TY - JOUR
T1 - Distal orogenic effects on peripheral bulge sedimentation
T2 - Middle and Upper Ordovician of the Nashville Dome
AU - Holland, Steven M.
AU - Patzkowsky, Mark E.
PY - 1997/3
Y1 - 1997/3
N2 - A major switch in depositional style in the Ordovician carbonates of the Nashville Dome corresponds closely with the onset of the late Middle Ordovician Taconic orogeny. This time marks a shift from tropical-type to temperate-type carbonates, the initiation of widespread major phosphate deposition, the introduction of large amounts of terrigenous silt and clay, the occurrence of widespread seismically induced soft-sediment deformation, and a change from a low-energy flat-topped carbonate shelf to a high-energy doubly dipping carbonate ramp. Soft-sediment deformation and the introduction of siliciclastics are direct effects of the Taconic orogeny; the switch from tropical-type to temperate-type carbonates, the initiation of phosphate deposition, and the switch in carbonate ramp are largely oceanographic effects triggered by the orogeny. In particular, phosphate deposition and the switch to temperate-type limestones appears to have been driven by upwelling along the eastern side of the Nashville Dome within the newly deepened Taconic foreland basin. A fourfold decrease in the rate of relative sea-level rise occurred on the Nashville Dome nearly 3 m.y. following the onset of thrusting and foreland basin initiation. Subsidence rates were constant before and after this decrease, and no evidence of a change in subsidence rates is seen to coincide with the onset of thrusting. The slowing of subsidence may reflect viscoelastic uplift of the Nashville Dome, but the abrupt change from one constant subsidence rate to another is not predicted by existing foreland basin models.
AB - A major switch in depositional style in the Ordovician carbonates of the Nashville Dome corresponds closely with the onset of the late Middle Ordovician Taconic orogeny. This time marks a shift from tropical-type to temperate-type carbonates, the initiation of widespread major phosphate deposition, the introduction of large amounts of terrigenous silt and clay, the occurrence of widespread seismically induced soft-sediment deformation, and a change from a low-energy flat-topped carbonate shelf to a high-energy doubly dipping carbonate ramp. Soft-sediment deformation and the introduction of siliciclastics are direct effects of the Taconic orogeny; the switch from tropical-type to temperate-type carbonates, the initiation of phosphate deposition, and the switch in carbonate ramp are largely oceanographic effects triggered by the orogeny. In particular, phosphate deposition and the switch to temperate-type limestones appears to have been driven by upwelling along the eastern side of the Nashville Dome within the newly deepened Taconic foreland basin. A fourfold decrease in the rate of relative sea-level rise occurred on the Nashville Dome nearly 3 m.y. following the onset of thrusting and foreland basin initiation. Subsidence rates were constant before and after this decrease, and no evidence of a change in subsidence rates is seen to coincide with the onset of thrusting. The slowing of subsidence may reflect viscoelastic uplift of the Nashville Dome, but the abrupt change from one constant subsidence rate to another is not predicted by existing foreland basin models.
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U2 - 10.1306/D4268545-2B26-11D7-8648000102C1865D
DO - 10.1306/D4268545-2B26-11D7-8648000102C1865D
M3 - Article
AN - SCOPUS:0030854408
SN - 1527-1404
VL - 67
SP - 250
EP - 263
JO - Journal of Sedimentary Research
JF - Journal of Sedimentary Research
IS - 2
ER -