Spring Lake Coal Member (abandoned)
Nelson, W.J., P.H. Heckel and J.M. Obrad, 2022, Pennsylvanian Subsystem in Illinois: Illinois State Geological Survey, Bulletin (in press).
Peppers (1970, p. 59) introduced the name Spring Lake Coal Member for a unit that lies 11 to 17 ft (3.3 to 5.1 m) below the Herrin Coal along the Vermilion River and its tributaries in LaSalle and Livingston Counties, Illinois.
The name refers to a body of water 1 mi (1.6 km) west of Streator, near which the coal formerly was strip mined (Figure 4-62).
Willman and Payne (1942) described this coal as Unit 43 in their general section. Cady (1948, p. 5) gave it the name “Spring Lake coal bed.” Kosanke et al. (1960) did not mention this unit. Citing Cady (1948) and Peppers (1970), Willman et al. (1975) included the Spring Lake Coal Member in their lexicon.
East bank of the Vermilion River “at greenhouse,” SE¼ SW¼ SW¼ sec. 23, T 31 N, R 3 E, LaSalle County (Figure 4-62).
Willman and Payne (1942, geologic section 20, p. 295) published the section. Peppers (1970, p. 59) named this as the stratotype, shown graphically here (Figure 4-63).
North bank of the Vermilion River east of Klein Bridge, NW¼ SW¼ SW¼ sec. 10, T 31 N, R 3 E, LaSalle County (Figure 4-62).
Willman and Payne (1942, geologic section 19, p. 295; Figure 4-63).
River bluff sections have good potential for long-term exposure.
The coal overlies the Vermilionville Sandstone and occurs a short distance beneath the Herrin Coal and its underclay (Figure 4-68). Above the coal is dark gray to black, thinly laminated, carbonaceous shale. Below is either nonfissile mudstone containing carbonate nodules or laminated shale that grades downward to the Vermilionville Sandstone. In one section, nodular limestone overlies the Spring Lake (Unit 49, column 19 in Figure 4-68).
In this report, the Spring Lake Coal is interpreted to be identical to the Briar Hill Coal Member, which is widely distributed in the southern part of the Illinois Basin.
Extent and thickness
The greatest reported thickness is 2.5 ft (76 cm; Willman and Payne 1942). The known extent is a few square miles (kilometers) along the Vermilion River west and northwest of Streator in LaSalle County, Illinois.
Where the coal is thick, it is bright banded and lacks clastic layers. Near its lateral limits, the coal becomes thin and shaly. The coal may rest directly on sandstone or on carbonaceous shale containing streaks of coal and fossil plants. Overlying the coal is laminated or fissile shale in alternating gray to black layers, containing fossil plants and the invertebrates Leaia and Estheria (Willman and Payne 1942).
Sections by Willman and Payne (1942) and unpublished field notes by L.C. McCabe and G. Land (1938) indicate both contacts are either sharp or gradational into carbonaceous shale having laminae of coal.
Well log characteristics
Peppers (1970) listed fossil spores and discussed their relative abundance.
Age and correlation
Based on palynology, Peppers (1970) interpreted the Spring Lake coal to be younger than the Briar Hill. However, Peppers’ samples came from two cores drilled near Ancona, several miles (kilometers) from outcrops, and neither the Springfield nor the Herrin Coal is present in the cores, casting doubt on the identity of the coal that Peppers analyzed.
Environments of deposition
Jacobson (1985, p. 9) suggested that the coal “probably represents an abandoned channel-fill deposit.” Channel geometry is evident in the diagram from Willman and Payne (1942; Figure 4-68).
The coal was mined on a small scale near Spring Lake.
- Cady, G.H., 1948, Analyses of Illinois coals: Illinois State Geological Survey, Supplement to Bulletin 62, 77 p.
- Jacobson, R.J., 1985, Coal resources of Grundy, La Salle, and Livingston Counties, Illinois: Illinois State Geological Survey, Circular 536, 58 p., 6 pls.
- Kosanke, R.M., J.A. Simon, H.R. Wanless, and H.B. Willman, 1960, Classification of the Pennsylvanian strata of Illinois: Illinois State Geological Survey, Report of Investigations 214, 84 p. and 1 pl.
- Peppers, R.A., 1970, Correlation and palynology of coals in the Carbondale and Spoon Formations (Pennsylvanian) of the northeastern part of the Illinois Basin: Illinois State Geological Survey, Bulletin 93, 173 p.
- Willman, H.B., E. Atherton, T.C. Buschbach, C. Collinson, J.C. Frye, M.E. Hopkins, J.A. Lineback, and J.A. Simon, 1975, Handbook of Illinois stratigraphy: Illinois State Geological Survey, Bulletin 95, 261 p.
- Willman, H.B., and J.N. Payne, 1942, Geology and mineral resources of the Marseilles, Ottawa, and Streator Quadrangles: Illinois State Geological Survey, Bulletin 66, 388 p., 29 pls.
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