Precambrian Boundary Essay

Although the Ediacaran period was well before the first appearance of dinosaurs it shows that there were fossils many years ago. When dinosaurs first appeared things had changed there was still shallow water which meant that bones could be fossilized.

One of the biggest pieces of evidence for the Flood is the Cambrian explosion. The Cambrian explosion is taught by evolutionist to be a sudden burst of evolution caused by an increase in favorable environments. An evolutionist article states, “Fossils provide solid evidence that organisms from the past are not the same as those found today; they show a progression of evolution… The resulting fossil record tells the story of the past and shows the evolution of form over millions of years. For example, scientists have recovered highly-detailed records showing the evolution of humans and horses.” (Evidence of Evolution, n.d.) In reality the fossil record shows that there was a sudden and nearly simultaneous appearance of all known phyla as well as species from the most distant parts of the family tree during the Cambrian period, instead of a gradual evolution. (Wieland, n.d.) (Wise, 2009) Fossils have been found worldwide in Precambrian rocks, but they were too bizarre and different

The author and his colleagues specifically chose to focus on 375 million year old rocks in their search for fossils because this was the time frame that provided fish that would be useful to study from. The 385 million year old rocks provided fish that look too similar to the ones we have now and the 365 million year old rocks have fossils that don’t resemble fish. The 375 million year old rocks, however, provide fossils that show the transition between fish and land living animals.

One of the major things noticeable from the cross section is that quite a few of the rock layers are over turned, where the older rock layers are above the newer rock layers. This is seen in the contact between the Quartz Monzonite of Papoose Flat and the Campito Formation which is also a disconformity. Next there is some fault zones separating the Camptio, Poleta, and Harkless formations. We then see some more overturned layers with the contacts between Saline Spring Valley Formation (lower and upper members) above the Mule Spring Formation along with some inferred folding. With a normal fault separating the inferred folding event, we see where the overturning occurs. In between the Cambrian layers we see Tertiary Basalt nonconformities also being folded, thus with that we know that the folding event was more recent than the formation of the Basalt. Next there is a large Basalt field with a spot of the Harkless formation. Again we see over tuning as the Basalt field ends there are the Devonian and Mississippian rock Layers on top of the basalt. Separating these overturned layers from the Harkless Formation and the Saline valley Formation (upper member), which are not overturned, is a thrust fault. From this information, there was a major stress event sometime after the Tertiary period causing the rock layers to fold and overturn. And from this stress event and from the folding, normal and thrust faults are formed. Finally we see that there were alluvial and landslide deposits from the Quaternary after the folding, faulting, and over

Sedimentary rocks interpret dinosaur habitats through encased environmental structures of the past. Through sedimentary rocks, paleoecologists’ can examine the arranged formation of sedimentary structures to specify what type of environment the dinosaurs’ lived in. An example of a specific sedimentary rock structure can be seen through formed weathering and ripple marks by how wind and sand formed distinct patterns in the past layered sediment. These arrangements provide interpretations on the structure of the sediment and the habitat of encased fossils, through modern day comparisons

The first chapter of the book discusses the way we can use fossil records to study the biological world. Fossils are one of the major lines of evidence we use to understand ourselves. Surprisingly, we are able to discover them with a high amount of precision and predictability. In particular, field paleontologists have it easier than it has ever been before due to the current information age. The physical hunt for important fossils, however, is much like it has always been. Three factors limiting the number of useful fossil sites include rock age, type (whether or not it can preserve fossils), and number of exposed rocks. So, it takes a bit of luck to reliably find fossils. Thankfully, rock

Almost every metazoan phylum with hard parts, and many that lack hard parts, made its first appearance in the Cambrian. The only modern phylum with an adequate fossil record to appear after the Cambrian was the phylum Bryozoa, which is not known before the early Ordovician. A few mineralized animal fossils, including sponge spicules and probable worm tubes, are known from the Vendian period immediately preceding the

In order to find evidence of the transition from fish to land animals, the author and his colleagues chose to focus on 375 million year old rocks. In 2004, they studied sedimentary rock on Ellesmere Island in Canada’s Arctic as they thought that the rocks there would be exposed and untouched by humans, which would be ideal for fossil excavations. They studied sedimentary rocks (limestone, sandstone, siltstone and shales) because these

The 440 million year old Georgian Bay Formation is largely composed of fossiliferous grey-black shale (L1R). It also consists grey fine-grained limestone, sandstone and green/grey siltstone interbedded with green/grey and blue/grey shales (Bond et. al. 1976). The frequency of hard rock units increases toward the top of the formation. Recurrent tropical storms across the Ordovician seas caused the formation of shady, thin limestone with wave ripples on top. Numerous fossils can be found in the siltstones and limestone including molluscs, crinoids and gastropods

Evidence  for  life  on  early  Earth  (e.g.  in  the  Pre Cambrian)  has  proved  difficult  to  find  because: SELECT  ALL  THAT  APPLY Select  one  or  more: A.  rocks  from  these  early  times  are  rare  due to  the  recycling  of  the  Earth's  crust  through plate  tectonics   B.  there  was  no  oxygen  in  the  Earth's atmosphere  at  this  time C.  life  at  this  time  lacked  hard  parts  (such as  shells  or  bones)  that  fossilise  easily   D.  life  had  not  yet  emerged  onto  land E.  life  at  this  time  was  mostly  microbial

These Paleozoic rocks are steeply plunging sandstones and siltstones, with a little event of limestone at Lilydale - the Early Devonian Lilydale Limestone. The Silurian rocks were stored in profound water, while the Devonian rocks, which are exceptionally fossiliferous, appear to have been stored in shallower water. These Silurian and Devonian rocks were folded into a progression of anticlines

The author and his colleagues chose to focus on 375 million year old rocks in their search for fossils because amphibians that look dissimilar to fish were discovered in 365 million year old rocks, while fish without amphibian characteristics were discovered in 385 million year old rocks. Thus, it is possible that the evolutionary intermediary, or the “missing link” between fish and amphibians, would be discovered in 375 million year old rocks, between the two time periods. The rocks examined were sedimentary in composition, as the gradual and relatively gentle formation of sedimentary rock under conditions of mild pressure and low heat are conducive to the fossilization of animal remains. Sedimentary rock is also often formed in rivers and seas, where animals are likely to live. This site provides a resource that describes means by which fossils are formed and how the fossil record may be interpreted, and shows some examples of fossils demonstrating evolution through geological periods: http://www.fossilmuseum.net/fossilrecord.htm. In 2004, Shubin and his colleagues were looking for fossils on Ellesmere Island, in northern Canada. This location was chosen because of its lack of human development, as well as of obstructing natural formations and life forms such as trees, which

Even though anoxia is in general reflected on as an essential pre-requisite, “anoxia alone is not sufficient enough to account for Burgess shale-type preservation,” (Garson 2012). Furthermore, the necessity of anoxia is not universally agreed upon (Garson 2012). Yet, while rare and commonly absent from today’s fossil record, this type of preservation is very common throughout most Burgess shale-type deposits of these ancient fossils (Gaines 2012). Localities of these types are somewhat confined to Series 2 and 3 of the Cambrian (Garson 2012).

My outside source for questions 3 and 4 is a journal by Pat Shipman titled Fossils. This journal was published in The New Scientist Vol. 215, Issue 2876, p. 8-16.

These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils.