Hardyston Quartzite Explained

Hardyston Quartzite
Type:	Metamorphic
Period:	Cambrian
Prilithology:	Quartzite
Otherlithology:	Limestone, shale, conglomerate
Namedfor:	Hardyston Township, New Jersey
Namedby:	Wolff & Brooks
Year Ts:	1898
Region:	Pennsylvania, New Jersey
Country:	United States
Unitof:	Leithsville Formation
Underlies:	Kittatinny Supergroup and Leithsville Formation
Overlies:	Wissahickon Formation
Extent:	Appalachian Basin

The Cambrian Hardyston Formation or Hardyston Quartzite is a mapped bedrock unit in Pennsylvania and New Jersey.

It was originally described by Wolff and Brooks in 1898,^[1] where two outcrops in Hardyston Township, Sussex County, New Jersey, were described. They originally named it the Hardistonville quartzite, but the name was later changed by and Weller in 1901 to Hardiston quartzite,^[2] and changed again by the same authors a year later to Hardyston quartzite.^[3]

Description

Richard Dalton described the Hardyston Formation in 1989^[4] as having a varying lithology. It is composed of a vitreous, light pink, steel gray or brown, locally arkosic, fine to coarse-grained, resistant quartzite. Pebble conglomerate is common at the base of the formation. Locally, where the unit is less than 10 ft thick, it is a fine- to medium-grained, gray, pyritic quartzite, grading into a dark-gray dolomitic sandstone.

Stratigraphy

The Hardyston unconformably overlies Precambrian crystalline basement rocks where it was deposited on an irregular surface and fills only the troughs or depressions. It gradationally underlies the Leithsville Formation of the Kittatinny Supergroup.^[4]

The Hardyston occurs in New Jersey only in the highly folded and faulted New Jersey Highlands, northeast of the much younger Mesozoic Newark Basin.^[5]

Miller and Myers extended the formation into Pennsylvania in 1939,^[6] where it underlies the Tomstown Dolomite.

Notable outcrops

• Cushion Peak, Berks County, Pennsylvania - the Hardyston has been thrust faulted over the limestone valley at this site^[7]

Age

Relative age dating places the Hardyston in the Early Cambrian.

Fossil content

Trilobites have been found in the calcareous sandstone beds of the formation.^[2] One genus is Olenellus.^[1]

Notes and References

1. Wolff, J.E., and Brooks, A.H., 1898, The age of the Franklin white limestone of Sussex County, New Jersey, IN Walcott, C.D., Eighteenth annual report of the United States Geological Survey to the Secretary of the Interior, 1896–1897; Part II, Papers chiefly of a theoretical nature: U.S. Geological Survey Annual Report, 18, pt. 2, p. 425-457.
2. Kummel, H.B., and Weller, Stuart, 1901, Paleozoic limestones of the Kittatinny Valley, New Jersey: Geological Society of America Bulletin, v. 12, p. 147-164.
3. Kummel, H.B., and Weller, Stuart, 1902, The rocks of the Green Pond Mountain region: New Jersey Geological Survey Annual Report of the State Geologist, 1901, p. 1-51.
4. Dalton, Richard, 1989, Stratigraphy of the "Kittatinny Limestone", IN Grossman, I.G., ed., Paleozoic geology of the Kittatinny Valley and southwest Highlands area, New Jersey; field guide and proceedings: Geological Association of New Jersey Annual Field Conference, 6th Annual Meeting, October 20–21, 1989, v. 6, p. 59-94. (Table of Contents)
5. Drake, A.A., Jr., Volkert, R.A., Monteverde, D.H., Herman, G.C., Houghton, H.F., Parker, R.A., and Dalton, R.F., 1996. Bedrock geologic map of northern New Jersey. U.S. Geological Survey. Miscellaneous Geologic Investigations Map I-2540-A. Map Scale: 1:100,000.
6. Miller, B.L., and Myers, P.B., 1939, Hardyston formation, IN Miller, B.L., and others, Northampton County, Pennsylvania: Pennsylvania Geological Survey County Report, 4th series, no. 48, p. 206-223.
7. MacLachlan, D. B., Buckwalter, T. V. and McLaughlin, D. B. (1975), Geology and mineral resources of the Sinking Spring 7-minute quadrangle, Berks and Lancaster Counties, Pennsylvania, Pennsylvania Geological Survey, 4th ser., Atlas 177d, 228 p.