Comments on: Where on (Google) Earth? #82 http://greengabbro.net/2007/12/25/where-on-google-earth-82/ rock out to the apparatus Tue, 30 Sep 2008 23:52:19 +0000 http://wordpress.org/?v=2.3.1 By: Ron Schott http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-25087 Ron Schott Wed, 02 Jan 2008 02:26:28 +0000 http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-25087 <a href="http://ron.outcrop.org/blog/?p=130" rel="nofollow">WoGE #83</a> is up. WoGE #83 is up.

]]> By: Lab Lemming http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-25049 Lab Lemming Tue, 01 Jan 2008 01:27:00 +0000 http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-25049 For some reason, all your posts list as having zero comments when viewing your blog. For some reason, all your posts list as having zero comments when viewing your blog.

]]> By: Lab Lemming http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-25046 Lab Lemming Tue, 01 Jan 2008 01:07:23 +0000 http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-25046 It looks to me like water is running downhill in that photo. Possibly with a clastic sediment load. It looks to me like water is running downhill in that photo. Possibly with a clastic sediment load.

]]> By: Ron Schott http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-24868 Ron Schott Thu, 27 Dec 2007 22:19:25 +0000 http://greengabbro.net/2007/12/25/where-on-google-earth-82/#comment-24868 I'm no fluvial geomorphologist, so I can't tell you too much about why the rivers in this area are alternately braided and meandering, but as a hard rock geologist I can tell you that it has something to do with the 1991 eruption of Mount Pinatubo. These valleys around the volcano, including <a href="http://ron.outcrop.org/kml/WoGE82.kmz" rel="nofollow">these on the west side</a>, were filled with an estimated 4-8 cubic kilometers of pyroclastic material during the cataclysmic eruption on June 15th. My guess is that in those areas where the pyroclastic material is voluminous enough you tend to get a braided channel morphology; other areas - perhaps where the deposits were not so thick or have already been significantly eroded away - show a meandering character that probably was prevalent prior to the eruption. It's scary how quick I found this one once I started looking. The grey colors in the drainages screamed out "recent pyroclastic eruption" and The Philippines was the first place I went looking - probably because of the lushness of the vegetation outside of the floodplains. Google Scholar offers these references in a search on "<a href="http://scholar.google.com/scholar?hl=en&num=10&as_epq=&as_oq=&as_eq=&lr=&cr=&as_ft=i&as_filetype=&as_qdr=all&as_nlo=&as_nhi=&as_occt=any&as_dt=i&as_sitesearch=&as_rights=&safe=images&q=pinatubo+fluvial+geomorphology&um=1&ie=UTF-8&sa=N&tab=ws" rel="nofollow">pinatubo fluvial geomorphology</a>". I’m no fluvial geomorphologist, so I can’t tell you too much about why the rivers in this area are alternately braided and meandering, but as a hard rock geologist I can tell you that it has something to do with the 1991 eruption of Mount Pinatubo. These valleys around the volcano, including these on the west side, were filled with an estimated 4-8 cubic kilometers of pyroclastic material during the cataclysmic eruption on June 15th. My guess is that in those areas where the pyroclastic material is voluminous enough you tend to get a braided channel morphology; other areas - perhaps where the deposits were not so thick or have already been significantly eroded away - show a meandering character that probably was prevalent prior to the eruption.

It’s scary how quick I found this one once I started looking. The grey colors in the drainages screamed out “recent pyroclastic eruption” and The Philippines was the first place I went looking - probably because of the lushness of the vegetation outside of the floodplains.

Google Scholar offers these references in a search on “pinatubo fluvial geomorphology“.

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