Geospatial–Temporal Quantification of Tectonically Constrained Marble Resources Within the Wadi El Shati Extensional Regime via Multi-Sensor Sentinel and DEM Data Fusion
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
This manuscript presents an integrated multi-sensor remote sensing and GIS framework using Sentinel-1, Sentinel-2, and DEM data to update lithological mapping and quantitatively estimate marble resources. The study reports high classification accuracy and links marble distribution to NE–SW extensional tectonics and basaltic intrusions, yielding an estimated marble volume of ~6 km³. The manuscript is overall nice with substantial results, but there are some aspects need to be clarified or improved:
- The texts in tables are not tight enough, causing the tables to be stretched vertically and become unreadable.
- The Monte Carlo simulation varies only thickness and DEM elevation. Structural uncertainty (e.g., fault truncation, karst voids) is mentioned elsewhere but not incorporated quantitatively. The authors should clarify why these uncertainties were excluded or discuss their potential magnitude relative to the reported ±9%.
- The manuscript would benefit from concise writing: many sections (especially Results and Discussion) are highly repetitive and overly verbose, which obscures the core scientific contributions and makes it difficult for readers to identify the main findings. For example, for the Results and discussion, the authors should reduce repetition by moving interpretive tectonic narratives into the Discussion and keeping the Results focused strictly on mapped patterns, statistics, and measurements.
- Equation (1) assumes spatially homogeneous thickness within each polygon, yet thickness variability is reported later. The authors should explicitly state this assumption and either justify it or include a sensitivity test showing how heterogeneous thickness distributions would change the 6 km³ estimate.
- The Conclusions section restates methodological details (e.g., FCCs, PCA, band ratios) at length. This section should instead focus on: (1) what is now known that was not known before, (2) how reliable the estimate is for decision-making, and (3) which conclusions are robust and which are speculative.
Author Response
Response to Reviewer 1
We sincerely thank Reviewers for their constructive and insightful comments, which have significantly improved the clarity, rigor, and readability of our manuscript. We have carefully addressed each point raised, as detailed below.
Comment 1:
“The texts in tables are not tight enough, causing the tables to be stretched vertically and become unreadable.”
Response:
The authors have revised Tables 2, 3, 4, 5, and 6 to improve readability by condensing text, merging redundant rows, and optimizing column widths. The tables are now more compact and legible while retaining all essential information.
Comment 2:
“The Monte Carlo simulation varies only thickness and DEM elevation. Structural uncertainty (e.g., fault truncation, karst voids) is mentioned elsewhere but not incorporated quantitatively. The authors should clarify why these uncertainties were excluded or discuss their potential magnitude relative to the reported ±9%.”
Response:
We have added the following clarification in the “Uncertainty and Predictive Analysis” section (Page 8): “Structural uncertainties such as fault truncation or karst voids were excluded from the simulation due to the lack of quantitative subsurface data. These factors could locally alter volumes but are not systematically quantifiable without detailed geophysical surveys. Their potential impact is considered secondary to the DEM and thickness errors in this regional-scale assessment.” This addition explains the exclusion of structural uncertainties and contextualizes their potential impact.
Comment 3:
“The manuscript would benefit from concise writing: many sections (especially Results and Discussion) are highly repetitive and overly verbose, which obscures the core scientific contributions and makes it difficult for readers to identify the main findings. For example, for the Results and discussion, the authors should reduce repetition by moving interpretive tectonic narratives into the Discussion and keeping the Results focused strictly on mapped patterns, statistics, and measurements.”
Response:
We have thoroughly revised the Results section (Pages 8–12) to remove all interpretive and causal language, retaining only factual descriptions of methods, accuracy metrics, mapped patterns, and volumetric estimates. All interpretive narratives—including the “Paradigm-Shifting Potential” and causal chain discussions—have been moved to the Discussion section under a new subheading: “Causal Interpretation of Remote Sensing Patterns” (Page 13–14). This separation ensures that Results remain strictly descriptive, while Discussion provides the interpretive and theoretical context.
Comment 4:
“Equation (1) assumes spatially homogeneous thickness within each polygon, yet thickness variability is reported later. The authors should explicitly state this assumption and either justify it or include a sensitivity test showing how heterogeneous thickness distributions would change the 6 km³ estimate.”
