65 D4. Geochemistry (Posters)

Sunday, 22 March 2020
1:30 PM - 5:30 PM
Grand Ballroom E–G

DIABASE AND ASSOCIATED SULFIDES AS POSSIBLE SOURCES OF BORON THAT CONTAMINATES THE GROUNDWATER OF THE NEWARK BASIN, EASTERN USA

Paper number: 65-5
Program: Technical Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

The Newark Basin was formed during the Triassic period and subsequently filled with the Triassic-Jurassic rocks. Diabase intruded these rocks and induced their metamorphism, leading to the formation of hornfels, sulfide ore (pyrite, chalcopyrite) and calcite. The analysis of sulfur isotope in both pyrite and chalcopyrite indicates derivation of sulfur from the magma that generated the diabase. In the studied area, groundwater is contaminated with boron, with concentration exceeding the children health advisory of 2,000 µg/L, set by the U.S. Environmental Protection Agency (USEPA). High levels of boron in the water pose health problems such as the risk of infertility and fetus developmental issues. Given the clustering of elevated occurrences of boron in the studied area, we hypothesize that the diabase and the associated mineralization and hornfels can be possible source of boron that contaminates groundwater. The identification of this source would enable the government to restrict the construction of houses near the diabase intrusions. The present project aims to identify this source by analyzing boron and other trace elements diabase, pyrite, and calcite using the Scanning Electron Microscope (SEM) and the Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The SEM examination of pyrite and calcite and the LA-ICP-MS analytical results of these minerals show an overall low concentration of boron (<10ppm). Hence, these minerals may have contributed, though very minimal, to the contamination of groundwater. Diabase can be considered a possible source of Boron in this area, but further studies are needed to confirm or refute this conclusion.

Geological Society of America Abstracts with Programs. Vol. 52, No. 2

doi: 10.1130/abs/2020SE-344546

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