Friday, February 11, 2011

Fish in the Santana Formation of Brazil

Fish remains of remarkable state of preservation and beauty have been found in calcareous concretions in the Santana Formation of north-east Brazil. The fossil-bearing concretions occur in the Araripe Basin at various localities at the boundary between Ceara, Pernambuco, and Piaui provinces. The strata containing the fish concretions lie at the base of the Araripe Plateau and are of Cretaceous age (Aptina-Albain, about 100 million years). At that time, Africa and South America were starting to rift apart and the South Atlantic was opening up in a narrow shallow sea. It is thought that salinity changes may have been responsible for the mass deaths of the marine fish fauna. The fish shown here has a length of 43 cm. Photos by P.Stacher.




Saturday, May 1, 2010

Deepwater Horizon oil spill.

The Deepwater Horizon oil rig owned by Transocean has drilled the deepest oil well in history (35,050 feet) in September 2009 in the Gulf of Mexico. In January, the rig started operation at a British Petroleum project, approximately 41 miles offshore Louisiana on Mississippi Canyon block 252. On April 20 a fatal explosion occurred on the rig. Of the 126-member crew, 115 were safely evacuated. Despite exhaustive rescue efforts, eleven crew members lost their lives, nine of which were Transocean employees. After an unsuccessful effort to douse the fire, the remains of the rig sank to the ocean floor 5,000 feet below.
The cause of the incident is not known at present. It is assumed that a minor blow-out has occured. Oil and gas, was flowing from the formation into the wellbore and was rising undetected up to the rig floor where the gas was ignited. After the explosion it was not possible anymore to shut the well by activating the underwater blowout-preventer (BOP). It was reported that the rig had apparently just finished cementing steel casing before the well was to be suspended. The plan was to re-enter the well later with another rig to complete the work and bring the well into production.
The Transocean Deepwater Horizon is a floating rig that moves with the waves. The pressure control equipment sits on the seabed and is controlled remotely from the platform. Although there are enormous safety measures in place to prevent drilling incidents the risks are always present in the industry. Transocean is one of the industry's most safety-conscious and experienced deep-water company that has recently moved head quarters to Zug, Switzerland.
A catastrophic amount of oil is spreading over the ocean and threatens land, wildlife and the seafood industry. An oil spill quite this bad had not been seen since the Exxon Valdez incident some twenty years ago.

Thursday, April 15, 2010

Eyjafjallajökull volcano eruption.



Eyjafjallajökull volcano eruption in south Iceland. Video by Icelandic National TV station RÚV. 24.03.2010. Music by Sion, Ambients, Freefalling. GPS coordinates of the eruption: 63.635° N, 19.440° W. YouTube
Read about Eyjafjallajökull volcano:
- Katla and Eyjafjallajökull Volcanoes: sciencedirect.com
- Eyjafjallajökull eruption: 20 March to present: earthice.hi.is

Friday, April 2, 2010

Ice Sheet Melt Identified as Trigger of 'Big Freeze'.

A new paper, which is published in Nature on April 1, 2010, has identified a mega-flood path across North America which channelled melt-water from a giant ice sheet into the oceans and triggering the Younger Dryas cold snap.

The study will help shed light on the implications of fresh water input into the North Atlantic today. There are current concerns that changes in the salinity of the ocean today, could cause another shut down of the Gulf Stream. Current climate changes, including global warming, may be altering the planetary system which regulates evaporation and precipitation, and moves fresh water around the globe. Cited from sciencedaily.com.

Read more ….

Friday, March 5, 2010

65 million years of climate change



The planet earth is 4.5 billion years old and has undergone many geologial and climatic changes. Geologists know: Earth history demonstrates continuous dynamic evolution. The above figure shows climate change over the last 65 million years. The data has been gained from oxygen isotope measurements (δ18O) on benthic foraminifera by Zachos et al. (2001) and reflect a combination of local temperature changes in their environment and changes in the isotopic composition of sea water associated with the growth and retreat of continental ice sheets. Figure and citation from wikipedia.com.
Ancient climate records provide clear evidence of abrupt episodes of greenhouse warming in the past. Understanding cause and effect for these events continues to remain a major challenge. For the best-documented example, a burst of warming some 55 million year ago termed the Palaeocene–Eocene thermal maximum (PETM), known increases in greenhouse gases fail to explain even half of the observed warming. Read more..nature.com

Monday, January 18, 2010

Haiti earthquake occurred in complex, active seismic region

Haiti earthquake occurred in complex, active seismic region. The magnitude 7.0 earthquake that triggered disastrous destruction and mounting death tolls in Haiti this week occurred in a highly complex tangle of tectonic faults near the intersection of the Caribbean and North American crustal plates, according to a quake expert at the Woods Hole Oceanographic Institution (WHOI) who has studied faults in the region and throughout the world.....read more...sciencedaily.com