Kathy C. turned me on to this example yesterday. I had no idea. Lava flow is only about 250 yrs old. It is in the Stikine Volcanic Field. There is a related, somewhat brief, paper:
This underwater picture shows a lone submerged tree in Clear Lake, OR.
There are many more than this. One (maybe most) date to about 2700 yrs
bp when a lava dam blocked the McKenzie River. Freezing water,
exceptionally clear.
Finally devised a way to confidently and easily extract profile data from the LiDAR data set in GlobalMapper. Surface profiles are simple. Basal profiles shown here are estimates based on some point measurements. Will vastly improve the basal profiles when GSA is over. Needed this figure, however, so spent too much time devising the method.
Preparing for my GSA lava talk and came up with these new versions of
the map of the Owyhee River study area. The second one is just the lava.
This one supports the tenet:
'Intracanyon lava flows, the gifts that keep on giving'.
A garishly colored map that underscores the tight linkage between
An obvious, but overlooked addition to the Oywhee River lava-dammed lake story. This is the approximate extent of the early Pleistocene lake caused by a Bogus Rim lava dam crest of 1210 m at Iron Point.
This upstream-looking 3-D block rendition of the Ryegrass Creek area on the Owyhee is intriguing. The color ramp works well here because the strata are flat-lying. Note the boulder-covered and very flat surface below the Qbsy and above Ryegrass Creek...I suspect it relates to the pre-Saddle Butte lava Owyhee or Ryegrass Ck channel in some way, but I have never actually stood on it. Also, look at the morphology of the eastern edge of the Qbsy where the lacustrine seds sit...distinct linear trace there was map as fault by Ferns et al., but isn't it just the contact between the paleovalley wall and the lava? What about that abrupt wall in the Qbsy flow just beyond there? Looks like it is heading down a narrow valley.
Screenshot that shows the current status of my mapping in a key area. Landslides are green and broken into three relative ages (brighter=younger). Red lines have not been attributed yet. Map is coming along nicely.
Ok, so maybe I spent enough time out there in 2007, 2008, and 2009. Yikes. As expected, the parts of the map that are the hardest to compile in the office are those areas I never hit on the ground.
Yes. I am a little late on getting my NSF annual report done...why these are due 3 months before the end of the year in question is beyond me. Most annual reports are due within 3 months of the end of the contract year. I suspect that someone made a mistake in the original paperwork and simply won't own up to it.
Sure, I have gone on and on about the amazing visualizations you can get with some tweaking of LiDAR data; however, it turns out that a pretty basic representation is also quite useful...contours. Yes, contours. Sometimes smaller scale features remain somewhat ambiguous in hillshades or slopeshades, but high-res, short interval contours from the LiDAR data can eliminate most of the ambiguity. In this case, it is a tiny area that I have struggled with on the Owyhee River. Here, a large landslide entered from the north, shoved the river channel to the south, and the river eventually worked its way back to the north to some extent. The array of surficial deposits in the void that comprises the right hand side of the image south of the river record this sequence of events as well as subsequent sedimentation by tributary fans. The contours really highlight the fans, and in conjunction with discernible drainage patterns evident in the LiDAR, it is clear what is fan and what is river, right?
I created this lake by generating a contour from the LiDAR dataset at an elevation of 1046 m. GlobalMapper does this in about 1.5 minutes. Then, exported the vector as a shapefile, cut out the parts of the line that occur downstream from the dam, stitch the remaining loose ends, build a poly from the line and there it is.
These were made in surfer and grapher. For further editing, the emf file can be modified in illustrator. Said file will be placed in shared folder.
Turns out that ArcMap has some very useful tools buried in the toolbox for evaluating the basic characteristics of LiDAR data. For example, using the 3D analyst extension, it is possible to collate the basic parameters of *.LAS tile sets. For example, the following steps:
Basically, this smooths out the sagebrush and rabbitbrush.
This figure uses the hillshaded LiDAR and high-res Naip imagery at 60% transparency.
Made with Global Mapper. Same conditions apply as previous. Note that I do know how to correct the no-data areas in the LiDAR with ArcGIS...learned at the Users Conference in San Diego last week. Just have not yet had a chance to apply the correction.
This was made with Global Mapper. Couldn't block out the no-data areas, but will use hillshade from prior post. It was made in Arc.
This is a straightfoward shaded relief image of the Dogleg Bar area using the 1-m LiDAR DEM.
