Evaporite borates are the largest industrial source of boron in the world. The major productions come from the Neogene lacustrine borate deposits in western Turkey and California, USA. The formation of large borate deposits is closely related to 1) magmatic processes to form volcanic rocks enriched in boron, 2) leaching of boron from rocks by hydrothermal activity, and 3) evaporation of playa lakes in a dry climate. Boron isotope could be a useful tool to identify the origin of boron and to constrain the physicochemical conditions (e.g., pH) during borate precipitation. This article reviews the studies on boron isotope geochemistry of borate deposits. The future possibility of lithium production from borate deposits is also presented.
Zr contents of granitic rocks of the major intrusive bodies in Japan were evaluated on the Harker diagrams. The contents show three patterns as (i) increasing type, (ii) decreasing type, and (iii) decreasing after increasing type. The first type is best shown in the M-type magnetite-series of Tanzawa tonalites, which was generated in Zr-poor mafic igneous source rocks at depth, then never saturated with Zr in magmas; thus the contents increase with the crystallization. The second type is common in the ilmenite series originated in crust materials, which was saturated with Zr at the beginning of crystallization; thus the content decreases as the silica increases. In the third-type magma, Zr increases with the increasing silica content, then around 66% SiO2 starting to decease after saturation of Zr. This is most commonly seen in the magnetite-series granitoids. Thus, variation of the Zr contents in granitoids is essentially controlled by the original Zr contents of the granitic magmas in Japan.
Remarkable topics in this one year are as follows: 1) oil was found at two structures in the Barents Sea, a marginal sea of the Arctic Ocean, 2) the oil and gas production has started at several oil fields such as Kashagan in Kazakhstan's zone of the Caspian Sea and Garraf in Iraq, 3) the Caserones mine began to produce copper and molybdenum concentrates following SX-EW coppor production in the last year, and 4) the Ichthys LNG Project has passed through the milestone of 50 % completion at the end of June.