Response:
We have amended the text following Equation (1) on Page 8 to include the following: “This formulation assumes homogeneous thickness within each polygon, a simplification necessitated by limited field transects. To assess the impact of internal thickness variability, a sensitivity test was conducted by applying a ±30% variation to ​, resulting in a volume range of 4.2–7.8 km³. This confirms that while local heterogeneity exists, the mean-thickness approach yields a robust regional estimate consistent with the reported ±9% uncertainty.” This addition explicitly states the assumption and provides a sensitivity analysis to support the volumetric estimate.
Comment 5:
“The Conclusions section restates methodological details (e.g., FCCs, PCA, band ratios) at length. This section should instead focus on: (1) what is now known that was not known before, (2) how reliable the estimate is for decision-making, and (3) which conclusions are robust and which are speculative.”
Response:
We have revised the Conclusions section (Page 20) to focus on key new findings, reliability, and robustness. The revised opening paragraph now reads: “Key new findings include: (1) a revised lithological map with 91% accuracy, correcting a 22% error in legacy maps; (2) identification of a dominant NE–SW structural trend controlling marble distribution; and (3) a marble resource estimate of ~6 km³ with a quantified uncertainty of ±9%. The volumetric estimate is sufficiently reliable for regional resource planning but requires subsurface validation for site-specific quarry design. The causal link between extensional tectonics and marble genesis is robust, while the assumption of homogeneous thickness within mapped polygons remains a simplification that warrants further local investigation.” Methodological details have been minimized, and the focus is now on scientific advancement and practical implications.
We believe these revisions have substantially strengthened the manuscript and addressed all concerns raised by Reviewer 1. We are grateful for the thorough and helpful review.
Sincerely, The Authors
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
Dear Authors,
This article is an interesting case study involving the use of Sentinel-1 and Sentinel-2 satellite imagery in assessing marble resources in the Wadi El Shati area. Based on DEM and TIN models, as well as unsupervised and supervised classification, the authors propose a different origin for the deposit, considering it a dynamic process consisting of several phases resulting from magmatic and metamorphic processes, as well as the location of carbonate components in correlation with the fracture network generated by stresses during orogeny. The presented research and results are consistent, but the narrative involves many repetitions that cause reader fatigue. I strongly suggest shortening the text by half and simplifying the language, which often refers to overly complex formulations that contribute little to the content. I believe that some words and sentences should also be replaced with more balanced ones, e.g., "the genius" - "the idea," "The 'marble-bearing zones predominantly occur adjacent to basalt flows' is a simple correlation that, within this analytical framework, transforms into a predictive, causal rule." Has this been verified elsewhere to consider this observation a rule? Unless, of course, it was already a validated thesis.
"The elevation data is not merely a topographic context but an active variable in the volume equation. The TIN model, generated from this DEM, allows for the translation of a two-dimensional classified polygon from Figure 10 into a three-dimensional volumetric estimate." After all, data in the Z-axis in R3 space always provides volume context—why add a philosophical aspect here? Moreover, you don't need a TIN model to extract volume information—it can be assessed without spanning triangular surfaces. Also in the chapter "Volumetric Quantification" (reiterating what is already known from the previous paragraphs), the authors state: "The volumetric formula (Equation 1) is deconstructed to reveal its inherent assumption of homogeneous strain..." - How can the volume formula reveal homogeneous strain? On what basis are such statements used?
In the same subchapter, the authors mention that the obtained volumetric accuracy is more of a precision than an accuracy. What, then, interferes with achieving accuracy? What are the systematic factors influencing this effect?
In the next chapter, the authors state: "The TIN model and DEM interpolation accurately capture the subsurface geometry..." - The TIN and DEM cannot detect subsurface structures, but only suggest them.
It is also worth introducing specific definitions of the formulations used for statistical evaluation - e.g., the Kappa coefficient (Cohen's Kappa significance test)?
