Sedimentary Elemental and Mineralogical Analysis of Deep-Sea Mining Influence in the Clarion-Clipperton Zone Using X-ray Fluorescence and Diffraction Methods

With the anticipated expansion of the deep-sea mining industry, it has become increasingly important to develop robust methodologies for assessing potential geochemical impacts on deep-sea environments. To address this need, multi-core sediment samples were collected within the NORI-D contract area of the Clarion-Clipperton Fracture Zone (CCZ) before and after The Metals Company’s nodule mining test in October 2022. Sampling campaigns were conducted to establish a baseline (August–September 2022), and assess benthic collector plume distribution one month post-collection (November–December 2022), and one year post-collection (November–December 2023). This ongoing study aims to refine and apply analytical techniques, including X-ray fluorescence (XRF) for the elemental composition of sediment, X-ray diffraction (XRD) for mineralogy, and complementary chemical digestion methods, to identify sediment plume redistribution and other geochemical alterations resulting from nodule extraction. This study examines sediment cores from the collector test field from within the direct collector track footprint sampled before track formation (prior to test mining), approximately four weeks after test mining, and one year later to evaluate visual, elemental, and mineralogical alterations. The data generated through this research contributes to a holistic understanding of the influence of deep-sea mining on the sedimentological and geochemical makeup of the seafloor. This, in turn, is key to interpreting biological responses to mining related geochemical changes over time, thus informing impact assessments and supporting best-practice management strategies for deep-sea resources.