With its abundance of genera, the Burgess Shale is one of the world’s most important fossil fields. It’s discovery in 1909 led to over 100 years of paleontological study in the Canadian Rockies, a majority of which has been carried out in two quarries known as the Walcott and Raymond quarries (Hagadorn, 2002). Though he was originally in search of trilobites in the Burgess Shale Formation, paleontologist Charles Walcott also discovered a diverse group of soft- and hard-bodied fossils, from algae and sponges to chordates and cirripeds (Hagadorn, 2002). Soft-bodied fossils are incredibly rare due to their delicate structure and susceptibility to decay, so it is hard-bodied fossils that more regularly occur in fossil findings. However over 75,000 soft-bodied specimens have been found in the Burgess Shale formation (Hagadorn, 2002). These specimens are preserved in layers of shale formed from deposits of fine mud. One of the most significant species discovered is the Pikaia gracilens. Believed to be an early chordate, the Pikaia gracilens existed very close to the beginning of the evolutionary path that ultimately lead to humans (McGraw-Hill Encyclopedia, 2006).
The Burgess Shale formation is characteristically informative of significant events in the evolutionary path of multiple organisms. Its abundance of exquisitely preserved Lagerstätte has inspired paleontologists to refer to this mode of preservation as ‘Burgess Shale-type’ (Williams, 2009).
The Burgess Shale is located in British Columbia’s Yoho National Park; Part of the ancient landmass called Laurentia (Scott, et al., 2000). Fossils found within the formation dating back 545-525 million years ago represent original species from the Cambrian explosion, a relativel...
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...deposition and blanket of sediment kept the organisms compressed with little exposure to oxygen for decay. If life was predominately terrestrial during the Cambrian, the organisms predictably would have been left untouched after death long enough to decay, preventing the fine preservation of many soft-bodied organisms. Fortunately enough, it was marine life that dominated the Cambrian (Scott, et al., 2000).
Over the past century, the Burgess Shale has revealed important information about the development of earth’s history. The excavation of the Burgess Shale formation provided evidence for what was once just a theory in evolution. The taphonomic findings of the Burgess Shale have played a significant role in understanding the large diversity that resulted from the Cambrian explosion, advancing the study of evolutionary assemblages for Paleontologists worldwide.
Stroud, M.M., Markwort, R.J., and Hepburn, J.C. (2009) Refining Temporal Constraints on Metamorphism in the Nashoba Terrane, Southeastern New England, Through Monazite Dating. Lithosphere, vol. 1, p. 337-342.
The shelf-edge includes carbonate-to-clastic facies transition and tectonic uplift and erosion of the carbonates followed by deposition of the clastics. The Saint Peter Sandstone is a well-sorted, almost pure quartz arenite deposited during a major mid-Ordovician low stand. Clastics spread across an exposed carbonate platform by transportation. This is shown by the well-rounded, frosted texture of the quartz grains.
Fleeger, Gary M., Bushnell, Kent O., and Watson, Donald W. “Moraine and McConnells Mill State Parks.” Pennsylvania Trail of Geology. 2003. Print. 29 April 2014.
"Sedimentary Rocks." Backyard Nature with Jim Conrad. N.p., 18 May 2015. Web. 25 Oct. 2015.
The new discoveries raise many questions about the origin of modern man. Tim D. White, the project’s director claims that the Herto fossils prove that...
Lawrence Formation is 20 meters thick, and is unique in that it is the first major carbonate unit in the Paleozoic strat column of Minnesota. A limestone unit would signify the dominance of chemical and biochemical precipitation of calcium carbonate out of the seawater, a lack of sand and mud reaching that part of the basin of deposition, and probably a depositional site far from shore. Most of the Paleozoic carbonates were originally composed of calcite but were altered by the replacement of calcium ions by magnesium to form the mineral dolomite. The St. Lawrence Formation is not clean but contains clay, silt, sand, and glauconite, indicating fluctuating conditions.
Geologic development contributed to the Cambrian explosion. There was a supercontinent called Rodina that broke up to make continents. There was an ice age but the Earth continued to warm creating new life forms. There things called invertebrates that had no backbone. Life forms also had a hard outer shell to protect them. The trilobite is an arthropod that had a hard outer shell. In only 15 million years many different types of organisms evolved. Cambrian reefs made up of sponges flourished.
