of the Old Red Sandstone. The vertically-oriented beds of the Silurian graywacke can be seen beneath the Old Red Sandstone.

A view back up the cliff face gives a good visual of the gently dipping Devonian Old Red Sandstone overlying the vertical beds of Silurian graywacke.

I know that we were very lucky to have good weather for our Siccar Point excursion, but I would have gone there whatever the weather. It is really one of the great geologic sites and well worth traveling part way around the world to see. For a drone view of Siccar Point, take a look at the video done by the British Geological Survey which is posted in an earlier Geopostings blog: Siccar Point from a drone’s view.

 

 

 

Canadian Rockies – Alberta Badlands Geology Guidebook

The Canadian Rockies to Alberta Badlands geology guidebook is published by the Association for Women Geoscientists.

The Association for Women Geoscientists (AWG) published their first geology field trip guidebook in late 2016 and it is now available for sale to the general public. This guideboook is a collection of geology road logs, associated geological information, and local cultural history of areas within the Canadian Rockies and the Alberta Badlands. The following text is a brief summary of the guidebook:

“TECTONICS, CLIMATE CHANGE AND EVOLUTION – SOUTHERN CANADIAN CORDILLERA: Road Log and Accompanying Narratives From: Calgary – Lake Louise – Icefields – Field – Revelstoke – Fernie -Dinosaur Provincial Park – Calgary”, published by the Association for Women Geoscientists, 2016.

This field trip guidebook is written by Katherine J.E. Boggs and Debra L. Hanneman, and edited by Janet Wert Crampton and Stephanie Yager. It is the AWG’s first fully published field trip guidebook and is a field-tested guide from their two-week 2014 field trip through the Canadian Rockies and Alberta’s Badlands area.

The guidebook is a 209-page geology tour through many of the well-known parts of the Alberta Canadian Rockies, including the Front and Main Ranges of the Canadian Rockies and the Columbia Icefields. The Burgess Shale’s Walcott Quarry, the Okanagan Valley vineyards, and the Rocky Mountain Trench are trip highlights for geo-tours in British Columbia. The field trip guidebook ends with a geology tour of the Crowsnest Pass area on the British Columbia/Alberta border, and with field stops in Alberta’s Dinosaur Provincial Park and at the Royal Tyrrell Museum, Drumheller, Alberta.

The field guide is printed on double-sided 8.5″ x 11″ pages with the guide cover on 100 lb paper and the text on 80 lb paper. It has black wire-o binding and a clear acetate front and a black acetate backing for improved field durability. The guidebook’s cost is $55 USD (which includes shipping), and can be purchased at the AWG online store or by phoning the AWG main office at 303-412-6219.

The Field Season Is Going Strong in Southwestern Montana

My field season is in full swing. I recently spent time with students from the Webb Schools in Claremont, CA, during their annual sojourn to southwestern Montana. We prospected a few Tertiary localities, with the students making some good fossil mammal and fossil invertebrate finds. We were also extremely lucky to have a southwest Montana landowner give us a tour of a buffalo jump that is on his land. The following photos are from our various fossil site and buffalo jump field adventures.

woodin-snails
Tertiary fossil snails (about 25 My in age) at one locality captured the interest of students. Once one snail was found, everyone was intent on finding more.

Bob Haseman talks about a buffalo jump in the Toston Valley. He is standing by one of the many tepee rings associated with the jump site.
Bob Haseman talks about a buffalo jump in the Toston Valley of southwestern Montana. He is standing by one of the many tepee rings associated with the jump site. The small boulders on the surface between Bob and the students are part of a tepee ring.

Webb School students hiking up to the "Looking-Out" site associated with the buffalo jump. A eagle catchment area is immediately below the highest point of the "Looking-Out" site.
Webb School students hiked up to the “Looking-Out” site associated with the buffalo jump. A eagle catchment area is immediately below the highest point of the “Looking-Out” site.

eagle-catchment
The eagle catchment area is a shallow depression where a person would hide beneath brush awaiting the approach of an eagle. A nearby animal carcass would aid the quest to capture a eagle which was then used for its feathers.

Chadronian (about 36 Ma) age rocks yielded a few brontothere teeth and bone fragments.
Chadronian (about 36 My in age) rocks near Three Forks, Montana yielded a few brontothere teeth and bone fragments for the curious students.

