It was a quick weekend trip of exploration. Our story is now up on our blog -
Pony Express Nevada - January 2015
We hope you enjoy tagging along.
Pony Express Nevada - January 2015
We hope you enjoy tagging along.
Pony Express Nevada
- Thread starter ski3pin
- Start date
Looks like a good trip, except for the vandals with guns. Fort Churchill has a bit more to offer than I expected. I think I stopped there briefly about 2009, but didn't explore at all.
Thanks for sharing!!!
Thanks for sharing!!!
Smokecreek1
Smokecreek1
I'll second that guys and it sure brought back allot of memories from the early 70's when I was on UNR field crew doing an excavation on one of those old pony express ruins east a little from where you were. Yep, our team had the luck to dig right down to a stack of old glass window panes that had been buried under the dirt in some old shed for the last 100 years or so. That was great fun, and once we figured out what we were excavating, it was time to take a sample and call that unit done. Thanks again, and an other place to add to my list of places to either revisit or go play in for the first time. The last time (1969)- I was headed to Fort Churchill, me thinks I never got there- stopped by Genoa for a pick me up, seems we never got out of the Genoa bar-shots of moon shine with beer backs and hot dogs with their very special hot sauce -all sold to us by by a one eyed Spanish veteran of the Spanish Civil War! Your TR's sure bring up a lot of good memories, keep 'em coming.
Smoke
Smoke
craig333
Riley's Human
Thanks. As I explore the historic routes east that'll definitely be on my list of places to see.
longhorn1
Ouch, that stings!
Ski, another great story. Thank you. Someday, when I retire, we will make a trip out west. Not sure we can keep up with you on the hikes, but I'm sure that I can play the old wagon cook and put a pretty good meal together when you make it back to camp. Just ask Stew. Once the grill starts anything can happen, anything can end up on the grill, along with some cold ones. jd
Foy
Resident Geologist
About those outcrop photos:
But first, thanks for sharing yet another fine trip. Your "backyard" and "neighborhood" provide endless opportunities to explore.
So, a s-swag (semi-sophisticated wild a## guess) as to your outcrop photos. Disclaimer: volcanics, particularly young volcanics were never my strong suit, and let's remember I haven't earned a dime as a geologist since 1983, but just for grins, here goes-- In the first picture, it appears the light colored rock was deposited over an irregular surface of the dark colored rock. The light colored rock does look like a tuff. Given the mapped geology of the vicinity, it could be a very young basalt flow which developed an a'a surface (typified by large "clinkers" of up to 10 meters in size, and often referred to as "malpais" when the outcrops are not overlain by ash, sediments, or soils which provide easier passage to man or horses). After the clinker surface developed upon the cooling of the basaltic flow, along came an ash fall or ash flow, covering the irregular surface with a blanket of material. Mapping in the general vicinity also shows extensive outcrops of Triassic-Jurassic metamorphosed volcanics and sedimentary rocks. This is interesting since an extensive stratigraphic interval of younger tuffs directly overlies the metamorphics. The mapped tuffs are water-laid tuffs, meaning they either fell into shallow waters, were reworked by flowing waters, or both. The mapped tuffs are believed to have originated from calderas in central Nevada and then redistributed westward by large paleo-rivers. If that's what you saw, the darker colored rock would presumably been Cenozoic metamorphic rock (crystalline, often finely crystalline) with the basal layer of the younger tuff draped over it. A third possibility is a weathering phenomenon--essentially the darker colored rock having weathered, due to exposure to the air and/or groundwaters, to a mixture of clay minerals, forming a "rind" of weathered-in-place clays. Back here in the East, the great majority of our crystalline rocks are covered by a thick layer of saprolite, as the weathered-in-place material is called, and it is possible to map rock units by the saprolite their chemical weathering produces. The saprolite retains the essential textures of the fresh rock from which it was derived. In fact, with only 2-4%, or less, of bedrock being exposed in outcrop down here in the Piedmont, mapping by saprolite is a large part of the field geologist's focus.
The second photo is harder to figure. Looks to me to be sedimentary at the core, with purple and green layers looking fine-grained and suggestive of a shaley or silty shale nature. Mapping in the vicinity indicates, as it does virtually all over the Great Basin and the Rockies, a wide range of Tertiary basin-fill deposits, from very coarse alluvial fan conglomerates to finer and well stratified siltstones. It appears there's some sort of "rind" draped over that outcrop, too. If the two outcrops are in close proximity to one another, perhaps the young a'a basalt and young basin fill being overlain by a young ash flow is the correct answer.
Foy
But first, thanks for sharing yet another fine trip. Your "backyard" and "neighborhood" provide endless opportunities to explore.
So, a s-swag (semi-sophisticated wild a## guess) as to your outcrop photos. Disclaimer: volcanics, particularly young volcanics were never my strong suit, and let's remember I haven't earned a dime as a geologist since 1983, but just for grins, here goes-- In the first picture, it appears the light colored rock was deposited over an irregular surface of the dark colored rock. The light colored rock does look like a tuff. Given the mapped geology of the vicinity, it could be a very young basalt flow which developed an a'a surface (typified by large "clinkers" of up to 10 meters in size, and often referred to as "malpais" when the outcrops are not overlain by ash, sediments, or soils which provide easier passage to man or horses). After the clinker surface developed upon the cooling of the basaltic flow, along came an ash fall or ash flow, covering the irregular surface with a blanket of material. Mapping in the general vicinity also shows extensive outcrops of Triassic-Jurassic metamorphosed volcanics and sedimentary rocks. This is interesting since an extensive stratigraphic interval of younger tuffs directly overlies the metamorphics. The mapped tuffs are water-laid tuffs, meaning they either fell into shallow waters, were reworked by flowing waters, or both. The mapped tuffs are believed to have originated from calderas in central Nevada and then redistributed westward by large paleo-rivers. If that's what you saw, the darker colored rock would presumably been Cenozoic metamorphic rock (crystalline, often finely crystalline) with the basal layer of the younger tuff draped over it. A third possibility is a weathering phenomenon--essentially the darker colored rock having weathered, due to exposure to the air and/or groundwaters, to a mixture of clay minerals, forming a "rind" of weathered-in-place clays. Back here in the East, the great majority of our crystalline rocks are covered by a thick layer of saprolite, as the weathered-in-place material is called, and it is possible to map rock units by the saprolite their chemical weathering produces. The saprolite retains the essential textures of the fresh rock from which it was derived. In fact, with only 2-4%, or less, of bedrock being exposed in outcrop down here in the Piedmont, mapping by saprolite is a large part of the field geologist's focus.
The second photo is harder to figure. Looks to me to be sedimentary at the core, with purple and green layers looking fine-grained and suggestive of a shaley or silty shale nature. Mapping in the vicinity indicates, as it does virtually all over the Great Basin and the Rockies, a wide range of Tertiary basin-fill deposits, from very coarse alluvial fan conglomerates to finer and well stratified siltstones. It appears there's some sort of "rind" draped over that outcrop, too. If the two outcrops are in close proximity to one another, perhaps the young a'a basalt and young basin fill being overlain by a young ash flow is the correct answer.
Foy
OP
OP
Foy, thank you for taking the time to help educate and decipher this. All the photos are taken on the same outcrop although this formation covered a wide area. What impressed me was the even thickness layering of the tuff over the outcrop and boulders, like a layer of snow or "rind" as you say. It just had the look of air deposited and not water, to me. The eastern slopes of the Dead Camels have incredible evidence of the wave action on the edge of Lake Lahontan. This outcrop was just above the shore line. The second photo layering underneath was a bit lower on the outcrop. So maybe we have the possibility that we are on the shoreline and the lake was covered with sticky volcanic ash "goo" that was thrown up and stuck to the rocks. We would need to climb higher and see if there is an elevation limit to this deposit. Anyway, it is fascinating to figure out the dynamics and history of this wonderful ball we are all taking a ride on! Thanks again. Why don't we all retire, you move out west, and we go look at things?
