Author Question: Early scientific estimates of Earth's age used observations of exposed marine fossils requiring a ... (Read 88 times)

tiffannnnyyyyyy

  • Hero Member
  • *****
  • Posts: 512
Early scientific estimates of Earth's age used observations of exposed marine fossils requiring a drop in sea level (Benoit de Maillet), cooling of a hotter Earth (Lord Kelvin), and the salinity of the ocean (John Joly).
 
  What age did each of these estimates come up with? What assumptions were made for each of these estimates that we now know to be incorrect?
  What will be an ideal response?

Question 2

As of 2015, more than 70 of the cost of toxic waste cleanup for most sites has been paid for by
 
  A) increasing taxes in the region affected.
  B) increased sales taxes in the affected state.
  C) federal dollars in the Superfund.
  D) the polluters.



Animal_Goddess

  • Sr. Member
  • ****
  • Posts: 339
Answer to Question 1

Benoit de Maillet came up with an age of 2.4 million years that would account for the locations of these fossils if they were left behind by the fall of a once all-encompassing deep sea. Geologists now know that sea level has risen and fallen countless times during Earth history, and that both falling sea level and uplift of land can explain the presences of marine fossils found above present sea level.
Lord Kelvin determined a most likely age of 2040 million years for Earth. It turns out that the most important assumptions in Kelvin's calculations were suspect. If, as geologists now think, Earth's mantle convects, then heat moves upward in the convecting mantle to maintain warm geothermal gradients near the surface for billions of years. Therefore, the geothermal gradient required to maintain high temperatures in deep mines can be maintained much longer than the 40 million years calculated by Kelvin. Kelvin's conduction assumption, therefore, yields an imprecise minimum age for Earth.
Joly calculated an age of 80100 million years. Modern geologists also see many problems with Joly's calculation. Oceanographers later explored the ocean depths and now know that oceans hold a much larger volume of seawater than estimated by Joly. Subsurface explorations for oil and gas and field excursions in remote lands reveal that rock-salt deposits also are much larger than known by Joly. Applying Joly's logic to these newer data would result in a substantially older age for Earth.

Answer to Question 2

D



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.

Did you know?

People often find it difficult to accept the idea that bacteria can be beneficial and improve health. Lactic acid bacteria are good, and when eaten, these bacteria improve health and increase longevity. These bacteria included in foods such as yogurt.

Did you know?

Chronic necrotizing aspergillosis has a slowly progressive process that, unlike invasive aspergillosis, does not spread to other organ systems or the blood vessels. It most often affects middle-aged and elderly individuals, spreading to surrounding tissue in the lungs. The disease often does not respond to conventionally successful treatments, and requires individualized therapies in order to keep it from becoming life-threatening.

Did you know?

A headache when you wake up in the morning is indicative of sinusitis. Other symptoms of sinusitis can include fever, weakness, tiredness, a cough that may be more severe at night, and a runny nose or nasal congestion.

Did you know?

If you use artificial sweeteners, such as cyclamates, your eyes may be more sensitive to light. Other factors that will make your eyes more sensitive to light include use of antibiotics, oral contraceptives, hypertension medications, diuretics, and antidiabetic medications.

For a complete list of videos, visit our video library