Take a close look at some of the amazing Dawn Redwood
|Metasequoia Stumped Field|
Well the picture is worth a thousand words. Getting back to the National Geographic 2002 interview of Paleo-geobologist Hope Jahren who you see here on the right, in the online article found here:
Arctic Redwood Fossils Are Clues to Ancient Climates
There are several relevant quotes I should point out that are related to this blog's purpose here.
"Axel Heiberg Island, at 82 degrees north and just a stone's throw from the North Pole, was once a great vacation spot—during the Eocene epoch, about 45 million years ago. Lush redwood forests, ferns, flowering plants, and a huge variety of animals, now extinct, once thrived here."
"Hope Jahren, a geobiologist at Johns Hopkins University in Baltimore, Maryland, is using wood fossils from Axel Heiberg to discover prehistoric weather patterns that enabled this now bleak, cold, and dry desert to support such a rich array of life."
"I've always been enraptured with the idea that the Earth can change so dramatically," said Jahren "The Earth today is very different compared to how it was millions of years ago."
During the Eocene epoch, Axel Heiberg and much of northern Siberia and Alaska were covered in temperate forests with redwood-like trees called Metasequoias, similar to those now seen in Northern California.
The trees were between 30 and 40 meters tall (98 and 131 feet) and densely packed, providing a canopy for a plethora of ferns and flowers, said Jahren. The largest tree found had a diameter of three meters (ten feet). What remains of these ancient redwoods today is "rather extraordinary," said Jahren.
"These trees look like driftwood on the beach—they are dry and flaky, with almost no other alterations," said Jahren. Unlike these trees, ancient forests often become petrified through the steady infiltration of minerals over many years, which eventually replaces the wood tissue with stone."
Chemical Signature (Now here's where you need to pay really close attention)
"Because the wood is unadulterated, the tissues hold a chemical record of weather patterns during the period the tree lived. Jahren studies carbon, hydrogen, oxygen, and nitrogen because these elements are taken from the soil, water, and air and incorporated into the tissue of plants and animals."
"Jahren and her colleague Leonel Silveira Lobo Sternberg of the University of Miami in Coral Gables, Florida, are examining chemically different forms, or isotopes, of oxygen in these ancient redwoods to reveal weather patterns during the Eocene period.
Oxygen that a plant uses, said Jahren, comes primarily from water. Determining the chemistry of that water could reveal exactly where it came from. Rain that arrives after traveling long distances over land has a very different chemical signature than rain that travels over the ocean or just very short distances, she explained."
"The researchers' analysis of the oxygen content of the wood revealed "a bizarre absence of oxygen-18, the heavy isotope," said Jahren. Water contains both oxygen 16—the more common and lighter isotope—and the more rare oxygen 18. The analysis suggests that the water contained almost exclusively oxygen 16."
"The study appeared a recent issue of GSA Today, a publication of the Geological Society of America. One way to get water with these characteristics, said Jahren, is for that water to have traveled large distances over land. As water travels over land, she explained, the heavier oxygen is removed as it rains."
"The only route allowing moisture laden air to travel thousands of kilometers over land before reaching Axel Heiberg would be across North America, possibly from the Gulf of Mexico, said Jahren. "This idea is compelling because it would supply water rich in oxygen 16 and supply warm air to this very northern region"—warm enough to nurture a forest."
Different Weather Patterns (Pay Further Attention to some hidden details here)
Jahren finds this model of water transport intriguing "because this weather pattern is radically different from today." Current weather systems over North America tend to travel from west to east. In the Eocene epoch, a much warmer period when the poles were free of ice, weather systems could shift from south to north, said Jahren."
"But there is another possible interpretation of Jahren's findings, cautioned Scott Wing, a paleontologist at the Smithsonian Institution in Washington, D.C."
"Water from snowfall also contains low quantities of oxygen 18, thus matching the water profile from the wood," he said. He suggested the possibility that snow, formed over the then ice-free Arctic Ocean, may have supplied the island with water. This would indicate that the northern regions were actually much colder than Jahren suggests.
"Isotope levels are very difficult to interpret, and there are lots of questions remaining," Wing said.
If Axel Heiberg were actually colder, it would imply that animals such as alligators, which were known to live at these latitudes, as well as plants must have been tolerant of the cold.
Whether Axel Heiberg actually received waters originating from equatorial regions is "still up for debate," said Wing.
