Anorthosites, which contains high amounts of plagioclase felspar, can use their magnetic properties to look at mineral deopsits and magnetic anomalies on other planets. Scientists looked at anorthosite in Norway and found that they had a natural remanent magnetism and contain strong signatures of the Earth’s magnetic field direction when the rock was crystallized. Microscopic studies revealed that the anorthosites contained illmenite and hematite, both of which are weakly magnetic. Other studies showed that the submicroscopic plates of hematite and illmenite interact to show magnetic anomalies.
Archive for January, 2009
This article discusses how a 18 million year old lizard-like fossil found in New Zealand was found and it’s causing debates on whether or not the continent was submerged 25 million years ago. In today’s times, the tuatara, which is a lizard-like reptile that is endangered in New Zealand, is the lone survivor of a group that was around at the age of dinosaurs. The oldest known fossil of the tuatara is roughly 34,000 years old, however the new fossil dates back 16-19 million years ago. The fossil resembles the tuatara and leaves a 70 million year gap in the fossil record. Scientists now believe that the tuatara were on land since it separated from Gondwana, which means that the continent was not fully submerged. Around 22-35 million years ago there was a global sea-level rise, but it is not certain how much was submerged. If it was completely submerged, the tuatara would have had to recolonize. Scientists are coming up with many theories to explain this, but they are mainly thinking that the whole continent wasn’t submerged.
This article discusses how clams can be used in determining toxins in water. Most streams that are polluted are expensive to clean up, however using this method is not that expensive. I thought this article was really neat, because I never thought clams would be considered all that useful. But when they feed, they clean up water, which results in them absorbing toxins in their tissues. Once the clams are collected back out of the water, biologists open then and detach them from their shell. The lab tests show the different kinds and amounts of pollutants in the water, and the pollutants can be traced back to the sources.
There was a discovery of an ostracod fossil in sediments in Antarctica. This ostracod was discovered along with fossils of algal mats and fossilized mosquito larva. These fossils are overlain by the same lake sediments with no fossils present. It is believed that this change shows the exact time when Antarctica froze killing these animals. The time that Antarctica froze was roughly 14.07 million years ago. This fossiliferous bed was discovered in 2004. I find paleoclimate reconstruction extremely interesting and thought this article was interesting although it is an older study. This article can be found at http://www.sciencenews.org/view/generic/id/34865/title/Time_to_chill_.
I read an article on sciencenews.org that discussed a study conducted by Marc Edwards from Virginia Tech that showed negative consequences of lead in drinking water in Washington D.C. from 2001 to 2004. The lead was introduced into the plumbing by a process called chlormination, which was supposed to clean the water. The lead was accidentally reallised and remained in sewer pipes to this day. Edwards showed that children from D.C. showed many negative health affects. I found this article to be shocking; if it was known that there was seriously unsafe levels of lead in the drinking water one would think that the region’s government would do more to remediate this problem. It appears that the government just let the problem go until all the lead was washed out of the system and into peoples homes.
Mineralogy brought up Redoubt this morning, so let me list a few sources of information that students can check to see what’s going on in Alaska:
- Alaska Volcanic Observatory (AVO) — problems today due to everyone checking every three minutes to see if the volcano has erupted yet…
- Erik Klemetti’s Eruptions blog
- Smithsonian Institution Global Volcanism Program — weekly list of what’s going on around the world + historical background on Holocene volcanoes
- Ralph Harrington’s Volcanism blog
Although this entry covers the broad spectrum of natural disasters i thought it complemented my recent hydrogeology case study: Groundwater Geohazards.
According to one of the world’s biggest re-insurance companies the past year, 2008, has been one of the most devastating ever in terms of natural disasters. The company Munich Re said the impact of the disasters was greater than in 2007 in both human and economic terms. Potential reasons for greater impact have been discussed and include climate change. The company suggested climate change was boosting the destructive power of disasters like hurricanes and flooding. As a result they have called for stricter regulations on emissions in hopes to prevent further uncontrollable weather scenarios.
The report concludes that 2008 was the third most expensive year on record, after 1995, when the Kobe earthquake struck Japan, and 2005, the year of Hurricane Katrina in the US. Torsten Jeworrek of Munich Re said the pattern continued a long-term trend already observed. He said “Climate change has already started and is very probably contributing to increasingly frequent weather extremes and ensuing natural catastrophes,”.