Jump to content

Polystrate fossil

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Paul H. (talk | contribs) at 19:54, 20 December 2005 (→Mainstream Geology Position). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

An upright tree preserved in the cliffs at Joggins, Nova Scotia, Canada (printed 1868).

Polystrate or upright fossil describes fossils of single organisms (such as tree trunks) that run through several geological strata. Entire "fossil forests" have been discovered. They are found all over the world— they are very common in the Eastern United States, Eastern Canada, England, France, Germany, and Australia — but especially in areas where coal seams are present. Within Carboniferous coal-bearing strata, it is also very common to find what are called Stigmaria (root stocks) in this same stratum, some of which can be traced directly to standing trees.

Mainstream Geology Position

In mainstream geology, such fossils are referred to as upright fossil, trunks or trees. Mainstream geologists explain their formation as being caused by episodes of rapid sedimentation within either an actively subsiding coastal plain or rift basin or by the rapid accumulation of volcanic material on the flanks and around the bases of stratovolcanoes as the result of periodic eruptions. Geologists have long accepted that a layer or set of layers containing polystrate fossils was created by a brief period of rapid sedimentation. Typically, this period of rapid sedimentation was followed by a period of time, decades to thousands of years long, characterized by very slow or no accumulation of sediments. In river deltas and other coastal plain settings, rapid sedimentation is often the end result of a brief period of accelerated subsidence of an area of coastal plain relative to sea level caused by salt tectonics, global sea level rise, growth faulting, continental margin collapse, or some combination of these factors (Gastaldo et al. 2004). For example, mainstream geologists such as Dr. John W. F. Waldron and Dr. Michael C. Rygel have argued that the rapid burial and preservation of polystrate fossil trees found at Joggins, Nova Scotia was the direct result of rapid subsidence, caused by salt tectonics within an already subsiding pull-apart basin,[1] and resulting rapid accumulation of sediments (Waldron and Rygel (2005).[2] In case of the polystrate trees of the Yellowstone petrified forest, which occur buried within the lahar and other volcanic deposits comprising the Lamar River Formation, the periods of rapid sedimentation are regarded by them to be the result of explosive volcanism. This type of volcanism generates and deposits large quantities of loose volcanic material as a blanket over the slope of a volcano as happened during the 1991 eruption of Mount Pinatubo. Both during and for years after a period of volcanism occurs, lahars and normal stream activity wash this loose volcanic material downslope. These processes result in the rapid burial of large areas of the surrounding countryside beneath several meters of sediment as directly observed during the 1991 eruption of Mount Pinatubo (Newhall and Punongbayan 1996).

Mainstream geologists have recognized innumerable buried soils, called "paleosols" throughout the strata containing polystrate fossils at Joggins, Nova Scotia, Yellowstone petrified forests, coal mines of the Black Warrior Basin of Alabama, and many other locations. Paleosols were soils formed by subaerial weathering during periods of very slow or no accumulation of sediments. Later, renewed sedimentation buried these soils to create "fossil" soils called paleosols. In sharp contrast to creationist geologists, i.e. Dr. Harold Coffin and Dr. N. A. Rupke, mainstream geologists, who have studied polystrate fossils found in sedimentary rocks exposed in various outcrops for the last 30 years, have described polystrate fossil trees as being deeply rooted in place and typically rooted in recognizable paleosols. Mainstream geologists, i.e. Falcon (2003a, 2003b, 2005, 2006) and Rygel et al. (2004, in press), have published detailed field sketches and pictures of intact root systems rooted within recognizable paleosols. In case of polystrate fossil trees of the Yellowstone petrified forests, mainstream geologists, again in sharp disagreement with creationist geologists, i.e. Dr. Harold Coffin, found that the polystrate fossil trees, except for relatively short stumps, are rooted in place within the underlying sediments. Typically, the sediments within which polystrate trees are rooted have paleosols developed within them (Amidon 1997; Retallack 1981, 1997)). Either pictures or diagrams of the Yellowstone polystrate fossil trees having intact root systems developed within paleosols found within these strata have been have been published in Retallack (1981, 1997). [3]

In addition, mainstream geologists found that some of the larger polystrate trees found within Carboniferous coal-bearing strata show evidence of regeneration after being partially buried by sediments. In case of these polystrate trees, they were clearly live when partially buried by sediments. Because of their size, the sediment, which accumulated around them, was insufficient to kill them. As a result, they developed a new set of roots from their trunks just below the new ground surface and grew higher to compensate for part of the trunk buried by sediment (Gastaldo et al. 2004). Until they either died or were overwhelmed by the accumulating sediments, these polystrate would likely continue to regenerate by growing by adding height and new roots with each increment of sediment eventually leaving several of meters of former "trunk" buried underground as sediments accumulated

