Beekmantown Group, Lower Part

(Clarke and Schuchert, 1899) - Very thin to thick-bedded, interbedded dolomite and minor limestone. Upper beds are light-olive-gray to dark-gray, fine- to medium-grained, thin- to thick-bedded dolomite. Middle part is olivegray-, light-brown-, or dark-yellowish-orange- weathering, dark-gray, aphanitic to fine-grained, laminated to medium-bedded dolomite and light-gray to light-bluish-gray-weathering, medium-dark- to dark-gray, fine-grained, thin- to medium-bedded limestone, that is characterized by mottling with reticulate dolomite and light-olive-gray to grayish-orange, dolomitic shale laminae surrounding limestone lenses. Limestone grades laterally and down section into medium- gray, fine-grained dolomite. Lower beds consist of medium-light- to dark-gray, aphanitic to coarse-grained, laminated to medium-bedded, locally slightly fetid dolomite having thin black chert beds, quartz-sand laminae, and oolites. Lenses of light-gray, very coarse to coarse-grained dolomite and floating quartz sand grains and quartz-sand stringers at base of sequence. Lower contact placed at top of distinctive medium-gray quartzite. Contains conodonts of Cordylodus proavus to Rossodus manitouensis zones of North American Midcontinent province as used by Sweet and Bergstrom (1986). Unit Obl forms Stonehenge Formation of Drake and Lyttle (1985) and Drake and others (1985), upper and middle beds are included in Epler Formation, and lower beds are in Rickenbach Dolomite of Markewicz and Dalton (1977). Unit is about 183 m (600 ft) thick.
State New Jersey
Name Beekmantown Group, Lower Part
Geologic age Lower Ordovician
Lithologic constituents
Major
Sedimentary > Carbonate > Dolostone (Bed)Very thin to thick-bedded, interbedded dolomite and minor limestone. Upper beds are light-olive-gray to dark-gray, fine- to medium-grained, thin- to thick-bedded dolomite. Middle part is olivegray-, light-brown-, or dark-yellowish-orange- weathering, dark-gray, aphanitic to fine-grained, laminated to medium-bedded dolomite. Lower beds consist of medium-light- to dark-gray, aphanitic to coarse-grained, laminated to medium-bedded, locally slightly fetid dolomite having thin black chert beds, quartz-sand laminae, and oolites.
Minor
Sedimentary > Carbonate > Limestone (Bed)light-gray to light-bluish-gray-weathering, medium-dark- to dark-gray, fine-grained, thin- to medium-bedded limestone.
Incidental
Sedimentary > Chemical > Chert (Bed)locally slightly fetid dolomite having thin black chert beds, quartz-sand laminae, and oolites.
Comments Kittatinny Supergroup (Lower Ordovician and Cambrian) (Drake and Lyttle, 1980)
References

Dalton, R.F., Herman, G.C., Monteverde, D.H., Pristas, R.S., Sugarman, P.J., and Volkert, R.A., 1999, New Jersey Department of Environmental Protection, Bedrock Geology and Topographic Base Maps of New Jersey: New Jersey Geological Survey CD Series CD 00-1; ARC/INFO (v. 7.1), scale 1:100,000.

Drake, Avery A. Jr.,Volkert, Richard, A., Monteverde, Donald H., Herman, Gregory C., Houghton,Hugh F., Parker, Ronald A., and Dalton, Richard F., 1996, Bedrock Geologic Map of Northern New Jersey: U.S. Geological Survey Miscellanenous Investigations Map I-2540-A, 4 cross sections, 2 sheets, size 56x40; 58x41, scale 1:100.000.

https://pubs.er.usgs.gov/publication/i2540A

Clarke, J.M., and Schuchert, Charles, 1899, The nomenclature of the New York series of geological formations: Science, new series, v. 10, p. 874-878.

Drake, A.A., Jr., and Lyttle, P.T., 1980, Alleghanian thrust faults in the Kittatinny Valley, New Jersey, in Manspeizer, Warren, ed., Field studies of New Jersey geology and guide to field trips; 52nd annual meeting of the New York State Geological Association: Newark, N.J., Rutgers University Press, p. 92-114.

Sweet, W.C., and Bergstrom, S.M., 1986, Conodonts and biostratigraphic correlation: Annual Review of Earth and Planetary Science, v. 14, p. 85-112.

Drake, A.A., Jr., and Lyttle, P.T., 1985, Geologic map of the Blairstown quadrangle, Warren County, New Jersey: U.S. Geological Survey Geologic Quadrangle Map GQ-1585, scale 1:24,000.

https://pubs.er.usgs.gov/publication/gq1585

Drake, A.A., Jr., Kastelic, R.L., Jr., and Lyttle, P.T., 1985, Geologic map of the eastern parts of the Belvidere and Portland Quadrangles, Warren County, New Jersey: U.S. Geological Survey Miscellaneous Investigations Series Map I-1530, scale 1:24,000.

https://pubs.er.usgs.gov/publication/i1530

Markewicz, F.J., and Dalton, Richard, 1977, Stratigraphy and applied geology of the lower Paleozoic carbonates in northwestern New Jersey, in Markewicz, F.J., Dalton, Richard, Spink, Walter, Metsger, Robert, and Lucey, Carol, Stratigraphy and applied geology of the lower Paleozoic carbonates in northwestern New Jersey, 42nd annual field conference of Pennsylvania Geologists, guidebook: Harrisburg, Pa., p. 1-37.

NGMDB product
Counties Hunterdon - Morris - Sussex - Warren