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B.M. Madsen

Publications and source records attributed to B.M. Madsen.

5 recordsLinked to original sources
USGS1986

Danburite in evaporites of the Paradox basin, Utah.

Danburite (CaB 2 Si 2 O 8 ) has been found as nodules in Pennsylvanian age marine evaporites of the Paradox basin, Utah. Originally danburite had been known as a high-temperature mineral that occurs at numerous localities in igneous and metamorphic rocks. Since its discovery in water-insoluble residues from a Louisiana salt dome in 1937, it has been found in several other evaporites. The occurrence of danburite and its relation to the host rock in the Paradox basin evaporites indicates that it most likely formed by diagenetic reaction of boron-rich, high-salinity brines with constituents in the anhydrite host rock.

Journal of Sedimentary Petrology↗
USGS1967

Carbon-13-rich diagenetic carbonates in miocene formations of California and Oregon

Carbon unusually rich in C 13 (δC 13 = +5.4 to +19.0 per mil relative to the Peedee belemnite carbonate standard of the University of Chicago) is characteristic of certain diagenetic limestones and dolomites in the Miocene Monterey Shale of California and the Nye Mudstone of Oregon. This heavy carbon may have originated through low-temperature equilibration between CO 3 - - and CO 2 in migrating carbonated waters or between CH 4 and CO 2 in natural gas. Light carbon (δC 13 = -5.6 to -18.2 per mil) derived through nonequilibrium oxidation of organic matter also occurs in the carbonate of Monterey Shale in some localities, but at most places it is much less common than heavy carbon.

California, Oregon↗
USGS1960

First natural occurrence of coesite

Coesite, the high-pressure polymorph of SiO 2 , hitherto known only as a synthetic compound, is identified as an abundant mineral in sheared Coconino sandstone at Meteor Crater, Arizona. This natural occurrence has important bearing on the recognition of meteorite impact craters in quartz-bearing geologic formations.

Arizona↗