Foy
Resident Geologist
Ski,
It is genuinely and completely my pleasure to comment on anything and everything related to geology. My vocation became my avocation over 30 years ago, and the arrival of the time of life when our sons are "off the payroll" has led to our re-discovery of exploration in the West where the geology is so spectacular and the other scenery is superb. To be able to follow along with your and others' explorations, particularly in the Eastern Sierra, DV, and Nevada, and see the textbook geology so well exposed, is icing on the cake. As to future travel plans, while little could please us more than retiring and spending summers wandering and winters skiing, the little which pleases us more is takes the form of a darling 2 year-old grandson and another, gender not yet known, on the way for a 2015 arrival. That, and duties related to an elderly mother preclude our consideration of pulling up stakes at any point in the foreseeable future.
Now, those outcrops: The topographic position being along an obvious Lahontan shoreline certainly suggests a relationship between shoreline wave action and the deposit of the light-colored material. The uniformity of thickness, however, suggests original subaerial deposition. Perhaps we have a young basalt with an a'a surface overlain by a densely welded tuff, then overlain by much younger Lahontan shoreline deposits.
As a part of my evening "wind-down" reading tonight I'll enjoy some more research concerning the geology of the eastern Dead Camels. I'll report any ideas which result!
Foy
It is genuinely and completely my pleasure to comment on anything and everything related to geology. My vocation became my avocation over 30 years ago, and the arrival of the time of life when our sons are "off the payroll" has led to our re-discovery of exploration in the West where the geology is so spectacular and the other scenery is superb. To be able to follow along with your and others' explorations, particularly in the Eastern Sierra, DV, and Nevada, and see the textbook geology so well exposed, is icing on the cake. As to future travel plans, while little could please us more than retiring and spending summers wandering and winters skiing, the little which pleases us more is takes the form of a darling 2 year-old grandson and another, gender not yet known, on the way for a 2015 arrival. That, and duties related to an elderly mother preclude our consideration of pulling up stakes at any point in the foreseeable future.
Now, those outcrops: The topographic position being along an obvious Lahontan shoreline certainly suggests a relationship between shoreline wave action and the deposit of the light-colored material. The uniformity of thickness, however, suggests original subaerial deposition. Perhaps we have a young basalt with an a'a surface overlain by a densely welded tuff, then overlain by much younger Lahontan shoreline deposits.
As a part of my evening "wind-down" reading tonight I'll enjoy some more research concerning the geology of the eastern Dead Camels. I'll report any ideas which result!
Foy
Lighthawk
Weekend warrior
Fun to follow along and revisit old haunts as well as new opportunities.
OP
OP
Foy, big congrats on the grandkids!Foy said:
..................and we are well acquainted with the demands/joys/concerns with elderly parents.
always...........Happy Travels!
OP
OP
thanks Andy! We think we spotted your tire tracks out there.Lighthawk said:
takesiteasy
Senior Member
Interesting report and thread discussion.
Dughlas Stiubhart
It's good to be Stew
Ah, the Great Basin!
Foy
Resident Geologist
Of windward ice-age lake shorelines, geochemistry of deposition of calcium carbonate, dead camels, and now the oldest petroglyphs in North America:
I couldn't stand it. I had to spend a few minutes looking into the odd rock outcrop photos. OK, it was an hour, but my boss approved (I'm self-employed). Here's what I think Ski and The Lady saw:
The second picture is the beginning point. The picture and their text show they were on a Lahontan shoreline, a bench perched well above the bottom of the basin today. Some searching on Lahontan shorelines and Dead Camel Mountains brought me to several professional papers describing the geology of the Lake Lahonta region (ice age Lake Lahonta) and the Carson Desert. The seminal work was published in 1964 as Lake Lahonta: Geology of the Carson Desert, Nevada. USGS Professional Paper 401. Author Roger Morrison. Students of the history of science will be fascinated to know that the prior principal research was USGS Monograph 11, by IC Russell. Russell reported to GK Gilbert, then Geologist-in-Charge, Division of the Great Basin, US Geological Survey. Gilbert thus submitted Russell's work to the Honorable J W Powell, Director, USGS, in 1885. That would be John Wesley Powell, the first head of the USGS and "Wanderer of the West Extraordinaire", only by boat instead of truck.
