Highlights d Allele-specific reporters revealed dynamic DNA methylation of Sox2 and miR290 SEs d DNMTs and transcription factor binding regulate methylation dynamics d SE DNA methylation directly regulates transcription in cis d Dynamic DNA methylation is co-regulated with MED1 recruitment and H3K27ac level
The morphology, mineralogy, and stratigraphic and lateral distribution of paleosols in Pennsylvanian (Moscovian-Gzhelian; Atokan-Virgilian) mixed marine and terrestrial coal-bearing strata (i.e., cyclothems) in the Illinois basin (IB) are presented in order to determine the dominant pedogenic processes within a cyclic sedimentary depositional framework. Paleosol morphologies range from weakly developed horizons with evidence of rooting and little to no pedogenic structure, to horizons with well-developed pedogenic slickensides, angular blocky structure, and carbonate nodules and tubules. The majority of paleosols in strata from the basin interior preserve (1) low chroma (gley) colors, (2) identifiable fossil plant organic matter that increases in abundance upward in the profiles toward the interpreted paleo-surface, and (3) calcite, sphaerosiderite, and pyrite cements and nodules. In contrast, paleosols in strata from the northern margin of the basin display high chroma colors and calcite cements and less fossil organic matter, sphaerosiderite, and pyrite cements. These observations indicate that paleosols from the basin interior underwent a multi-phase pedogenic and shallow burial history characterized by an initial better-drained, oxygenated stage under seasonal precipitation, followed by a poorly drained, reducing stage, while paleosols from the northern margin of the basin experienced overall more oxygenated conditions throughout their pedogenic development. X-ray diffraction analysis of the , 2 mm size fraction of paleosol matrix in IB paleosols indicates a mineralogical composition dominated by kaolinite, randomly interstratified (R0) and ordered (R1) illite-smectite (I/S), and subordinate amounts of chlorite. These combined observational and mineralogical datasets indicate that significant changes in paleohydrology were largely responsible for the development of Pennsylvanian soil profiles in the IB.
Distinct lateral and stratigraphic trends in paleosol morphology and clay mineralogy, in conjunction with the stable-isotope composition of sub-millimeter-scale spherulitic siderite (sphaerosiderite) and flint-clay kaolinite in middle-upper Pennsylvanian cyclic coal-bearing strata of the Illinois basin (IB) presented herein provide proxy records of middle-late Pennsylvanian equatorial terrestrial environments. Collectively, these data provide a better understanding of the polygenetic history of ancient soils preserved in cyclic strata and indicate that low-latitude Pennsylvanian IB soil profiles were influenced by a combination of autogenic and allogenic controls.Lateral variations in paleosol morphology from the interior of the basin to the northern margin indicate that soil development was dominantly influenced by autogenic controls, such as differences in local paleohydrology (i.e., groundwater fluctuations) and subsidence rates across the basin. Conversely, allogenic controls (i.e., glacioeustasy and climate) are interpreted to be principally responsible for the preservation of features in gleyed Protosols, gleyed Vertisols, and gleyed calcic Vertisols that occur in the interior of the IB. These paleosols are characterized by a polygenetic development history that includes (1) an initial period of soil formation in well-drained environments with seasonal wetting and drying of the profile, followed by (2) a subsequent period of waterlogging and development of reducing conditions. Paleosols that lack evidence for extensive periods of waterlogging are restricted, with the exception of two examples, to the northern margin of the basin, and they become abundant in the stratigraphic record near the middle-upper Pennsylvanian boundary (uppermost Desmoinesian). The stratigraphic distribution of these paleosols, in conjunction with a decrease in the relative abundance of kaolinite in the , 2 mm size fraction of IB paleosols near the Desmoinesian-Missourian (D-M) boundary, is interpreted to reflect a shift in the overall low-latitude regional climate to drier conditions. The stable-isotope compositions of sphaerosiderite and flint-clay kaolinite in middle-upper Pennsylvanian strata of the IB provide an additional proxy record of past equatorial terrestrial environments and are used to constrain the magnitude of paleoclimate change across the D-M (, Moscovian-Kasimovian) boundary. Sphaerosiderite d 18 O V-PDB and d 13 C V-PDB values range from 23.6% to 20.5% and 212.8% to 23.2%, respectively. In particular, sphaerosiderite d 18 O values from the B horizons of paleosols display an approximate 21.5% shift across the D-M boundary. This stratigraphically short isotopic shift occurs across the D-M boundary, on the order of one cyclothem (, 400 kyr), and is followed by a subsequent shift on the order of one cyclothem, back to more positive siderite d 18 O values. The average d 18 O V-SMOW and dD V-SMOW values of kaolinite isolated from the , 0.2 mm size fraction of a latest Desmoinesian flint-clay breccia are +21.0% and 246.5...
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