The Arctic islands are one of the coldest places on the planet. People in Murmansk, Norilsk, and Vorkuta, which are three communities in Russia inhabit a portion of the Arctic Circle, along with people in Alaska, Russia, Greenland, and Scandinavia (“Arctic Circle”). According to the requirements laid out by Neil Shubin such as finding “rocks of the right age, rocks of the right type to preserve fossils, and rocks that are exposed at the surface” (5), is it possible to find fossils in these cold and snow/ice packed environments? In other words, can bones fossilize and remain preserved underground for hundreds of years even though the soil above them is not at normal temperature and the environment is not suitable for minerals such as apatite and fluorine in ground water? Apatite and fluorine are required for bones to fossilize. If it is not possible for bones to fossilize or remain fossilized for hundreds of years, what factors contribute to this?
Chandrika Darbha
(shiningstar0393@gmail.com)
“Arctic Circle”. Wikipedia. Retrieved March 28, 2011, from
Fossilization is extremely rare. When an organism dies, the environmental conditions must be just right in order for the organism to be fossilized. One such environmental factor is the presence of bacteria. Bacteria causes the corpse to rot, thus preventing the organism from fossilizing. Dying in the sand, mud, or soil is ideal for fossilization to occur, since they protect the corpse from elements that may prevent fossilization. Even after being buried under sand or mud, decay can take place, but the absence of oxygen slows this process. As the bones get buried deper in the soil, minerals and rocks change the chemical composition of the bones, allowing them to last for a long period of time. (http://www.bbc.co.uk/nature/fossils)
ReplyDeleteAs recently as 2009, fossils have been found in the arctic region, specifically 800 miles away from the north pole on a Norwegian island. Scientists have uncovered 2 partial skeletons of a species of pliosaurs, an extinct reptile that lived 150 million years ago. When scientists go excavating, they go to areas with varying weather conditions, whether it be humid or dry, warm or freezing cold. In order to uncover these fossils, the scientists had to use jackhammers to break through the permafrost, in order to access the lower fossil beds. So yes, it is possible to find fossils preserved in frigid weather, but they may take more effort to uncover, since they lie underneath such hard surfaces, which is why we rarely hear about findings in the arctic. (http://www.nytimes.com/2009/03/17/science/17foss.html)
Another discovery, made around the same time, revealed why fossilization is possible, even in cold regions. Scientists uncovered a tropical turtle fossil in the Arctic region. This discovery revealed that the arctic was much warmer millions of years ago, allowing fossil preservation. (http://dsc.discovery.com/news/2009/03/06/arctic-turtle-fossil.html). Since the environment was tropical, and thus more humid, the organism did not erode, which is a problem when the environment is too dry.
Both of these organisms were fossilized before the arctic got as cold as it is now, and since the environmental conditions were right when they were fossilized, they have been preserved in the soil, despite the fact that the current temperature in the region is extremely low.
Anna Leng (annaissbananas@yahoo.com)
Anna does a great job explaining how fossils can form and why they can be found in the Arctic. An interesting occurrence that Anna failed to cover was how fossils can be found literally frozen in ice or snow. But first, it’s important to clarify what makes something a fossil. A fossil is anything that serves as evidence to an organism that was once living as well as has to be at least 10,000 years old. Hard parts are the last parts of an organism to decompose. As Chandrika mentioned, they are made of Apatite as well as Calcite and Opal. In order for fossils to truly be preserved in the highest quality possible, there has to be little to no oxygen present, causing little decomposition, and the original environment has to be calm (1). All three of these requirements are found in a completely frozen environment. The only such area that this can occur is in the Arctic.
ReplyDeleteA great example of how this can occur is the story of Otzi the Iceman. Otzi was found in the mountains that form the border between Austria and Italy. Unfortunately, he is only 5,300 years old so not a fossil. However, this is still before the period of written history and thus gives an insight into the era that he lived in. What makes Otzi so significant is that after he was killed, he fell into the snow 10,500 feet above sea level and remained perfectly frozen until discovered. He is the most well preserved natural mummy in history (2).
Why Otzi is so significant is that he is proof of the preservative powers of ice. If an animal were to fall and freeze, it would be able to be preserved perfectly as a fossil. However, we also know that the Earth is constantly shifting due to tectonic plates. Therefore, an animal that fell and froze millions of years ago might not be able to be perfectly preserved in ice. An area that was once tropical will eventually become arctic as Anna referred to in her response. Otzi even offers a unique insight into the depths of interdependence in nature. The reason why specimens that live in lakes or in tropical areas can’t be preserved as well as those that are frozen or trapped in rocks is because of decomposition. Decomposition is the process by which bacteria and scavengers feed off of dead organisms. As the saying goes, one man’s junk is another man’s treasure. The organisms that aid in decomposition depend on the death of other organisms in order to survive and reproduce. If all animals are trapped and preserved perfectly in ice, the bacteria and scavengers will die out. The bacteria that aid in decomposition often also help the earth and plants to grow. If the scavengers can’t feed off the organisms, they will most likely die out. In this way, humans are connected to bacteria which are intertwined with the plants that humans or other organisms eat in order to survive. This is the epitome of interdependence in nature.
1. http://www.geology.wmich.edu/haas/geos2000/4s.pdf
2. http://www.laughtergenealogy.com/bin/histprof/misc/iceman.html
-Robbie Thomashow
(diehardcubsfan93@comcast.net)