AboutGeorge Ardies Expertise Sedimentology and Petroleum Geology - I am also very well versed in general sciences. I am not an expert in igneous and metamorphic geology. I have completed B.Sc. in Environmental Geology at Concordia University in Montreal, Quebec and a M.Sc. degree in Sedimentology at Queen`s University in Kingston, Ontario. I have about 12 years of experience in oil and gas exploration and development.
Experience Military service (Montreal, Quebec, Canada).
Bachelor of Science degree(Montreal, Quebec, Canada).
Master of Science degree (Kingston, Ontario, Canada).
Oil and gas experience for about 10 years (Calgary, Alberta, Canada).
Professional Geologist Certification.
Expert: George Ardies Date: 7/10/2008 Subject: Questions about the earth
Question Dear Mr. George Ardies ,
We are a group of syrian teachers.
We like to ask you some questions :
1. What is the most accurate criteria to certify the Earth age ?
2. What is your vision for the Earth in 100 years ?
waitin for your response, cinerley yours,
Khalida
Ghada
Aida
Answer Dear Khalida, Ghada and Aida,
he generally accepted age for the Earth and the rest of the solar system is about 4.55 billion years (plus or minus about 1%). This value is derived from several different lines of evidence.
Unfortunately, the age cannot be computed directly from material that is solely from the Earth. There is evidence that energy from the Earth's accumulation caused the surface to be molten. Further, the processes of erosion and crustal recycling have apparently destroyed all of the earliest surface.
The oldest rocks which have been found so far (on the Earth) date to about 3.8 to 3.9 billion years ago (by several radiometric dating methods). Some of these rocks are sedimentary, and include minerals which are themselves as old as 4.1 to 4.2 billion years. Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.
While these values do not compute an age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it). This lower limit is at least concordant with the independently derived figure of 4.55 billion years for the Earth's actual age.
The most direct means for calculating the Earth's age is a Pb/Pb isochron age, derived from samples of the Earth and meteorites. This involves measurement of three isotopes of lead (Pb-206, Pb-207, and either Pb-208 or Pb-204). A plot is constructed of Pb-206/Pb-204 versus Pb-207/Pb-204.
If the solar system formed from a common pool of matter, which was uniformly distributed in terms of Pb isotope ratios, then the initial plots for all objects from that pool of matter would fall on a single point.
Over time, the amounts of Pb-206 and Pb-207 will change in some samples, as these isotopes are decay end-products of uranium decay (U-238 decays to Pb-206, and U-235 decays to Pb-207). This causes the data points to separate from each other. The higher the uranium-to-lead ratio of a rock, the more the Pb-206/Pb-204 and Pb-207/Pb-204 values will change with time.
If the source of the solar system was also uniformly distributed with respect to uranium isotope ratios, then the data points will always fall on a single line. And from the slope of the line we can compute the amount of time which has passed since the pool of matter became separated into individual objects. See the Isochron Dating FAQ or Faure (1986, chapter 18) for technical detail.
A young-Earther would object to all of the "assumptions" listed above. However, the test for these assumptions is the plot of the data itself. The actual underlying assumption is that, if those requirements have not been met, there is no reason for the data points to fall on a line.
Regarding the Earth 100 years from now....great question. It will certainly be much more populated with humans and human buildings. The pollution problem will have probably been solved. The climates will probably be very similar to what they are now.