Chadronian strata in this area contain brown to reddish, popcorn textured floodplain deposits and whitish-colored fine-sand channel deposits.
Chadronian strata in this area consist of brown to reddish popcorn-textured floodplain deposits that contain paleosols and whitish-colored fine-sand channel deposits.

 

 

Siccar Point – The Roots of Modern Geology

Siccar Point, located on the southeast coast of Scotland, is well revered in the geological community. Outcrops at this locale display ‘Hutton’s Unconformity’. This is an angular unconformity where tilted rock units of about 370 million years in age called the Old Red Sandstone (with a basal layer of conglomerate) lie atop nearly vertical strata of greywacke that are approximately 435 million years in age. James Hutton observed these rock juxtapositions while on a boat trip past Siccar Point in 1788 with James Hall and John Playfair. His observations and contemplation of this unconformity formed a basis for his theory of repeated cycles of deposition, uplift, and erosion, which was later known as uniformitarianism.

The British Geological Survey posted a new video on Siccar Point a few days ago. Their video features amazing drone video of the locale and good accompanying audio. It is well worth a view!

A High-Elevation Eocene Fossil Vertebrate Site in the Elkhorn Mountains, Southwestern Montana

dogtown1Af
The Dog Town Mine vertebrate fossil locality is an isolated occurrence of Eocene strata found on the divide between the Toston-Townsend Valley (on the east side of the photo)  and the North Boulder Valley (on the western edge of the photo), southwestern Montana.

The Dog Town Mine Tertiary fossil vertebrate locality is nestled on private property within the southern extent of the Elkhorn Mountains, southwestern Montana. The locality is about 20 miles southwest of Townsend, Montana, where Mesozoic and Paleozoic carbonate, quartzite, and red-colored mudstone, siltstone, and sandstone rocks underlie Eocene (Chadronian) strata. These unconformable Eocene strata contain the Dog Town Mine vertebrate fossil locality.

Earl Douglass (yes, that Earl Douglass of the Dinosaur National Monument fame) first collected at the site on Friday, June 27, 1902 (based on transcriptions from Earl Douglass’ journals done by Alan Tabrum and volunteers from the Carnegie Museum of Natural History). According to his journal, Douglass met a man from Toston, Montana, on horseback and this person told him about the Dog Town Mine, which was located on the divide between the Toston/Townsend and North Boulder Valleys. Douglass was headed to the North Boulder Valley anyways, so he rode to the mine where he found invertebrate fossils (brachiopods and bryozoa) in carbonate rock which was in contact with the ore deposit. A Mr. Allen, who he dined with that evening, told him that more fossils could be found a little ways west of the mine. After dinner Douglass rode a short way west of the mine and found banks along a ravine that looked like Tertiary White River beds. Here he found  “Oreodont, Ischyromys, Palaeolagus, Titanotherium, and turtle remains” (June 28, 1902, Douglass Journal entry). This area is the present Dog Town Mine vertebrate fossil locality.

The Dog Town Mine site encompasses all of the light-colored exposures on the right side of the county road.
The Dog Town Mine locality encompasses all of the light-colored exposures on the right side of the county road seen in this photograph.

 

Tertiary strata at the Dog Town Mine are fine-grained, predominantly consisting of siltstone with minor fine-grained sandstone units. The deposits are probably of aeolian origin, originating from areal sediments rich in volcanic ash. These deposits are probably similar lithologically and in mode of origin to those Tertiary White River units found at high elevations within the Laramie Range and Medicine Bow Mountains (Evanoff, E., 1990, Early Oligocene paleovalleys in southern and central Wyoming: Evidence of high local relief on the late Eocene unconformity: Geology, v. 18, p. 443–446; Lloyd and Eberle, 2012, A late Eocene (Chadronian) mammalian fauna from the White River Formation in Kings Canyon, northern Colorado: Rocky Mountain Geology, v. 47, no. 2, p. 113–132).

Vertebrate fossils have been collected at the Dog Town Mine site for various museums since Douglass’ initial collection. The Carnegie Museum of Natural History in Pittsburgh, PA houses a collection from the site as well as the Museum of the Rockies in Bozeman, MT.