Edit a page: Porters Creek Formation

You do not have permission to edit this page, for the following reason:

The action you have requested is limited to users in the group: Users.

For Help in formatting please see the Wiki Help

Categories:
	1:	2:
	3:	4:
	5:	6:
	7:	8:
	9:	10:

Lithostratigraphy
	1:	2:
	3:	4:
	5:	6:
	7:	8:
	9:	10:

Chronostratigraphy
	1:	2:
	3:	4:
	5:	6:
	7:	8:
	9:	10:

Allostratigraphy
	1:	2:
	3:	4:
	5:	6:
	7:	8:
	9:	10:

Hydrostratigraphy
	1:	2:
	3:	4:
	5:	6:
	7:	8:
	9:	10:

Primary source

Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.

Contributing author(s)

H. B. Willman and John C. Frye

Name

Original description

Porters Creek Formation (Safford, 1864, p. 361, 368).

Derivation

Named for exposures on Porters Creek in Hardeman County, Tennessee.

Other names

===History/background=== ==Type section== ===Type location=== ===Type author(s)=== ===Type status=== ==Reference section== ===Reference location=== ===Reference author(s)=== ===Reference status=== ==Stratigraphic relationships== The Porters Creek is overlain unconformably by the Wilcox Formation, which locally cuts deeply into the Porters Creek. ==Extent and thickness== It is present in Alexander and Pulaski Counties in southern Illinois (Lamar, 1928b; Pryor and Ross, 1962) and is well exposed in pits south of Olmsted, Pulaski County (NE SE 27, 15S-1E), in the Ohio River bluffs near U.S. Dam 53, and along the Cache River near Unity. It is 50-150 feet thick, but north of the Cache Valley it is completely truncated by the Mounds Gravel. ==Lithology== The Porters Creek is largely massive, compact, essentially unbedded or weakly bedded, dark gray to nearly black clay that has a blocky fracture. It is gray-tan to white where weathered. Because it does not readily become plastic when wet, it can stand in steeper faces than most clays. It is more than 80 percent montmorillonite. Because the clay has the absorptive and filtering properties of fuller's earth, it has been mined commercially south of Olmsted, Pulaski County. ==Core(s)== ==Photograph(s)== ==Contacts== ==Well log characteristics== ==Fossils== Microfossils (Radiolaria, Hystrichospheridae, and Foraminifera) are abundant, but fish scales, shark teeth, and casts and molds of pelecypods and gastropods are also common. ==Age and correlation== ==Environments of deposition== The Porters Creek is a marine deposit representing an advance of the sea over essentially the entire area of the embayment. ==Economic importance== ==Remarks== ==References== LAMAR, J. E., 1928b, Preliminary report on the fuller's earth deposits of Pulaski County: Illinois State Geological Survey Report of Investigations 15, 31 p.<br> PRYOR, W. A., and C. A. ROSS, 1962, Geology of the Illinois parts of the Cairo, La Center, and Thebes Quadrangles: Illinois State Geological Survey Circular 332, 39 p.<br> SAFFORD, J. M., 1864, On the Cretaceous and superior formations of west Tennessee: American Journal of Science, v. 37, p. 360-372. {{Codes |membercode=1280 |geo_unit=Tpc }}

History/background

Type section

Type location

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

Extent and thickness

Lithology

Core(s)

Photograph(s)

Contacts

Well log characteristics

Fossils

Age and correlation

Environments of deposition

Economic importance

Remarks

Reference(s)

place a <pre><br></pre>at the end of a line to get a line return

Membercode:
Geo_unit:
Geo_image:	Upload file

Summary:

This is a minor edit

Watch this page

Cancel