Geologic Froth: Geofroth at AGU 2008

Geologic Froth: Geofroth at AGU 2008

I'm done with the map, I'm done with the map, etc.

Finished just in time to attend a meeting about heavy budget cuts at UNR. Check the earlier entries to see how far this came. On this version, the lava dams are indicated and I have exercised my urges to name stuff.

I will only change something if it is factually and not only aesthetically erroneous.

I'm sick of the map, I'm sick of the map, I'm sick of the map, etc.

Here is one version...had some plotter problems (shocking, no?) and dumbed the base down a little. This one is about 24 by 28.

I'm the map, I'm the map, I'm the map, etc.

This is what I came up with for a draft layout for the map. I will add the base material images when back at my office computer. Any votes for shaded relief vs topo or some other possibility (e.g. a combination of those, the NAIP imagery, satellite imagery)? I am traveling after noon tomorrow and will be unavailable on Thursday and Friday. Weekend is possible, but I have a talk to prepare for AGU and haven't started that yet.

The draft above shows some labels on the lava flows. I could add more or delete the ones on there. Anyone have a preference? Let me know soon.

Owyhee Map for AGU...almost there

I have reached a point of no return on the map and have gotten close to a final draft for inclusion on AGU poster(s). In this version, a lot of the detail is left out:

no bedrock older than Bogus Rim flow
undivided landslides,
undivided mainstem fluvial deposits (active channel is divided),
undivided lacsutrine deposits.

Reasons: map is too complicated for showing everything and too many loose ends in some units (mainly generalized bedrock) to build polys.

The colors are chosen to highlight the various features and are obviously not conventional geologic map colors. Mainly, those conventions are a real annoyance when you map detailed surficial units anyway. The snippets in this post should give you a good idea of where things stand. I am leaving town tomorrow afternoon and cannot have this map hanging over my head...and I bet that spud is tired of waiting.

It will be pretty easy to create a basemap using these data as the 1:250,000 version indicates. I need some feedback on where to go from here.

Cool Tangent...Rocky Butte and Jordan Creek

I have been mapping the Q basalt flows that didn't make it to the Owyhee and have learned that the lava v. water situation on Jordan Creek is exceptionally cool and interesting. We should really check this out this spring if time permits. The photo here shows a very well developed overflow channel. It appears to have filled in and then incised some depressions on the flow surface. Lots of interesting features associated with this flow.

Map-tacular Effort

Great job on the mapping Kyle! I am looking forward to seeing it on our poster.
-Spud

Miraculous Late Night Recovery!

GeoMap-a-thon, Day 6. The curse of Topology

Put in 7 hours on map today to find an inexplicable topology error that precluded building polygons. I was so excited for this to happen. After lengthy consultation with local GIS supergeek, turns out that exporting feature dataset as shapefile and then reimporting it as feature dataset worked. Took 1.5 hours to figure that out. If you get this error in your life, don't panic like I did, it is not worth it (just follow the steps above):


Despite this roadblock, I made alot of progress. Will post map tomorrow AM...can't work on it much at all beyond tomorrow.

Holy Crap, day 5 was a bad one

Lots of tedium, lots of cursing, lots of computer problems. Nonetheless, I made a lot of progress. Here is a snippet of the Bogus Rim / Lambert Area. Don't be alarmed...there are still some tiny holes that lead to bleeding polys. This does show my interp of the landslides vs. in situ rox in the Bogus Rim area. Until Monday....

Yeehow GeoMap-a-thon, Day 4

I don't have a particularly meaningful map to post today. Have been mired in correcting imported linework from the vr...topology issues. However, did spend a lot of time mapping in the landslides coming off of Bogus Rim and had a good online chat with Spud about some contentious mapping calls of mine. Worthy of a group discussion in the field for sure.

Using the vr is instructive, but it is most useful in topographically complex areas. Many of the lines I added were redundant with respect to prior flat mapping and field mapping. By placing the vr lines on high-res imagery using ArcExplorer (get it now) also proved just how useful it would be to be able to directly edit arc-ish linework. The screen shot below is what my computer looked like most of the day. The area is the large foundering slab of Qbw above Dogleg. Check the killer perspective on the right vs. the flat map perspective on the left. Note also that the overprinted lines on the left are the imported vr lines and the prior flat mapping lines. My goal is to now find out why I can't place vectors on precisely georeferenced images draped on topography.

Check out ArcExplorer. It is free. Not as good as Google Earth, but possibly more functional? At least it has the high-res imagery for our area. Lastly, it cannot adequately render the gorge because of the extreme relief and some bad orthorectification inthe NAIP data. Turns out that careful orthorecitification of high-res photo scans in the vr has some (but less) trouble here. If we can drape images on the LiDAR and map on that....

Yeehow GeoMap-a-thon Day 3-D

No map to post today, instead here is a shot of me totally geeked-out (electric glasses, mp3 player, Blackberry) working away on the map. The 3-D mapping is great, but it takes some serious time. Since it allows you to check the elevation of any point in the image, it allows for some checks of in situ vs. landslide strat...this has led to some significant reinterpretations of the suite of landslides off of Bogus Rim...lots to talk about. Lots more in situ rock there than appears at first, second, and third glance.

Yeehow GeoMap-a-Thon day 2

Good progress today despite interminable interruptions. Heather (NBMG Yeehow in training...YIT) set up Rome Valley on the VR today...the 3-D computer mapping device. I will get to mapping that in more detail tomorrow AM. 3-D will help immensely in that reach. Have relied on much of Cooper's mapping to get the lava flow extents. Some refinement added. Some questions about where some begin and where some end still remain. Anyway, here it is:

A big week for the Yeehow GeoMap

Howdy. Here is a 1:200k version of the map as it stands at the end of the day today. I will commit to updating this image via blog entry each day through Friday as a form of personal motivation. Many of the color bleeds will go away with some topology corrections and some additional lines. Yes. I did start mapping the Q lava flows to their sources. At some point, I need a little help from Cooper with this. Note the major league lava-water interface in the Danner area (east of Arock)...yowza. Looks like a good side trip for Yeehows. Totally cool and unexpected (by me, at least). Sometimes it is good to look beyond the map area, no?

