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Figure 3. Cross section A–A′ showing correlation of Bakken lithostratigraphic units shown in Figure 2. Cross
section location in Figure 1. GR—gamma ray; MFS—maximum flooding surface.
Figure 4. Cross section B–B′ shows lithostratigraphic-biostratigraphic-chemostratigraphic correlations for the Lower Member of the
Bakken Formation for two seaward wells (from Hogancamp and Pocknall, 2018, fig. 5), and gamma-ray correlations for landward wells.
Cross section location in Figure 1. API—American Petroleum Institute.
pyritic (7%), low-calcite (1%), silty shale. extending progressively farther landward. facies (MMBbur), and an upper laminated
Cross section B–B′ (Fig. 4) shows a regional The Middle Member A (MMA) lithostrati- siltstone facies (MMBlam). The Middle
north-south correlation of the LB1, LB2, graphic unit consists of silty, burrowed, Member C (MMC) lithostratigraphic unit is
and LB3 subunits within the shale (see bio- argillaceous limestone. The Middle Member defined by a low gamma-ray response (Fig.
stratigraphy below). This illustrates land- B (MMB) lithostratigraphic unit consists of 5) that represents the lowest clay content
ward, intra-shale onlap with younger units two facies: a lower bioturbated siltstone (4%) within the Bakken Formation. The
6 GSA TODAY | July 2022
