Introducing the Lomashell of Makran coast and their use for supplementing aquatic feed

The study area is located in the southeastern coast of the Iran, in Sistan and Baluchistan province. The sandy and shallow coasts of this region have provided a very suitable environment for the joining of bivalves, foraminifera and ostracods shells with a low degree of cementation and the formation of Lomashell (Coquinoid limestone) deposits. A large part of these deposits are used as borrow pits in the construction of breakwaters on the Makran coast. However; the evidence shows that these deposits have a high economic potential.

Therefore, in the present research, by identifying and introducing the Lomashell deposits of Makran coast, sampling them and investigating the geochemical characteristics of these deposits, the economic value of these ore has been evaluated and the possibility of using them to supplementing aquatic feed has been analyzed.

Based on the results of chemical analysis, the average amount of CaO in Lomashell is 44.76 %wt., equivalent to 86.91%wt of CaCO3. In addition, other nutrient elements and compounds such as Na, K, Fe, Mg and P are 1.03, 0.59, 1.36, 0.86 and 0.26 respectively. On the other hand, the average concentration of some toxic elements such as Pb, Zn, As, F, and Hg in Lomashell samples is 14.96, 12.8, 7.06, 19.43, and 18.33 (ppm), respectively. Compared to the very high concentration of calcium as ore mineral, they are insignificant.

The high purity of calcium carbonate, the low contamination with toxic and waste elements, the small amount of silica, in addition to the appropriate tonnage, the low range of vertical and lateral changes of the ore body, the low amount of gangue with ore deposits and also the bright color of the ore mineral, all of them represent the best quality of the ore mineral in three areas of Makran coast, and show that the Lomashell deposits has the best quality for processing micronized calcium carbonate powder in the preparation of food supplements for aquatic feed.