Fossil Forests and the Flood

1883 sketch of upright Lycopod trees, Carboniferous 'Fossil Grove' Victoria Park, Glasgow. From Transactions of the Geological Society of Glasgow. 8, 227-235.

The YEC hypothesis that the sedimentary record originated as a result of a single, year-long global flood is directly contradicted by the presence of a variety of biogenic structures preserved within the sedimentary record which could not form in the time allotted for the flood, or under the depositional conditions associated with the flood. One type of structure that could not form via the flood is "fossil forests," containing upright trees preserved in growth position. Here we review a few such occurences which have been described in the geologic literature.

1. Eocene Fossil Forests in Yellowstone National Park

The Lamar River Formation in Yellowstone Park contains the best known example of a "fossil forest." Here we find multiple levels of in situ trees. The upright trees at Specimen Ridge are rooted in fine-grained tuffaceous sandstone and encased in conglomeratic mudflows. The grain size of the conglomerate decreases away from the location of the volcanic source areas, the East and West Absaroka belts. Also, the ratio of upright, in situ trees to horizontal trees increases away from the Eocene volcanic source areas - the eruptions and mud flows flattened whole forests proximal to the source, while many trees are preserved in growth position in more distal locations, such as at Specimen Ridge. Although it is unclear how many successive forest layers are present in the Lamar River Formation, estimates range from 9-12 for Specimen Ridge. Some of the levels have very wide and old trees trunks.

The mud flows caused by the Mt St Helens eruption in 1980 provide an excellent analogue for the geologic processes which produced the Yellowstone deposits. Fritz noted that the mixture of transported of upright and transported trees found in mudflows were virtually identical to the deposits seen at Yellowstone. In fact, several 'recent' fossil forests, containing in situ trees up to 7m tall, are present in the vicinity of Mount St Helens, each buried by lahar flows and/or pyroclastics. Exposures of these were exhumed by mudflows after the 1980 eruption. Most of the forest-bearing deposits have been dated to the period 1479-1857 by tree ring analyses of buried trees. These subfossil 'fossil' forests are excellent modern analogues for the Yellowstone forests exposed at Specimen Ridge. Karowe and Jefferson note that the "striking similarity between features of of trees buried in situ by Mount St Helens mudflows and features of upright fossil trees in the Specimen Ridge section of Yellowstone National Park strongly supports a depositional model of in situ burial for the upright trees at Yellowstone" (p. 203; see also Yamaguchi and Hoblitt, 1995).

As evidence against the concept of successive forests, creationists have cited William Fritz (1980a), who observed that mudflows originating from the Mt St Helens eruption transported and deposited some short stumps in an upright position. Fritz stated that many upright stumps in the conglomerates of the Yellowstone forests were probably transported as well. The argument is made that since some stumps can be transported upright, the forest horizons at Yellowstone need not be interpreted as successive forest horizons, only successive mudflows.

This hypothesis clearly is not supported by the data presented by Fritz. Fritz has repeatedly pointed out that it is only the relatively short, abraded stumps within the Eocene conglomerates that he suggested were transported, not the numerous, tall upright trees rooted in the underlying sediments and buried by the overlying conglomerate. This mixture of in place and transported trees is just like the situation seen at Mt St Helens, for instance the photo in Fritz 1984, p. 14. In his reply to Yuretich, Fritz (1981, p. 146) pointed out:

I did not argue that in situ trees of the Eocene 'forests' were not preserved . . . they contain numerous transported upright stumps with short trunks . . . preserved alongside in situ vertical trees with long trunks . . this mixture of transported and in situ trunks appears nearly identical to that seen in the Toutle River Valley.

Retallack also commented on Fritz's (1980) paper, stating that "there are at least some cases of petrified tree stumps unquestionably in place," with roots penetrating incipient soils horizons that, "compared to previous accounts, are suprisingly well differentiated" (p. 52). In his reply to Retallack, Fritz (1981, p. 54) again stated:

Tall upright trees with unbroken trunks. narrow root systems, and intact roots penetrating the substrate were apparently preserved were they grew. Unlike the tall in situ trees, many upright stumps have short trunks and roots broken prior to burial in a conglomerate with no organic zone, weathering profile, or color change. The bark of these trees is rarely preserved, owing to abrasion

Fritz (1985) also pointed out that only 10% of the stumps in the Mt St Helens flows were transported and redeposited in an upright attitude, which contrasts sharply with what we find at Specimen Ridge, where up to 80% of the trees are upright, and almost all of the horizontal logs are restricted to the conglomerates burying the upright trees.