...nd Stromatoporoids (a kind of sponge with a layered skeleton) were common rock builders of the Northern Hemisphere. Moss was common in shallow seas. Among the arthropods, the giant eurypterids (sea scorpions) have been found in the Old Red Sandston facies (see image above). The first insect was part of a group of wingless insects that feed off of debris and soil. Conodonts were vertebrate animals abundant in marine life. Many of the fish were heavily armored and the earlier fish (agnathans) had no jaws and were mud eaters and scavengers. Chondrichthians are sharklike fishes that were first found in the Middle Devonian. In terms of plants, many vascular plants emerged and a varied flora was established. There is evidence of algae, bryophytes, and charophytes. Algae and fungi also existed. As previously stated, the first known forests are from the Devonian Period.
...nder, C., Tsai, C., Wu, P., Speer, B. R., Rieboldt, S., & Smith, D. (1998/1999/2002). The permian period. Informally published manuscript, Biology 1B project for Section 115, University of California Museum of Paleontology, CA, Retrieved from http://www.ucmp.berkely.edu/permian/permian.php
Have you ever experienced peer pressure where you were pushed to do something you didn’t want to do? Well, in this short story titled ‘’The Ravine’’ by Garrett Salisbury, four friends set out to go diving at a ravine in Hawaii where 2 weeks ago a boy their age drowned, and his body was never found. Among these friends was Vinny and Joe-Boy who are the same age but are different in more ways than similar. It started when the boys were making their way down a muddy trail and through thick brush to get to the ravine. Along the way, Joe-boy focuses on trying to scare Vinny by pointing out things which the boy who drowned might have done.
The Burgess Shale Fauna is a fauna that was constructed based on a group of fossils that were initially found, in the Burgess Shale area in the Canadian Rockies (Gould, 1989). They are a very important group of fossils as “modern multicellular animals make their first unprotected appearance in the fossil record some 570 million years ago” through this group (Gould, 1989, pp. 24). Moreover the Burgess Shales are known to have preserved the soft parts of animals enabling us to get a better understanding of life at the time.
Colorado is home to eleven national parks, with different stories to be told in each one! One of those parks is the Rocky Mountain National Park. In this park alone you can find all three rock types of all ages. For example, there is Silver Plume granite that “intruded upward into the metamorphic rocks about 300 million years after the formation of the Proterozoic mountains” and can be found in the eastern side of the park (“Geology resources division,” 2007). Geologist are unsure what caused this
There are several theories about how the Cambrian Explosion started. There were major changes in marine environments and chemistry from the late Precambrian into the Cambrian, and these also may have impacted the rise of mineralized skeletons among previously soft-bodied organisms. One theory as to what happened is that oxygen in the atmosphere, with the contribution of photosy...
Since this time, the term uniformitarianism has been manipulated, altered, and redefined to mean a variety of different meanings spanning various fields of science. However, in the field of geology, uniformitarianism (or actualism) means something very specific. The term does not denote that every process we see before us now has been going on for eons, rather it stand for the chemical and physical laws that govern today’s processes. Evidence shows that the ancient atmosphere of the earth is extremely different from the one we can see today. There fore, the means by which erosi...
Reptiles are vertebrate, or backboned animals constituting the class Reptilia and are characterized by a combination of features, none of which alone could separate all reptiles from all other animals.The characteristics of reptiles are numerous, therefore can not be explained in great detail in this report. In no special order, the characteristics of reptiles are: cold-bloodedness; the presence of lungs; direct development, without larval forms as in amphibians; a dry skin with scales but not feathers or hair; an amniote egg; internal fertilization; a three or four-chambered heart; two aortic arches (blood vessels) carrying blood from the heart to the body, unlike mammals and birds that only have one; a metanephric kidney; twelve pairs of cranial nerves; and skeletal features such as limbs with usually five clawed fingers or toes, at least two spinal bones associated with the pelvis, a single ball-and-socket connection at the head-neck joint instead of two, as in advanced amphibians and mammals, and an incomplete or complete partition along the roof of the mouth, separating the food and air passageways so that breathing can continue while food is being chewed. These and other traditional defining characteristics of reptiles have been subjected to considerable modification in recent times. The extinct flying reptiles, called pterosaurs or pterodactyls, are now thought to have been warm-blooded and covered with hair. Also, the dinosaurs are also now considered by many authorities to have been warm-blooded. The earliest known bird, archaeopteryx, is now regarded by many to have been a small dinosaur, despite its covering of feathers The extinct ancestors of the mammals, the therapsids, or mammallike reptiles, are also believed to have been warm-blooded and haired.