Spatial variation of micrometeorite abundance in global ocean

Abstract

Annually, Earth accumulates ∼40,000 tons of cosmic dust, with ∼4000–6000 tons reaching the surface as micrometeorites (MMs). This study analyzes ∼3 tons of wet sediments and ∼5000 MMs from the Central Indian Ocean Basin, using a machine learning algorithm based on terrestrial sedimentation rate (TSR) and MM abundance to identify optimal collection regions. Deep-sea sediments (TSR <0.01 cm/kyr) contain ∼50 MM/kg of dry sediments, yet remain largely unexplored. Moderately deep-sea sediments (0.01 < TSR <0.1 cm/kyr), like those in this study, average ∼15 MM/kg, while shallow-sea sediments yield far fewer. Modelling indicates that ocean regions between 45° N and 45° S latitude are ideal for MM collection. The eastern Pacific Ocean (10-40° N and 10-30° S) and the Central Indian Ocean (0-45° S) are particularly suitable. Apart from deep-sea collection, ancient rocks deposited in calm environments with low TSR (e.g. shale, claystone, mudstone, chert, and limestone) are promising for collecting fossil MMs. Overall, this research enhances micrometeorite collection strategies, enabling more accurate flux estimation and providing a foundation for researchers to effectively target specific ocean areas and ancient rock formations, thereby facilitating investigations into extraterrestrial activities and their impacts on Earth's processes.