On Nov.18, 2003, Will_Drotar wrote:
"What would be those non-catastrophic
events that would create polystrate trees?"
In case of the Philippines, not only are polystrate trees, which in time will become polystrate fossils, being formed, but also polystrate telephone poles, polystrate glass factories, other polystrate buildings, and so forth. That geologists can watch all manner of polystrate features being formed by burial in real time alone refutes the Young Earth creationist argument that only a massive global catastrophe can create polystrate fossils.
A picture of the polystrate telephone pole can be seen in "Photographic Record of Rapid Geomorphic Change at Mount Pinatubo", 1991-94 by Raymundo S. Punongbayan, Christopher G. Newhall, and Richard P. Hoblitt at:
http://pubs.usgs.gov/pinatubo/punong1/index.html
specifically at:
http://pubs.usgs.gov/pinatubo/punong1/fig18f.jpg
"A second-generation, 10-m-tall buried
telephone pole (the first generation was
completely buried). Remains of the glass
factory are in the background. The budding
scientist in the photograph was spray
painting marks at 2-m elevations on
third-generation posts, such as that in
the background. (C.G. Newhall, August 13,
1994)"
The non-catastrophic process creating this polystrate telephone pole consist simply of torrential tropical rains eroding the enormous amount of loose volcanic material that accumulated on the slopes of Mount Pinatubo beacause of a massive eruption. Each of a series of torrential rains eroded these volcanic sediments with each creating a volcanic mud flow (lahar) that moved down stream / river. As each lahar flowed downriver, it filled valleys and buried the landscape adjacent to the river with an additional layer of sediment. In many places in valleys and along to rivers and streams, the accumulation of sediment was thick enough over a period of weeks to years to bury trees, telephone poles, houses, and other tall objects.
In another example, non-catastorphic processes completely and deeply buried the "bridge to Poonbato, Botolan, Zambales, across the Bucao River" under volcanic mud flow (lahar) deposits. Because the deposits accumulated as the result of multiple lahars, the bridge is buried, not by a single layer of volcanic sediments, but multiple layers resulting in the formation of a polystrate bridge.
The before picture can be seen in figure 27A at:
http://pubs.usgs.gov/pinatubo/punong1/fig27a.jpg
The after picture can be seen in figure 27B at:
http://pubs.usgs.gov/pinatubo/punong1/fig27b.jpg
"Poonbato bridge was buried (but not swept
away) by lahars of 1991 and 1992. Deposits
are approximately 25 m thick. Barangay
Poonbato (immediately to the right of the
field of view) was buried. View is to the
east, upstream. (R.S. Punongbayan, May 16,
1994)"
The processes creating the polystrate trees, telephone poles, and so forth are documented in great detail by various papers in:
Newhall, C. G., and Punongbayan, R. S.,
eds., 1996, Fire and Mud - Eruptions and
Lahars of Mount Pinatubo, Philippines.
Philippine Institute of Volcanology and
Seismology and the University of
Washington Press, 1126p.
Fire and Mud - Eruptions and Lahars of Mount Pinatubo, Philippines
http://vulcan.wr.usgs.gov/Volcanoes/Philippines/Pinatubo 1st link
http://vulcan.wr.usgs.gov/Volcanoes/Philippines/Pinatubo 2nd link
http://pubs.usgs.gov/pinatubo/contents.html
In case of the Louisiana polystrate trees, they were buried by the piracy of the flow of the Mississippi River by the Atchafalaya River. When the flow of the Mississippi River, was diverted down the Atchafalaya River, the amount of sediment of sediment flowing down the Atchafalaya River increased tremendously. Because of this, there was a rapid increase in the sedimentation occurring during floods, of increasing magnitude, on the backswamp bordering the river causing its natural levees built up by 4 to 5 meters. The dumping of sediment also compacted backswamp clays underlying the natural levees causing the land to subside and providing more vertical space in which sediment sediments could accumulate. Historical maps and records for the Atchafalaya River demonstrate beyond any doubt that the burial of these trees occurred between 1870s, when the piracy of Mississippi River waters by the Atchafalaya River started, and 1960, when the construction of artificial levees prevented direct flooding of the location where the polystrate tree was found.
The polystrate trees in Louisiana are being dated by a number of means, in addition to historical records. According to the people I met at the GCAGS meeting, a detailed scientific report will be published about them in four to six months. When my sources tell me where it can be ordered, I will post that information to this list.
Some Background References
Fisk, H. N., 1944, Geological investigation of
the Alluvial Valley of the Lower Mississippi
River: US Army Corps of Engineers, Mississippi
River Commission, Vicksburg, Mississippi.
Fisk, H.,N., 1952, Geological investigation of
the Atchafalaya Basin and problems of
Mississippi River diversion, Vol. I and II:
US Army Corps of Engineers, Mississippi River
Commission, Vicksburg, Mississippi.
Another references that I came across was:
Heinrich, P., 2002, Buried forests could provide
clues to the past. Louisiana Geological Survey
News. vol. 12, no. 2, p. 1 (December 2002)
Louisiana Geological Survey, Louisiana State
University, Baton Rouge, LA.
This article discusses other polystrate trees that have been found beneath the modern surface of the flood and delta plains of the Mississippi River. Polystrate trees are repeatedly found by burrow pits, bridge and canal construction, and in engineering borings beneath larges parts of the surface of the flood and delta plains of the Mississippi River.
Yours,
Bill Birkeland
edited links to fix page width - The Queen
[This message has been edited by AdminAsgara, 11-20-2003]