The Arctic: Interglacial period with a break
Reconstruction of Arctic climate conditions in the Cretaceous period
FRANKFURT. Scientists at the Goethe University Frankfurt and at the Senckenberg Biodiversity and Climate Research Centre working together with their Canadian counterparts, have reconstructed the climatic development of the Arctic Ocean during the Cretaceous period, 145 to 66 million years ago. The research team comes to the conclusion that there was a severe cold snap during the geological age known for its extreme greenhouse climate. The study published in the professional journal Geology is also intended to help improve prognoses of future climate and environmental development and the assessment of human influence on climate change.
The Cretaceous, which occurred approximately 145 million to 66 million years ago, was one of the warmest periods in the history of the earth. The poles were devoid of ice and average temperatures of up to 35 degrees Celsius prevailed in the oceans. “A typical greenhouse climate; some even refer to it as a ‘super greenhouse’ “, explains Professor Dr. Jens Herrle of the Goethe University and Senckenberg Biodiversity and Climate Research Centre, and adds: “We have now found indications in the Arctic that this warm era 112 to 118 million years ago was interrupted for a period of about 6 million years.”
In cooperation with his Canadian colleague Professor Claudia Schröder-Adams of the Carleton University in Ottawa, the Frankfurt palaeontologist sampled the Arctic Fjord Glacier and the Lost Hammer diapir locality on Axel Heiberg Island in 5 to 10 metre intervals. “In so doing, we also found so-called glendonites”, Herrle recounts. Glendonite refers to star-shaped calcite minerals, which have taken on the crystal shape of the mineral ikaite. “These so-called pseudomorphs from calcite to ikaite are formed because ikaite is stable only below 8 degrees Celsius and metamorphoses into calcite at warmer temperatures”, explains Herrle and adds: “Thus, our sedimentological analyses and age dating provide a concrete indication for the environmental conditions in the cretaceous Arctic and substantiate the assumption that there was an extended interruption of the interglacial period in the Arctic Ocean at that time.”
In two research expeditions to the Arctic undertaken in 2011 and 2014, Herrle brought 1700 rock samples back to Frankfurt, where he and his working group analysed them using geochemical and paleontological methods. But can the Cretaceous rocks from the polar region also help to get a better understanding of the current climate change? “Yes”, Herrle thinks, elaborating: “The polar regions are particularly sensitive to global climatic fluctuations. Looking into the geological past allows us to gain fundamental knowledge regarding the dynamics of climate change and oceanic circulation under extreme greenhouse conditions. To be capable of better assessing the current man-made climate change, we must, for example, understand what processes in an extreme greenhouse climate contribute significantly to climate change.” In the case of the Cretaceous cold snap, Herrle assumes that due to the opening of the Atlantic in conjunction with changes in oceanic circulation and marine productivity, more carbon was incorporated into the sediments. This resulted in a decrease in the carbon dioxide content in the atmosphere, which in turn produced global cooling.
The Frankfurt scientist’s newly acquired data from the Cretaceous period will now be correlated with results for this era derived from the Atlantic, “in order to achieve a more accurate stratigraphic classification of the Cretaceous period and to better understand the interrelationships between the polar regions and the subtropics”, is the outlook Herrle provides.
