02534nas a2200205 4500008004100000245015300041210006900194260003700263300001000300520179500310653002202105653002202127653002002149653001802169653002002187100002502207700001702232700002202249856005702271 2007 eng d00aBasinwide Stratigraphic Synthesis and Sequence Stratigraphy, Upper Pragian, Emsian and Eifelian Stages (Lower to Middle Devonian), Appalachian Basin0 aBasinwide Stratigraphic Synthesis and Sequence Stratigraphy Uppe bThe Geological Society of London a39-813 a

The late Eifelian–earliest Givetian interval (Middle Devonian) represents a time of significant faunal turnover in the eastern Laurentia and globally. A synthesis of biostratigraphic, K-bentonite and sequence stratigraphic data indicates that physical and biotic events in the Appalachian foreland basin sections in New York are coeval with the predominantly carbonate platform sections of southern Ontario and Ohio. The upper Eifelian (australis to ensensis conodont zones) Marcellus Subgroup in New York comprises two large-scale (3rd-order) composite depositional sequences dominated by black shale, which are here assigned to the Union Springs and Oatka Creek Formations. The succession includes portions of three distinctive benthic faunas or ecological–evolutionary sub-units (EESUs): ‘Onondaga’, ‘Stony Hollow’ and ‘Hamilton’. In the northern Appalachian Basin in New York, the boundaries of these bioevents show evidence of abrupt, widespread extinctions, immigration and ecological restructuring. In the Niagara Peninsula of Ontario and from central to northern Ohio, the same sequence stratigraphic pattern and bioevents are recognized in coeval, carbonate-dominated facies.

The correlations underscore a relatively simple pattern of two major sequences and four subsequences that can be recognized throughout much of eastern Laurentia. Moreover, the biotic changes appear to be synchronous across the foreland basin and adjacent cratonic platform. However, the degree of change differs substantially, being less pronounced in carbonatedominated mid-continent sections. Finally, we make the case that the two major faunal changes align with regional sequence stratigraphic patterns as well as with the global Kačák bioevents.

10aearliest Givetian10aeastern Laurentia10afaunal turnover10alate Eifelian10aMiddle Devonian1 aVer Straeten, C., A.1 aBecker, R.T.1 aKirchgasser, W.T. uhttp://sp.lyellcollection.org/content/278/1/83.short