Mainstream geologists find nothing anomalous about polystrate trees found in Carboniferous coal-bearing strata being associated with marine or brackish water fossils. Because they lived on subsiding coastal plains or pull-apart basins open to the coast, it was quite frequent for subsidence to periodically outpace the accumulation of sediments such that adjacent shallow marine waters would periodically inundate coastal plains in which the polsytrate trees were buried. As a result, sediments, containing marine fossils, would periodically accumulate within these areas before being replaced by coastal swamps as sediments either filled in the shallow sea or sea level fell. Also, according to ecological reconstructions by mainstream geologists, specific assemblages of the types of trees found as polystrate fossils occupied brackish water even saline coastal swamps much like modern mangrove swamps. Thus according to mainstream geologists, finding marine and brackish water fossils associated with these polystrate trees is no different than finding brackish water or marine animals living in modern mangrove swamps (Falcon 2005, 2006).

Thus, according to mainstream science, polystrate fossils are just fossils which were buried in a relatively short time span either by one large depositional event or by several smaller ones. Mainstream geologists see no need to invoke a global flood to explain upright fossils.

This position of mainstream geologists is supported by numerous examples, which have been found at numerous locations, of polystrate, upright, trees completely buried within either late Holocene or historic sediments. These polystrate trees demonstrate that conventional geologic processes are capable of burying and preserving trees in an upright position such that in time, they will become fossilized.

At this time, the best documented occurrences of unfossilized polystrate trees found within historic and late Holocene volcanic deposits of Mount St. Helens, Skamania County, Washington, and Mount Pinatubo, Philippines. At Mount St. Helens, both unfossilized and partially fossilized polystrate trees were observed in many outcrops of volcanic debris and mud flows (lahars) and pyroclastic flow deposits, which date to 1885 to over 30,000 BP., along the South Toutle and other rivers. Late Holocene forests of polystrate trees have also been observed as occurring within the volcanic deposits of other Cascade Range volcanoes(Karowe1987, Yamaguchi1995). In a few years after the eruption of Mount Pinatubo in 1991, the erosion of loose pyroclastic deposits covering it slopes created a series of volcanic lahars, which ultimately buried large parts of the countryside along major streams draining these slopes beneath several meters of volcanic sediments. The repeated deposition of sediments by volcanic lahars and sediment filled rivers not only created innumerable polystrate trees, but also “polystrate” telephone poles, churches, and houses, over a period a few years (Newhall and Punongbayan 1996).

Within excavations for Interstate Highway 10, borrow pits, landfills, and archaeological surveys, unfossilized polystrate trees have also been found buried within late Holocene, even historic, fluvial and deltaic sediments underlying the surface of the Mississippi River Delta and the Atchafalaya Basin of Louisiana. In one case, borrow pits dug in the natural levees of Bayou Teche near Patterson, Louisiana, have exposed completely buried, 4 to 6 foot (1.2 to 1.8 meters) high, upright trunks of cypress trees. Northeast of Donaldsonville, Louisiana, a borrow pit excavated for fill used to maintain nearby artificial levees, exposed three levels of rooted upright tree trunks stacked on top of each other lying completely buried beneath the surface of Point Houmas, an patch of floodplain lying within a meander loop of the current course of the Mississippi River (Heinrich 2002, 2005). While searching for buried archaeological sites, archaeologists excavated a 12 ft (3.6 meter) high upright rooted cypress tree completely buried within a natural levee of the Atchafalaya River within the Indian Bayou Wildlife Management Area just south of Krotz Springs, Louisiana. Radiocarbon dates and historic documents collected for this archaeological survey, during which this and other polystrate trees were found, of the Indian Bayou Wildlife Management demonstrated that these polystrate trees were buried sometime during the 1800s (Godzinski 2005).

Citations for Mainstream Position

Amidon, L. (1997) Paleoclimate Study of Eocene Fossil Woods and Associated Paleosols from the Gallatin Petrified Forest, Gallatin National Forest, SW Montana. unpublished Master's thesis. University of Montana.

Falcon-Lang, H. J. (2003a) Late Carboniferous dryland tropical vegetation, Joggins, Nova Scotia, Canada. Palaios. 18:197– 211.

Falcon-Lang, H. J., (2003b) Early Mississippian lycopsid forests in a delta-plain setting at Norton, near Sussex, New Brunswick, Canada. Journal of the Geological Society, London. 161:969–981.

Falcon-Lang, H. J., (2005) Small cordaitalean trees in a marine-influenced coastal habitat in the Pennsylvanian Joggins Formation, Nova Scotia. Journal of the Geological Society. 162(3): 485-500.

