Abstract
Abstract Drill core is critical for robust and high-resolution reconstructions of Earth’s climate record, as well demonstrated from both marine successions and modern long-lived lake systems. Deep-time climate reconstructions increasingly require core-based data, but some facies, notably red beds and evaporites, have garnered less attention for both paleoclimatic and geochronologic analyses. Here, we highlight studies from the Rebecca K. Bounds (RKB) core, a nearly continuous, >1.6 km drill core extending from the Cretaceous to the Mississippian, recovered from the US Midcontinent by Amoco Production Company in 1988, and serendipitously made available for academic research. Recent research conducted on this core illustrates the potential to recover high-resolution data for geochronologic and climatic reconstructions from both the fine-grained red bed strata, which largely represent paleo-loess deposits, and associated evaporite strata. In this case, availability of core was instrumental for (1) accessing a continuous vertical section that establishes unambiguous superposition key to both magnetostratigraphic and paleoclimatic analyses, and (2) providing pristine sample material from friable, soluble, and/or lithofacies and mineralogical species otherwise poorly preserved in surface exposures. The potential for high-resolution paleoclimatic reconstruction from coring of deep-time loess strata in particular remains severely underutilized.
Highlights
Drill core is well recognized as a key data set for reconstructing climate records
The core was drilled as an experimental project, primarily to test the capabilities of Amoco’s () newly developed “SHADS” (Slim-Hole Advanced Drilling System) rig (Walker and Millhein 1989), and secondarily to buttress biostratigraphic work on composite standards for the Paleozoic and Mesozoic
Several publications have focused on the Mesozoic strata of the Rebecca K. Bounds No 1 (RKB) core (e.g., Arthur 1993; Dean et al 1995; Dean and Arthur 1998)
Summary
Drill core is well recognized as a key data set for reconstructing climate records. Drilling marine sediments has been long exploited to clarify climate dynamics and atmospheric-oceanic linkages, especially for the Neogene, but extending even to the Cretaceous (e.g., IODP 2008). Sedimentary structures and primary fluid inclusions in Cenozoic and Permian bedded halite can represent arid climate floodingevaporation-desiccation cycles and air temperature proxies, respectively (Benison and Goldstein 1999; Lowenstein et al 1999; Zambito and Benison 2013) Paleoclimate reconstructions from such strata, are dependent upon obtaining cores drilled using methods suitable for extracting intact evaporites and (commonly friable) finegrained red beds. Lithofacies in the Midcontinent Permian range from red beds interbedded with marine limestone low, to entirely continental red beds and evaporites high in the section (McKee and Oriel 1967) This transition reflects a well-documented eustatic and climatic shift driven by (1) the evolution from the Permo-Carboniferous icehouse climate to full greenhouse conditions in the Permo-Triassic (Frakes 1979), with attendant high-frequency glacioeustasy detectable predominately low in the section (e.g., Heckel 2008) and (2) the gradual emergence of the Pangaean supercontinent, as relative sea level reached its Phanerozoic minimum near the end of the Permian (Ross and Ross 1988, 1994, 1995). Detailed study of environments and paleoclimate of the Midcontinent Permian, A
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