Anyway, the gist is that over 120 years of geologic mapping has identified widespread deposits of tufa along ice age shorelines including Lake Lahonta and Lake Bonneville. Tufa is a form of limestone--calcium carbonate and is unrelated to a tuff, of volcanic ash origin. In other parts of the West, tufa forms in lacustrine environments where lake bottom springs provide the chemical environment favoring precipitation of tufa from calcium carbonate rich waters. The tufa towers at Mono Lake are prime examples. Elsewhere, including Lake Lahonta, its sub-basins (including Pyramid Lake), and Lake Bonneville, tufas form where heavy wave activity along windward shorelines aerates the water sufficiently to cause "de-gassing" and thus promotes precipitation of calcium carbonates due to declines in the partial pressure of CO2 gas within the waters. At Lake Bonneville, 400 miles east of the Dead Camels, a 2010 study noted the primary wind direction was from the northeast, so we might assume the same at Lahonta. The east slopes of the Dead Camel Mountains would then have been a windward shoreline facing northeast, having lots of "fetch" (open waters across which wave energy builds up" and then very favorable for precipitation and deposition of "encrusting tufa" upon whatever rock substrate was present within a few meters depth of the elevation of the shoreline. The first picture thus appears to be an encrusting tufa inasmuch as it's draped all over the bedrock's irregularities. The second picture also seems to depict an encrusting tufa, but this one is draped over a slightly older layer of Tertiary lacustrine sediments, mapped by geologists on the opposite side of Lahonta (at Grimes Point and the Lahontan Mountains) as green, gray, and red siltstones and shales. The second picture must be oriented to the southeast, with the Dead Camels on the right and the present-day Lahontan basin on the left.
A mere 5 minutes of work showed Ski's work as to the origin of "Dead Camel" as a place name may be right on target, where Fort Tejon, CA was the western terminus of the US Army Camel Corps operations which originated in West Texas, and where stray camels were spotted throughout the Southwest as recently as the middle of the 20th century. It's also possible that the Wisconsonian Ice Age, from about 26,000 to 12,000 years ago, during which the Lahonta and Bonneville lake elevations fluctuated considerably, left remains of the many mastodons, giant ground sloths, and yes, camels, as fossilized remains in soft sediments as the glacial lakes receded. Back here in the East, the Valley and Ridge of southwest Virginia includes extensive surficial salt deposits which were the death traps for mastodons and sloths, there just one to two hundred miles south of the ice sheets. Saltville, VA has some terrific museum displays of such fossils.
Lastly, Ski's post from today concerning the Pyramid Lake petroglyphs indicated dating of the limestones upon which the works were carved showed the rock was around 14,000 years old. Since Pyramid is a Lanhontan sub-basin, the carvings were likely done on tufas on the Pyramid shoreline, then hundreds of feet higher than the remnants of Pyramid today.
A sardonic but good humored "gee, thanks buddy" to Ski, without whose inquisitiveness and photography skills I would have been able to reach my billable hours quota today. Keep 'em coming, Ski!
Foy
I couldn't stand it. I had to spend a few minutes looking into the odd rock outcrop photos. OK, it was an hour, but my boss approved (I'm self-employed). Here's what I think Ski and The Lady saw:
The second picture is the beginning point. The picture and their text show they were on a Lahontan shoreline, a bench perched well above the bottom of the basin today. Some searching on Lahontan shorelines and Dead Camel Mountains brought me to several professional papers describing the geology of the Lake Lahonta region (ice age Lake Lahonta) and the Carson Desert. The seminal work was published in 1964 as Lake Lahonta: Geology of the Carson Desert, Nevada. USGS Professional Paper 401. Author Roger Morrison. Students of the history of science will be fascinated to know that the prior principal research was USGS Monograph 11, by IC Russell. Russell reported to GK Gilbert, then Geologist-in-Charge, Division of the Great Basin, US Geological Survey. Gilbert thus submitted Russell's work to the Honorable J W Powell, Director, USGS, in 1885. That would be John Wesley Powell, the first head of the USGS and "Wanderer of the West Extraordinaire", only by boat instead of truck.