Incision of Hell's Canyon

Hi again,

If you are not up on the evolution of the Western Snake River Plain (WSRP) and the timing of the cutting of Hell's Canyon in relation to the Owyhee intra-canyon lava flows then consider reading a paper by BSU Emeritus geomorphology professor Spencer Wood and his colleague Drew Clemens, "Geologic and Tectonic history of the Western Snake River Plain, Idaho and Oregon" Find it at:
http://earth.boisestate.edu/home/swood/WOODCLEM-2002.PDF
Among other things, the paper discusses where and when Lake Idaho existed and how and when Hell's Canyon was cut. It refers to work done by Kurt Otherberg, who Jim had mentioned before in the context of Hell's Canyon.
-Spud

Paleoclimate of northern Great Basin and Owyhee area

Hi folks,

Two years ago I asked Peter Wigand for some direction in
searching for papers that might help us understand the
paleoclimate (and therefore perhaps river discharge and
stream power) of the Owyhee River basin.  He replied to
me but I never was able to track down all the papers he
suggested.  I am providing his suggestions here in the
hopes that we can improve our understanding of what the
Owyhee River might have looked like during the existence
of the lava dams.  He said to start with the first one
which had an extensive bibliography that would
lead to some of the others.
-Spud




Wigand, P. E. and D. Rhode. 2002. Great Basin
Vegetation History and Aquatic Systems: The Last
150,000 years. Pp. 309-367. In Hershler, R., D. B.
Madsen and D. R. Currey (eds.), Great Basin Aquatic
Systems History. Smithsonian Contributions to Earth
Sciences 33. Smithsonian Institution Press,
Washington, D.C.

Mladen Zic, Robert M. Negrini, Peter E. Wigand. 2002.
Evidence of synchronous climate change across the
northern hemisphere between the north Atlantic and the
northwestern Great Basin, USA. Geology 30(7):635-638.

Cohen, A. S., M. Palacios, R. M. Negrini, P. E.
Wigand, and D. B. Erbes. 2000. A paleoclimate record
for the past 250,000 years from Summer Lake, Oregon,
U.S.A.: II. Sedimentology, paleontology, and
geochemistry. Journal of Paleolimnology 24
(2):151-182.

Negrini, R. M., D.l B. Erbes, K. Faber, A. M. Herrera,
A. P. Roberts, A. S. Cohen, P. E. Wigand, and Franklin
F. Foit, Jr. 2000. A paleoclimate record for the past
250,000 years from Summer Lake, Oregon, U.S.A.: I.
Chronology and magnetic proxies for lake level.
Journal of Paleolimnology 24 (2):125-149.

Mehringer, P.J., Jr. and P.E. Wigand. 1990. Comparison
of Late Holocene environments from woodrat middens and
pollen, Diamond Craters, Oregon. In Martin, P.S., J.
Betancourt and T.R. Van Devender (eds.), Fossil
Packrat Middens: The Last 40,000 Years of Biotic
Change. University of Arizona Press.

Wigand, P.E. 1987. Diamond Pond, Harney County,
Oregon: Vegetation history and water table in the
eastern Oregon desert. Great Basin Naturalist 47
(3):427-458.

OWY-19, river left outcrop of WC between Bogus Falls and Dogleg

Here are two photos--long overdue--that show the contact relations of the WC lava where I collected sample OWY-19. One shows the modern swale that has eroded around the WC lava that filled the paleo-swale. The other photo shows the nature of the contact between WC and lava flows within the Tertiary section: the WC lava sits on top of the Tertiary section there.
-Spud

Cascadian Pyroclastic Goodness

The results are in. Nick Foit's lab at WSU has analyzed some Owyhee tephra samples with a new probe. The delay in getting the data owes to the time it takes to set up such a device. Turns out that it was worth the wait. The tephra id's match Yeehow conventional wisdom in so much as they match the most likely candidates at each site.

I don't have time to work up anything fancy for this post (leaving for different field area in AM...not ready yet, but here is the dirt:

Mt. St Helens Set C, approximate age 47.2 ka found in lacustrine seds on river right and left above West Crater flow (image above is from sample on river right). These are the samples that we both related to OSL ages of approximately 20 ka. The occurrence of this tephra on both sides of the river and at disparate elevations is interesting and is evidence for sedimentation at two different levels here. One associated with the Owyhee, and one associated with the perched paleo Ryegrass Creek.

Mazama Tephra was found in auger holes in depressions on the Bogus Point landslide and on one of the Heaven's Gate landslides. The Trego Hot Springs tephra was also found deep in the core of the Bogus Point landslide sag. This bed (from Newberry Volcano, I believe) dates to approximately 23.2 ka.

We also found Mazama (6850 c14 yrs BP; ~7600 real years) tephra in an arroyo cut formed in a breached sag on a landslide on river left in Heavens Gate.


View Larger Map

Geologic Compilation Celebration

Today, I finally began to georectify O'Connor's field maps to cross-check against and augment my mapping. Using GlobalMapper this process takes only about 1 minute per map. Love that program. As expected, Jim's mapping is good. Take a bow. Our overlapping mapping only differs by refinement owing to more overland work and hi-res imagery. Of course, the man found some things I missed under both of those circumstances. Don't worry Cooper, your mapping is next. Will pay attention to your paleochannels on West Crater, relax.

While compiling Jim's compilations, I noticed a couple of intracanyon flow remnants in the gorge that I had forgotten about. They are labeled as Lambert (West Crater) but are most likely Clark's Butte given their elevation. I believe that the northernmost one is in the Tertiary section...but am not sure.

Any clarification / confirmation / elevation/ consternation that any Yeehow may have about these blobs would be appreciated. Photos would be super neato.

Reply to depocenter in middle of WC flow

Yes, the comment fcn on the blog seems to be out of order--this post is in regard to Dr. Jerque's post of WC in VR hindsight, etc. etc.

