A kimberlite crater in Canada, said to be 53 million years old, yielded exquisitely preserved unfossilized wood.
Miners were digging for diamonds and found unfossilized wood encased in the rock. Diamonds are usually found in kimberlite dikes that erupt the gems rapidly from deep in the earth in “explosive phreatomagmatic events” (1/12/2012, 5/07/2007). The discovery was reported on PLoS ONE by Wolfe et al. (“Pristine Early Eocene Wood Buried Deeply in Kimberlite from Northern Canada,” PLoS ONE 7(9): e45537. doi:10.1371/journal.pone.0045537):
We report exceptional preservation of fossil wood buried deeply in a kimberlite pipe that intruded northwestern Canada’s Slave Province 53.3±0.6 million years ago (Ma), revealed during excavation of diamond source rock. The wood originated from forest surrounding the eruption zone and collapsed into the diatreme before resettling in volcaniclastic kimberlite to depths >300 m, where it was mummified in a sterile environment. Anatomy of the unpermineralized wood permits conclusive identification to the genus Metasequoia (Cupressaceae). The wood yields genuine cellulose and occluded amber, both of which have been characterized spectroscopically and isotopically. From cellulose δ18O and δ2H measurements, we infer that Early Eocene paleoclimates in the western Canadian subarctic were 12–17°C warmer and four times wetter than present. Canadian kimberlites offer Lagerstätte-quality preservation of wood from a region with limited alternate sources of paleobotanical information.
The genus Metasequoia includes the dawn redwood, a “living fossil” rediscovered in China. “Metasequoia was common in southern Alaska in the Late Paleocene and Early Eocene, producing a rich record of foliage and cones,” they said. Fossils are rare in the discovery region due to extensive denudation and erosion by subsequent glaciers. Finding warm-climate conifer wood in a glaciated environment indicates huge climatic changes over time, and periods that supported extensive forestation in spite of much higher relative temperatures.
Fossil material can fall into a kimberlite crater as a result of the eruption, or can be washed in later. Both mechanisms occurred in the many kimberlite pipes in the region. Numerous pieces of fossil wood have been found by diamond miners over the years. The authors believe the “exceptional” sample they analyzed was entombed at the time of eruption:
We envisage that the source tree collapsed into the diatreme at the time of kimberlite emplacement. The great depth of burial suggests that it entered a narrow marginal boundary layer between the blast zone and the wall rock before becoming entombed. We consider the wood to be representative of the Early Eocene forest growing at the site at the time of magmatism. The lack of permineralization suggests that burial was rapid, and that little post-eruptive thermal or tectonic alteration has occurred at the locality.
Photographs of the wood tissues in the paper show clear cellular tissues at the microscopic level that retain their original material (“unpermineralized”), including tracheids and parenchyma cells. Most surprising was original cellulose, still intact:
Cellulose preservation in fossil conifers varies tremendously given the labile nature of constituent polysaccharides, mandating the need for quality control prior to isotopic analysis.… To our knowledge, this is the oldest verified instance of α-cellulose preservation to date, testifying to the remarkable preservation potential of kimberlite-hosted wood.
Amber fragments were also found within the wood. How could such delicate features survive a high-temperature eruption?
Despite the relatively subtle features attributed to thermal alteration noted above, we find little evidence that either the quality of cellulose preservation or the isotopic signatures of the various analyzed fractions have been overprinted. We thus envisage that cooling of the igneous body following emplacement in the diatreme was extremely rapid, potentially near-instantaneous, and surmise that any chemical changes to the entombed organic matter occurred in a closed system.
From oxygen isotope ratios, they inferred that the forest lived in a much warmer climate with rainfall four times higher than today. “The state of preservation of this wood is unequalled for material of this age, as exemplified by the exquisite quality of anatomical detail and the presence of α-cellulose,” they said, using used the word “remarkable” three times in the paper. The crater was dated by the rubidium-strontium isochron method to be 53.3 million years old.
Update 9/22/2012: Live Science reported on the discovery. The article includes a photo of the specimen; it looks like a good-size chunk of firewood. The tree lived in a “swampier past” it said, noteworthy for the high latitude today (Northwest Territories); the fragment was found 1,000 feet down in the kimberlite pipe.
Well, this should raise some eyebrows. Original intact cellulose 53.3 million years old? Here’s another opportunity for skeptics of the Moyboy Club (millions-of-years, billions-of-years) to look critically at this evidence. How long can original cellulose survive intact? You can’t even keep it in your freezer for a century. The problem is not the data, but the story painted over it to make it look ancient, like an antiquing trick. (For reasons why isochron dating methods can produce fictitious results that are meaningless, see the 1/12/2005 entry.)
The millions-of-years riff adds nothing. It’s like waving a magic wand over the observations to hypnotize the reader into thinking the wood must be incredibly ancient. Why? Because Darwin needs the time. Well, Darwin skeptics don’t. Notice how everything else in the story was rapid: explosive eruption, tree falls in that same minute, cools “instantaneously,” — 53 million yearzzzzzzzzz — quick discovery of intact cellulose in 2012.
The authors didn’t think to look for carbon 14 in the wood, undoubtedly, because they believe (based on their commitment to deep time) that it would be hopeless – all traces of carbon 14 should be long gone. Here’s an experiment someone should undertake. If these scientists got samples, there must be many others. Someone go look for carbon 14. Remember, the Moyboys were wrong before. They thought Metasequoia died out 20 million years ago, only to find them alive and well in China. Now you can buy dawn redwoods at the local nursery. Grow this “living fossil” in your yard as a living lesson in the fallibility of experts.