Anyway, the gist is that over 120 years of geologic mapping has identified widespread deposits of tufa along ice age shorelines including Lake Lahonta and Lake Bonneville. Tufa is a form of limestone--calcium carbonate and is unrelated to a tuff, of volcanic ash origin. In other parts of the West, tufa forms in lacustrine environments where lake bottom springs provide the chemical environment favoring precipitation of tufa from calcium carbonate rich waters. The tufa towers at Mono Lake are prime examples. Elsewhere, including Lake Lahonta, its sub-basins (including Pyramid Lake), and Lake Bonneville, tufas form where heavy wave activity along windward shorelines aerates the water sufficiently to cause "de-gassing" and thus promotes precipitation of calcium carbonates due to declines in the partial pressure of CO2 gas within the waters. At Lake Bonneville, 400 miles east of the Dead Camels, a 2010 study noted the primary wind direction was from the northeast, so we might assume the same at Lahonta. The east slopes of the Dead Camel Mountains would then have been a windward shoreline facing northeast, having lots of "fetch" (open waters across which wave energy builds up" and then very favorable for precipitation and deposition of "encrusting tufa" upon whatever rock substrate was present within a few meters depth of the elevation of the shoreline. The first picture thus appears to be an encrusting tufa inasmuch as it's draped all over the bedrock's irregularities. The second picture also seems to depict an encrusting tufa, but this one is draped over a slightly older layer of Tertiary lacustrine sediments, mapped by geologists on the opposite side of Lahonta (at Grimes Point and the Lahontan Mountains) as green, gray, and red siltstones and shales. The second picture must be oriented to the southeast, with the Dead Camels on the right and the present-day Lahontan basin on the left.
A mere 5 minutes of work showed Ski's work as to the origin of "Dead Camel" as a place name may be right on target, where Fort Tejon, CA was the western terminus of the US Army Camel Corps operations which originated in West Texas, and where stray camels were spotted throughout the Southwest as recently as the middle of the 20th century. It's also possible that the Wisconsonian Ice Age, from about 26,000 to 12,000 years ago, during which the Lahonta and Bonneville lake elevations fluctuated considerably, left remains of the many mastodons, giant ground sloths, and yes, camels, as fossilized remains in soft sediments as the glacial lakes receded. Back here in the East, the Valley and Ridge of southwest Virginia includes extensive surficial salt deposits which were the death traps for mastodons and sloths, there just one to two hundred miles south of the ice sheets. Saltville, VA has some terrific museum displays of such fossils.
Lastly, Ski's post from today concerning the Pyramid Lake petroglyphs indicated dating of the limestones upon which the works were carved showed the rock was around 14,000 years old. Since Pyramid is a Lanhontan sub-basin, the carvings were likely done on tufas on the Pyramid shoreline, then hundreds of feet higher than the remnants of Pyramid today.
A sardonic but good humored "gee, thanks buddy" to Ski, without whose inquisitiveness and photography skills I would have been able to reach my billable hours quota today. Keep 'em coming, Ski!
Foy
Smokecreek1
Smokecreek1
Ya got that right Foy, I'm an old BLM archaeologist and I've spent many years doing allot of arch research out in that country and that whole area today is one big tufa formation with lot's of old tufa tubes staining for that once existing lake's surface; there are also quite a few hot springs and a few tule marshes still on the deserts edge. You can see the old Lanhontan shorelines clearly today! Lot's of basalt formations out there-complete with attendant prehistoric quarry sites, caves and lots places to explore. Something sort of interesting is that some of the formations out there are granitic in nature, not basaltic, like everything else. Even more interesting is that we found endocene bubbles/tubes (formed from within the lava inside of the rock) within some of them that erosion and pot hunters had exposed (they had been utilized during prehistoric times), as opposed to the usual exocene (formed by outside wind erosion, etc.,) caves most people are used to seeing. Anyway, enough of this geologic/ark speak, it is interesting country full of surprises!Foy said:
Smoke
OP
OP
No, no, no, keep it coming!Smokecreek1 said:
Foy
Resident Geologist
I hear you Smoke. We most often think of tufa towers forming at lake bottoms, but there are lots of tufas formed where hot springs or other waters flow into a lake. What's most interesting to me is the tufa horizons forming away from such water inflows, formed by the degassing of the lakes waters in a high-energy wave environment. On the one hand, you wonder how the calcium can precipitate out of solution and "stick" to the substrate in a shorebreak area. On the other hand, you have extensive coral reefs developed around the youngest and steepest-sloped of the Hawaiian Islands, the Big Island, so clearly calcite can latch on in environments we don't anticipate it could.
