Physical Sciences and Mathematics Commons^™

Does The Great Valley Group Contain Jurassic Strata? Reevaluation Of The Age And Early Evolution Of A Classic Forearc Basin, Kathleen D. Surpless, Stephan A. Graham, Jacob A. Covault, Joseph L. Wooden

Kathleen D. Surpless

The presence of Cretaceous detrital zircon in Upper Jurassic strata of the Great Valley Group may require revision of the lower Great Valley Group chronostratigraphy, with significant implications for the Late Jurassic–Cretaceous evolution of the continental margin. Samples (n = 7) collected from 100 km along strike in the purported Tithonian strata of the Great Valley Group contain 20 Cretaceous detrital zircon grains, based on sensitive high-resolution ion microprobe age determinations. These results suggest that Great Valley Group deposition was largely Cretaceous, creating a discrepancy between biostratigraphy based on Buchia zones and chronostratigraphy based on radiometric age dates. These …

Recent Discoveries And A Review Of The Ordovician Faunas Of New Zealand, Ian Percival, Roger Cooper, Yong Yi Zhen, J Simes, Anthony Wright

Anthony Wright

Fossiliferous Ordovician rocks are of limited extent in New Zealand, being largely restricted to northwest Nelson and Westland in the northern part of the South Island, with some isolated exposures at the southern extremity of Fiordland (Fig. 1). The known stratigraphic record, though incomplete, covers much of the period, and new information from study and revision of old collections (mostly dating from the 1960s and 1970s) continues to fill in the gaps. These data are critical to a better understanding of New Zealand’s place in the Ordovician world, when it occupied an isolated position facing the palaeo-Pacific Ocean offshore to …

Darriwilian (Middle Ordovician) Conodonts From Thompson Creek, Nelson Province, New Zealand, Yong Yi Zhen, Ian G. Percival, Roger A. Cooper, John E. Simes, Anthony J. Wright

Anthony Wright

A well preserved Middle Ordovician conodont fauna of 24 species has been recovered from seven samples of a small limestone lens exposed in Thompson Creek, northwest of Nelson, on the South Island of New Zealand. The presence of Histiodella holodentata, Baltoniodus? sp., Paroistodus originalis, P. horridus, Periodon macrodentatus, Protopanderodus sp. cf. P. varicostatus, Costiconus ethingtoni and Venoistodus balticus in the fauna indicates a Darriwilian (late Da2 to mid Da3) age. The occurrence of Ansella jemtlandica, Baltoniodus? sp., Periodon macrodentatus, Spinodus sp., Spinodus? sp. and Histiodella holodentata suggests a relatively deeper water (outer shelf to slope) setting, comparable with contemporaneous faunas, …

Forum On The Flood/Post-Flood Boudary, Marcus R. Ross

Marcus R. Ross

The location of the Flood/post-Flood boundary is an important issue for Flood geology because it is the starting point for a host of research questions. Many papers have been published on this topic, but its placement is still controversial. Three main views are advocated: a low Flood boundary in the Paleozoic or below, a boundary at or near the Cretaceous-Tertiary boundary (now the Cretaceous/Paleogene boundary), and a variable boundary towards the upper Cenozoic but with each geographical area to be evaluated on its merits.

In 2012, Marcus Ross, published a biostratigraphic analysis and argued that a Flood/post-Flood boundary at or …

Letter: A Developing Schism In Flood Geology, Marcus R. Ross

Marcus R. Ross

First paragraph: Froede and Akridge are correct to recognize that creation geology includes two widely divergent groups seeking to reconstruct Earth history within a Biblical framework. Such has been the case throughout the history of creationism, going back to disagreements between Harold Clark and George McCready Price over the reality (or not) of the geologic column. With the increased number of geologically trained young-Earth creationists, discussions over these issues have become more common.

Trans-Atlantic Correlation Of Upper Cretaceous Marine Sediments, Marcus Ross, David Fastovsky

David Fastovsky

Upper Cretaceous marine deposits from the Mid-Atlantic region of North America (Delaware, Maryland, and New Jersey) and the Maastricht area (southern Netherlands, and nearby Belgium and Gennany) are correlated across the Atlantic using a variety of macro invertebrates, nannofossils, and sequence stratigraphy. Four late Cretaceous Mid-Atlantic sequences, the Marshalltown, Englishtown, Merchantville, and Navesink, span the upper Santonian to lowennost Danian, and have direct correlatives in the Maastricht area. Correlations between the Mid-Atlantic and the Maastricht regions (respectively) are as follows: the upper Santonian to lower Campanian Merchantville and Matawan formations with the Achen and lower Vaals fonnations; the middle Campanian …

The Flood/Post-Flood Boundary (Comment And Reply), Marcus R. Ross

Marcus R. Ross

First paragraph: Michael Oard’s recent article on the Flood/post-Flood boundary consists of two parts: the first is response to my earlier paper on utilizing mammalian biostratigraphy in evaluating post-Flood boundary locations, which found placement of this boundary at or near the Pliocene/Pleistocene boundary untenable; the second part is a set of disparate observations placed in support of a high post-Flood boundary placed at variable locations in the “Late Cenozoic”. (comment continues; download for full comment and reply by Michael Oard)

Evaluating Potential Post-Flood Boundaries With Biostratigraphy--The Pliocene/Pleistocene Boundary, Marcus R. Ross

Marcus R. Ross

Here I report a biostratigraphic analysis of 303 genera from 28 North American terrestrial mammalian families, in which all families contain members that are either extant or last appear in Pliocene or Pleistocene deposits. The distribution of these taxa within the Cenozoic rock record is used to evaluate proposed demarcations for the Flood/post-Flood boundary. A pronounced biostratigraphic break is expected at the Flood/post-Flood boundary since the final devastation and burial of pre-Flood nephesh creatures should be stratigraphically overlain by the arrival of post-Flood migrants. It is found that when the Flood/post-Flood boundary is placed at or near the Pliocene/Pleistocene boundary, …

How Synchronous Are Neogene Marine Plankton Events?, Cinzia Spencer-Cervato, Hans R. Thierstein, David B. Lazarus, Jean-Pierre Beckmann

Cinzia Cervato

An electronic supplement of this material may be obtained on adiskette or Anonymous FTP from KOSMOS.AGU.ORG. (LOGIN toAGU's FTP account using ANONYMOUS as the username andGUEST as the password. Go to the right directory by typing CDAPEND. Type LS to see what files are available. Type GET and thename of the file to get it. Finally, type EXIT to leave the system.)(Paper 94PA01456, How synchronous are Neogene marine planktonevents?, by C. Spencer-Cervato, H. R. Thierstein, D. B. Lazarus, andJ-P Beckmann). Diskette may be ordered from American GeophysicalUnion, 2000 Florida Avenue, N.W., Washington, DC 20009; $15.00.Payment must accompany order. We analyzed …