###
Publication
Jens O. Herrle, Claudia J., Schröder-Adams, William Davis, Adam T. Pugh, Jennifer M. Galloway, and Jared Fath: Mid-Cretaceous High Arctic stratigraphy, climate, and Oceanic Anoxic Events, in: Geology, 19 Mai 2015, 10.1130/G36439.1 Open Access http://geology.gsapubs.org/cgi/content/abstract/G36439.1v1
Abstract
Over the past decades, much research has focused on the mid-Cretaceous greenhouse climate, the formation of widespread organic-rich black shales, and cooling intervals from low- to mid-latitude sections. Data from the High Arctic, however, are limited. In this paper, we present high-resolution geochemical records for an ∼1.8-km-thick sedimentary succession exposed on Axel Heiberg Island in the Canadian Arctic Archipelago at a paleolatitude of ∼71°N. For the first time, we have data constraints for the timing and magnitude of most major Oceanic Anoxic Events (OAEs) in brackish-water (OAE1a) and shelf (OAE1b and OAE2) settings in the mid-Cretaceous High Arctic. These are consistent with carbon-climate perturbations reported from deep-water records of lower latitudes. Glendonite beds are observed in the upper Aptian to lower Albian, covering an interval of ∼6 m.y. between 118 and 112 Ma. Although the formation of glendonites is still under discussion, these well-dated occurrences may support the existence of cool shelf waters in the High Arctic Sverdrup Basin at this time, coeval with recent geochemical data from the subtropical Atlantic indicating a drop in sea-surface temperature of nearly 4 °C.
Full paper: http://geology.gsapubs.org/content/early/2015/03/19/G36439.1.full.pdf
Can’t say I trust any climate proxy of 135-65milion years ago. Whatever it is there is a good chance the researcher is squeezing way to much certainty out of it.
These findings, even from a 100 m. stratigraphic section, were no surprise to me. In 1972, I attended a meeting and talked with a Canadian geologist I knew. He had been mapping in the Arctic for the Geological Survey of Canada (GSC) and explained to me that they had identified CRETACEOUS glacial till. Unfortunately, when he returned the following summer, the helicopter crashed and all on board died.
I have often suggested that those interested should go to the GSC archives in Ottawa and find any field notes on record by Dr.Roger Dean to verify those findings. It would add further credence to the German/Canadian work.
The likelihood of cooling is much greater than for warming:
[click in chart to embiggen]
http://upload.wikimedia.org/wikipedia/commons/8/82/Past_740_kyrs_Dome-Concordia_ice_core_temperature_reconstructions.png
If one looks at the Holocene, it appears that there is a downward trend, nemely that the Holocene Optimum was warmer than the peak of the Minoan Warm Period which in turn was warmer than the Roman Warm Period which in turn was warmer than the Viking (Medieval) Warm Period which in turn was warmer than the late 20th Century Warm Period.
Each of these peaks which punctuate the past 8,000 years is peaking at a slightly lower high. Of course, we do not know whether the late 20th Century Warm Period is over, that will depend upon what heappens long term following the end of the ‘pause’/current ‘hiatus’. But if the past is anything to go by (and warmists will argue that it is not since man has altered the CO2 balance), the immediate future (by which I mean the next few thosusands years) will be variable and interupted by temperature peaks slightly lower than the preceding one, ie., the next peak in the Holocene will be somewhat lower than the late 20th Century Warm Period.
Of course, as they say about stocks and shares, past performance is not a guide to future performance, so you can read what you will out of it. One thing appears reasonably certain, namely manmade emissions of GHGs did not drive the Holocene Optimum, the Minoan Warm Period, the Roman Warm Period or the Viking Warm Period and that point alone casts doubt on whether CO2 is a significant driver of temperature (especially as it appears that CO2 lages temperature on every time scale), and therefore sheds doubt on whether manmade emissions of CO2 have driven/are driving the late 20th Century Warm Period.
I note that the warmups in dbstealey’s graph seem much faster than the cooldowns. Earth is normally warmer than at present. Does the swiftness of warming reflect a weakening of whatever agents cause cold conditions, and a “snap” (sorry) back towards normal warmth?
Rain melts ice fast.
Evaporating oceans in cold to make snow buildup to ice is slow mass transport.
Or: Melt has gravity on its side, making snow in the sky fights gravity.
mellryn
The earth is actually normally colder in the last 750,000 yrs.
Glendonites, ice rafted boulders etc have long been known from the Australian Cretaceous in the Eromanga Basin, and even Cretaceous age glacial striations have been described from South Australia. Why is this news?
