H. Okada S. Honjo J.C. Hathaway E.T. Degens 1972 <div id="Abs1-section" class="c-article-section"><div id="Abs1-content" class="c-article-section__content"><p>The origin and chemical nature of micron-sized spheres found as suspended particles in Lake Kivu are examined. It can be shown that the hollow spheres, with a wall thickness of 500 Å, consist of a complex polymeric resinous material which has little functionality, except for hydroxyl groups. The spheres arise in the process of degassing of water samples at depth. Tiny gas bubbles, about 1 micron in size, act as scavengers of dissolved resinous material. The newly created resinous membrane promotes the selective coordination of zinc dissolved in the water column. In the prevailing H₂S regime, formation of sphalerite crystals in induced. The size range of the crystals, 5 to 50 Å, corresponds to 1 to 10 unit cells and suggests that the resinous membrane also acts as a template in sphalerite growth processes. The sources of the zinc and dissolved gases (CO₂, CH₄, H₂S) are hydrothermal springs seeping from the lake bottom into the basin. Water discharge is substantial; about 100 years are required to fill the lake to its present level (ca. 550 km³<span>&nbsp;</span>water). The average Kivu water contains 2 ppm zinc. Thus, 1 million tons of zinc are contained in Lake Kivu in the form of sphalerite.</p></div></div><div id="Abs2-section" class="c-article-section"><br></div> application/pdf 10.1007/BF00206891 en Springer Microcrystalline sphalerite in resin globules suspended in Lake Kivu, East Africa article