Paleogeomorphology Restoration of Post-Rift Basin: Volcanic Activity and Differential Subsidence Influence in Xihu Sag, East China Sea
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn the manuscript the authors examin the subsidences sedimentary facies and sedimentary processes by restoring paleogeomorphology in post-rift basins. Paleogeomorphology is the main factor influencing the formation and distribution of sediments in general. Geophysical and geological data and methods are referred in the work to reconstruct and reproduce the post-rift paleogeomorphology, conditioned by magmatic processes. Geological and geophysical data are well exposed in the text and by using the EBM software to compute the tectonic subsidence, load subsidence, and their respective proportions according the main wells.
In my opinion the geological and regional framework can be improved. In addition, tectonic role in a rifting and postrift stages is unclear observing map (where are the faults?) and in the general schematic section.
In an overall I think that the work reconstructs the paleogeomorphology of the basin in a positive and interesting way. Suggestions and corrections are directly on the revised file.
Cordially,
Comments for author File: 
Comments.pdf
Author Response
Comments 1: In my opinion the geological and regional framework can be improved. In addition, tectonic role in a rifting and postrift stages is unclear observing map (where are the faults?) and in the general schematic section. Suggestions and corrections are directly on the revised file.
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, We have revised Figure 1 and removed the original Figure 1c to reduce ambiguity. We have also added a location map of the East China Sea continental shelf basin (Figure 1a) and made targeted modifications to the figures based on the content of the response file. Other pictures have been modified accordingly. Mention exactly where in the revised manuscript this change can be found-Page3, Line105-108
Reviewer 2 Report
Comments and Suggestions for Authors
Journal of Marine Science and Engineering
Manuscript ID: jmse-3095656
Type of manuscript: Article
Title: Paleogeomorphology Restoration of Post-rift Basin from Volcanic and Differential Subsidence Retrospect
Authors: Xiongbiao Yu, Qianghu Liu *, Hongtao Zhu, Zhiyao Li *, Lanzhi Qin, Donghao Xu
Dear Editor,
Dear Editor,
Thank you for inviting me to participate in the review process of this manuscript. I read the manuscript thoroughly. The manuscript entitled “Paleogeomorphology Restoration of Post-rift Basin from Volcanic and Differential Subsidence Retrospect”. The study focused on the Oligocene era paleogeomorphology of the Huangyan district, taking into account the presence of possible Large Igneous Provinces. The researchers used the residual thickness method and differential subsidence recovery to recreate the paleogeomorphology. They found that the northern region, characterized by a larger thickness of strata and coarse-grained lithology, represents the thickness center. In contrast, the southern region, with thinner layers and fine-grained sediments, was identified as the primary location for the deposition of fine-grained sediments. The study revealed that the stratigraphy in the northern region is 40% thicker than in the southern part, and both the tectonic subsidence and the load subsidence are much higher in the north. However, the paleowater depth in the southern region is higher than in the north. The study also found that intense volcanic activity causes the Earth’s crust to become thinner, affecting the process of differential thermal subsidence of the layers above. This leads to a situation where the center of the fine-grained deposits is not coincident with the center of thickness. The findings of this study are significant as they provide a theoretical basis and support for identifying favorable hydrocarbon generation centers and structural highs. The restoration of paleogeomorphology in the center of the post-rift basin can help clarify the fine-grained center of the sedimentary basin. In brief, this study offers valuable insights into the geological characteristics of the Xihu Sag and has potential implications for future exploration and development activities in the area.
