Hmmm....the seafloor at the northpole is over 13,000 feet down. Are you saying that there is evidence that grass once grew there?
I'm pretty sure that undersea deposits of oil were formed mostly from
plankton(scroll down a bit), not plant matter (which tends to form coal instead), and the Arctic ocean is extremely rich in plankton, which is why it is such a rich fishing area.
Yes, the seafloor is 13,000 feet down, now.
I will concede that was underwater 51 million yrs ago, but it was fresh water not sea water.
Tropical with fern and plankton and land locked from the oceans.
Here are a few excepts from Purdue University reporting on a news story that appeared in Nature magazine;
Researchers aboard a fleet of icebreakers collected samples by drilling into the floor of the Arctic Ocean during a 2004 expedition, and scientific findings will be published for the first time in several papers to appear Thursday (June 1) in Nature magazine.
The expedition was part of an international research effort called the Integrated Ocean Drilling Program, which explores the Earth's history and structure as recorded in seafloor sediments and rocks.
Huber used new data from the research to compare against results from complex climate-model simulations he performed to study and predict the effects of greenhouse gases. He co-authored two research papers to appear in Nature detailing conditions in the Arctic Ocean 55 to 50 million years ago during a time of unprecedented global warmth.
The cylindrical core samples contained the remains of ancient plant and animal life, which yielded critical new information about the Arctic Ocean during that time. Researchers used a recently developed technique called TEX-86, which enables scientists to measure the temperatures that existed when ancient organisms lived by analyzing the composition of fatty substances called lipids in their cell membranes. Using this technique, the researchers found that sea surface temperatures at the North Pole had soared to 23 degrees Celsius, or around 73 degrees Fahrenheit, during the Paleocene-Eocene Thermal Maximum, or the PETM, about 55 million years ago. Today's mean annual temperature at the North Pole is around minus 20 degrees Celsius, Huber said.
around 50 million years ago, the Arctic Ocean was frequently covered with dense mats of a freshwater fern called Azolla, which flourishes in ponds, said Henk Brinkhuis, a marine palynologist and biogeologist from Utrecht University in the Netherlands and lead author on one of the Nature papers.
"Imagine that the Arctic Ocean was a giant lake, with this vegetation growing in it," Brinkhuis said. "What these findings say is that the Arctic Ocean must have been isolated, or nearly cut off, from the Atlantic Ocean by land masses that later shifted into the present continents. Today, if you hop in a boat and head north in the Atlantic Ocean, you could go all the way to the Arctic Ocean. But back then it was more isolated, which prevented salt water from ocean surface currents from reaching there."
The concentration of carbon dioxide in today's atmosphere is about 380 parts per million, whereas the concentration 55 million years ago was about 2,000 parts per million.
While the climate models had predicted that researchers would discover the Arctic Ocean's freshwater past, the models have consistently underestimated by at least 10 degrees how hot the Earth would have been during that time, Huber said.
The models fail to explain another puzzling fact. The temperature difference between the North Pole and the equator today is about 45 degrees C. But the difference appears to have been much smaller during the Paleocene-Eocene Thermal Maximum time frame. Otherwise, it would have been too hot for vegetation to survive in equatorial latitudes.
"We still haven't explained why the tropics stayed cool," Huber said. "Somehow, we have to explain how you can warm the poles up to 23 degrees Celsius without having the tropics rise to at least 50 degrees, which is 10 degrees too hot for plants to carry out photosynthesis."
"Today's models underpredict how warm the poles were back then, which tells you something disturbing — that the models, if anything, aren't sensitive enough to greenhouse gases," Huber said. "At the same time, it is possible that other forces in addition to higher-than-normal greenhouse gas concentrations were involved, otherwise we can't explain how the tropics maintained livable conditions.
"People have conjectured that polar stratospheric clouds or hurricane-induced ocean heat transport might have played crucial roles in amplifying polar heating, but much work needs to be done to prove this. Mechanisms that feed back onto global warming are poorly understood and not well represented into our current generation of models. This should be of great concern and will continue to be debated and explored in future research.
Scientists may explore several issues in future work, including research aimed at explaining specifically why the temperatures were so high 55.5 million years ago.
"There is a fundamental discrepancy between what kind of climate we expect to result from high atmospheric greenhouse gas concentrations, and what kind of climate really prevailed during these ancient epochs," Sluijs said. "We, hence, need to improve our climate models. An important question is, what was seasonality like in the Arctic? Was there an as-large temperature difference between summer and winter as there is nowadays?"
You are right. No grass, but it was tropical.
PAX