Yuretich (1984) presented additional petrographic and stratigraphic evidence that the upright trees at Specimen Ridge were in place. He concluded that "field and petrographic data indicate that most, if not all, of the upright Eocene tree stumps preserved at Specimen Ridge were buried in place and were not moved long distances by mudflows and floods" (p. 161). As evidence for in place burial, Yuretich notes that:

(1) Tree stumps are not rooted in conglomerates, but rather in underlying fine-grained tuffaceous sandstones. (2) Some of the conglomerates have flow structures that show that they buried in-place trees. (3) The upper parts of some stumps and logs surrounded by conglomerates are severely abraded, but the lower parts contained within tuffaceous sandstones commonly have good root systems. This also suggests that mudflows moved over preexisting trees. (4) Thin sections show no evidence of extensive current activity in the tuffaceous sandstone in which the stumps are rooted. In contrast, most textural evidence indicates the existence of a soil around the roots (p. 161).

With regard to point (4), Yuretich summarizes petrographic study of thin sections taken from the root zones underlying the in place trees. He notes:

Specimens were collected of material surrounding the roots of vertical tree stumps at each of the 8 forest levels examined . . . Thin sections of 12 of these rtocks give no indication of significant current activity at any of the stump levels. Most of the sandstones consist of poorly sorted, angular volcanic rock fragments in a groundmass of small, broken crystals of plagioclase . . . Neither the rock fragments nor plagioclase grains show preferred orientation or imbrication, characteristics that would a current-dominated depositional system. All but two of the samples from the root zones [however] exhibit a 'swirly' texture in thin section, which is characteristic of the disturbed upper part of a soil zone (p. 161).

2. Early Cretaceous Fossil Forests, Alexander Island, Antarctica

Jefferson (1982) described 4 levels of fossil forests within a 15m section on Alexander Island. Tree stumps in 2 of the levels are only 1m or so tall, while those in the other 2 levels are up to 5-7m tall. Each of the forest horizons is associated with organic and clay-rich, weathered volcanic paleosols. Flat-lying trees are very rare. Regarding the tree roots, Jefferson writes:

. . . roots were confined to this fine-grained, organic-rich soil . . . Casts of roots witha carbonaceous coating extend from the tree through the thin remnant paleosol layer, and into the underlying sandstone. . . These paleosols are packed with poorly-preserved leaf litter . . . Rootlets, on a much smaller scale. are occasionally preserved within the coarse siliciclastic bed. Although no cellular detail is preserved, the general pattern of rooting is clear (p. 691).

3. Late Cretaceous "Forest," New Mexico

Bucl and Mack (1995) describe large in situ trees in fluvial deposits of the McRae Formation. The McRae Formation in south-central New Mexico is about 420m thick, and consists of two members, the Jose Creek and the Hall Lake. The formation is of latest Cretaceous age, based upon the included dinosaur fauna. The formation is rich in paleosols (at least 26), many of which contain in situ tree trunks.

14 paleosols, from 45-150m thick, are recognized in the Jose Creek Member. These are classified as argillisols. These display well-developed soil horizonation (A-E-Bt-Bc-C), and soil structures such as blocky peds and clay cutans. Downward bifurcating, downward-tapering root traces are abundant, some of which are silicified (root petrifactions).

Several of these paleosols are blanketed by ash-fall tuffs burying tree stumps up to 1.7m! in diameter, with preerved large roots penetrating and cross-cutting the underlying palesol horizons (see fig. 5).

12 paleosols are recognized in the overlying Hall Lake Member, from 70-450cm thick. These are classified as calcisols and vertic calcisols. Soil horizons and soil structures are well-developed, and at least one paleosol includes a "massive, well-indurated bed of pedogenic calcrete up to 4m thick," which indicates a very advanced stage of calcisol development. Calcisols are diagnostic of semi-arid environments.

4. Mid-Jurassic Fossil Forests, New Zealand

Pole (1999; 2001) documents several stacked conifer forest horizons from Jurassic sediments exposed at Curio Bay, South Island. 10 stratigraphically distinct horizons are recognized within an exposed 40m section (Pole 2001, p. 223). The base of each level is "associated with relatively softer, fine-grained sediment, interpreted as a soil horizon. Each forest is preserved within the coarser, more resistant sediments of a flood event" (Pole, 1999, p. 122). Pole 1999 also notes that the paleosols preserve "what is clearly a layer of forest floor litter surrounding even the smallest (~20mm diameter) gymnospermous trunks and osmundaceous fern trunks in growth position" (p. 122). The forests are buried by fine to coarse grained sandstones [rather than conglomerate as at Yellowstone], interpreted as deposits left by intermittant flood events. Most of the trees exposed at Curio Bay appear to be rather young, the oldest only about 200 years old (Pole 2001, p. 237).

