James Poole, age 10 of Albany, N. Y
How are tar pits formed?
The most famous tar pits in North America are on Rancho la Brea, in the pity of Los Angeles. Here the tacky tar, or asphalt, oozes up to the surface of the ground in glossy black pools and puddles. Sometimes the dry winds cover them with films of dust. It is then hard to tell where the solid ground ends and the treacherous tar begins. In the dim light of dawn and sunset, when wild animals come down to drink, the glossy tar pools may be mistaken for pools of water.
Through the ages, these famous tar pits have been a death trap for wild animals fossil bones found there date back when the world was in the cruel grip of the Ice Ages. Saber‑toothed tigers wolves and horses, camels, cloths and even mammoth elephants perished in the treacherous tar. For tar preserves whatever it covers. In ancient days it was used to preserve the bodies of Egypt’s pharoahs.
Another famous tar pit is near Trinidad. This vast hoard of asphalt was discovered by Sir Walter Raleigh in the year 1597. It covers an area of 147 acres and at the center it is 200 feet deep. Bermudez tar pit in Venezuela covers a thousand acres, but it is no deeper than two or three feet.
These tar pits are all near buried petroleum. They occur where this precious oil comes near the surface. However, we do not always find tar pits near petroleum, Let's look for some clues to explain this in the history of petroleum. Most scientists agree on how this precious rook oil was formed in the ground, though their theory is not proved.
Petroleum we suspect, forma from the fossil remains of ancient sea‑going plants and animals. These bitsy living things teemed in the seas hundreds of millions of years ago.
The ancient seas flooded and retreated from the lard. Pockets of water, teeming with tiny living things, were left to dry on the continents. In time they were buried under new layers of dust and debris. Masses of plant and animal life were also buried and through the ages they became processed into oily goo.
At various times in the earth’s history, oil was formed in Pennsylvania, in Mexico, in the Middle East, in California and many other areas. However, conditions were never quite the same in any two places. The petroleum formed was of different types and different qualities. The petroleum of Pennsylvania, for example, has a paraffin base. When the light gases and liquids are removed, this petroleum leaves a belly of paraffin wax. The petroleums of Texas and California have a base of tar or asphalt.
In California and other regions where tar pits are found, we find these petroleums near the surface of the ground. The oil ooozes up to the surface where the gases and fight liquids evaporate into the air. The gooy, asphalt base is left to form a tacky tar pit.