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The Discovery of Black Smokers






Essay

To the regional mineralogy

Prepared by Oksana Stych

Kiev, 2015

Content

1. Black Smokers

1.1. The Discovery of Black Smokers

1.2. What Fuels the Black Smokers?

1.3. Special Seawater

1.4. How Black Smokers Form

1.5. Different Formations Reflect Different Conditions

1.6. Life in Extreme Environments

2. Lava tubes

2.1. Formation

2.2. Characteristics

3. Jupiter

4. Mercury

4.1. The composition and internal structure of Mercury

4.2. Origin of Mercury

4.3. Surface structure

4.4. The heavily cratered terrain

4.5. The intercrater plains

4.6. The Caloris Basin: a mercurian cataclysm?

4.7. The smooth plains

4.8. The origin of the plains: a Cayley Plains analog?

4.9. Primary and secondary crusts on Mercury?

4.10. Atmosphere

5. Venus: a twin planet to Earth?

5.1. The enigma of Venus

5.2. Surface features of Venus

5.3. Volcanoes

5.4. Coronae

5.5. Tesserae

5.6. Crustal composition

Black Smokers

The Discovery of Black Smokers

In 1977 the scientific community was astonished by the discovery of hot springs on the ocean floor, thousands of meters below sea level. These sulfide chimneys or hot springs supported rich biological communities that thrived in the absence of sunlight. Equally surprising was the finding that these unusual animal colonies were sustained by microorganisms that feed on chemicals in hot water. The chemicals are released from magma. In this illustration, the Alvin explores the base of the 15-story tall smoker dubbed Godzilla. Deep within the oceanic crust, then picked up by superheated seawater which circulates within the basaltic rocks that make up the ocean floor. The sulfide chimneys, which emit hot plumes laden with fine, dark particles of sulfide material became known as “black smokers.” Sulfide is a term for a certain group of minerals that contain sulfur. The areas around black smokers are oases for vibrantly colored tube worm colonies, clams, crabs, and other animals in the desert of the surrounding deep-ocean environment. Since that pivotal discovery, numerous underwater hot springs sites have been found along most of the major oceanic spreading centers. Ongoing discoveries associated with these incredible environments continue to astound us. For example, the black smoker “Godzilla, ” discovered along the Endeavour Segment of the Juan de Fuca Ridge in 1991, was as high as a fifteen-story building and towered over the surrounding volcanic terrain before it toppled over in 1996. It is now also known that these “rocks” are literally alive with microbes that thrive within their warm, sulfide-rich, water-saturated interiors. Perhaps the most far-reaching idea to come from these hotsprings is that life itself may have originated within these dynamic systems, in which geological, chemical, and biological processes are intimately linked.

What Fuels the Black Smokers?

The spectacular development of vigorously venting black smokers on the ocean floor is fueled by circulation and heating of seawater at depths of 2–8 kilometers within the oceanic crust. The same process also fuels more subdued, lower-temperature venting systems. In volcanically active areas such as the East Pacific Rise, the convection of heated seawater, or hydrothermal fluid, is driven by heating from a chamber of molten rock, or magma, at depths of two kilometers below the seafloor. The temperature of this magma is 1, 200°C. In contrast, in areas such as the Endeavour Segment where there is little current volcanic activity, circulation is believed to be driven by the cracking of hot crystalline rocks, heated to 500–700°C, deep in the ocean crust. Along their downward journey from the ocean floor to depths of 2–8 kilometers beneath it, the fluids undergo significant changes in temperature and chemical composition as they approach the heat source. The fluids obtain their final chemical composition at the deepest point of this circulating process?






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