Dr. Jerque,

The area marked by a question mark on the image you posted could certainly contain sediment from the Owyhee River as the river flowed over the top of the WC lava. I have been there and was impressed by this expansive, low relief area made mostly of silts. I will review my notes at home tonight on the matter. I do recall also acknowledging that the area could easily be a depocenter for Bogus Creek. The road that you can see in the upper right corner of the image is built on a ~1.5-2 m high (man-made) berm (levee!!) that ensures all of Bogus Creek flows north rather than between some tumuli down to the low relief silty area as it clearly could do in the drop of a hat (or a March rain-on-frozen-ground event).

Yes, there are some large gravel/cobble bars along the lower reaches of Bogus Creek near the kipuka. If i recall correctly, these happen to be low enough in elevation and downstream enough to be within reach of overflows from the Owyhee River passing through the possible depocenter but also from other overflows further downstream. (Having said that, there are some sizable ephemeral channels that pour off the Bogus Rim directly to the east of the kipuka and these could contribute a lot of discharge in a large convective event or spring rain on snow.) It may be worth considering auguring this silty depocenter or digging some test pits there to understand the deposits or find some datable material.


And yes, there are several different lobes and inflationary flow fronts to the WC lava flow that wrap around Bogus Point and create some unique positive and negative relief. I looked at these in stereo many times and walked around on the ground there with an eye towards assessing the timing of these lava pulses and the potential interaction with the river. After a lot of back and forth, I continue to return to my original interpretation that there is only one lava flow in the area--the WC-- and that water flowed through a narrow gap between several tumuli far more upstream than the rounded boulders on the edge of the modern cliff of WC adjacent to Chalk Basin show. I am pretty sure that this nascent paleo channel is the upstream-most one shown on my maps of several years ago. Furthermore, there probably is a complex set of damming and overflow events because even though there is probably only one lava flow there, it probably made several surges or advances in its battle with the river and rising lake.

I sure wish I could have come to Bend!
-Spud

Ouch. I missed these... comment by Lisa

Lisa e-mailed a nice comment that I have placed on the blog for the record. I agree with her points. Something appears to be wrong with the commenting function in blogger...not with Lisa.

I recently re-read Howard et al.'s paper. The difference I see is that they stop short of going into detail about the impact of the lava dams on the geomorphic evolution of the canyon. Their paper provides a great basis of comparison for ours, but we can take ours much further with our more extensive dating, mapping and our possibly greater interest in the river canyon geomorphology. The Howard et al. paper was not that long, and mainly focused on the description of the lava flows and dams. We have more controls on incision rates through different lava flows at different times and places on the river, which I think will lead to interesting discussion.

I've sent away for a few more references to lava dams in the last couple of days. I'll circulate them when I get a chance to look them over. Quite a few on the Snake River, some in Canada, one in China.

Ouch. I missed these...

On my (not so) recent trip down the Grand Canyon, I had a lingering memory of Cassie suggesting that Keith Howard had been a little hard to convince as to the reality of lava dam failure and catastrophic flooding there, but that some of the field evidence finally convinced him. I had that lingering memory because I was weakly skeptical based on the lack of such evidence on the Owyhee, but was confused because I had read (and reviewed) a couple of her papers. Turned out that I really needed to see the stuff in person with a better backlog of personal observations. As I noted in a previous post, some of the flood evidence was (to me) hilariously clear and my skepticism was baseless for the most part.

Now that I have finally read Keith's Boise River lava dam paper, I can understand why he was skeptical given the striking parallels between the Boise River story and the Owyhee River story. (thanks to Lisa for sending the pdf). Moreover, the Howard and Fenton abstract (that, admittedly, I was not aware of) reads just like the thoughts I had in mind while thinking of the Owyhee while floating the Colorado. Some of the differences are profound.

Admission of guilt: I am truly embarrassed that I had not read the Howard et al. paper years ago, as it would have made it far easier and faster for me to understand the history of the Owyhee River. Oh well....As for the more recent abstract...no excuses there either.

We should really consider checking out the Boise River sites sometime.

LAVA DAMS COMPARED IN BOISE RIVER CANYON AND GRAND CANYON

HOWARD, Keith A., U.S. Geol Survey, Menlo Park, CA 94025, khoward@usgs.gov and FENTON, Cassandra R., U.S. Geol Survey, 1675 W. Anklam Rd, Tucson, AZ 85745 Pleistocene intracanyon basalt flows that dammed the Boise River, Idaho offer comparisons to those that dammed the more powerful Colorado River in Grand Canyon. In both canyons, olivine basalts erupted several times from vents near canyon rims, and flowed down steep canyon walls into the rivers and onto thick gravel beds. The multiple lava dams in Grand Canyon exhibit many stratigraphic complexities as compared to the simpler stratigraphic structure of the dams built on the Boise River, best exemplified by the Steamboat Rock Basalt and the Smith Prairie Basalt on the Boise River’s south fork. These two dams were each constructed to heights of 150 m from multiple flow units of basalt, which flowed tens of kilometers downstream while building lava deltas into the growing reservoirs on the dam’s upstream faces. Paleowater levels in the lava deltas, where lava flowed into rising reservoir waters behind the dams on the Boise River, are easily recognized as passage zones where topsets of subaerial pahoehoe pass abruptly downward into upstream-dipping foresets of pillows and hyaloclastite. Successive flow units entering a rising reservoir resulted in an asymmetric dam, much longer on the downstream face, and cored by massive subaerial basalt that interfingered upstream with a series of upstream-thickening wedges of pillow basalt. Grand Canyon lava dams also show evidence of upstream deltas where lava interacted with dammed water (described by Hamblin), but coarse hydroclastitc breccia dominates over pillows and foreset-bedded hyaloclastite; the deltaic structures are complex. Whereas several dams in the Grand Canyon failed catastrophically to produce outburst floods (described by Fenton and colleagues), the dams on the Boise River were incised gradually. Their long downstream lengths contributed stability. The long flows and abundant pillows relative to breccias suggest fluidity of the lavas, and suggest rates of eruption and lava flow that were high relative to the discharge of the river that they entered. The Colorado’s discharge is twenty times that of the Boise River South Fork.

