DISTRIBUTION PATTERN OF RARE EARTH ELEMENTS IN HARMON COAL BED NORTH DAKOTA

In recent years, rare earth elements (REE) have become recognized as crucial materials for a wide range of consumer goods, energy system components and military defense applications. Due to reliance on imports of REE, the United States has been funding research to investigate promising sources of domestic REE. Coal and coal byproducts have been identified as one of these promising resources. In this study, the REE in a stratigraphic section of the Harmon lignite coal bed in North Dakota were determined through Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and the distribution pattern studied. The total amount of REE in samples ranged from 29.01 to 262.54mg/g on a dry whole coal basis, with highest concentrations near the upper margins of the coal seam and below a major clay parting. The chondrite normalized distribution patterns are uniform and characterized by negative Eu anomaly with mean value of 0.17. Three enrichment types (L-type, M-type, and H-type) were identified using the Upper Continental Crust (UCC) normalization pattern.The ratio of heavy rare earth element (HREE) to light rare earth element (LREE) is 0.49. This paper will use these data to examine REE accumulation mechanisms and depositional environment.