Mississippian strata in the Ottawa County, Oklahoma, within the Tri-State Mining District, are a well-known hosts to MVT lead and zinc ore deposits. They are also important to our understanding of the geological story of the southern midcontinent. They include the Osagean–lower Meramecian Boone Group and the Chesterian Hindsville Formation of the Mayes Group. It is important to note that upper Meramecian strata, as well as lowermost Chesterian strata, are absent in Ottawa County, but are present to the south and southwest in Mayes County (lower Mayes Group) and into the subsurface. Northeastern Oklahoma is transected by the Neosho and Spring Rivers, the confluence of which represents the northern end of Grand Lake. Of these two, the Spring Rivers offers access to numerous bluffs in which Mississippian rocks are exposed.
Join us for a virtual float trip down the Spring River in northern Oklahoma. We will explore the Middle Mississippian (Visean; upper Osagean-lower Meramecian) strata of the Boone Group as exposed in roadcuts, quarries, and natural outcroppings across Ottawa County in northeastern Oklahoma.
The segment of Spring River discussed herein runs from just north of the Oklahoma-Kansas state line to its convergence with the Neosho River, a distance of approximately 25 miles. Launching from Baxter Springs campground in Baxter Springs, Kansas and ending at Twin Bridges State Park, this the Spring River makes for a nice one- or two-day geological river trip Other river access is available at Bicentennial Park (east of Quapaw, OK), Devil’s Den (also known as “Lover’s Leap” if you are looking at Google Maps, on the east end of the E 57 Rd bridge), and Moccasin Bend just east of Miami, OK (east end of OK Hwy 10 bridge), all three of which are adjacent to important exposures.
Rocks along the Spring River include most commonly the lower Meramecian Ritchey Formation (a lower cherty lime mudstone-wackestone interval and upper cherty packstone-grainstone interval) and Moccasin Bend Formation (cherty lime mudstone to microbioclastic packstone-grainstone) of the upper Boone Group. An unconformity is evident between the Ritchey and Moccasin Bend (sub-Mocccasin Bend unconformity). From north to south along the Spring River, and then farther south along OK Hwy 10 toward Grove, the Ritchey Formation appears to be truncated by the sub-Moccasin Bend unconformity. The lower Meramecian Quapaw Limestone (cross-bedded grainstone, also of the Boone Group) is not now known to be present in exposures along the river but is accessible in an active quarry south of Quapaw, just west of the river, where conformably overlies the Moccasin Bend Formation and unconformably overlain by the Chesterian Hindsville Formation (silty grain-dominated limestone) of the Mayes Group. Absent within Quapaw County is the lower Mayes Group (upper Meramecian–lowermost Chesterian). Within some exposures the lower Boone Group is accessible, which includes the uppermost Bentonville Formation (cherty limestone, Burlington-Keokuk of others) and the Short Creek Oolite Member. The Short Creek Oolite, representing the top of the lower Boone Group is unconformably overlain by the Ritchey Formation (sub-Ritchey unconformity) in northeastern Oklahoma, where the latter can be seen to truncate the lower Boone Group in a quarry west of Twin Bridges State Park at the southern end of the Spring River. The upper Boone Group, generally absent to the south in the outcrop area and west-southwest into the subsurface, records additional shallowing-upward cycles in addition to those known within the lower Boone Group in Oklahoma, Missouri, and Arkansas. Within the Ritchey Formation, the lower cherty mudstone and upper cherty packstone-grainstone represent one such cycle and together the Moccasin Bend Formation and Quapaw Limestone represent another, ending with a major unconformity separating all Boone Group strata (and older) from younger Mayes Group strata, represented by the Hindsville Formation in this area.