Rocky Mountain (56th Annual) and Cordilleran (100th Annual) Joint Meeting (May 3–5, 2004)

Funny aside: at the meeting in Bend, I 'independently' developed a diagram for how we could graphically convey the last 1.8 my of the persistently interrupted incision history of the Owyhee. Much to my dismay, within minutes of touting the merits of my exmple figure, I was faced with a nearly exact example prepared by Howard et al. Lisa had the paper with her and I read it for the first time right then and there. In addition to the figure, many of the concepts presented in the paper were identical to discussions that we always have and were having that day. We then became concerned about how we could distinguish our study from theirs beyond just stating that it also happened somewhere else not very far away. I keep verging toward a discussion of the differences between landslide dams and lava dams with interesting counterpoints from the Colorado River and the Rio Grande.

West Crater flow (Qbw) in VR...old new insight

For the past few days, I have begun to compiling mapping using vr...the 3d visualization and digital mapping tool I mentioned last February--(http://yeehowcentral.blogspot.com/2008/02/virtual-reality-on-owyhee-almost.html). This has been very illuminating because it allows for me to zoom in to key areas in very clear 3D. Since I have already done so much flat-mapping (heads-up digitizing on NAIP images with stereopairs nearby) I have opted to focus on only key and slippery contacts or particularly complicated areas (i.e., the Hole in the Ground). I spent most of yesterday gawking at the Lambert Rocks, Bogus Point, and AM-PM areas.

In conjunction with recent field work (which was, in hindsight, inadequately thorough) I began to recall / notice that the low-relief area in the middle of Qbw is a likely depocenter for overflow related sedimentation by the Owyhee before it cut a canyon through the area. I traced rounded basalt gravel and sand through a sinuous tract across the lava flow toward that area but, alas, opted to head to my vehicle instead of trapsing (yet again) across the lava flow surface. It seems that all of my traverses on the flow have missed this key area. Anyone in the group happened to have been here?...Cooper?

Also, there are some fairly large gravel bars evident in parts of the Bogus Creek course near the large kipuka that are curious as well. Anyone been there?

Have also noticed that there are at least 3 conspicuous flow fronts of Qbw lobes in the Lambert area and am wondering if there is a more complex damming and overflow story there than it appears at first glance.

Saddle Butte Lake v. West Crater Lake

On my last field trip, I collected high precision GPS points on the highest evidence of overflow that I could find on each likely lava dam. In the case of the Saddle Butte lava dam (SBLD), there is evidence of shallow overflow over most of the extant dam crest...I had not realized this before. There are some photos of this in the recent album I posted. The highest overflow evidence was at 1044m (3425 ft). As for West Crater, the elevation of the first evidence for overflow (rounded basalt cobbles on the extant flow margin) is found at 1029 m (3375 ft)(*note that this is reported incorrectly in the figure caption). There is not nearly as clear a lava dam edifice here as there is at Saddle Butte, you may recall.

For what it is worth, the difference is more than expected or could be read from a topo map. As the figure indicates, a 15 m difference in depth has a locally significant effect on the extent of the lake. This is based, or course, on modern topography.

Thermodisappointmence commentary

Figure showing extent of possible lake above West Crater lava dam

Minding and (yes) chuckling about the technology gap, I have added some recent commentary from Yeehow Principals about the OSL results (see below).

I am leaning toward analytical or sample problems based in part on other OSL experiences, but admit that Jim's ideas hadn't occurred to me. I will mull them over. It is notable that the lake would have been fairly large and it may have taken sediment a long time to make it to the dam itself.

Kyle,
Can't blog on the site because I can't remember my user name or password or some such immense Luddite hurdle.
But my immediate thought (assuming that 22ka isn't just the standard OSL result) is that the lake (and its deposits) might owe to changing basin hydrologic characteristics rather than the timing of the blockage. Perhaps the blockage was not sealed sufficiently to form a lake until things got much wetter during the maximum of the last glacial. Or alternatively, significant sediment didn't accumulate until then in a lake that did date back to initial blockage. And recall that when the Alvord basin was full and spilling (at least for several hundred years) at some point loosely around this time during last glacial, there would have been a lot more water coming down the Owyhee from the expanded source area. This could be another twist on the story...
Perhaps the Crooked Creek flood triggered incision (would the terraces ages at Dog Leg jibe with that?).

I'll check on the tephra situation--I have many more samples that have been sitting there even longer. As I said when you sent them my way, you get what you pay for, and when you don't pay anything it's hard to whine.
...Jim

Yeehows,

Sorry, Kyle. I tried to post a comment to the blog, I really did. Same
luddite excuse as Jim. I seem to have set up multiple accounts with
multiple passwords and the matrix of possible matches is too much for me.

I've thought a lot about these OSL results. It's possible that the lowest
deposits are related to a landslide dam downstream, but highly unlikely
that the others are. The deposits on river left can be directly traced up
to the rim on top of the Saddle Butte. Any landslide that blocked the
river that high would have been close to the height of the West Crater dam
itself. I haven't been to the higher site on river left, but it looks like
it is on top of the WC lava itself. Jim's ideas are worth considering, but
my hunch is that something went wrong with the OSL dating itself. The
fine-grained samples we have to work with are not ideal. These ages are at
least 20,000 years younger than the youngest date on the West Crater flow,
and 40ka younger than our best estimate.

Caitlin has started reading up on OSL and the possible reasons behind
erroneous dates, especially those that are younger than the true age.
Next week, after we've discussed this at our Bend summit, I'll contact
Tammy with some specific questions about possible sources of problems with
these results and get her take on them. I have submitted additional OSL
samples from Sand Spring, behind Saddle Butte II flow (could also be
backed up from West Crater), 2 more samples from top and base and middle
of same WC section on river left, and one from sediments way up on rim
behind Bogus Rim flow. We'll see what comes of those. Should shed some
light on the issue, as some of them should be from older damming episodes.