The importance of Hillshade shading is repeatedly mentioned, but nowhere in the attached figures does its application or use in analyses appear. It would be worthwhile to include such a figure, showing the schematic fault lines on which the authors base their analyses. It is also worthwhile to use an illustrative figure to illustrate the marble formation process described based on the generated movements and dynamic interactions in fault zones accompanied by basalt rocks.
I also believe that the Core Summary chapter is essentially an 80% repetition of what is presented in the previous chapters and, moreover, could successfully replace the Conclusions, which reiterates the same statements and cites the same determined values ​​describing the structure of the marble formation. I again suggest significantly shortening the text.
I believe that after implementing the above suggestions, the manuscript will be a valuable article in the journal Geosciences.
Author Response
Response to Reviewer-2
We sincerely thank the reviewer for their thorough and constructive feedback, which has significantly helped improve the clarity, accuracy, and overall quality of our manuscript. Below, we detail how we have addressed each of the reviewer’s comments.
Comment 1:
The narrative involves many repetitions that cause reader fatigue. I strongly suggest shortening the text by half and simplifying the language, which often refers to overly complex formulations that contribute little to the content.
Response 1:
We have significantly condensed the manuscript by removing redundant sections, most notably the Core Summary (Pages 20–21), which largely repeated earlier content. We have also streamlined repetitive passages in the Discussions and Conclusions sections. Throughout the manuscript, we have simplified overly complex language and removed philosophical elaborations that did not add scientific value.
Comment 2:
Some words and sentences should be replaced with more balanced ones, e.g., “the genius” – “the idea,” and “The ‘marble-bearing zones predominantly occur adjacent to basalt flows’ is a simple correlation that, within this analytical framework, transforms into a predictive, causal rule.” Has this been verified elsewhere to consider this observation a rule?
Response 2:
We have replaced “the genius” with “the idea” where appropriate. The sentence regarding “predictive, causal rule” has been revised to: “The observed spatial association of marble-bearing zones with basalt flows, interpreted through this analytical framework, suggests a predictive model for resource localization.” This phrasing better reflects the interpretative rather than prescriptive nature of our finding (see page 14).
Comment 3:
“The elevation data is not merely a topographic context but an active variable in the volume equation. The TIN model, generated from this DEM, allows for the translation of a two-dimensional classified polygon from Figure 10 into a three-dimensional volumetric estimate.” After all, data in the Z-axis in R3 space always provides volume context—why add a philosophical aspect here? Moreover, you don’t need a TIN model to extract volume information—it can be assessed without spanning triangular surfaces.
Response 3:
We agree and have simplified this statement. The revised text now reads: “The DEM elevation data and the derived TIN model enable the conversion of two-dimensional lithological polygons into three-dimensional volumetric estimates.” (page 9)
Comment 4:
In the chapter "Volumetric Quantification," the authors state: “The volumetric formula (Equation 1) is deconstructed to reveal its inherent assumption of homogeneous strain...” – How can the volume formula reveal homogeneous strain? On what basis are such statements used?
Response 4:
This was an inaccurate conflation of geometric and geological concepts. We have revised the paragraph to clarify: “The volumetric formula (Equation 1) assumes a constant thickness within each polygon; however, the reported thickness variability (8–55 m) and the mixed lithology (marble, dolomite, limestone/sandstone) within the Al Mahruqah Formation indicate significant internal heterogeneity” (page 18)
Comment 5:
In the same subchapter, the authors mention that the obtained volumetric accuracy is more of a precision than an accuracy. What, then, interferes with achieving accuracy? What are the systematic factors influencing this effect?
Response 5:
We have expanded this section to clarify the distinction. The revised text now states: “The reported (±9%) uncertainty, quantified through RSS propagation, primarily reflects measurement precision. Achieving true accuracy is limited by systematic factors including the DEM's vertical error, interpolation assumptions across large areas, and the lack of direct subsurface validation, which could reveal unmodeled complexities like karst voids or fault truncations” (page 18)
Comment 6:
In the next chapter, the authors state: “The TIN model and DEM interpolation accurately capture the subsurface geometry...” – The TIN and DEM cannot detect subsurface structures, but only suggest them.
