I. On the probable origin of some magnesian rocks

• Published in: Proceedings of the Royal Society of London
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1859
• Subjects: Struve; Carbonic acid
• Online Access: http://dx.doi.org/10.1098/rspl.1857.0035; https://royalsocietypublishing.org/doi/pdf/10.1098/rspl.1857.0035

The deposits of mineral matters from natural waters offer many points of interest to the geologist. Besides the rock-salt and gypsum, which in many cases have doubtless been formed by the spontaneous evaporation of saline waters, it is well known that many mineral springs charged with carbonic acid under pressure, deposit great quantities of earthy salts when they come to the surface, and that the travertines thus formed often constitute extensive masses. The deposit from the hot alkaline saline springs of Carlsbad, which forms great beds, was found by Berzelius to consist chiefly of carbonate of lime, with portions of oxide or carbonate of iron, and small quantities of silica, strontia, phosphoric acid and fluorine; the analyses of other chemists have added to the list of elements met with in these and similar precipitates, manganese, zinc, cohalt, nickel, chromium, arsenic, antimony, tin, copper and lead. Carbonate of magnesia is however wanting, or present only in very small proportion in these deposits, and the same is true of the calcareous sinter from cold springs. The Carlsbad water, however, contains for 17 parts of carbonate of lime, 10 parts of carbonate of magnesia; hut this latter salt, according to Berzelius, is only deposited after evaporation. The analyses by Berzelius and Struve of the various carbonated waters of Germany, show that carbonate of lime is generally present in much larger quantities than carbonate of magnesia; and it is only in the waters of Püllna and the Elisenbrunnen of Kreuznach, which contain very little carbonic acid, that we find a large amount of carbonate of magnesia, with a small portion of carbonate of lime. The water of Püllna, according to Struve, contains in 1000 parts, 32·72 of solid matters, consisting of sulphates and chlorides of sodium, magnesium and a little calcium, besides ·10 of carbonate of lime and ·83 of carbonate of magnesia; it contains only 7/100 ths of its volume of carbonic acid gas.