Lisa

Back to the Bogus Lake

Here is a more detailed example of how large a lake dammed by the Bogus Rim lava would have been. This image assumes a dam at Iron Point with a crest elevation of 1200 meters. Made in a flash with GlobalMapper.

OSL Results....Thermodisappointmence?

Before my last field outing, I contacted the USU OSL lab about our samples. The good news: preliminary data are available. The bad news: wtf do they mean?

From: *Tammy Rittenour* <tammy.rittenour@usu.edu

tammy.rittenour@usu.edu>>
Date: Tue, Sep 30, 2008 at 3:03 PM
Subject: RE: Owyhee OSL?

To: Kyle House <pkhouse@gmail.com pkhouse@gmail.com>>

Kyle-

Ive attached the preliminary results from your Owyhee River samples.
They are about 75% complete at this moment. I am working on sending
them in for further processing because of some initial feldspar
contamination, but you should have the final results by the end of the
month.

The samples are all ~22-23ka, if they were taken from the same deposit,
then OSL seems to be working quite well.

Errors on the ages will go down when they are completed, but I dont
expect them to change much at all.

Good luck in the field,

Tammy

What do we make of this information? Well. We suspected that these lacustrine seds were related to damming by the West Crater flow. Given their distribution with respect to the upstream face of that flow this seems like a valid assumption. However, these ages are far younger than the likely age of the West Crater flow. That is a problem. Also, the samples cover a large range of elevation. I expected that there would possibly be a correlation between the elevation of the sample below the likely dam and its age. This is not the case. Check the figure below for a visual cross-check:This figure is a profile from the 10 m DEM data. The profile hits the four sample spots in the area. The geology is schematic (obviously) and hastily drawn (more obviouslyer).

Note the large elevation range of the three sample areas*. Each sample is denoted by a yellow circle (excpet the highest circle, that is a gravel deposit that wasn't sampled). We are still awaiting an identification of an obvious tephra bed that was sampled below the lowest OSL sample. Sent that (and all others) to WSU in early August....USGS has been sitting on it for over a year. If that comes back with a confident ID, then we will have some additional perspective on the OSL data. Any thoughts? Break down and add to the blog....

*I have wondered aloud on numerous occassions about the lowest one...possibly related to landslide dam? Its elevation is pretty low relative to the sublava paleochannel of Ryegrass Creek. The paleotopography implied by this (if related to West Crater) is pretty deep.

Topo Profiles in Study Area

I whipped up these images while revisiting the mapping in earnest today. These can be made in seconds using GlobalMapper. All offer some insights and are interesting to consider. We need to choose some key ones to illustrate with stratigraphy etc. If you lose your bearings, just click to go to the online album and check the map.

Geologic Froth: The Ultimate Digital Tool for Dummies and Luddites?

Geologic Froth: The Ultimate Digital Tool for Dummies and Luddites?

Precision GPS Data from Dogleg Bend

Last week, I spent some time collecting presumably high-precision GPS data with my new Trimble GeoXH unit. The first dataset that I have corrected is from Dogleg. Now we have some pretty robust numbers for incision rate calculations.

Grand Yeehow challenge. Someone out there break down and do the calculations. Post it to the blog and ruminate on it. My guess is that it will be sort of high.

Geologic Froth: My new digital love, the cheap and rugged Laser Range Finder.

Gadget alert:

Geologic Froth: My new digital love, the cheap and rugged Laser Range Finder.

Dave's landslide blog: The Yigong Rock Avalanche, Tibet

Dave's landslide blog: The Yigong Rock Avalanche, Tibet

Yet another interesting post from Dave. Great photos of landslide and ensuing effects of river blockage.

Compelling evidence for lava-dam failure in Grand Canyon

As I noted earlier, there are some pretty clear indications for linkages between lava dams and large floods on the Colorado River in Grand Canyon that stand in contrast to what we see on the Owyhee. One particularly interesting morpho-stratgraphic association includes the following assemblage:

1. Lava flow on river gravel; no evidence for water interaction other than flowing down the channel.
2. Flagrant flow morphology characterized by relatively thin colonnade (with very fat columns in the example below) overlain by considerably thicker entablature.
3. Coarse-grained, complex fluvial deposit containing abundant reworked lava and hyaloclastite material.

Here is a 'Grand' example from mile 192:


What might be going on here? Well, following some discussion with Ryan Crow and some reading about entablature formation that he recommended, I think that this assemblage permits the following interpretation:

1. Lava flow enters canyon and blocks river, allowing flow to continue unimpeded downstream (lava on gravel with no evidence for lava-water interaction)
2. Clear water begins to pass over or through the dam (or both) and greatly accelerates cooling of the lava (induces the elaborate and thick entablature structure)
3. Dam eventually (soon) fails catastrophically and coarse gravel is deposited on the lava flow that now forms the bed of the river.
   

The overlying gravel deposit in this case is notable for the large blocks of poorly rounded colluvial gravel that it contains. That appears to be a common characteristic of these flood deposits. Some likely reasons include: elevation of the channel bed and conveyance of deep high velocity flow at stages not typical of the pre-lava dam river. It is also reasonable to expect that the demise of the dam may have occurred at the buttress of lava on colluvium. I am certain that Cassie suggested this in one or more papers.

With respect to the distinct morphology of the cooling structure of the lava flow, it seems almost inevitable that the very thick and elaborate colonnade reflects the influence of rapid cooling of the lava flow by a very large volume of water. In this case, I am inferring that this huge amount of water is the continuous, initially clear flow of the Colorado around, over, or through the dam. It is also notable that the overlying deposit is multi-phased. There are several beds and only some are extremely coarse. The sequence may contain evidence for the progressive failure of the dam and other vagaries of the hydrograph.

It would be interesting to know if there was any evidence that the gravels were deposited on a cooling lava flow...maybe there are some key erosional forms to look for. Didn't think of that at the time.

This seems like a strong case for failure of a lava dam. There are no assemblages like this on the Owyhee River.