In the brief scans of the professional literature today, mention of granites and rhyolites (extrusive granites) in northwest Nevada, related to Pacific Plate subduction, was frequent.
With those "encrusted" tufas which formed along the Ice Age shorelines must be, in many places, effectively an armor plate today. In arid environments, calcium carbonate (limestone) is a resistant ridge or ledge former. I rather expect an immature, unconsolidated occurrence of tufa exposed at the surface in the East or Midwest would have been long gone due to dissolution by mildly acidic groundwater and rainwater. In Nevada and Utah, they're rock-hard "rings around the tub". Completely cool!
Foy
In the brief scans of the professional literature today, mention of granites and rhyolites (extrusive granites) in northwest Nevada, related to Pacific Plate subduction, was frequent.
With those "encrusted" tufas which formed along the Ice Age shorelines must be, in many places, effectively an armor plate today. In arid environments, calcium carbonate (limestone) is a resistant ridge or ledge former. I rather expect an immature, unconsolidated occurrence of tufa exposed at the surface in the East or Midwest would have been long gone due to dissolution by mildly acidic groundwater and rainwater. In Nevada and Utah, they're rock-hard "rings around the tub". Completely cool!
Foy
OP
OP
Foy:
Thanks so much for the research! My boss kept me working 'til quitting time this afternoon...................
I was aware of tufa formation in the Grimes Point area
and also at Lovelock Cave over in the Humboldt Sink. I was assuming tufa was only deposited from springs as we are use to seeing at Mono Lake and the Trona Pinnacles. These wave action deposits are a whole new idea for me. So interesting. And, thanks for tying in history and Powell. I love this stuff!
Now I'm curious about the real origin of "Dead Camel". Is it from fossils or Army camels wandering about? If it is the latter, we'll have to start searching for camels on our Nevada explorations. Thanks again!
Thanks so much for the research! My boss kept me working 'til quitting time this afternoon...................
I was aware of tufa formation in the Grimes Point area
and also at Lovelock Cave over in the Humboldt Sink. I was assuming tufa was only deposited from springs as we are use to seeing at Mono Lake and the Trona Pinnacles. These wave action deposits are a whole new idea for me. So interesting. And, thanks for tying in history and Powell. I love this stuff!
Now I'm curious about the real origin of "Dead Camel". Is it from fossils or Army camels wandering about? If it is the latter, we'll have to start searching for camels on our Nevada explorations. Thanks again!
Foy
Resident Geologist
I thoroughly enjoyed it. As a benefit, I am far more relaxed now than I'd be if I'd spent the entire day sorting out vagaries of the Federal and State tax codes. I actually used to worry that Congress would legislate me out of my new profession when the '86 tax act was passed. Silly me.
I'll be interested to hear what the provenance of Dead Camel Range is. Surely there is some abundance of Ice Age fossils in dry lake beds and flats across the West.
A biography of John Wesley Powell is a good read. I believe I've mentioned such in the "favorite books" thread herein. Like most persons of genius, he was a complicated guy and in many respects was roundly despised during parts of his life.
Foy
I'll be interested to hear what the provenance of Dead Camel Range is. Surely there is some abundance of Ice Age fossils in dry lake beds and flats across the West.
A biography of John Wesley Powell is a good read. I believe I've mentioned such in the "favorite books" thread herein. Like most persons of genius, he was a complicated guy and in many respects was roundly despised during parts of his life.
Foy
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