Fig Tree Area Stromatolite
Size: 1 3/4" W X 1 5/8" H X 7/8" D, Weight: 53.8 grams, smooth ventifact face
Fig Tree Area Stromatolite; Comes in attractive display case with information and authenticity. A nice, attractive specimen.
Age: About 3.1 Ga Swaziland Supergroup, South Africa
The Swaziland Supergroup of the Barberton Greenstone belt, South Africa, contains some of the oldest-known, least -metamorphosed sedimentary and volcanic rocks on Earth. These rocks represent a superbly preserved archive of life for the early earth. Chert is the most abundant sedimentary rock type within the volcanic part of this succession. The Fig Tree Group ranges to about 3.225 GA and consists of interfingering felsic pyroclastic, orogenic terrigenous clastic, and siliceous, carbonate and baritic chemical deposits. Most Phanerozoic cherts have quartz crystals. The oceans during this time were about 40 degrees centigrade warmer than our present climate. Fossilized bacteria, including cyanobacteria, lie peacefully arranged in smooth layers within the rock. They are commonly low-relief, nearly stratiform, laterally linked domes. Rarer forms include pseudocolumns and crinkly stratiform stromatolites. The stromatolites grew on a substrate of altered komatiitic lava and sediments deposited on the lava surface, and in most places are covered by later komatiitic flows. Some fine-grained tourmaline included within the stromatolite laminae suggests that stromatolites formed in an environment dominated by boron-rich hot-spring emissions and evaporitic brines.
More about Fig Tree Chert: The oldest amino acids known to exist were found in 1968 in the Fig Tree Chert, a formation of Precambrian rock located near Barberton, South Africa. The rocks were dated as being 3.1 billion years old. Older rocks containing fossils have been found since then, but this was the oldest known at the time. The rocks, studied by J. William Schopf and Elso S. Barghoorn of Harvard and Keith A. Kvenovolden of the National Aeronautics and Space Administration (NASA), were known to contain what looked like fossils of algae and bacteria, some of the earliest forms of life. Using a process called chromotography to separate chemicals, the scientists found a series of amino acids. The Fig Tree Chert contained two free and seventeen combined amino acids. There are about twenty natural amino acids, and they link together to form proteins, the essential element of living organisms. Amino acids can form without any living creature making them, and the idea of spontaneously formed life molecules was a hot research topic in the 1960s. Several labs were showing that conditions on the early earth were just right for forming amino acids. The challenge facing the scientists working on the Fig Tree Chert was to prove the chemicals they found were originally in living organisms.
Proof of Organic Remains -
The amino acids they found in the chert are found in life-forms today, and glycine was the most abundant, as expected, because glycine is chemically stable and some other amino acids break down to form glycine over time. To prove the hypothesis that the Fig Tree Chert contained the remains of living organisms, the scientists studied other, younger rock formations whose age was known. They knew how much organic material was present in them. They found a mathematical relationship between the age of rocks and the amount of organic material remaining in them. The mathematical formula suggested how much organic matter would remain after 3.1 billion years, which was precisely how much scientists found in the Fig Tree Chert.
This specimen comes with a display case, COA, information and similar display stand. Click on image to enlarge.