Check this abstract for a discussion of the role of water in forming the colonnade:

Here are some other articles of interest (from a longer list compiled in 5 minutes using Zotero)

Grossenbacher, K. A., and S. M. McDuffie. “Conductive cooling of lava: columnar joint diameter and stria width as functions of cooling rate and thermal gradient.” Journal of Volcanology and Geothermal Research 69, no. 1-2 (1995): 95-103.

Long, P. E., and B. J. Wood. “Structures, textures, and cooling histories of Columbia River Basalt flows.” Bulletin of the Geological Society of America 97, no. 9 (1986): 1144-1155.

Lyle, P. The eruption environment of multi-tiered columnar basalt lava flows. Vol. 157. Geological Soc London, 2000.

Walker, G. P. L. “Basaltic-volcano systems.” Geological Society London Special Publications 76, no. 1 (1993): 3.

GC vs Owyhee

Dr. Jerque,

In a rare moment of 9-5 nonbillable geology work I submit:

The four observations you list (added below in italics) as some of the differences between the Owyhee and GC intra-canyon lava dams are some of the exact same ones I note in the manuscript that is collecting dust on my desk at home.
1. Volume of lava vs. volume of water
2. Mode of entry: canyon rim cascade vs. tributary valley route
3. Severity of topography (vertical and lateral trajectory of lava incursion)
4. Proximity of volcanic vent to the canyon; abundance of pyroclastic material.
This is fabulous! I look forward to hearing more about these items and your other GC observations.
-Spud

Best Owyhee example of lava dam features

The Sand Springs Wash area on the Owyhee retains the best example of a lava dam in the field area. At this site, there are two lava flows from the Saddle Butte vent to the west. The overlying flow is separated from the underlying flow by a spectacularly well-developed lava delta with pillow-laden foresets that dip upvalley. The dam forebay is a turtle-back like feature with a 'carapace' of chilled lava. The surface of the older Saddle Butte lava upstream of the dam is covered with lacustrine mud which is capped with fluvial gravel.

Upstream of this site, the older Saddle Butte lava flow overlies Owyhee River gravel at the site of the Weeping Wall where a spring issues from the contact between the gravel and the lava. Upstream of Weeping Wall, the older Saddle Butte lava contains a sequence of lava deltas and subaerial lavas that suggest a complex interaction with the river.

Downstream, the eastern margin of the younger Saddle Butte flow is wasting away on a grand scale.

First insights from the Grand Canyon

Probably the most striking aspect of my recent trip down the Grand Canyon is the stark contrasts of the intracanyon lava flows and related response of the river there with those of the Owyhee.

• The lava stratigraphy in the GC is notably more complicated than the Owyhee.
• In GC the variability in lava textures and the facies variability of related volcaniclastic deposits is much greater. Some GC volcaniclastic deposits are downright bizarre looking to me.
• In several circumstances, there is strong evidence supporting the occurrence of catastrophic flooding in conjunction with the incursion of lava into the Grand Canyon (note photo above); whereas on the Owyhee, there is no clear evidence of this.
• In GC, there are few to no really good examples of lava deltas. The Owyhee has world class examples.
• In GC, the intracanyon flows are not associated with large-scale (post-emplacement) mass wasting processes. The Owyhee has some spectacular post-emplacement landsliding of lava flow remnants and, thus, continue to plague the river for 1000s of years.
  

Bottom line is that there is great evidence in the Grand Canyon for lava dam failure and related catastrophic flooding. There is weak to no evidence in the Grand Canyon for effective, relatively long-lived damming of the river. In contrast, there is weak to no evidence on the Owyhee River to support catastrophic flooding related to lava dams. There is great evidence on the Owyhee that substantiates effective, relatively long-lived damming of the river by lava.

Obvious questions: Why the profound differences? Why is the Owyhee so much easier to dam with lava than the Colorado?


1. Volume of lava vs. volume of water
2. Mode of entry: canyon rim cascade vs. tributary valley route
3. Severity of topography (vertical and lateral trajectory of lava incursion)
4. Proximity of volcanic vent to the canyon; abundance of pyroclastic material.

I am pretty sure it involves aspect of each of these factors. Stay tuned for more maunderings and some more details on the points above.

SHRIMP in the Owyhee?? Fire up the barbee mate!

Dear Dr. Froude et al.:

I concur with Dr. Jerque. He refers to a plethora of field evidence that adds detail to the story presented in Ninad's work. I'd like to add that you may want to check out a paper from the Idaho State crowd of Beranek, Link, and Fanning (see below). This paper came out some time back and offers a few possible numbers for ages of big picture events in the region. If I recall correctly, the most Owyhee-relevant discussion items are based on only a few data points compared to other drainages studied and could be strengthened by additional analyses. Nontheless, it is pretty darn interesting to this spud farmer trapped in the concrete jungle.

Miocene to Holocene landscape evolution of the western Snake River Plain region, Idaho: Using the SHRIMP detrital zircon provenance record to track eastward migration of the Yellowstone hotspot

Luke P. Beranek, Paul Karl Link, and C. Mark Fanning

Geological Society of America Bulletin Volume 118, Issue 9 (September 2006) pp. 1027–1050 DOI: 10.1130/B25896.1

-Spud

P.S. Dr. Jerque: I think we are on the same page about the Rytuba and Vander Meulen work. I did overstate its relevance in reference to the Now Voluminous (Once Dreaded) Rim Gravels but refer to it merely in the context that it provides evidence of a long-occurring interaction between volcanism, the fluvial system, and expansive sedimentation in the region. I wonder if it is even relevant to the latest question because "The inital influx of major fluvial systems into the volcanic field after about 14.5 Ma is reflected...."(see abstract)?

How old is the Owyhee?