Falcon-Lang, H. J., (2006) Latest Mid-Pennsylvanian tree-fern forests in retrograding coastal plain deposits, Sydney Mines Formation, Nova Scotia, Canada. Journal of the Geological Society. 163(1): 81-93.

Falcon-Lang, H. J. (in press) Vegetation ecology of Early Pennsylvanian alluvial fan and piedmont environments in southern New Brunswick, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology.

Gastaldo, R. A., Stevanovic-Walls, I., and Ware, W. N. (2004) Erect forests are evidence for coseismic base-level changes in Pennsylvanian cyclothems of the Black Warrior Basin, U.S.A., in Pashin, J.C., and Gastaldo, R.A., eds., Sequence Stratigraphy, Paleoclimate, and Tectonics of Coal-Bearing Strata. American Association of Petroleum Geologists Studies in Geology. 51:219–238.

Godzinski, M., Smith, R., Maygarden, B., Landrum, E., Lorenzo, J., Yakubik, J.-K., and and Weed, M. E. (2005) Cultural Resources Investigations of Public Access Lands in the Atchafalaya Basin Floodway, Indian Bayou South Project Area, St. Landry and St. Martin Parishes, Louisiana. Report submitted by Earth Search, Inc., New Orleans to the U.S. Army Corps of Engineers under contract number DACW29-02-D-0005, Delivery Order 05[4]

Heinrich, P. V. (2002) Buried forest provide clues to the past. Louisiana Geological Survey News. 12(2):1

Heinrich, P. V. (2005) Significance of buried forests exposed in the Lemannville cutoff road pit, St. James Parish, Louisiana. Louisiana Geological Survey NewsInsights. 15(2):8-9.

Karowe, A.L. and Jefferson, T.H. (1987) Burial of trees by eruptions of Mount St. Helens, Washington: Implications for the interpretation of fossil forests. Geological Magazine. 124(3):191-204.

Newhall, C. G., and Punongbayan, R. S. (1996) Fire and Mud: Eruptions and Lahars of Mount Pinatubo, Phillipines. University of Washington Press. ISBN: 0295975857

Retallack, G. J., (1981) Reinterpretation of the depositional environment of Yellowstone fossil forest: Comment. Geology 9:52-53.

Retallack, G. J. (1997) A Colour Guide to Paleosols. John Wiley and Sons. ISBN: 0471967114

Rygel, M. C., Gibling, M. R., and Calder, J. H. (2004) Vegetation-induced sedimentary structures from fossil forests in the Pennsylvanian Joggins Formation, Nova Scotia. Sedimentology 51:531– 552.

Waldron, J. W. F., and Rygel, M. C. (2005) Role of evaporite withdrawal in the preservation of a unique coal-bearing succession: Pennsylvanian Joggins Formation, Nova Scotia. Geology 33(5):37-340.

Yamaguchi, D. K., and Hoblitt, R. P. (1995) Tree-ring dating of pre-1980 volcanic flowage deposits at Mount St. Helens, Washington. Geological Society of America Bulletin 107(9):1077-1093.

Notes for Mainstream Position

^ 1. Pull-apart basins, also called strike-slip basins, are regional topographic depressions created by lateral movement at a bend or discontinuity within in strike slip fault.

^ 2. For popular articles on their findings go read (1.) Sedimentology: Fossil forests sunk by salt by Sara Pratt, July 2005 Geotimes and (2.) Geologists probe mystery behind Nova Scotia’s fossil forests by Scott Lingley, ExpressNews,December 20, 2005

^ 3. Mainstream geologists, at this time, agree with Dr. Harold Coffin that his "organic layers" are not paleosols. The layers, which mainstream geologists currently recognize as being paleosols, are completely ignored by all of Dr. Harold Coffins's various papers on the Yellowstone petrified forests. Mainstream geologists, i.e. Amidon (1997), have documented the presence of soil structures unique to soil forming processes and distinct alternation of volcanic deposits by pedogenic processes, which identify thin layers within the Yellowstone petrified forests as paleosols. These layers are not mentioned by Dr. Harold Coffins and other creationists in their discussions.

^ 4. Godzinski (2005) is on file with and can be consulted at the Louisiana Division of Archaeology in Baton Rouge, Louisiana.

Creation Science Position

The creation science position is that the strata must have been laid down in rapid succession, rather than millions of years apart, so creation scientists sometimes use polystrate fossils as evidence against strict Uniformitarianism and the mainstream geologic timescale. The Biblical flood described in Genesis is often presented as an explanation for polystrate fossils.

Mainstream Geological

Creationist

Retrieved from "https://en.wikipedia.org/w/index.php?title=Polystrate_fossil&oldid=32138357"