Geoscience Reference
In-Depth Information
(a)
Figure 7.11 (a) Reelfoot Rift and its outboard faults (from Van Arsdale and Cupples,
2013
)
. Right-
lateral simple shear is occurring along the N45°E basement faults driven by the regional horizontal
maximum compressive stress (red arrows). The resulting strain field has caused north-striking com-
pressional uplifts bound by black fault lines (e.g., Joiner ridge) and the late Pliocene to perhaps
Holocene west-striking normal faults with barbs on the down-dropped side. CG, Commerce geo-
physical lineament/fault; WM, northwestern Reelfoot Rift margin; AF, Axial fault (Cottonwood
Grove fault); EM, southeastern Reelfoot Rift margin; BC, Big Creek/Ellendale fault; CU, Charleston
uplift; RFN, Reelfoot North fault/Lake County uplift; NMN, NewMadrid North fault; BA, Blytheville
arch; JR, Joiner ridge; MS, Meeman-Shelby fault zone; LR, Little Rock, Arkansas; C, Cairo, Illinois;
NM, New Madrid, Missouri; M, Memphis, Tennessee. For color version, see Plates section.
strongly suggests that the Reelfoot Rift pillow was either intruded or reactivated during
A fourth possible contributing factor for the contemporary faulting may be that the
Reelfoot Rift faults have been intermittently active since the mid Cretaceous. When the
central Mississippi River valley passed over the Bermuda hotspot, the Reelfoot Rift was
heated and uplifted 3 km as part of the Mississippi Embayment arch (Cox and Van Arsdale,
sequent Late Cretaceous cooling subsidence of the Mississippi Embayment that occurred
after passing off the hotspot continued at least through the Paleocene, which may have kept