Ciao
John
“Extended interruption in the “interglacial'” is either a poor translation or a geologist who doesn’t understand the term interglacial. Interglacial is a warm period between colder ‘glacial’ conditions. The research ‘may’ show that the climate went back into a more ‘glacial’ condition and colder temperatures that lasted (based on the tentative age dating of the sediment layer) 6 million years and produced conditions that led to the deposition of the black sediment layer. That is all one can state from this paper, which is generally characteristic of glacially driven climates (albeit shorter time intervals today between glacial/interglacials), and not significantly relevant to the Holocene/Pleistocene or AGW ‘climate’ discussion.
Evidence of a Cretaceous glaciation or two has been around for a long time. You don’t get tillites without glaciers. Maybe just at the interglacial scale, like today.
We don’t have the first clue why climate change happened then, we don’t understand why it is happening now.
This paper follows Hansen’s weathering scenario for CO2 sequestration, while likewise ignoring the production side of the vulcanism that would drive India into Eurasia in Hansen’s case, and open the Atlantic in the above.
The Cretaceous is noteworthy for the “twin towers” of large igneous province production and the longest known period without a geomagnetic reversal.
Whatever actually causes glaciations trumps CO2, Milankovitch, continental drift, galactic cosmic rays, and the all the rest of bit players.
Chaotic, yes, nonlinear and chaotic…not. It is an elephant we have yet to discover in the room.
What really happened in the Cretaceous is that the continents were mainly concentrated toward the equator.
ie there was no polar land glaciers and the sea ice just got sept/circulated rapidly away from the poles to melt in the warmer mid-latitude oceans. Less ice means less reflection of sunlight.
And sea level was much much higher in the hot periods of the Cretaceous because the newly formed Atlantic Ocean was much shallower than it is today. The average depth of all the oceans was only 3100 metres versus today’s 3350 metres and sea level was 265 metres higher than today. Ie. the ocean had nowhere to got except onto the low altitude land. Europe was under water, the Middle East was under a shallow ocean. The centre of North America was flooded from Texas to Inuvik. The Gulf Stream probably flowed right up this central sea. The majority of our shallow easily accessible oil came from this period when algae grew in the warm shallow oceans on the continents and made the sea floor bottom, very rich in Carbon organics. See it all fits together.
The combination of less ice and more shallow oceans meant that the Earth’s Albedo was lower at approximately 25% versus today’s 30% – I built an Albedo calculation spreadsheet which produces this value.
That is the Cretaceous Hothouse explanation which follows very logically and does not require any CO2 level to work.
New palaeo climate data are always welcome, including with higher resolution.
What is not welcome is the obsequious, servile, ingratiating, sycophantic, fawning, boot-licking CO2 stream of consciousness, added irrelevantly and meaninglessly to the text.
“Herrle assumes…” = Herrle assumes the position.
When will climate scientists hold their heads up and show some self-respect?
The timing of the glacial periods – blue bars at the bottom of the above climate history – with 150 million year spacing, calls to mind Shaviv’s hypothesis of galactic orbit and dust clouds containing energetic cosmic ray emitters.
This is not new science. I remember reading this in an OU course in geology some years ago.
Why doesn’t heat ever come in snaps and cold come in waves? Now that would really be climate change.
It should be pointed out that Palentology seems to be very much in the grips of “post normal” science.
I just saw a video about the whale skeletons that are proposed as the best example of evolution. It turns out the proposed transition fossil was a fabrication. In museums all over the world, there are life-sized Rodhecetus skeletons. But when they were first discovered, Phil Gingerich didn’t have the part of the skeleton where the proposed blow-hole, flippers, or fluke were located. He knew they must be there, so the discoverer simply made that part up. Now that a more complete skeleton reveals more of the skeleton, he has egg on his face. Here is more, http://thegrandexperiment.com/whale-evolution.html
Radiometric dating has similar post-normal issues. When you send a rock to be dated, you generally must tell them the approximate date you expect the rock to be, so they can use a dating method that works in that range. But, if you tell them fake dates, you can get a different answer.
Reporting from Snowball Earth….during the great CAGW warming, the main diet of warm blooded two legged animals was cabbage and beer, which were banned in 2015.