Florence Bascom Geoscience Center

Publications

Filter Total Items: 553
Publication Thumbnail
Year Published: 1994

The Pennsylvanian Fire Clay tonstein of the Appalachian basin—Its distribution, biostratigraphy, and mineralogy

The Middle Pennsylvanian Fire Clay tonstein, mostly kaolinite and minor accessory minerals, is an altered and lithified volcanic ash preserved as a thin, isochronous layer associated with the Fire Clay coal bed. Seven samples of the tonstein, taken along a 300-km traverse of the central Appalachian basin, contain cogenetic phenocrysts and trapped...

Rice, C.L.; Belkin, Harvey E.; Henry, T.W.; Zartman, R.E.; Kunk, Michael J.

Publication Thumbnail
Year Published: 1993

A detailed taxonomy of Upper Cretaceous and lower Tertiary Crassatellidae in the Eastern United States: An example of the nature of extinction at the boundary

Current theories on the causes of extinction at the CretaceousTertiary boundary have been based on previously published data; however, few workers have stopped to ask the question, 'How good is the basic data set?' To test the accuracy of the published record, a quantitative and qualitative analysis of the Crassatellidae (Mollusca, Bivalvia) of...

Wingard, G. Lynn
A detailed taxonomy of Upper Cretaceous and lower Tertiary Crassatellidae in the Eastern United States; an example of the nature of extinction at the boundary; 1993; PP; 1535; Wingard, G. Lynn

Publication Thumbnail
Year Published: 1993

The Manson Impact Structure: 40Ar/39Ar age and its distal impact ejecta in the Pierre Shale in southeastern South Dakota

The 40Ar/39Ar ages of a sanidine clast from a melt-matrix breccia of the Manson, Iowa, impact structure (MIS) indicate that the MIS formed 73.8 ± 0.3 million years ago (Ma) and is not coincident with the Cretaceous-Tertiary boundary (64.43 ± 0.05 Ma). The MIS sanidine is 9 million years older than 40Ar/39Ar age spectra of MIS shock-...

Izett, G. A.; Cobban, W.A.; Obradovich, J.; Kunk, Michael J.

Publication Thumbnail
Year Published: 1993

40Ar/39Ar thermochronology and Alleghanian development of the southernmost Appalachian Piedmont, Alabama and southwest Georgia

40Ar/39Ar age spectra of hornblende, muscovite, and microcline, and total fusion ages of biotite from metamorphic rocks of the Inner Piedmont, Pine Mountain, and Uchee belts are reported. Mineral cooling ages from the eastern part of the Inner Piedmont are as follows: hornblende, 320 Ma; muscovite, 296 Ma; biotite, 293 Ma; and microcline (...

Steltenpohl, Mark G.; Kunk, Michael J.

Publication Thumbnail
Year Published: 1993

Exhumation of eclogitized continental basement during Variscan lithospheric delamination and gravitational collapse, Sudety Mountains, Poland

A Variscan,deep-crustal-level (eclogite-facies),continental basement massif in western Poland, the Snieznik complex, was tectonically exhumed. Crustal-penetrating mylonite zones record three main kinematic events: early top-to-the-north-directed thrusting, right-slip transpression-tension, and late top-to-the-south and -east normal faulting....

Steltenpohl, Mark G.; Cymerman, Zbignew; Krogh, E.J.; Kunk, Michael J.

Publication Thumbnail
Year Published: 1993

Dinoflagellates

No abstract available.

Edwards, Lucy E.

Publication Thumbnail
Year Published: 1992

Hydrogeology of thick till deposits in Connecticut

No abstract available.

Melvin, Robert L.; Stone, Byron D.; Stone, J. R.; Trask, N.J.

Publication Thumbnail
Year Published: 1992

Contrasting P‐T‐t paths: Thermochronologic evidence for a Late Paleozoic final assembly of the Avalon Composite Terrane in the New England Appalachians

Strongly contrasting pressure‐temperature‐time paths for the Avalon composite terrane and the structurally overlying Putnam‐Nashoba zone in eastern New England obtained from thermochronologic and thermobarometric data are best explained by a late Paleozoic underthrusting of cover rocks by the Avalon composite terrane. We present new Ar and U‐Pb...

Wintsch, R. P.; Sutter, J. F.; Kunk, Michael J.; Aleinikoff, John N.; Dorais, Michael J.

Publication Thumbnail
Year Published: 1992

Alleghanian development of the Goat Rock fault zone, southernmost Appalachians: Temporal compatibility with the master decollement

The Goat Rock and associated Bartletts Ferry fault zones, which mark the eastern margin of the Pine Mountain Grenville basement massif, are controversial due to the suggestion that they are rare exposed segments of the late Paleozoic southern Appalachian master decollement. The controversy in part stems from reported middle Paleozoic (Acadian)...

Steltenpohl, Mark G.; Goldberg, S.; Hanley, T.B.; Kunk, Michael J.

Publication Thumbnail
Year Published: 1992

Calibration of the latest Eocene-Oligocene geomagnetic polarity time scale using 40 Ar/ 39 Ar dated ignimbrites

A discontinuous record of late Eocene-Oligocene geomagnetic polarity has been determined using high-precision (±<0.15 m.y.) 40Ar/39Ar sanidine dating and a paleomagnetic study of 37-27 Ma ignimbrites in New Mexico, Colorado, and Texas. This record provides age control for several geomagnetic polarity reversals that occurred during three...

McIntosh, W.C.; Geissman, J. W.; Chapin, C.E.; Kunk, Michael J.

Publication Thumbnail
Year Published: 1991

Pliocene paleoclimatic reconstruction using dinoflagellate cysts: Comparison of methods

The application of quantitative and semiquantitative methods to assemblage data from dinoflagellate cysts shows potential for interpreting past environments, both in terms of paleotemperature estimates and in recognizing water masses and circulation patterns. Estimates of winter sea-surface temperature (WSST) were produced by using the...

Edwards, Lucy E.; Mudie, P.J.; de Vernal, A.

Publication Thumbnail
Year Published: 1990

Dinoflagellate-cyst census data from the seabed samples of Wall and others (1977) and Turon (1984)

No abstract available.

Edwards, Lucy E.; Andrle, Victoria A.S.
Dinoflagellate-cyst census data from the seabed samples of Wall and others (1977) and Turon (1984); 1990; OFR; 90-613; Edwards, L. E.; Andrle, Victoria A. S.