Today, Dr. Froude presented the most basic question: How old is the Owyhee River. I pulled some stuff out of the air in a quick response, and ultimately claimed the river developed between about 5-8 Ma and 1.8 Ma. I decided my response was too quick, and too poorly founded, so I started looking for some of Ninad's data. Turns out that Miami Univ puts all of their dissertations online. Very handy. Thus, I present some of Ninad's dissertation below to serve as a reference point for all of us. By combining his data with our collective field observations, I think we can answer the question. For the sake of completeness, here is my response to Froude's query:

Bogus Rim flow and underlying flows fill a surprisingly deep paleovalley that runs along the alignment of the modern canyon below iron point. Gravels are present at the base of the sequence in a few places (including possibly in the Owyhee Breaks area) and there are erosional intervals preserved between some of the flows. Not sure how well constrained the ages of the lowest flow (the 'lower Bogus lavas') are, but somewhere between 5 and 8 comes to mind (without looking anything up). There was a river flowing north before the Bogus lavas were emplaced. This river created the paleotopography in the Grassy Mountain Rhyolite and sediments before the first big barf of basalt flowed north. Based on the thickness of the Bogus Lavas in the Rinehart Canyon area, there were some deeply incised tributaries flowing into the river.

In terms of field evidence, the biggest influx of gravel occurs in conjunction with the end of the damming event caused by the Bogus Rim flow. I believe that evidence is mounting that a very large lake occupied the area upstream of where the Bogus Rim flow would have created a dam somewhere near Iron Point. Thus, the pre Bogus Rim river was probably a nearly full blown Owyhee. Possibly the full blown river developed in conjunction with surmounting the Bogus Rim dam? That should have been sometime after about 1.8 Ma. I recently collected a tephra from the lake sediments that I postulate were deposited into a Bogus Rim dammed lake. Dating that may be of some value.

Here is the geochronology from our area as reported by Ninad Bondre:

Here is a nifty map that places these data in a better context:

Also, Ninad's thesis includes a handy little geologic map:

Some thoughts:

Despite the geochronology, I am thinking that the Owyhee Butte lava must predate the Bogus Bench lava. Field relations suggest that the gravel that pervasively overlies the Owyhee Butte lava is related to damming of the Owyhee River by the Bogus Bench (Rim) lava. I have not seen any gravel below the Owyhee Butte lava (forms the Artillery Rim), but Liz and I noted in July that there are hyaloclastite units in the upper parts of this package. Note also that the Bogus Bench (Rim...Brim?) lava has no gravel on top until you get a few km downstream from Iron Point. There, you find a 5-8 m thick deposit of locally derived, but rounded gravels. (I have shown pictures of this before in a previous post, but may add them again soon for emphasis). We know from multiple locations that the Bogus Rim lava flowed down a channel of the Owyhee River and overlies rounded gravel in various places. The local gravel pile likely relates to decommissioning of the dam.

Thus, the river is at least 1.92 Ma old. Note that the 4569 vent has a date of approximately 5.64 Ma. The one-sided plateau morphology of that vent and flow complex supports the idea that it formed a lake on its south side, much like Bogus Bench. However, I have not seen (nor looked hard for) gravel. My hunch is that this may be related to a precursor drainage. Speculative.

My preliminary conclusion is that the river formed between 5.6 and 1.92 Ma, probably closer to 1.92. Any thoughts?

All figures and the table in this post taken from:

Bondre, N.R., 2006, Field and geochemical investigation of basaltic magmatism in the western United States and India. PhD. Dissertation, Miami University, Miami, OH., 252 p.

http://www.ohiolink.edu/etd/send-pdf.cgi/Bondre%20Ninad%20R.pdf?miami1164916380

Grand Hiatus for Dr Jerque

Fellow Yeehows. Unfortunately I will be spending the next three weeks slogging through the Grand Canyon with various experts on its geology. Special attention will be given to lava flows, lava dams(?), and all sorts of other things. I am hiking down to Phantom Ranch on Wednesday morning with a pack full of all the stuff I forgot to send ahead. Of special note is a new 10 MP Pentax camera that is waterproof and dustproof. This way I hope to get some fearless shots from the river. Recently took it to Tahoe to try it out:

I will certainly provide a synopsis when I return.

What's up with upper-tier landslides?

After looking at landslide after landslide along the Owyhee, it is pretty clear that there are several modes of failure typical of the river corridor. Of course we have the basic earthflow type (the Hole in the Ground has great examples); the basic rotational slump type (Artillery landslide complex; Heaven's Gate landslide complex); and the basic cantilever slab type failures along the margins of the Quaternary intracanyon lava flows. Yes, there are complex combinations of all of these things as well. Recently, Liz and I were noting that there are areas where only the upper part of an exposued section is peeling away...this is particularly true in areas where there are stacks of massive lavas with occassional interbeds of lacustrine sediments or, more importantly, piles of lava-water interaction deposits. The Bullseye landslide in 'Sweetwater Canyon' (name from river guidebook) is a good example. There, the upper lava flow is peeling back across a cruddy looking bed of lava-water interaction deposits (LWID). The LWIDs overlie a relatively massive stack of lavas. It appears that the Bullseye landslide's head scarp is below the peeling section. Its ultimate failure would not have been possible without the peeling in the upper tiers of the section. This makes Bullseye a lower-tier slide candidate.


There are lots of examples of upper-tier sliding along the river. Possibly the most impressive is right across from Iron Point. In that case, the failing area is pinned on rhyolite. There are several landslides in this general reach that sole-out on rhyolite. Not sure whether they occurred when the river was at the level or if they freaking cascading over the rhyolite into the river. Probably the former since the latter sounds so cool.


There are many examples where the upper-tier sliding seems to be associated with an underlying LWID (like a lava delta) or otherwise incompetent unit (like a lens of mud). In some places, the lava deltas are obviously linked to massive landlsiding; in others, they support massive cliffs. Maybe when you peel away the top, they lead to massive landslides. Probably not that simple. Any thoughts? Anyone?

Is the Bogus Lake bogus?

Check out the extent of a lake with surface elevation of 3900'...

