Dating Techniques Essay and Discussion Responses

After reading Chapter 4, address the following prompt.  The goal is to demonstrate your knowledge of the course material.  Review Writing Guide module.

You will need the book that i shared with you last time. Let me know if you have it. 

POSTING/ESSAY 1:
What do you feel are the two most effective dating techniques? Why? Support your answer with evidence from the text and module.

POSTINGS 2 AND 3:

Respond to two class members essays as it relates to the course material.   

POST

https://drive.google.com/file/d/1rwUdjlaYr8JHuXuWmcE7lCchtKbzmKTi/view?usp=sharing

POST1 

One of the dating techniques I find useful is the radiocarbon dating. Carbon-14 dating  is based on the decay of carbon 14, and it measures the age of an organic object using the ratio of carbon-14 to carbon-12 that remains in the object. It is one of the first radiometric dating methods that were developed hence it is quite significant. The method is limited to 50,000 years generally, although it can sometimes be used to date objects as old as 70,000 years when correction factors are present. It is a fairly accurate method but dates may be off only by a few decades for more recent objects and dates for objects tens of thousands of years old can be off by as much as 5,000 years. This is especially If the sample that is used had been contaminated. An advantage of this carbon-14 dating method is that only a handful of charcoal, shell, hair, burned bone, wood or another organic substance is required for analysis to be done in the laboratory. When this method was created, it allowed the direct dating of small items such as bone tools, wooden artifacts and human fossils for the very first time.The other dating method I found useful was a chemical dating technique called aspartic amino acid racemization. This method  can be used to date bones, teeth, and shells that are between 1,000 years and 1,000,000 years old. The basis of it is the structures of amino acids in living things changes over time. Most of the amino acids in living organisms come in what is called the levorotary form, even though a dextrorotary form exists for all amino acids except glycine. When these amino acids start to convert from their levorotary form to their dextrorotary form when a creature dies, this process is called racemization. When the conversion rate is known, racemization provides a clock mechanism that can be used to determine the time of death.

POST 2

Post 3 now : Of all the dating techniques, the stratigraphy and deep-sea core dating seem to be the most effective.  Stratigraphy relies on the natural geographic lineage to determine a timeline while other techniques play more of a guessing game. You can physically test and tell when and how long something has been around by the layering of the soil that may have been affected by natural or human interferences. “Part of this work involves detecting whether there has been any human or natural disturbance of the layers since they were originally deposited (such as garbage pits dug down by later occupants of a site into earlier layers, or animals burrowing holes).”(Renfrew and Bahn 109) The deep-sea core dating method is more effective than methods like association dating and pollen dating because the ocean was here before everything else was meaning any evidence or genetic tracing from there is probably more reliable than evidence on land. Life on Earth began in the oceans so if we can analyze their chemical structure, it’ll allow us to make clear predictions as to what their environments were like. “These cores contain shells of microscopic marine organisms known as foraminifera, laid down on the ocean floor through the slow continuous process of sedimentation. Variations in the chemical structure of these shells are a good indicator of the sea temperature at the time the organisms were alive. Cold episodes in the deep-sea cores relate to glacial periods of ice advance, and the warm episodes to interglacial periods of ice retreat.”(Renfrew and Bahn 114) Scientists are also relying on the sediment that these organisms are found in for extra validation.. With a better, more precise understanding of ancient environments and the organisms that inhabited them, we can create clearer chronologies.