Tous les articles par Alain Préat

Full-time professor at the Free University of Brussels, Belgium • Department of Earth Sciences and Environment Res. Grp. - Biogeochemistry & Modeling of the Earth System Sedimentology & Basin Analysis • Alumnus, Collège des Alumni, Académie Royale de Sciences, des Lettres et des Beaux Arts de Belgique (mars 2013). • Prof. Invited, Université de Mons-Hainaut (2010-present-day) • Prof. Coordinator and invited to the Royal Academy of Sciences of Belgium (Belgian College) (2009- present day) • Prof. partim to the DEA (third cycle) led by the University of Lille (9 universities from 1999 to 2004) - Prof. partim at the University of Paris-Sud/Orsay, European-Socrates Agreement (1995-1998) • Prof. partim at the University of Louvain, Convention ULB-UCL (1993-2000) • Since 2015 : Member of Comité éditorial de la Revue Géologie de la France • Since 2014 : Regular author of texts for ‘la Revue Science et Pseudosciences’ • Many field works (several weeks to 2 months) (Meso- and Paleozoic carbonates, Paleo- to Neoproterozoic carbonates) in Europe, USA (Nevada), Papouasia (Holocene), North Africa (Algeria, Morrocco, Tunisia), West Africa (Gabon, DRC, Congo-Brazzaville, South Africa, Angola), Iraq... Recently : field works (3 to 5 weeks) Congo- Brazzaville 2012, 2015, 2016 (carbonate Neoproterozoic). Degree in geological sciences at the Free University of Brussels (ULB) in 1974, I went to Algeria for two years teaching mining geology at the University of Constantine. Back in Belgium I worked for two years as an expert for the EEC (European Commission), first on the prospecting of Pb and Zn in carbonate environments, then the uranium exploration in Belgium. Then Assistant at ULB, Department of Geology I got the degree of Doctor of Sciences (Geology) in 1985. My thesis, devoted to the study of the Devonian carbonate sedimentology of northern France and southern Belgium, comprised a significant portion of field work whose interpretation and synthesis conducted to the establishment of model of carbonate platforms and ramps with reefal constructions. I then worked for Petrofina SA and shared a little more than two years in Angola as Director of the Research Laboratory of this oil company. The lab included 22 people (micropaleontology, sedimentology, petrophysics). My main activity was to interpret facies reservoirs from drillings in the Cretaceous, sometimes in the Tertiary. I carried out many studies for oil companies operating in this country. I returned to the ULB in 1988 as First Assistant and was appointed Professor in 1990. I carried out various missions for mining companies in Belgium and oil companies abroad and continued research, particularly through projects of the Scientific Research National Funds (FNRS). My research still concerns sedimentology, geochemistry and diagenesis of carbonate rocks which leads me to travel many countries in Europe or outside Europe, North Africa, Papua New Guinea and the USA, to conduct field missions. Since the late 90's, I expanded my field of research in addressing the problem of mass extinctions of organisms from the Upper Devonian series across Euramerica (from North America to Poland) and I also specialized in microbiological and geochemical analyses of ancient carbonate series developing a sustained collaboration with biologists of my university. We are at the origin of a paleoecological model based on the presence of iron-bacterial microfossils, which led me to travel many countries in Europe and North Africa. This model accounts for the red pigmentation of many marble and ornamental stones used in the world. This research also has implications on the emergence of Life from the earliest stages of formation of Earth, as well as in the field of exobiology or extraterrestrial life ... More recently I invested in the study from the Precambrian series of Gabon and Congo. These works with colleagues from BRGM (Orléans) are as much about the academic side (consequences of the appearance of oxygen in the Paleoproterozoic and study of Neoproterozoic glaciations) that the potential applications in reservoir rocks and source rocks of oil (in collaboration with oil companies). Finally I recently established a close collaboration with the Royal Institute of Natural Sciences of Belgium to study the susceptibility magnetic signal from various European Paleozoic series. All these works allowed me to gain a thorough understanding of carbonate rocks (petrology, micropaleontology, geobiology, geochemistry, sequence stratigraphy, diagenesis) as well in Precambrian (2.2 Ga and 0.6 Ga), Paleozoic (from Silurian to Carboniferous) and Mesozoic (Jurassic and Cretaceous) rocks. Recently (2010) I have established a collaboration with Iraqi Kurdistan as part of a government program to boost scientific research in this country. My research led me to publish about 180 papers in international and national journals and presented more than 170 conference papers. I am a holder of eight courses at the ULB (5 mandatory and 3 optional), excursions and field stages, I taught at the third cycle in several French universities and led or co-managed a score of 20 Doctoral (PhD) and Post-doctoral theses and has been the promotor of more than 50 Masters theses.

Mars volcano, Earth’s dinosaurs went extinct about the same time

by NASA/Goddard Space Flight Center, March 21, 2017

Arsia Mons produced one new lava flow at its summit every 1 to 3 million years during the final peak of activity, about 50 million years ago. The last volcanic activity there ceased about 50 million years ago — around the time of Earth’s Cretaceous-Paleogene extinction, when large numbers of our planet’s plant and animal species (including dinosaurs) went extinct.

Journal Reference:Jacob A. Richardson, James A. Wilson, Charles B. Connor, Jacob E. Bleacher, Koji Kiyosugi. Recurrence rate and magma effusion rate for the latest volcanism on Arsia Mons, Mars. Earth and Planetary Science Letters, 2017; 458: 170 DOI: 10.1016/j.epsl.2016.10.040


by VENCORE WEATHER, March 20, 2017

Third weakest solar cycle since 1755
A recent publication has analyzed the current solar cycle and has found that when sunspot anomalies are compared to the mean for the number of months after cycle start, there have been only two weaker cycles since observations began in 1755.  Solar cycle 24 began in 2008 after a historically long and deep solar minimum which puts us more than eight years into the current cycle.

The Logarithmic Effect of Carbon Dioxide

by David Archibald, March 8, 2010

The greenhouse gasses keep the Earth 30° C warmer than it would otherwise be without them in the atmosphere, so instead of the average surface temperature being -15° C, it is 15° C. Carbon dioxide contributes 10% of the effect so that is 3° C. The pre-industrial level of carbon dioxide in the atmosphere was 280 ppm. So roughly, if the heating effect was a linear relationship, each 100 ppm contributes 1° C. With the atmospheric concentration rising by 2 ppm annually, it would go up by 100 ppm every 50 years and we would all fry as per the IPCC predictions.

But the relationship isn’t linear, it is logarithmic. In 2006, Willis Eschenbach posted this graph on Climate Audit showing the logarithmic heating effect of carbon dioxide relative to atmospheric concentration

“No country would find 173 billion barrels of oil in the ground and just leave them there.”

by David Middleton, March 20, 2017

Firstly, the prime minister is exactly correct: “No country would find 173 billion barrels of oil in the ground and just leave them there.” Particularly if those 173 billion barrels were proved reserves.  At $50/bbl, 173 billion barrels is worth a lot of dollars… both US and Canadian.

Secondly, the prime minister is exactly correct here too: “The prime minister has long maintained that developing fossil-fuel resources can go ‘hand in hand’ with fighting climate change.”  Since fighting climate change is about as possible as fighting plate tectonics or entropy, it absolutely “can go ‘hand in hand’ with” developing fossil fuel resources.

Marché du charbon vapeur en 2016 : le choc de l’offre

par Ifri, 20 mars 2017

Après cinq ans de baisse continue, les prix du charbon « vapeur » (type de charbon principalement utilisé dans les centrales thermiques et dans certaines industries, notamment pour fabriquer du ciment) ont doublé entre le début et la fin de l’année 2016, tant en Europe qu’en Asie. La demande mondiale de charbon, qui provient toujours pour moitié de la Chine, a pourtant baissé en 2016.

Modern ‘Warmth’ A Brief Excursion From 8,000-Year (Continuing) Cooling Trend

by Kenneth Richard, March 20, 2017

According to an estimate of global sea surface temperature (SST) changes during the last 2,000 years (“Robust global ocean cooling trend for the pre-industrial Common Era“), the addition of the last 2 centuries (1800 to 2000 C.E.) of relatively modest SST warming only changes the overall per-millennium global cooling trend (~0.4°C) by one tenth of one degree.  In other words, using a long-term perspective, the Holocene cooling trend has continued largely uninterrupted during the last two centuries.

