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!
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:
Traveling to Ireland has been something I’ve wanted to do. So, when the opportunity came up to go to Scotland, I couldn’t leave the general area without seeing at least some of both Northern Ireland and the Republic of Ireland. I only made it as far south as Dublin, but I guess on the positive side, that leaves many places that I need to visit on a future trip.
I flew from Glasgow into Dublin, rented a car, and first headed for Northern Ireland which is the subject of this blog. The causeway coastal route in Northern Ireland (from the North Channel coast eastward to the Irish Sea coastline) is a drive that I wanted to try. I ended up driving only about half of it – from Ballycastle east to Port Stewart because I spent so much time stopping to look at rocks and scenery.
The total area of these flows is now much reduced compared to their original extent, but they still constitute, at 3,800km2, Europe’s most extensive lava field. Traditionally the lavas of the Antrim Lava Group have been divided into three main phases of activity, separated by two extended periods of quiescence or limited, local activity.
The two areas that I spent most time at during my coastal causeway drive are the Carrick-a-rede Bridge and the Giant’s Causeway. These areas are developed within the Lower and Middle Basalts of the Antrim Lava Group and contain an Inter-basaltic Bed of reddish-weathered regolith and paleosols. A photo tour of the two areas are shown below –
A rope bridge connects the mainland with Carrick-a- Rede island. The first rope bridge was built in 1755 to facilitate fishing of Atlantic salmon. The salmon fishery has since died out, but the bridge is maintained as part of National Trust lands.
The Giant’s Causeway is a UNESCO World Heritage Site. As noted on its UNESCO website:
The Giant’s Causeway lies at the foot of the basalt cliffs along the sea coast on the edge of the Antrim plateau in Northern Ireland. It is made up of some 40,000 massive black basalt columns sticking out of the sea. The dramatic sight has inspired legends of giants striding over the sea to Scotland.
Twenty-five years after the Union of Concerned Scientists and over 1700 independent scientists published their “World Scientists’ Warning to Humanity”, a new group of scientists (bolstered by 15,364 scientist signatories from 184 countries) have again issued a warning that humanity has not made significant progress in mitigating environmental challenges.
The recently published viewpoint of these scientists and signatories appears in the 11/13/17 issue of BioScience and can be read on line at “World Scientists’ Warning to Humanity: A Second Notice”. The authors review the 1992 warning of major environmental challenges and our response to it by:
we look back at their warning
and evaluate the human response
by exploring available time-series
data. Since 1992, with the exception
of stabilizing the stratospheric ozone
layer, humanity has failed to make
sufficient progress in generally solving
these foreseen environmental challenges,
and alarmingly, most of them
are getting far worse…
The newly published warning of our need to deal with these major challenges – catastrophic climate change, deforestation, agricultural production associated with farming ruminants for meat consumption, and a sixth mass extinction event (just to name a few of them) – makes the reading of this viewpoint critical. It takes less than 10 minutes to read this, and – if you are a scientist, then sign on to support it. More than signing, find a way to become active in really dealing with these challenges.
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 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.
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.
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!
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.
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.
I took part in a central California tectonics field trip a few weeks ago that the Association for Women Geoscientists (AWG) sponsored. Tanya Atwater and Art Sylvester, professors emeriti at the University of California Santa Barbara, Department of Earth Sciences, led the field trip. During the field trip, we made numerous stops between Los Angeles and Hollister at areas where the San Andreas Fault bounds the North American/Pacific plates. Interspersed with fault-specific localities, we explored associated geology such as turbidites around Point Lobos, marine terraces in the Morro Bay area, and pillow/flow basalt at Port San Luis. The final stop on the field trip was an overlook on Santa Barbara geology at La Cumbre Peak with Tanya’s explanation on the tectonic evolution of the Transverse Ranges. If you are not familiar with the tectonic history of this general area, go to Tanya’s web site (http://emvc.geol.ucsb.edu/) and download her visualizations on global/regional tectonics. There are also visualization downloads on ice-age earth and sea level changes, so treat yourself to some very worthwhile earth science information by downloading these visualizations, too.
The following photos are from what I think are field trip highlights, including a brief caption regarding the geology shown in each photo. More information on many of the photo localities can be found in “Roadside Geology of Southern California“, 2016, by Art Sylvester and Elizabeth Gans.
A few days ago I did the hike to Grinnell Glacier, one of the iconic glaciers in Glacier National Park. The glacier lies within the Swiftcurrent drainage area, in the northeastern part of the park. The hike, at least the way I did it, is about 11.6 miles round trip. It is possible to catch a boat ride at the Lake Josephine Boat Dock by the Many Glacier Hotel, which cuts the hike down to about 7.5 miles round trip. But – the first boat goes out at about 8.30 am, and as I didn’t want to wait around for it, I decided that adding on the extra miles for a fairly level stretch around Swiftcurrent Lake and Josephine Lake would be easy to do. It is an easy hike around the lakes and a very good warm-up for the rest of the climb to Grinnell Glacier. But – be aware that this area is known for grizzly bear activity as I found out when I met up with a grizzly on the trail. Because I’m writing about this encounter, it obviously ended OK, although I was glad I had bear spray readily available.
