Tsunami Deposits on a Paleoproterozoic Unconformity? The 2.2 Ga Yerrida Marine Transgression on the Northern Margin of the Yilgarn Craton, Western Australia

Round 1

Reviewer 1 Report

I have some familiarity with Western Australia and have visited outcrops of the Banded Iron Formation that occur farther north from the described study site, therefore I enjoyed reading this article.  Since I’ve also worked with the equations of Nott (2003) and later modifications relative to wave action on similarly high-density rocks in Norway, the paper was attractive to me.

I believe that the equations are properly applied as intended with respect to tsunami deposits (Section 4.1), but these equations should have been introduced in a specific Methods
Section, much earlier, as should a description of an independent test for rock density of BIF samples from the study site.  In fact, there is no Methods Section.  And there is no attempt to follow the basic outline for JMSE articles specified for authors.

The color diagrams are well executed and (of course, being native English speakers) the use of language is fine.

In keeping with JMSE policy to show original data, it is entirely appropriate to see Table 2 with a listing of 35 blocks of measured BIF.  However, I am confused by the differentiation of the “a and b” columns under “Long axis.”  Likewise, “c and d” under short axis.  This is not explained and is expected to be explained in a good Methods Section.  In my own practice, I list measurements for long, intermediate, and short axes – all at right angles to one another.

On the whole, I find that the submission was not designed with the JMSE in mind.  For example, the guidelines for numerical citations of the literature within the text are not followed and the required style for the writing of the references is not adhered to.

I have no reason to doubt the accuracy of the author’s observations, but I am dissatisfied with the photographic plates (Figures 5 and 6, especially), in which six individual photos are crammed into a single plate.  Stylistically, the images are squashed too close together (requiring a greater white space in the grid between photos).  The first image I wanted to have a closer look at was Figure 6A, for example.  When I tried to magnify the image for a closer look at what is presumably one of the largest blocks of BIF disturbed by a tsunami event, I found that the pixilation is much too coarse.  Higher resolution is definitely needed.

It is my personal opinion, but the authors have packed too many images into the space for one figure.  They would be better advised to make a cluster of four images, each with more space separating them from one another.  This would require more “Figures” to cover all the material, but that would be ok.

In conclusion, I believe this is a paper that could be accepted for publication in the JSME, but it must be extensively revised to fit the journal’s format.

Markes E. Johnson

Author Response

A new Methods section has been inserted including equations and rock density measurement information.

The whole paper has been re-organised to follow JMSE practice. Literature citations have been numbered and References style corrected. All changes have been highlighted.

Table 2 columns a,b and c,d have been explained.

Photos were figured in accordance with usual requirements for subscription printed journals with space limitations. I could re-format them  have at 2 per page with much greater resolution if required. 4 per page would be no larger at constant page width.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript is really interesting even if a detailed knowledge of the geological structure of the area is requested for the full comprehension of the text. Fortunately, figures help to overcome this aspect.

I don't find any particular problems with the manuscript except one:

why Authors exclude a strong earthquake on ocean sea-floor as the causative event of the tsunami which produced the studied boulder accumulation?

At present, in fact, this is the first cause of strongest tsunami. There are some reasons that forced Authors to neglect this cause?

I would invite Authors to discuss this aspect in the 4.2 chapter "Speculation on Possible Cause of the Flood".

Author Response

Earthquake on the sea floor as a possible cause of the Tsunami?

The scale of the event was much greater than any known historical event and the quake would have to have an instantaneous displacement several orders of magnitude greater. Only tsunami waves would be produced with no flood due to splash.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have satisfied my criticisms for the most part by insertion of the required "Methods Section."  I am glad to see the discussion of rock density based on core samples.  Also, the paper now follows the essential format for the JMSE.

I think more could be done to improve the color field photos, but they are adequate as presented.