Application of ASTER Data for Differentiating Carbonate Minerals and Evaluating MgO Content of Magnesite in the Jiao-Liao-Ji Belt, North China Craton

Round 1

Reviewer 1 Report

Line 150: how did you re-sample the 30m data to 15m? NN? Bi-linear? Cubic? Only NN preserves the original spectral information.

 

Very nice, thorough piece of work!

Author Response

We would like to thank your review of the paper. 

reviewer's comment:

Line 150: how did you re-sample the 30m data to 15m? NN? Bi-linear? Cubic? Only NN preserves the original spectral information.

Response:

We resampled ASTER data using NN method (L155-156 in the revised manuscript).

Reviewer 2 Report

This paper presents an application of ASER data for differentiating carbonate minerals and evaluating MgO contents of magnesite. Please consider following comments.

1. Figure 1 compares the reflectance spectra of carbonate mineral samples, i.e., magnesite, dolomite and calcite, used in the study area. In the caption of the figure, explain how these spectra were obtained. Were the spectra acquired using ASD TerraSpec Halo and then subsetted?

2. When were the ASTER images acquired? Please provide acquisition date of the ASTER images used in this study. Four ASTER images were used for mapping (line 145). Was mosaicking processes applied before mapping minerals?

3. In preprocessing step of ASTER image, cross-talk effect was compensated using scalar correction values (lines 158–168). Why were the images of Liaoning, China and Dancheon, North Korea calibrated using different values?

4. In table 1, check for typos in the proposed equation for calcite mapping. Is B9 in the denominator correct?

5. Between the band ratio values of 1.025 (line 200) and 1.026 (figure 4(c)), which Is the correct threshold for distinguishing magnesite and dolomite?

6. Please provide a table describing the number of samples per rock type and site.

7. In figure 6(b), Tanchon needs to be modified to Dancheon.

8. In table 2 (line 310), Table 1 in caption needs to be modified to Table 2.

9. There is a sentence, “In the Daeheung open-pit mine, the classification results of magnesite by RBD and band ratio are almost the same” in lines 351–353. Please provide more detained explanation how the classification results of magnesite by RBD and band ratio are similar like the comparison using pixel numbers or proportions in lines 251–254.

Author Response

We would like to thank your review of the paper. In accordance with the comments and suggestions, we revised the manuscript.

 

"Please see the attachment."

Author Response File: Author Response.docx

Reviewer 3 Report

The paper is well written, and ready for publishing.  I have included some comments on calibration that the authors may want to consider in future work.  The authors may also want to comment if muscovite is present in the magnesite deposits and if so, how this would impact their 5/6 ratio for determining magnesite purity. 

Comments for author File: Comments.pdf

Author Response

We would like to thank your review of the paper. In accordance with the comments and suggestions, we revised the manuscript. Reviewers' comments on the calibration will be useful for our future work.

"Please see the attachment."

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Revisions for all comments have been applied to the revised manuscript. So I do not raise additional comments.