TY - GEN
T1 - Coordination of depositional sequences and Delta (super 13) C excursions in the Silurian strata of northeastern Illinois
AU - Mikulic, Donald G.
AU - Kluessendorf, Joanne
AU - McLaughlin, Patrick
N1 - Conference Proceedings
Geological Society of America, 2010 annual meeting, Denver, CO, USA, United States, Oct. 31-Nov. 3, 2010
PY - 2010
Y1 - 2010
N2 - Extensive litho- and biostratigraphic study of Silurian dolomitic strata in the Chicago region are integrated with ∂>13) C values from a core at Thornton Reef. Previously, four glacio-eustatic depositional sequences were recognized in the Silurian of this area. Sequence boundaries are developed at intensively burrowed unconformable surfaces. Each sequence begins with transgressive argillaceous strata that grade up into clean highstand carbonates. A pentameriid brachiopod epibole characterizes the upper highstand, succeeded by a series of grainstones with localized ooids. Sequence A (early Rhuddanian) unconformably overlies Ordovician strata. Sequence B (Aeronian) has a less argillaceous transgressive stage than other sequences. Sequence C (late Telychian-early Wenlock), distinguished by reddish argillaceous sediments and abundant diverse conodonts, is the most notable sequence in Silurian strata of the central U. S., and was previously correlated with the Snipklint Primo episode. In the youngest Sequence D (Homerian-Gorstian), moderately argillaceous sediments overlie a pronounced unconformity. No younger Silurian rocks occur in this area. Whole rock ∂>13) C 13) C excursions in the Silurian.
AB - Extensive litho- and biostratigraphic study of Silurian dolomitic strata in the Chicago region are integrated with ∂>13) C values from a core at Thornton Reef. Previously, four glacio-eustatic depositional sequences were recognized in the Silurian of this area. Sequence boundaries are developed at intensively burrowed unconformable surfaces. Each sequence begins with transgressive argillaceous strata that grade up into clean highstand carbonates. A pentameriid brachiopod epibole characterizes the upper highstand, succeeded by a series of grainstones with localized ooids. Sequence A (early Rhuddanian) unconformably overlies Ordovician strata. Sequence B (Aeronian) has a less argillaceous transgressive stage than other sequences. Sequence C (late Telychian-early Wenlock), distinguished by reddish argillaceous sediments and abundant diverse conodonts, is the most notable sequence in Silurian strata of the central U. S., and was previously correlated with the Snipklint Primo episode. In the youngest Sequence D (Homerian-Gorstian), moderately argillaceous sediments overlie a pronounced unconformity. No younger Silurian rocks occur in this area. Whole rock ∂>13) C 13) C excursions in the Silurian.
KW - ISGS
UR - https://gsa.confex.com/gsa/2010AM/finalprogram/abstract_181789.htm
M3 - Conference contribution
SN - 0016-7592
VL - 42
SP - 468
BT - Abstracts with Programs - Geological Society of America
PB - Geological Society of America (GSA), Boulder, CO, United States (USA)
ER -