Shockingly Voluminous (Once Dreaded) Rim Gravel, redux

Alas, brother spud, unless we are on different conceptual planes here, the paper in question does not directly address the SV(OD)RG. Instead, it is focused on the fluvial sediments in the middle Miocene part of the section, specifically the arkosic sandstone and mudstones that we see interbedded with rhyolite just downstream from AM-PM camp:

In the context of our studies, this part of the record is only a glimpse into an ancient precursor drainage system. In fact, I think that a fair amount of the SV(OD)RG in our study area is related to lava damming events in the latest(?) Miocene and into the Pliocene (i.e. the Bogus Rim).Thus, is is possible that the SV(OD)RG represent blockage of an integrated / partially integrated Owyhee. Recall that the base of the Bogus lava sits on river gravel in various places between Iron Point and Birch Creek. I suspect it was the blockage of this system in the early Pliocene to late Miocene(?) that deposited the gravels that form a flat surface at 3900'. Subsequent and possibly sporadic incision through the gravel cover after the breach formed several discernible levels of gravel. This is directly analogous to the distribution of the much less widespread and voluminous gravels above the Quaternary blockages. It is that latter point that really pulls me in. Any counter arguments? Anyone?

In the figure below, I have pointed out some features of the gravel. I have approximated its MINIMUM extent using the snow-like pattern. Have also noted the problem with the Ice Axe as Bogus Rim (stay tuned for explanatory post on that one). This is a crude mock-up. A more formal figure will be forthcoming with lots of elevation data...(just got me a Trimble XH...arrived today!).

(click on image for full size)

Reference related to the "Shockingly Voluminous" Rim Gravel

Hi Folks:

Here is a reference from my thesis that a very nice man (who once offered me a job in mineral exploration) turned me on to:

Rytuba, James J., and Vander Meulen, Dean B., 1991, Hot-Spring Precious
Metal Systems in the Lake Owyhee Volcanic Field, Oregon-Idaho;
in Raines, G.L., et al., 1991, Geology and Ore Deposits of the Great Basin,
Symposium Proceedings, USGS and Geological Society Nevada, Reno, Nevada,
Volume II, pp. 1085-1096.

If I remember correctly, I think it is pretty relevant to the dreadfully voluminous rim gravel and provides some corroboration of some of the things Dr. Jerque and others are finding in the field. Dr. Jerque may have a copy and I can scan you a copy sometime if you can't find it.

Traverse Map, PKH, July 2008

Using some very handy applications and hardware (Garmin 60csx; GlobalMapper; ArcGIS), I created this nice little map of my recent field excursion. Note that using the bridge in Rome Valley instead of the Arock route gets you into the field much more quickly. I took a ridiculously rough road out of Arock at first and returned via the bridge near Crooked Creek.

Summer 2008 on the Owyhee, Part 1

Spent all of last week on the Owyhee. Many rim hikes and a few forays down to the wet stuff. The latter with Liz and her students. Learned alot. Found a fault in Sweetwater Canyon (that between Jordan Creek and Hike-out Camp). Determined that the once 'dreaded' rim gravels are really the 'shockingly voluminous' rim gravels. As for the latter, there appears to be a culmination of aggradation on a platform at about 3900'. Multiple levels are present below this, mainly on the Artillery Rim. Found a tephra in a rare exposed section at the 3900' level near Owyhee Butte. Learned that the Heaven's Gate landslide complex (including an upper reach and a lower reach) is quite huge, particulary when viewed from the perspective of the canyon rim...wow. Can't imagine how this complex was not the source of multiple blockages and breaches. Liz nearly single-handedly augered a 4 m hole in a perfect closed depression. We found the Mazama, and certainly drilled into the late Pleistocene...but didn't find the fat tephra bed that we found in the slide below Bogus Point. For now, please view the following slide show for substantiation of most of the claims above (view in Google Maps or Google Earth for the full informative effect):

Model this Breaching Mechanism!

Chinese Landslide Dam Failure Flood in Action

This photo pair is interesting. Amazing how close the community is to the landslide dam...it so easily could have been partly buried by the landslide...but in that case, maybe the valley could not have been dammed so easily. Moot, obviously.

Landslide Dam Failure in China

The significance of these photos to the average Yeehow is quite clear. The principal landslide dam following the recent major earthquake in China has failed. These photos show the breach and the incredibly cool draw-down tongue. For some cogent discussion about this event, check out the blog of Dr. David Petley at which I found the bottom two images and a lot of commentary: http://daveslandslideblog.blogspot.com/

Damming Ruminations by Brother Spud

Hi Folks,
Here are the figures from my thesis that relate to the last post I made on friday night. I hope they help you visualize some of what I described.

-Spud


Figure 2. Exposure of the Saddle Butte lava near Read-it-and-Weep rapid (river kilometer 34.25). Exposure shows foreset beds of hyaloclastite and lava pillows, the passage zone, and subaerial lava. The foreset beds of pillow lavas and hyaloclastite dip down to the right, indicating that the lava advanced from left to right into a body of standing water. Much of the hyaloclastite has altered to orange-colored palagonite. The passage zone marks the elevation of the water surface. Above the passage zone, subaerial lava was emplaced. Exposure is ~60 m thick.

Figure 15. Aerial photograph of river kilometers 37.5–39.5 showing presumed initial location of West Crater lava dam. The Owyhee River flows to the north in this image. The red dashed ellipse marks the location of a possible spillway in the West Crater dam and/or the initial point of breaching. The asterisk denotes the location of the sediment lens depicted in Figure 16. Ryegrass Creek defines the western edge of the Saddle Butte lava flow. The West Crater lava flow entered the Owyhee Canyon by flowing down the Bogus Creek canyon. Enough lava was supplied to the Owyhee Canyon that the dam was able to grow upstream towards Ryegrass Hot Spring.

Figure 16. Photograph of outcrop relations at river kilometer 39.25. The Saddle Butte lava appears to underlie the sediment lens in the center of the photograph. The head of the West Crater lava dam overlies the sediment lens and the Saddle Butte lava. Foreset beds of pillow lavas and hyaloclastite dip down to the right in this image. Several different passage zones (indicated by PZ) indicate the lake level rose during construction of the dam. The location of the paleovalley wall discussed in Figure 15 is indicated by a dashed ellipse. The lens of sediment interpreted to be paleo-Ryegrass Creek is visible in the center of the photograph.