IEA finds CO2 emissions flat for third straight year even as global economy grew in 2016

International Energy Agency, March 17, 2017

The biggest drop came from the United States, where carbon dioxide emissions fell 3%, or 160 million tonnes, while the economy grew by 1.6%. The decline was driven by a surge in shale gas supplies and more attractive renewable power that displaced coal. Emissions in the United States last year were at their lowest level since 1992, a period during which the economy grew by 80%.

The world’s energy needs continue to grow, but many millions are left behind

World Energy Outlook 2016 IEA, March 16, 2017

Executive summary

In our main scenario, a 30% rise in global energy demand to 2040 means an increase in consump on for all modern fuels, but the global aggregates mask a mul tude of diverse trends and signi cant switching between fuels. Moreover, hundreds of millions of people are s ll le in 2040 without basic energy services. Globally, renewable energy – the subject of an in-depth focus in WEO-2016 – sees by far the fastest growth. Natural gas fares best among the fossil fuels, with consump on rising by 50%. Growth in oil demand slows over the projec on period, but tops 103 million barrels per day (mb/d) by 2040. Coal use is hit hard by environmental concerns and, a er the rapid expansion of recent years, growth essen ally grinds to a halt. The increase in nuclear output is spurred mainly by deployment in China.

Ice age thermostat prevented extreme climate cooling

Universitat Autònoma de Barcelona, March 14, 2017
from E. D. Galbraith, S. EgglestonA lower limit to atmospheric CO2 concentrations over the past 800,000 yearsNature Geoscience, 2017

During the ice ages, an unidentified regulatory mechanism prevented atmospheric carbon dioxide concentrations from falling below a level that could have led to runaway cooling, reports a team of researchers. The study suggests the mechanism may have involved the biosphere, as plants and plankton struggled to grow under very low carbon dioxide levels.

The second shale revolution

by Nick Butler, March 13, 2017

After the dip last year, production of oil from shale rocks in the US is increasing again. Estimates for this year range from a net increase of between 400,000 and 800,000 b/d. And 2017 is not a one-off year. The Permian Basin in Texas — the main focus for the new activity — has oil reserves that exceed those of all the largest discovered fields globally, such as Ghawar in Saudi Arabia and Prudhoe Bay in Alaska

Oil below $50: OPEC’s production cap plan is backfiring as U.S. shale enters ‘near nirvana’

by Jesse Snyder, March 10, 2017

Vicky Hollub, the CEO of Occidental Petroleum Corp., speculated that Permian production could in coming years reach as high as four or five million barrels per day, up from around 2.2 million bpd today.

A confluence of factors has created “near nirvana” for the U.S. shale industry, analysts at Citi Group said in a recent research note. Among those factors was the OPEC-led agreement to curb oil supplies in an attempt to lift prices.

Country Analysis Brief: Australia

by U.S. Energy Information Administration, update March 7, 2017

Australia, rich in hydrocarbons and uranium resources, was the world’s largest coal exporter in 2015 and the second-largest liquefied natural gas (LNG) exporter in 2015.

Australia is rich in commodities, including fossil fuel and uranium reserves, and is one of the few countries belonging to the Organization for Economic Cooperation and Development (OECD) that is a significant net energy exporter. Australia sent about 68% of its total energy production (includes uranium exports and excludes total energy imports) overseas in fiscal year 2015 (July 2014—June 2015), according to data from the Australian government

Interview : les sables bitumineux au Canada

par Peter Budgell, 12 février 2016

Si le Canada est le 5e producteur mondial de pétrole (derrière les États-Unis, l’Arabie saoudite, la Russie et la Chine), il le doit à ses gisements de sables bitumineux qui le placent au 3e rang en matière de réserves prouvées (derrière le Venezuela et l’Arabie saoudite). Face à la chute des cours du brut, l’Alberta est toutefois en difficultés et le Premier ministre canadien Justin Trudeau a récemment annoncé une aide financière pour relancer l’économie de cette province pétrolière. Les sables bitumineux sont d’autre part montrés du doigt en raison de leur impact environnemental. Quel sera l’avenir de ces ressources ?

Egalement : les ressources naturelles sont-elles inépuisables?

California Megaflood: Lessons from a Forgotten Catastrophe

by B. Lynn Ingram, January 1, 2013

 43-day storm that began in December 1861 put central and southern California underwater for up to six months, and it could happen again

Geologic evidence shows that truly massive floods, caused by rainfall alone, have occurred in California every 100 to 200 years. Such floods are likely caused by atmospheric rivers: narrow bands of water vapor about a mile above the ocean that extend for thousands of kilometers.

