The first magnetotelluric (MT) analysis of the Ouachita Mountains region is
presented. Magnetotelluric data acquired at 19 sites along a 60-km profile
in southeastern Oklahoma were used to image the western extension of the O
uachita Mountains and to determine the poorly known subsurface interaction
between the Pennsylvanian Tishomingo-Belton uplift and the subsurface exten
sion of the exposed western Ouachita Mountains. Drill-hole data, geologic m
apping, seismic reflection profiles, and 1-D and 2-D MT-derived models indi
cate that lying beneath the low-resistivity Gulf Coastal Plain sediments ar
e 2-3 km of deep-water lower Pennsylvanian (Jackfork Group) sediments and 6
-8 km of Ouachita facies Lithologies, mainly consisting of the Stanley Grou
p. Beneath the profile's northern section are 2-4 km of Atoka Formation sed
iments. probably deposited within the Arkoma basin. that underlie thrusted
zones of the Stanley Group. The most unique feature is a high-resistivity z
one beneath stations 7-9, interpreted to be Precambrian/Cambrian granite si
milar to that exposed in the Tishomingo-Belton uplift. A deep (5-6 km) low-
resistivity zone that may represent the northern border of the subsurface e
xtension of the Broken Bow uplift is located along the Texas/Oklahoma borde
r; however, this zone is not required by the MT data.