Virginia is for (province) lovers: Part I

I’m from Virginia, and for that reason, I’m pretty partial to it compared to other states in the USA. In fact, I have this memory from elementary school chorus during which we sang a song called the “Fifty Nifty United States.” At the end of the song, patriotic school children are to exclaim that their home state “is the best of the fifty nifty United States.” In my case, Virginia earned that title, and I still believe that after all these years.

I also began learning geology in Virginia, so the foundations of my geologic knowledge are based upon Virginia’s regional characteristics. The first geology course I took was called “Regional Geology of Great Falls Park, Virginia” and the very first thing we were taught during that course was the physiographic provinces of the state.

Virginia is separated into five provinces that run approximately NE to SW and include (from west to east): the Allegheny (Appalachian) Plateau, the Valley and Ridge, the Blue Ridge, the Piedmont, and the Coastal Plain. About a year and a half ago I was traveling to Georgia with some other University of Kentucky geology students, and as we passed some of these provinces, I became excited and remarked that we were entering a physiographic region with which I shared some history. This earned me a nickname close to “province [queen]” but a little less appropriate for online publication.

RW02b-Relief-Map

Physiographic map of the mid-Atlantic region. The yellow line marks the approximate location of the southern border of Virginia. (Image courtesy of the United States Geological Survey, source for annotated image)

As a “province queen,” over the next two posts, I’d like to recount some recent experiences during travels across some of these areas in the last week or so. I left Lexington (crossing the Allegheny Plateau) to participate in a trail race in Blacksburg, VA and to visit my husband in Radford, Virginia. Blacksburg and Radford are parts of the greater New River Valley, one valley that makes up the “Valley and Ridge Province” in Southwest Virginia. The province is given this name because of the “crinkled carpet” sort of topography that exists there. The valleys are underlain by rocks (like carbonates) that erode easily while the ridges are made up of more resistant sandstones and conglomerates. Before being eroded, these rocks were deformed during Appalachian mountain building. They responded to contractional stresses by folding and thrust faulting along weaker rock layers in an orientation consistent with the distribution of stress associated with the collision (perpendicular to the direction of force).

Maker:0x4c,Date:2017-11-10,Ver:4,Lens:Kan03,Act:Lar01,E-Y

Friends and I pre-race with scenic valleys and ridges in the background near Blacksburg, VA

A couple of days after the race, I spent a half-day with my husband near Floyd, VA. We drove to the Blue Ridge Parkway to do a trail run and then enjoyed some wine at Chateau Morrisette, which is nearby. The Blue Ridge Parkway is a road that runs through another physiographic province (can you guess which one? Correct, the Blue Ridge!). As in the Valley and Ridge province, the rocks that make up this province were exposed during Appalachian mountain building: they were deformed and transported along faults. The rock types that make up this province; however, are different from those rocks that make up the Valley and Ridge. Exposed along the Blue Ridge are “basement rocks” that have deeper, more “complex” origins: they show evidence of an even older period of mountain building that happened prior to the formation of the Appalachians. This “basement-involved” process exposed older metamorphosed volcanic and sedimentary rocks that erode differently than those in the Valley and Ridge and therefore result in different topography.

Maker:0x4c,Date:2017-11-10,Ver:4,Lens:Kan03,Act:Lar01,E-Y

Running along the Blue Ridge Parkway: views to the west show the nearby Valley and Ridge province.

This topography – which has been evolving over several millions of years – creates breathtaking views that make running along trails and relaxing with a glass of local wine one of the most pleasant experiences!

There’s plenty more Virginia travel and geology to discuss in my next post: Virginia is for (province) lovers: Part II. Stay tuned!

Machhapuchare: “Like a spire of a higher kingdom”

I study the Himalaya, and I’m not alone. Many geologists for many years have gone to South Asia to attempt to understand one of the most magnificent orogens on Earth. It’s also commonly referred to as the “type example” for continent on continent collision and is usually the first of this type to come to mind for most students of geology. The Himalayan mountains and the Tibetan Plateau to the North formed as a result of the collision between the Indian subcontinent and the Eurasian tectonic plate which began about sixty million years ago. Since both plates are made up of continental lithosphere, the crust thickened at the convergent boundary, and the Himalaya peaks uplifted. Weathering and erosion by glaciers and rivers at the surface also sculpted these peaks. All of this combined created some of the most beautiful mountains in the world.

I study the complex processes at work during this type of tectonic event using computer simulations. I also like to have a way to “ground-truth” my numerical models so one year ago I traveled to the field with my colleagues to collect rocks along transects that span the major rock units and faults in the Himalayan range. We trekked to the Annapurna region along the Modi Khola and Marshyangdi Rivers in central Nepal collecting rocks, taking measurements, and making field observations.

20170503_085612

Farmed foothills en route from Kathmandu to Pokhara

As my first time in the Himalaya, I was beyond excited to have this opportunity. Also, since I didn’t study geology as an undergraduate, this gave me a chance to develop some skill in field methods.

20170503_112009

Enjoying Dal Bhat for lunch along the Trishuli River

There is a lot I can write about regarding that field season, and I hope to cover it across many entries. For this post; though I want to describe the first time I saw one of those magnificent Himalayan peaks.

The Himalaya is unique in that it has some of the highest topographic relief in the world. The difference in elevation changes very dramatically in this region. Due to this relief, as one approaches the high Himalaya, there is an abrupt change in climate such that at one moment it feels almost like a jungle and the next there are snowfields and glaciers everywhere.

20170506_055939

Machhapuchare at dawn.

I was riding in a jeep from Kathmandu with my colleagues observing the tree-covered foothills and cloudy skies associated with the onset the of monsoon season and then all of a sudden I saw it – a blinding white abstraction proffering from between the clouds – Machapuchare. As the first Himalayan peak to which I’d bared witness, and rhapsody challenging to describe overcame me. To see something that beautiful but with such threatening presence flooded my being with complex emotion. I’m not the only one to feel this way. In fact, I will borrow some words from my favorite writer, Peter Matthiessen:

“[Four] miles above these mud streets of the lowlands, at a point so high as to seem overheard, a luminous whiteness shone – the light of snows. Glaciers loomed and vanished in the grays, and the sky parted, and the snow cone of Machhapuchare glistened like a spire of a higher kingdom.”

Stay tuned for more on Macchapuchare.