Vision, not limbs, led fish onto land 385 million years ago

through ScienceDaily, March 7, 2017

A new study suggests it was the power of the eyes and not the limbs that first led our aquatic ancestors to make the leap from water to land. The researchers discovered that eyes nearly tripled in size before — not after — the water-to-land transition. Crocodile-like animals saw easy meals on land and then evolved limbs that enabled them to get there, the researchers argue.

Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms

by Björn Baresel et al., March 6, 2017, Nature

Since the early days of stratigraphy, mass extinctions were noticed to coincide with major and global sea-level changes1,2 that significantly alter extinction patterns and time-series of geochemical proxies. In the case of the Permian-Triassic boundary mass extinction (PTBME), the system boundary itself has been initially placed during a global eustatic regression3, but was subsequently placed during a global transgression4 …

Shock finding : P-T mass extinction was due to an ice age, and not to warming

Geologic Evidence of Recurring Climate Cycles and Their Implications for the Cause of Global Climate Changes. The Past is the Key to the Future

Don J. Easterbrook, 2011

Department of Geology, Western Washington University, Bellingham, WA 98225, USA

Temperatures have risen approximately a degree or so per century since the coldest part of the Little Ice Age ~500 years ago, but the rise has not been linear. Global temperatures have warmed and cooled many times in 25-35-year cycles, well before the atmospheric CO2 began to rise significantly.

Two episodes of global warming and two episodes of global cooling occurred during the 20th century (Fig. 1). Overall, temperatures during the century rose about the same as the rate of warming per century since the Little Ice Age 500 years ago.

World’s oldest fossils unearthed

by University College London, March 1, 2017

Remains of microorganisms at least 3,770 million years old have been discovered by an international team led by UCL scientists, providing direct evidence of one of the oldest life forms on Earth.

Tiny filaments and tubes formed by bacteria that lived on iron were found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt (NSB), Quebec, Canada.

The NSB contains some of the oldest sedimentary rocks known on Earth which likely formed part of an iron-rich deep-sea hydrothermal vent system that provided a habitat for Earth’s first life forms between 3,770 and 4,300 million years ago …

Scrutinizing the carbon cycle and CO2 residence time in the atmosphere

by Hermann Harde, Global and Planetary Change, 24 February 2017


An alternative carbon cycle is presented in agreement with the carbon 14 decay.

The CO2 uptake rate scales proportional to the COconcentration.

Temperature dependent natural emission and absorption rates are considered.

The average residence time of CO2 in the atmosphere is found to be 4 years.

Paleoclimatic CO2 variations and the actual CO2 growth rate are well-reproduced.

The anthropogenic fraction of CO2 in the atmosphere is only 4.3%.

Human emissions only contribute 15% to the CO2 increase over the Industrial Era.

Also this link

Diamond’s 2-billion-year growth charts tectonic shift in early Earth’s carbon cycle

Science Daily, February 23, 2017

A study of tiny mineral ‘inclusions’ within diamonds from Botswana has shown that diamond crystals can take billions of years to grow. One diamond was found to contain silicate material that formed 2.3 billion years ago in its interior and a 250 million-year-old garnet crystal towards its outer rim, the largest age range ever detected in a single specimen. Analysis of the inclusions also suggests that the way that carbon is exchanged and deposited between the atmosphere, biosphere, oceans and geosphere may have changed significantly over the past 2.5 billion years.

S. Timmerman, J.M. Koornneef, I.L. Chinn, G.R. Davies. Dated eclogitic diamond growth zones reveal variable recycling of crustal carbon through timeEarth and Planetary Science Letters, 2017; 463: 178 DOI: 10.1016/j.epsl.2017.02.001

Baffin Bay and Kane Basin polar bears not ‘declining’ concludes new report

by Polar Bear Science, February 15, 2017

The 2016 Scientific Working Group report on Baffin Bay and Kane Basin polar bears was released online without fanfare last week, confirming what local Inuit have been saying for years: contrary to the assertions of Polar Bear Specialist Group scientists, Baffin Bay and Kane Basin subpopulations have not been declining but are stable.