Other
Scientific paper
Dec 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005agufm.p41b0938b&link_type=abstract
American Geophysical Union, Fall Meeting 2005, abstract #P41B-0938
Other
5470 Surface Materials And Properties, 5480 Volcanism (6063, 8148, 8450), 8429 Lava Rheology And Morphology
Scientific paper
We measured block sizes along 15-25m orthogonal transects on 12 lava flows of compositions ranging from basalt to rhyolite. At each site, we stretched a line across the flow surface then measured the length of each block cut by this line that were greater than 3-12cm (depending on composition). The measurements from each site were reduced to cumulative size frequency distribution plots, with block size (D) plotted against the fraction of the line f(D) composed of blocks greater than or equal to that size, and fitted with an exponential curve of the form f(D) = k exp(-qD) where k is the intercept and q is the decay parameter. Average block size and geometric mean were also determined for each site. Our data show no clear trends linking average or mean block size to composition, although there does seem to be relationship between block size and the decay parameter. Block size corresponds with the decay parameter at each site except for the basaltic andesite flow at Paint Pot Crater (CA). Many sites at this flow were covered with secondary spatter deposits. Largest blocks and smallest decay parameters were found for the andesite flows at Sabancaya (Peru), while the basalt flows at Cima (CA) exhibited the smallest blocks and largest decay parameters. The second largest block sizes occurred at the four Inyo domes composed of both crystal-rich and glassy rhyolite, and these domes also showed the second smallest decay parameters. All four of the Inyo domes were emplaced along the same feeder dike trend, and the average and mean sizes and decay parameters at these domes are nearly identical, suggesting that composition, extrusion rate, or eruption history controls the block size distributions. However, values for the two andesitic flows, Mt. Shasta (CA) and Sabancaya, were very different, suggesting that extrusion rate and/or eruption history exert a stronger control over the block size distributions than does composition. LIDAR data sets are capable of detecting sub-meter variations in topography that can be related to block size. High-resolution topographic characteristics measured from LIDAR data sets can therefore supply us with another avenue to study the emplacement histories of lava flows using block size distributions.
Anderson Stephen W.
Bulmer Mark H.
Burke M. P.
No associations
LandOfFree
Rock size distributions on lava flow surfaces: New results from a range of compositions does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Rock size distributions on lava flow surfaces: New results from a range of compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rock size distributions on lava flow surfaces: New results from a range of compositions will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-750033