The Deep Dust Drilling Project: Earth-System Responses to the Penultimate Icehouse Collapse and Greenhouse Intensification
Revised Full-proposal: ICDP-2022/01
For the funding-period starting 2022-01-15
For the funding-period starting 2022-01-15
The climatic, biotic, and tectonic events of the Permian are amongst the most profound in Earth history. Earth’s penultimate global icehouse peaked in the earliest Permian, collapsed soon thereafter, and transitioned to intense greenhouse conditions by the late Permian, recording Earth’s only example of icehouse termination under conditions of a complex terrestrial biosphere. The Late Paleozoic Icehouse was the longest and most intense glaciation of the Phanerozoic, aided by the lowest CO2 levels of the Phanerozoic—values comparable to preindustrial. Global orogeny leading to Pangaean assembly prevailed, notably along the equatorial Central Pangaean Mountains, and included widespread volcanism. Pangaean assembly perturbed atmospheric circulation, leading to megamonsoonal circulation. Extreme environments and events are well documented in the form of, e.g., voluminous dust deposits, acid saline lakes, extreme continental temperatures, and major extinctions/extirpations—the latter including the largest extinction of Earth history. We seek to constrain paleoclimatic conditions, climate forcings, and biospheric responses through Permian time in a key region of the paleoequatorial zone. Our approach includes temporal scales ranging from sub-millennial to Milankovitch and beyond by acquiring cores in a continental lowland preserving stratigraphically complete records dominated by loess and lacustrine strata, and an adjacent upland. We target locales in the U.S. (Anadarko Basin and adjacent Wichita Uplift, Oklahoma) as globally unique sites, as they capture high-resolution continental Permian facies that span the entire Permian, and yoked paleo-uplands preserving hinterland environments. The target sections include evaporite strata housing inclusions that trap Permian surface- and groundwater, enabling exploration of diurnal surface temperatures, atmospheric compositions and— potentially— remnants of the fossil microbial biosphere— a truly unique aspect of this project. In addition, we plan exploration of the modern deep microbial biosphere in a region known to harbor complex microbial ecosystems from basinal fluid seeps. We propose this as Phase 1 of a two-phase project that will ultimately include coring a complimentary section in eastern equatorial Pangaea (western Europe). All cores will be split, with one portion dedicated to sampling, and the other designated for archival at the US Continental Science Drilling Facility repository. These cores will serve as reference sections for the Permian Earth, valuable for correlation to extant records globally to synergize our understanding of this time period, and available to all following an embargo period.
- Four major objectives relate to the ICDP theme on Environmental Change: Objective I — Paleoclimates/Environments of the end-Carboniferous through Permian— Constraining forcings and mechanistic linkages that controlled major climate events, including the icehouse apogee, collapse, and subsequent development/intensification of megamonsoonal and greenhouse conditions. The driving motivation is learning from our sole example of icehouse collapse on a vegetated planet— to illuminate planetary behavior under deglaciation and increasing pCO2. Objective II— Assessing Impacts of Environmental Changes on the Biosphere—Focusing on the responses of terrestrial life to the major climate shifts archived in the Permian. Objective III— Probing the Extent and Nature of the Microbial Biosphere (Modern Deep and Fossil Surface)— Investigating the limits to life in deep basins, AND in extreme environments of the fossil biosphere— as uniquely preserved in Permian fluid inclusions. Objective IV— Providing Spatial and Temporal Constraints for the Permian World— Transforming our abilities to learn from the Permian Earth System by providing spatial and temporal constraints and world-class reference sections, for this and all future projects on the Permian. Auxiliary science themes include investigating red bed origins, orogenic exhumation rates, and georesources (e.g. geothermal, carbon sequestration) and geohazards (induced seismicity).
Biosphere, Carbon, Carbon Cycle, Equatorial Pangea, Paleoclimate