Response 6:
We have corrected this overstatement. The sentence now reads: “The TIN model and DEM interpolation provide a surface-constrained model of the subsurface geometry, and the estimated volume represents a conservative resource base” (pages 18–19)
Comment 7:
It is also worth introducing specific definitions of the formulations used for statistical evaluation - e.g., the Kappa coefficient (Cohen's Kappa significance test)?
Response 7:
We have added a brief explanation of the Kappa coefficient in the Validation and Bias Mitigation section: “The Kappa coefficient (Cohen's Kappa) is a statistic used to measure inter-rater reliability for categorical items, adjusting for agreement occurring by chance. A value of 0.86 indicates almost perfect agreement between the classification and validation data” (page 7)
Comment 8:
The importance of Hillshade shading is repeatedly mentioned, but nowhere in the attached figures does its application or use in analyses appear. It would be worthwhile to include such a figure, showing the schematic fault lines on which the authors base their analyses.
Response 8:
We acknowledge this omission. A new figure showing the Hillshade model with extracted lineaments and lineament density has been added to the manuscript (Page 38). This figure visually supports our structural interpretations and highlights the dominant NE–SW trend aligned with the regional extensional stress direction ().
Comment 9:
I also believe that the Core Summary chapter is essentially an 80% repetition of what is presented in the previous chapters and, moreover, could successfully replace the Conclusions, which reiterates the same statements and cites the same determined values describing the structure of the marble formation. I again suggest significantly shortening the text.
Response 9:
As noted in Response 1, we have removed the Core Summary section entirely. The key findings have been integrated into the Conclusions, which have been revised to be concise and non-repetitive.
We believe that these revisions have addressed all of the reviewer’s concerns, resulting in a more focused, accurate, and readable manuscript. We are grateful for the reviewer’s insightful comments, which have strengthened the paper considerably.
Thank you for the opportunity to revise our work.
Sincerely, The Authors
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for Authors
The manuscript has improved and I suggest publication.
Author Response
Your suggestion for publication is greatly appreciated.
Reviewer 2 Report
Comments and Suggestions for Authors
The revised manuscript presented here is much more readable and logically presents the analyses performed. However, I believe that some figures should still be embedded after being cited in the text (e.g., Figs. 6 and 8). I think that some repetition of statements in the text could still be eliminated, but it is no longer as burdensome. In summary, I believe that, with very minor corrections, the article is ready for publication in its current form.
Author Response
- Embedding of Figures 6 and 8 after their first citation in the text:
Following your guidance, we have embedded most of figures directly after their first textual mention. To achieve this seamless placement, we renumbered the figure sequence and updated all corresponding in-text citations. The specific changes are as follows:
Figure 6 (Spectral Signatures): Moved from its original location to follow its first citation.
Figure 8 (DEM): Moved from its original location to follow its first citation.
Consequential Renumbering: This insertion required renumbering the Figures (5, 6, 7, 8, 9, and 10) are now presented sequentially as Figures in their new, logically ordered positions in the text. Every citation for these figures has been updated throughout the manuscript to reflect the new numbering.
- Elimination of remaining repetitive statements:
We performed a thorough edit to remove redundant phrasing and streamline the text, particularly in the Results and Discussion sections. Key deletions/condensations include:
Page 17, second paragraph: The repetitive re-introduction of the study's purpose and hypotheses ("This study advances the quantification... The foundational purpose is to resolve... The primary hypotheses posit that...") has been removed. The paragraph now starts directly with the synthesis of findings: "The study advances the quantification of tectonically constrained marble resources by integrating multi-sensor Sentinel-1/2 data and DEMs."
Page 17, last paragraph: The lengthy, repetitive opening ("This research fundamentally reorients the discourse... to deconstruct the tectonically constrained genesis of marble within the Wadi El Shati extensional regime.") was shortened to focus on the key reinterpretation.
Page 22, "Lithological Discrimination..." section: A repetitive sentence describing structural analysis ("Structural analysis, derived from a synthesis... structural predispostion.") was deleted, as the same information is clearly conveyed in the preceding and subsequent sentences.
Page 23, "Integration of Multi-Sensor Data" section: A repetitive clause ("For instance, Sentinel-2's spectral bands... fracture density and metamorphic fabric.") that reiterated previously stated methodology was removed to improve conciseness.
