Integration of macrofossil biostratigraphy and magnetostratigraphy for the Pacific Coast Upper Cretaceous (Campanian-Maastrichtian) of North America and implications for correlation with the Western Interior and Tethys

Abstract

New biostratigraphic data obtained from measured stratigraphic sections of Santonian through Maastrichtian age located along the west coast of North America necessitate changes to the currently accepted chronostratigraphic framework for this region of the North Pacifi c biotic province. We recognize and/or defi ne 12 molluscan zones over this interval of the Upper Cretaceous and propose revisions to the currently accepted integration of ammonite zones with global Upper Cretaceous magnetochrons. Our fi ndings demonstrate that there was signifi cantly more faunal interchange between the North American Pacifi c Coast and both the Western Interior and Gulf Coast regions of North America during the Late Cretaceous than has previously been recognized, and because of this, novel and direct biostratigraphic correlations can be made. These new faunal correla tions are augmented with the magneto stratigraphic record from Pacifi c Coast localities to arrive at better interregional correlation for the Upper Cretaceous globally. The new integration of the global polarity time scale with the local, west coast ammonite zonation now allows better correlation between sections both within the North Pacifi c province (but geographically far from our study areas) as well as to sections outside of the province itself. However, we note here that previous correlations between biostratigraphy and the top and bottom of magnetochron 33r in west coast North American sections appear to have been in error due to unrecognized, modern-day normal-fi eld overprint of originally reversed polarity in Upper Cretaceous sections. We reinterpret the position of this chron based on this new information.

Early diverging asterids of the Late Cretaceous:Suciacarpa starriigen. et sp. nov. and the initial radiation of Cornales

“…The depositional setting of the Sucia Islands localities is interpreted as a shallow marine environment (Ward et al 2012). The permineralized fossil plant material from these sources is preserved in calciumcarbonate concretions alongside ammonites, terrestrial gastropods, inoceramid bivalves, and a theropod femur (Ward 1978;Roth 2000;Ward et al 2012;Peecook and Sidor 2015).…”

“…The permineralized fossil plant material from these sources is preserved in calciumcarbonate concretions alongside ammonites, terrestrial gastropods, inoceramid bivalves, and a theropod femur (Ward 1978;Roth 2000;Ward et al 2012;Peecook and Sidor 2015). Combined biostratigraphy, magnetostratigraphy, and preliminary strontium isotopic data were used to infer a lower-middle Campanian (ϳ80 Ma) date for the Sucia and Little Sucia Island section of the Cedar District Formation (Ward et al 2012).…”

Magnetostratigraphy of the Campanian/Maastrichtian boundary succession from the Middle Vistula River section, central Poland

“…1). Struc tur ally, the area of the Mid dle Vistula val ley belongs to the south ern wing of the Bor der Synclinorium, one of the main geo log i cal struc ture of ex tra-Carpathian Po land, trending NW-SE through the whole coun try (Po¿aryski, 1974;Kutek, 2001;¯elaŸniewicz et al, 2011). Con se quently, the observed strata gently dip (5 to 10°) homoclinally to the NE (Po¿aryski, 1948).…”

“…Due to endemism/pro vin cial ism (e.g., bel em nites, ammonites) and diachroneity (e.g., ammonites, planktic foraminifera) of a num ber of biostratigraphic mark ers across the Campanian/Maastrichtian bound ary (see e.g., Bur nett, 1998;Christensen et al, 2000;Howe et al, 2003;Mutterlose et al, 2005;Ward et al, 2012;Peryt and Dubicka, 2015), there are prob lems with sim ple long-dis tance bio-cor re la tion within this in ter val. The ap pli ca tion of the o ret i cally isochronous and po ten tially very ef fec tive meth ods, in de pend ent of avail able biostratigraphies, is thus of im por tance.…”

“…The re corded mag netic sig nal in the Tercis sec tion does not range to the base of the Maastrichtian (see Odin and Lamaurelle, 2001; also Voigt et al, 2012: fig 3). This makes the Mid dle Vistula an im por tant ref er ence point to other sec tions, with good/ex cel lent magnetostratigraphic scale, how ever, with lim ited biostratigraphic con trol (e.g., the Gubbio sec tions; Ar thur and Fischer, 1977;Lowrie and Alvarez, 1981;Coccioni and Premoli Silva, 2015) or to those quite re mote biogeographically (such as the Red Bird sec tion, US West ern In te rior; see Gill and Cobban, 1966;Hicks and Obradovich, 1995 and lit er a ture therein; or the east ern North Pa cific, see Ward et al, 2012).…”