Thorn (2001) describes a very similar succession of fossil forests of about the same age exposed at Kawhia Harbour, North Island, New Zealand, about 600km or so north of Curio Bay. The succession consists of about about 8-10 conifer forests, with stumps rooted in coal-rich layers up to 27cm thick. Some of the trees have deeply-penetrating tap-roots. A diverse amd well-preserved micro- and macroflora is present as well, including leaves, seed cones, fern and fungal spores, and pollen (p. 276).

5. Fossil Forest atop coal seams

There are many lycopsid tree fossil forests preserved above Carboniferous coal seams. These forests represent the last generation of trees that existed atop the peat-forming ecosystem before it was buried by sediments. Petrographic analyses of the coals themselves show that they are composed largely of the remains of such lycopside trees. Thus the fossil forests represent the last of many, many generations of such forests that formed the coal seams.

The evidence that trees in such settings are preserved in growth position is clear. Roots can be seen radiating outward and downward into the underlying coal. The helical arrangement of the tiny rootlets protruding from the main root axes, which penetrate the surrounding matrix and show no deformation around the larger axes, is unequivocal evidence for in place preservation (Gastaldo 1984; 1999). The structure of the encasing sediments also provides evidence that they trees were buried in place. For instance, the presence of so-called centroclinal cross strata (Underwood and Lambert 1974) around many of the lycopsids shows that the trees were firmly in place and that the enclosing sediments flowed around them (e.g. Calder et al. 1996; Leeder 1984; Fielding et al. 2001).

One of many examples is documented by DiMichele et al. (1996) immediately above the Mahoning coal in eastern Ohio. Over 800 mud-cast stumps are documented along several transects across the roof of the Sterling mine. The number of stumps per hectare is estimated at 573.2 (p. 258). Abundant stigmaria root systems are documented penetrating the coal at the interface of the coal and the overlying sediments. DiMichele et al. note that "unequivocal examples of trees rooted at the coal-bone [bone coal -ps] interface . . . indicate that most of the lycopsid forest was rooted in peat and originated just before or during the earliest phase of inundation" (p. 260).

6. A Holocene Buried Forest

Pregitzer et al. (2000) describe a ~10,000 year old buried spruce forest in Marquette County, Michigan, USA. This forest occupied a lowland area immediately prior to the Younger Dryas warming period, and was buried, along with the rest of the lowland 'channels,' in sandy glacial outwash released by the ablation of the Marquette glaciers. 14C dates from the outer rings of 4 of the trees yield an uncalibrated, average age of 9928 (+/- 133) yrs BP. A 15 cm thick layer of plant litter, bryophates and needles mark the level of the former forest floor.

Other Examples:

Lehman, T.M., and Wheeler, E.A., 2001. A Fossil Dicotyledonous Woodland/Forest From The Upper Cretaceous of Big Bend National Park, Texas. Palaiaos 16 pp. 102-108.

Reports an assemblage of dicotyledonous angiosperm trees, up to 1.3m in diameter, buried in alluvial deposits within the Aguja Formation. Stumps are reported with roots penetrating an underlying olive-gray mudstone paleosol with weak horizonation. Several of the stumps were hollowed and filled by mudstone prior to complete burial ('heart rot'). This type of heart rot is observed in modern trees in Washington partially buried around 1700 as a result of coseismic subsidence (Atwater, 1996, fig. 5d; Benson et al., 2001).

Roberts, E.M., and Hendrix, M.S., 2000. Taphonomy of a Petrified Forest in the Two Medicine Formation (Campanian), Northwest Montana: Implications for Palinspastic Restoration of the Boulder Batholith and Elkhorn Mountains Volcanics. PALAIOS 15(5), pp. 476-482.

Numerous charcoalified coniferous trees, up to 1m+ thick, buried by pyroclastic ash-tuff. Most are prone but several are in situ.

Links

A Prehistoric Forest
The Little Skookum Inlet
Buried Forests of the Yokouchi River Reservoir
10,000-YEAR-OLD BURIED FOREST
Polystrate Tree Fossils
"Polystrate" Fossils
AiG on Coal and the Flood

References

Atwater, B.F., 1996. Coastal evidence for great earthquakes in western Washington. In Assessing Earthquake Hazards and Reducing Risk in the Pacific Northwest, A.M. Rogers, T.J Walsh, W.J. Kockelman, and G.R. Priest, eds., USGS Professional Paper 1560, pp. 77-90.