From near Bogus point across the kipuka, etc. Shockingly simple to extract in GlobalMaper or ArcGIS. Smoothed in Grapher. Mocked-up in Illustrator. Will work on another that brings in other members of the family.
The slope-shading method looks a bit less 'real' but provides an amazing enhancement of slope contrasts that reflect important contact relations. Try it out on the data yourself and you will be amazed at the new array of relations that will jump out at you. For example, look at the young landslide nested in a larger slide along the Saddle Butte lava flow in the lower left corner. Pretty obvious now, no? Probably blocked the channel. During field camp, I found one of these in the Artillery Rim complex that is nested in the older slide complex. It too flanks a notably narrow reach of the river and may be associated with a young blockage.
Mapping update. Things are cranking along. Still have some aberrant unattributed polys...
Hillslope Deposits
Qcf Undivided colluvium and alluvial fan deposits, Holocene to Pleistocene
Qc Colluvium, undivided, Holocene to Pleistocene
Eolian Deposits
Qe Eolian sediments, Holocene to late Pleistocene(?)
Deposits of the Owyhee River
Qra Active channel and floodplain alluvium, Recent to late Holocene
Qry Young fluvial sediments, Holocene
Qrty Young floodplain terraces, Holocene
Qrt1-n Fluvial terrace gravels, Pleistocene (numbered in local depositional order where appropriate)
Qrg Fluvial gravel, undivided, Pleistocene
Qgb Fluvial boulder bars, Pleistocene
Qgw Fluvial gravel of West Crater lava, late Pleistocene
Qrgo Older fluvial gravel, Pleistocene
Qgbr Fluvial gravels of Bogus Rim lava, early Pleistocene
QTgl Ancient, inter-lava flow fluvial gravel, early Pleistocene to Pliocene
QTga Fluvial gravel of Artillery rim, early Pleistocene to Pliocene(?)
Lacustrine deposits of the Owyhee River corridor
Qfl Fluvio-lacustrine sediments, undivided, late Pleistocene
Qflw Fluvio-lacustrine sediments of West Crater lava dam, late Pleistocene
Qfls Fluvio-lacustrine sediments of Saddle Butte lava dam, late Pleistocene
QTfa Fluvio-lacustrine sediments of Artillery Rim, early Pleistocene to Pliocene
Landslide Deposits
Qls Landslide deposits, undivided, Holocene to early(?) Pleistocene
Qlsy Young landslide deposits, Holocene to late Pleistocene
Qlsby Young landslide deposits composed dominantly of coarse basalt breccia, Holocene to late Pleistocene
Qlsi Intermediate age landslide deposits, late Pleistocene
Qlso Old landslide deposits, middle to early (?) Pleistocene
Alluvium of Owyhee River tributaries and local drainages
Qa Alluvium of tributary washes and alluvial fans, undivided, Holocene to Pleistocene
Qas Alluvium and related sediments of active springs, Holocene to late Pleistocene
Qad Alluvium of closed depressions and sags, Holocene to late Pleistocene
Qay Young alluvium of tributary washes and alluvial fans, Recent to Holocene
Qai Intermediate age alluvium of tributary washes and alluvial fans, late Pleistocene
Qao Old alluvium of tributary washes and alluvial fans, middle to early Pleistocene
QTa Ancient alluvium of tributary washes and alluvial fans, early Pleistocene to Pliocene
Basalt lavas of the Owyhee River corridor and surrounding areas
Qbcp Basalt of Coffee Pot Crater, Holocene*
Qbrb Basalt of Rocky Butte, Holocene (?) to late Pleistocene*
Qbw Basalt of West Crater, Pleistocene
Qbs Basalt of Saddle Butte
Qbsy Younger basalt of Saddle Butte
Qbso Older basalt of Saddle Butte
Qbc Basalt of Clarks Butte
Qbg Basalt of Greely bar, early Pleistocene
Qbr Basalt of Bogus Rim, early Pleistocene
QTbc Basalt of Bogus cliffs, early Pleistocene to Pliocene
QTb Basalt, undivided, early Pleistocene to Pliocene
Tb Undivided basalt lavas, Pliocene to Miocene (?)
Tbs Undivided basalt lavas and interbedded sediments, Miocene to Pliocene
*These lavas only on regional map, not in river corridor
Rhyolite lavas and sedimentary rocks
Tsv Interbedded volcanic, volcaniclastic, and other sedimentary rocks, Miocene
Tr Undifferentiated rhyolite lavas, Miocene
