Comments (here below) to the Reply by Gerta Keller, Thierry Adatte, Gerald Baum, Zsolt Berner, a reply to Comment by Schulte et al., Earth and Planetary Science Letters (2008) in press, doi: 10.1016/j.epsl.2007.12.025

1. Introduction
We appreciate this opportunity for further discussion of the Brazos, Texas, K-T boundary sequences and their timing with respect to the Chicxulub impact. Keller et al. [1] used a multidisciplinary approach to document the stratigraphy, paleontology, mineralogy and geochemistry of the newly drilled Mullinax-1 core and a new outcrop sequence. Based on this multi-proxy dataset very strong evidence was presented that reveals that the Chicxulub impact predates the K-T mass extinction [1]. Schulte et al. take issue with this approach and our findings largely because they believe (1)that the Chicxulub impact caused the K-T mass extinction and therefore the K-T boundary must be placed at the impact spherule layer [2-4]. We welcome this opportunity to clarify misunderstandings, misconceptions and misinterpretations of the K-T record in Texas and elsewhere.   At the heart of our disagreements is the decades old controversy about the cause of the end-Cretaceous mass extinction. Schulte and collaborators have long argued that the sandstone complex, or event deposit, with impact spherules at the base in NE Mexico and Texas mark Chicxulub impact-generated tsunami deposits at the K-T boundary [3-7]. Keller and others have documented that these sandstone complexes were deposited over a long time period, that the K-T boundary is above these deposits and the original Chicxulub impact layer is in late Maastrichtian sediments predating the K-T mass extinction by about 300 ky [8-12] (2). With the stratigraphic sequences in Mexico and Texas in direct conflict(3) with the Chicxulub as K-T impact scenario, Schulte and collaborators now consider these sequences as too complex to reveal the K-T and Chicxulub impact history. Instead, they favor condensed deep-sea(4) and terrestrial sections(5) as the ultimate support for the Chicxulub K-T age claim because they juxtapose the spherule layer and early Danian sediments [13-15]. But the ultimate test for any historical sequence of events lies in the expanded records of continental shelf and slope areas (7) where high sedimentation rates reveal stratigraphic separation and normal sedimentation(8) between events, such as we documented for Texas [1](6). We stand by our published data and interpretations and present new data and graphics to clarify their misconceptions and misrepresentations on the placement of the K-T boundary.

Here below follow some comments on the reply by Gerta Keller, Thierry Adatte, Gerald Baum, Zsolt Berner (in Press) 2008 to <<Chicxulub impact predates K-T boundary: New evidence from Brazos, Texas’, a comment by Schulte et al.>> , which is a critique on:
G. Keller, T. Adatte, Z. Berner, M. Harting, G. Baum, M. Prauss, A. Tantawy, D. Stueben, Chicxulub impact predates K-T boundary: New evidence from Brazos, Texas, Earth and Planetary Science Letters 255 (2007) 339-356
What we believe is immaterial to the discussion. It is about sound fieldwork, data gathering and interpretations, which we demonstrated are lacking in the Keller 2007 paper. (top)
All these papers are flawed in the same way because they all repeat the same mistakes (top)
That is what Keller believes. We have demonstrated many times that the complex sequences around the Gulf of Mexico are one coherent unit, with no 'direct conflict' between Chicxulub and the KT extinctions whatsoever, but Keller does not want to listen. (top)
Hmpf? Condensed? This is hard to reconcile with opinions of others [a] , who claim these sections are among the most complete (top)
Terrestrial sections!, awful ! Thus completely ignored by Keller et al. We come back to this later (at 6), but have a look here. (top)
These expanded records also occur outside the Gulf of Mexico area. The Gulf has been influenced by the Chicxulub impact, and is therefore one of the least suitable areas to test the idea of one or more impacts at K-T. The expanded records are found on the continental shelf of Spain (Zumaya, Caravaca, Agost) and Tunisia (Kef, Siliana, Elles, Ein Settara). And in all those sections there is not a trace of two impact ejecta layers separated by this mythical 300.000 years. (top)
Texas is one of the areas where the disturbance by the Chicxulub impact is well visible, but the section is also riddled with discontinuities. Many still consider the section just above the clastic layers with the iridium anomaly in the top as one of the most expanded, and we agree. The iridium anomaly and the clastic layers including the spherules are one and the same event and therefore 'very strongly' (using the words of Keller) demonstrate that the KT boundary and the Chicxulub impact do coincide! (top)
(8) Normal sedimentation separating these events is non existent. Grainsize analysis clearly shows these sediments to be part of the clastic units [b] (top)
[a] K.G. MacLeod, D.L. Whitney, B.T. Huber, C. Koeberl, Impact and extinction in
remarkably complete Cretaceous-Tertiary boundary sections from Demerara Rise,
tropical western North Atlantic: Geological Society of America Bulletin, 119 (2006) 101-
[b] Smit, J., T. B. Roep, et al. (1996). Coarse grained, clastic sandstone complex at the K/T boundary around the Gulf of Mexico: Deposition by tsunami waves induced by the Chicxulub impact? The Cretaceous-Tertiary Event and Other Catastrophes in Earth History. G. Ryder, D. Fastovski and S. Gartner. Boulder, Geol. Soc. of Amer. Sp. Pap. 307: 151-182.