A review of the ocean drilling Hole 504B research： From oceanic crust structure to the frontiers of earth system science

Abstract:

The ocean drilling Hole 504B is a milestone in deep-sea scientific drilling. After more than 40 years and nine expeditions， it has reached a cumulative drilling depth of 2111m， and for the first time， it has systematically revealed the complete sequence of the upper oceanic crust in the Costa Rica Rift of the eastern Pacific Ocean （sedimentary layer-pillow basalt-transition zone-sheeted dyke complex）. Through logging technology and the CORK in-situ monitoring device， the research has clarified the “shallow convection-deep supply” mechanism of the oceanic crust hydrothermal circulation， and discovered that there are chemolithoautotrophic microbial communities in the micro-fissures of the sheeted dyke section， with H? as the energy source. Its achievements have verified the core framework of the Penrose oceanic crust model， quantified the contribution of the hydrothermal system to the global carbon cycle （annual input of inorganic carbon accounts for 15% of the river input）， and provided key analogies for the exploration of ancient hydrothermal activities on Mars and the subsurface ocean of Europa. Despite controversies such as the structural differences of oceanic crust with different spreading rates， the 504B borehole has promoted the paradigm shift in the study of deep Earth processes through an interdisciplinary approach， and its technical experience （such as high-temperature logging and data sharing platforms） has laid the foundation for deep-sea exploration and the study of extraterrestrial life.