The Proceedings of the Eighth International Conference on Creationism (2018)

Snelling, A.A. 2018. Locating the Flood/post-Flood boundary using the relative dating of the weathering of ore deposits. In Proceedings of the Eighth International Conference on Creationism , ed. J.H. Whitmore, pp. 553–566. Pittsburgh, Pennsylvania: Creation Science Fellowship. LOCATING THE FLOOD/POST-FLOOD BOUNDARY USING THE RELATIVE DATING OF THE WEATHERING OF ORE DEPOSITS Andrew A. Snelling , Answers in Genesis, PO Box 510, Hebron, KY 41048 USA, asnelling@answersingenesis.org ABSTRACT Erosion at the end of and after the Flood exposed the tops of primary ore deposits to subsequent weathering and the formation of supergene minerals. The 40 Ar/ 39 Ar and (U-Th)/He radioisotope methods applied to these supergene minerals provide the dates for when these minerals formed. But given the documented problems with the radioisotope methods, they can only provide at best relative dates. When the Flood waters retreated, the ground surface was dry, but extra time was needed to allow the water table to drop, soil to form and plants to grow before Noah stepped off the Ark, which marked the end of the Flood event. The weathering front then progressed downwards during the early post-Flood decades for supergene minerals to start forming. Residual post-Flood catastrophism may have involved mountains still rising and ore deposits still forming, such as the porphyry copper deposits associated with granite intrusions as the Andes continued to rise. Erosion exposed those later-formed ore deposits to subsequent weathering to produce supergene minerals well into the early post-Flood era. Thus, the relative ages of the supergene iron oxides, and potassium-bearing sulfates and manganese oxides produced span the whole Cenozoic. It is proposed that relative dates for the first formation of supergene minerals can possibly be used as a criterion for determining the placement of the Flood/post-Flood boundary at the K-Pg boundary with a relative age of 66 Ma. The few slightly earlier relative ages likely resulted from weathering that commenced before the Flood event ended, though deep weathering would have required decades. The spread of relative ages through the Cenozoic thus represents the progressive formation of supergene minerals as primary ore deposits emplaced during, and maybe after, the Flood were subsequently exposed to weathering by residual catastrophism. Continuing investigation of this criterion for placement of the Flood/post-Flood boundary seems warranted. KEY WORDS Flood/post-Flood boundary, ore deposits, weathering, erosion, supergene minerals, 40 Ar/ 39 Ar dating, (U-Th)/He dating, relative dating, K-Pg boundary Copyright 2018 Creation Science Fellowship, Inc., Pittsburgh, Pennsylvania, USA www.creationicc.org 553 INTRODUCTION The location of the Flood/post-Flood boundary in the geologic record has long been a contentious issue debated in the creationist literature (Snelling 2014a, c). However, it is crucial for the coherency and advancement of the Creation-Flood model of earth history for this issue to be resolved definitively. There are primarily two contenders which have been proposed for this boundary’s location. The first proposed location is at the Cretaceous/Paleogene (K/ Pg) boundary (formerly known as the Cretaceous/Tertiary or K/T boundary) (Austin et al 1994). Above this boundary are lineages of mammal fossils that link extant mammals to their fossilized within-kind ancestors, even within the same geographic regions (Ross 2012, 2014a, b; Snelling 2014c; Whitmore and Wise 2008). Opponents of this view have failed to explain in a consistent and coherent scenario why both the Cenozoic fossil and related extant mammals are found in the same geographic regions, unless all belong to the same post-Flood population lineages (Oard 2007, 2010c, 2013a; Walker 2014a, b). For example, if Miocene fossil kangaroos found only in Australia are pre-Flood kangaroos buried by the Flood, then it is highly fortuitous that the related living kangaroos are also only found in Australia. However, Clarey (2016) raised the question of how large mammals could disperse in a post-Flood world prior to the Ice Age land bridges. The alternate proposed location is at or very near the Pliocene/ Pleistocene boundary (or what used to be called the Tertiary/ Quaternary boundary). Several arguments have been advanced. Some proponents argue that there is too large a volume of Cenozoic sedimentary and volcanic rocks, which would make the post-Flood world too catastrophic, when instead they maintain those sediments and volcanics required Flood rate and scale geologic processes well beyond local catastrophes (Clarey 2015a, c, 2017; Holt 1996; Oard 2010b, 2011, 2013a). Others point to examples of large-scale Cenozoic erosion and its products that they claim had to happen when the Flood waters were receding in order to explain the scale of erosion that is observed (Holt 1996; Oard 2004, 2007, 2013a, b). Whitmore and Garner (2008) attempted to develop a list of criteria which can be used to delineate the location of this boundary in strata sequences. Included in their list was the category “true paleosols”. They reasoned that since the Flood involved the rapid accumulation of sediments without the passage of long periods between the deposition of individual layers, we would not expect the development of true soil horizons during the Flood. On the other hand, after the Flood weathered horizons and paleosols would be expected to become more abundant due to the extended time for their development. Nevertheless, they ranked this as only a tertiary criterion, because true paleosols are difficult to diagnose and they