期刊论文详细信息
Minerals
Mixed-Layer Illite-Smectite in Pennsylvanian-Aged Paleosols: Assessing Sources of Illitization in the Illinois Basin
NicholasA. Rosenau1  NeilJ. Tabor2  JuliaA. McIntosh2 
[1] Ocean and Coastal Management Branch, Office of Wetlands Oceans and Watersheds, United States Environmental Protection Agency, Washington, DC 20004, USA;Roy M. Huffington Department of Earth Sciences, Southern Methodist University, P.O. Box 750395, Dallas, TX 75275, USA;
关键词: clay mineralogy;    Desmoinesian;    diagenesis;    Missourian;    pedogenesis;    Reichweite Ordering;   
DOI  :  10.3390/min11020108
来源: DOAJ
【 摘 要 】

Mixed-layer illite-smectite (I-S) from a new set of Pennsylvanian-aged Illinois Basin underclays, identified as paleosols, are investigated to assess the impact of (1) regional diagenesis across the basin and (2) the extent to which ancient environments promoted illitization during episodes of soil formation. Interpretations from Reichweite Ordering and Δ° 2θ metrics applied to X-ray diffraction patterns suggest that most I-S in Illinois Basin paleosols are likely the product of burial diagenetic processes and not ancient soil formation processes. Acid leaching from abundant coal units and hydrothermal brines are likely diagenetic mechanisms that may have impacted I-S in Pennsylvanian paleosols. These findings also suggest that shallowly buried basins (<3 km) such as the Illinois Basin may still promote clay mineral alteration through illitization pathways if maximum burial occurred in the deep past and remained within the diagenetic window for extended periods of time. More importantly, since many pedogenic clay minerals may have been geochemically reset during illitization, sources of diagenetic alteration in the Illinois Basin should be better understood if Pennsylvanian paleosol minerals are to be utilized for paleoclimate reconstructions.

【 授权许可】

Unknown   

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