Reports: B8
42533-B8 Eifelian-Givetian Stage Boundary (Middle Devonian) in the Appalachian and Michigan Basins
Four students funded by the grant, and myself, worked on the E-G project in the summer of 2009. Three sections in New York State, two in Michigan, the Prout Limestone in northcentral Ohio, and the Tsakir-section in southern Mongolia, that likely contain the stage boundary interval were measured, described, and collected. Additional work was done on materials collected last year and on four drill cores. The localities visited and collected include:
Delaware Limestone at Lazarus Run, Delaware, Ohio
Prout Limestone at Brogan Farm on Ohio 113, Norwalk, Ohio
Oatka Creek, LeRoy, New York
Govi Altai Formation, near Tsakir, Signjinst, southern Mongolia
Bell and Rogers City formations at Rogers City Quarry, Rogers City, Michigan
Bell Formation at Calcite Quarry, Alpena, Michigan
Hannacroix Creek, East Berne, New York
West Limestone Creek, Marcellus, New York
Hanson Honeoye Falls Quarry, Honeoye Falls, New York
AKZO 9454 – Genesee River Valley, New York
AKZO 9455 – Genesee River Valley, New York
AKZO 9456 – Genesee River Valley, New York
AKZO 9457 – Genesee River Valley, New York
Tentaculitids, conodonts, and magnetic susceptibility samples were collected from the Seneca Member of the Onondaga Limestone, Union Springs Formation, Cherry Valley, East Berne, and Chittenango members of the Oatka Creek Formation in New York State. At Hannacroix Creek the East Berne Member is significantly thicker – eastern portion of the Appalachian Basin – than to the west. A possible ash bed was sampled just below a goniatite-bearing interval below the Dave Elliot Bed. No conodonts or tentaculitids were recovered from strata east of Syracuse, although the goniatite Tornocerous aff. T. mesopleuron indicates Givetian strata. Magnetic susceptibility data were inconclusive for placement of the E-G boundary at Hannacroix and West Limestone creeks. Materials collected from the Rogers City, Bell, Prout, and Govi Altai formations have not yet been processed or analyzed. In New York State the Eifelian-Givetian boundary is likely in the lower East Berne Member, on the contact or just above the Cherry Valley Limestone.