The glacier is named after George Bird Grinnell, who first explored this area during the summer of 1885. Because of bad weather, he did not actually get to the glacier during his 1885 travels. However, during the late fall of 1887, he was able to pack most of the way into the glacier by mules, and then hike the remaining distance by foot. Although he certainly was not the first person to see the glacier, the glacier does bear his name, presumably given it by a Lieutenant John H. Beacom of the United States Army, 3rd Infantry, who accompanied him on the 1887 trip to the glacier.
Back to the hike – after about a mile from the junction of the Swiftcurrent Lake Trail with the trail coming from the North Shore of Lake Josephine boat dock, Grinnell Lake comes into view. A little further along the trail one can see Grinnell Falls dropping several hundred feet down from the headwall behind Grinnell Lake.
And – even at this distance, Salamander and Gem glaciers pop into view in the distant cirque. The hike continues along beautiful alpine meadows and even through one waterfall that cascades down the cliff adjacent to the trail. There is a rest area with pit toilets right before hiking the final switchbacks that traverse the terminal moraine to the Grinnell Glacier Overlook.
The three glaciers that once comprised the Grinnell Glacier occupy parts of a cirque developed along the area called the Garden Wall.
Grinnell Glacier is still the largest of the three ice fields and covers about 152 acres. Unfortunately, this glacier is receding rapidly as the U.S.Geological Survey notes that from 1966 to 2005 it lost about 40% of its acreage. At about 5 acres, the hanging glacier called Gem Glacier, is the smallest named glacier in the park. It sits in the notch on the cliff face above the Grinnell Glacier. This glacier lost about 30 percent of its acreage from 1966 to 2005. The Salamander Glacier covers about 57 acres on a ledge off to the east side of the Grinnell Glacier. It apparently separated from the Grinnell Glacier sometime before 1929 and has undergone a 23% size reduction from 1966 to 2005.
For those interested in viewing photographs of the Grinnell Glacier from various times and viewpoints, the U.S. Geological Survey’s Repeat Photography Project has many archived photographs. This project is a documentation of glacial decline through photography and it is well worth perusing through their photo archives. Two of the earlier photographs are shown below – one from the original 1887 trek and a later view of the glacier from 1940 just to pique one’s interest.
A part of my recent geological field work includes working on high elevation Tertiary strata in the Gravelly Range, southwestern Montana. The Gravelly Range is located in southwest Montana, about 10 miles southwest of Ennis, Montana. For some background on this area and what my field work is about, see an older blog that I posted at Geopostings.
So – now that one field season is done and field data compiled, both my co-worker, Don Lofgren and myself have interpreted some of our data. We recently outlined our work at the Geological Society of America’s (GSA) Rocky Mountain section meeting in Calgary. Alberta. The abstract from our session is given below as well as the poster itself in both a jpeg format and as a link to our GSA presentation.
“Tertiary strata exposed in four high elevation areas in the south-central
Gravelly Range yield significant assemblages of Late Eocene to Oligocene
mammals. The thickest stratigraphic sections of Tertiary strata are in the
Lion Mountain-Black Butte area. The Lion Mountain section age is based
primarily on American Museum of Natural History collections; the lower
part of this section is Duchesnean-Chadronian (39-33 Ma) and the
uppermost beds are Whitneyan (32-31 Ma). Age of the basal part of the
Black Butte section is Duchesnean-Chadronian based on Harvard Museum of Comparative Zoology collections. Recent collections that include Miohippus indicate a probable Orellan age for uppermost exposures. The Tepee Mountain section is notable for abundant brontothere remains and is probably Duchesnean-Chadronian (approx. 39-33 Ma). The Rapamys site is the oldest vertebrate locality and is late Uintan to early Duchesnean (42-38 Ma) based on recently recovered specimens of Rapamys, Protoreodon, and Lycophocyon.
The Tertiary strata in this part of the Gravelly Range include fluvial, aeolian, and tufa deposits that are most likely mainly associated with localized Oligocene volcanism. The Lion Mountain section is about 270 meters in thickness; the lower half of the section is largely aeolian, with fluvial units comprising much of the upper section. Based upon age data, the 140 meter Black Butte section correlates to the lower 50-70 meters of the Lion Mountain section. The basal 20 meters of the Black Butte section contain some fluvial features, but much of the remaining section is largely aeolian in origin. Paleosols and extensive burrowing also occur within the Black Butte section. Stratigraphic section thickness decreases rapidly away from the Black Butte-Lion Mountain area, with section thicknesses of about 20 meters for the largely aeolian Rapamys and Tepee Mountain sections. Tufa deposits are located along the west-central edge of the Gravelly Range where they are associated with previously mapped thrust faults. Leaf imprint assemblages of Eocene-Miocene age are contained within these tufas. Strata previously mapped as Upper Cretaceous-Paleocene Beaverhead Formation are now variously reassigned to the lower Cretaceous Kootenai Formation, southwestern Montana Cenozoic Sequence 2, and diverse Quaternary units.” From: Abstract from Geological Society of America Abstracts with Programs. Vol. 49, No. 5 doi: 10.1130/abs/2017RM-293156.
The poster presented at the 2017 Rocky Mountain GSA is available below as a jpeg and at GSA as a pdf.
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.