But there are other questions left to answer. "These forests had four months of daylight and four months of complete darkness. Finding trees that could survive under these conditions is as flabbergasting as finding humans that live underwater," said Jahren.
Uncovering ancient weather patterns provides greater understanding of how ecosystems work, opening a window into the Earth's capabilities. It also offers new ideas about the kind of conditions that plants and animals might be able to survive in.
16O and 18O values - What are the implications of a plant's wood tissue being exclusively 16O ?
So what does all of this isotope research really tell us ? Working with wood probably seems like an odd choice if you want to study climate data, even if you're trying to determine a climate of countless centuries ago, but the oxygen ratios of all these parts are inter-linked. The water molecules in any given leaf or wood sample of modern day plants and trees as we know them contain a mixture of the two oxygen isotopes. Now remember this quote from Hope Jahren in the interview:
"Oxygen that a plant uses, said Jahren, comes primarily from water. Determining the chemistry of that water could reveal exactly where it came from. Rain that arrives after traveling long distances over land has a very different chemical signature than rain that travels over the ocean or just very short distances"
So water influenced by the Earth or the land has a different chemical signature than water which originates as evaporation into Storm Cloud formations originating over the Earth's Oceans. Though the hypothesis or educated interpretation which is influenced heavily by the mandated conventional thinking which would rule out any minerotrophic hydrological cycling, the solution for them is to rationalize and reason that somehow tropical monsoonal moisture from the Gulf of Mexico (that's if even the same geological layout still existed then as it does now) must have somehow mysteriously moved north by forces we have no idea of identifying. As admitted, they acknowledge that Earth's 'Coriolis Effect' still would have existed as it does today. The problem here is that the wind air movements governed by the Jet Stream would still have prevented any strong northern flow of tropic moisture. The hang up here I think is still trying to rationalize things as we know them to be today, but we forget that the mechanisms today could NOT have existed then or otherwise we'd still have mild forested polar regions both north and south. The one important bottomline here is that rainstorm mechanisms which form over oceans and move over continents and falling as rain to hydrate all life DID NOT happen in these polar regions or there would be a chemical record of it and that simply DOES NOT exist.
Hope Jahren references the work of her colleague Professor Leonel Silveira Lobo Sternberg from Florida who studied a fascinating phenomena of something called hydraulic lift and redistribution down in the Amazon River Basin Drainage Areas, where specific deep rooted trees pull up massive amounts of moisture during the dry season, transport the water to the surface to share with other neighbouring plants and the resultant evaporation and humidity creates cloud formations which once again in turn fall as rain in the form of electrically charged Tropical Thunderstorms. And all with no influence from the Ocean's water cycling mechanisms. At this point I have to relate my personal experience with the high water quality of electrically charged thunderstorms. In the area where I lived in Anza , California, we had summer monsoonal moisture which moved up north from Mexico which developed thunderheads in the hot summer afternoons which released electrically charged rain during the two summer months of July/August. Chemical signature of that specific water from that source causes an EXPLOSION of vegetative growth in every and all plants. It's a phenomena not found in the chemical and structural signature of water molecules from winter rains. It has other effects for example on truffle formation, but that is for a later post on the "Earth Internet" BLOG. So basically I can understand their rationalizing the lack of Oxygen-18 in the wood samples to a monsoonal type of moisture. I probably would also if I wasn't aware of a few other details and possibilities.
Another conclusion to the Atmospheric conditions they arrived at was the from the mummified tree rings, there was no evidence of snowfall in winter or even a mere frost. From the isotope studies they determined that the temperature never went below 14 Celsius (57.2 Fahrenheit) and that humidity levels were far above that of present day Arctic. Again moisture retains heat better than dry land. One reading stated that if you took a low level of humidity of about 20% and a high level of tropical 98%, then the Arctic humidity was probably somewhere in the middle at 65-70%. The other anomaly was that in those rings, there was no late summer growth discoloration. This discoloration is common in wood today where late frosts trigger a slow down in growth reflected in some cell damage which slows the process to a halt. Back in the ancient Arctic, these trees growth rings acted as if someone through a light switch to "Off" and then turned it to "On" in the Spring again. It was that pronounced and abrupted. The same exactly findings have been written about in evidence from the Antarctice.
Still, why shouldn't the minerotrophic hydrological cycle ever be considered ? There are other reasons recently for considering such a cycle. I'll consider this from the link here on another page.