Benson, B.E., B. F. Atwater, D. K. Yamaguchi, L. J. Amidon, S. L. Brown and R. C. Lewis., 2001. Renewal of tidal forests in Washington State after a subduction earthquake in A.D. 1700. Quaternary Research 56, pp. 139-147.

Buck, B.J., and G.H. Mack. 1995. Latest Cretaceous (Maastrichtian) aridity indicated by paleosols in the McRae Formation, south-central New Mexico. Cretaceous Research 16(5): 599-572.

Calder, J.H., Gibling, M.R., Eble, C.F., Scott, A.C., and MacNeil, D.J. 1996. The Westphalian D fossil lepidodendrid forest at Table Head, Sydney Basin, Nova Scotia; sedimentology, paleoecology and floral response to changing edaphic conditions. International Journal of Coal Geology, 31 (1-4), pp. 277-313.

DiMichele, W. A., C. F. Eble, and D. S. Chaney, A drowned lycopsid forest above the Mahoning coal (Conemaugh Group, Upper Pennsylvanian) in eastern Ohio, U.S.A. International Journal of Coal Geology 31:249-276.

Fielding, C.R., Alexander, J. 2001. Fossil trees in ancient fluvial channel deposits: evidence of seasonal and longer-term climatic variability, 170(1-2) Palaeogeography Palaeoclimatology Palaeoecology pp. 59-80.

Fritz, W.J., 1984. Comment and Reply on "Yellowstone fossil forests: New evidence for burial in place." Geology, 12, p.638-639

Fritz, W.J., 1985. Roadside Geology of Yellowstone Country, Mountain Press.

Gastaldo, R. A., 1984, A case against pelagochthony: the untenability of Carboniferous arborescent Lycopod-dominated floating mats. in Walker, K.R., ed., The Evolution-Creation Controversy, Perspectives on Religion, Philosophy, Science and Education, The Paleontological Society Special Publication No.1, p. 97-116.

Gastaldo, R.A. 1999. Debates on Autochthonous and Allochthonous Origin of Coal: Empirical Science versus the Diluvialists. in Manger, W.L., ed., The Evolution-Creation Controversy II: Perspectives on Science, Religion, and Geological Education, The Paleontological Society Papers, v. 5, p. 135-167.

Jefferson, T.H., 1982. Fossil Forests from the Lower Cretaceous of Alexander Island, Antarctica. Paleontology, v. 25, pp. 681-708.

Karowe, A. and T. Jefferson, 1987. Burial of trees by eruptions of Mt. St. Helens, Washington: implications for the interpretation of fossil forests. Geology Magazine 124:191-204.

Leeder, M.R., Nami, M., Scott, A.C., Gardiner, A. 1984. Studies on the sedimentology, palaeontology and palaeoecology of the Middle Coal Measures, (Westphalian B, Upper Carboniferous) at Swillington, Yorkshire. II. Centroclinal cross strata preserved around an in situ vertical tree trunk. Transactions of the Leeds Geological Association 10, 17-21.

Pole, M. 1999. Structure of a near-polar latitude forest from the New Zealand Jurassic. Palaeogeography, Palaeoclimatology, Palaeoecology, 147 (1-2) pp. 121-139.

Pole, M., 2001. Repeated flood events and fossil forests at Curio Bay (Middle Jurassic), New Zealand. Sedimentary Geology, v. 144, pp. 223-242.

Pregitzer, K. S. et al., 2000. A buried spruce forest provides evidence at the stand and landscape scale for the effects of environment on vegetation at the Pleistocene/Holocene boundary. Journal of Ecology, 88, 45-53.

Retallack, G., 1981. Comment and Reply on "Reinterpetation of the Depositional Environment of Yellowstone Fossil Forests," Geology, v. 9, pp. 52-5.

Thorn, V., 2001. Vegetation commnuities of a high paleolatitude Middle Jurassic forest in New Zealand. Palaeogeography, Palaeoclimatology, Palaeoecology, 168, pp. 273-289.

Underwood, J.R., and Lambert, W., 1974. Centroclinal cross strata, a distinctive sedimentary structure. Journal Sedimentary Petrology, 44:1111-1113.

Yamaguchi, D. K., and Hoblitt, 1995. Tree-ring dating of pre-1980 volcanic flowage deposits at Mount St. Helens, Washington, GSA Bulletin 107, pp. 1077-1093.

Yuretich, R.F., 1984a. Yellowstone fossil forests: New evidence for burial in place. Geology, v.12, p.159-162.

Yuretich, R.F., 1984b. Comment and Reply on "Yellowstone fossil forests: New evidence for burial in place." Geology, v.12, p.639.