I would like to commend the authors for conducting a valuable and high-level scientific study that has yielded significant and noteworthy results. Their work is undoubtedly important for researchers in this field. However, I have some concerns that I believe need to be addressed. The authors have made a series of simplistic assumptions from the outset, which have been carried throughout the paper. These assumptions, particularly the notion that the characteristics of the fine-grained deposit center and thickness center solely correspond to the subsidence center, seem to be an oversimplification. Additionally, the lack of consideration for integrating and validating other data sets is concerning. While the authors possess extensive drilling and lithology data, as well as seismic data, it is observed that in many instances, to recreate the paleogeomorphology, they have relied solely on sediment thickness, lithology, or grain size, especially using the Extension Basin Modeling (EBM) software to conduct settlement history analysis. The rationale for restoring paleogeomorphology is substantiated by the sedimentary context and paleowater depth conditions, but these two factors are not easily determined. Relying solely on the aforementioned methods may not be sufficient to resolve the issue. While the use of sediment thickness data is a standard approach, I am compelled to inquire about the integration of other significant data sets that the study has access to, such as changes in logging facies, sedimentary features, lithofacies, and sedimentary facies, as indicated by drilling data. Furthermore, the reliability of the residual thickness approach hinges on the identification of a truly isochronous datum plane, which remains ambiguous.
Main comments:
1. The hypothesis posits that "The genesis and position of the fine-grained deposit center and thickness center are strongly influenced by the subsidence center." While the importance of the subsidence center in shaping the basin's morphology is undeniable, I believe this statement does not fully capture the complexity of the processes at play. It is true that subsidence can significantly impact the thickness of sedimentary deposits. However, the genesis of these centers is also heavily influenced by the depositional environment and the sedimentary processes involved in the settling of basin-center deposits. The supply of sediment to the basin center and the controlling processes are equally critical. To attribute the characteristics of the fine-grained deposit center and thickness center solely to the subsidence center would be an oversimplification. The depositional environment, including factors such as sediment supply, transport mechanisms, and depositional energy, plays a pivotal role in the formation of these centers. These factors contribute to the heterogeneity of sediment distribution and composition, which is often observed in basin analysis.
2. Authors mentioned, "The rationale for restoring paleogeomorphology is substantiated by the sedimentary context and paleowater depth conditions." However, it is imperative to consider that if our interpretations and analyses for restoring paleogeomorphology are solely based on these two factors, they necessitate a thorough examination of precise sedimentological data and facies analysis. Relying solely on sediment thickness, lithology, or grain size may not provide a reliable foundation for our conclusions. Sedimentary systems are inherently complex, and it would be an oversimplification to assume that deeper areas are consistently characterized by finer-grained mudstone and shallower regions by coarser sandstone. Such generalizations do not always hold true, as autogenic and allogenic processes during the deposition of sedimentary sequences can influence and complicate these relationships. Therefore, it is crucial to incorporate a comprehensive suite of sedimentological and facies data to ensure the accuracy of our paleogeomorphology restoration efforts. This will allow us to account for the intricate interplay of depositional processes and better understand the sedimentary environment of the past.
3. Authors outlined, "The residual thickness approach for studying paleogeomorphology is based on the premise that the original sedimentary thickness of the strata being investigated remains relatively constant prior to denudation. In this method, a marker layer underneath the strata is chosen as the isochronous datum plane. The residual thickness between the datum plane and the top interface of the ancient geomorphology is utilized to describe the morphology of the ancient landforms that are being restored." My inquiry pertains to the nature of the marker layer and the basis for its selection. Specifically, I have raised concerns about whether the determination of this layer is solely based on composition and lithology, which, if so, may not be entirely reliable. I would like to clarify that while lithology can serve as an initial guide in identifying potential marker layers, it is not the sole criterion for selection. The reliability of the residual thickness approach hinges on the identification of a truly isochronous datum plane, which requires a layer that is time-equivalent across the study area. To ensure the accuracy of our paleogeomorphological reconstructions, geologists incorporate biostratigraphic data and sequence boundaries that provide age constraints and corroborate the isochronous nature of the chosen marker layer. This integration of sedimentological, biostratigraphic, and chronostratigraphic information is crucial for a robust interpretation of the ancient landforms.
4. In this study, authors have delineated the paleogeomorphology based on sediment thickness data, identifying the centers of layer thickness and fine-grained deposits, as well as classifying slope areas. While the use of sediment thickness data is a standard approach, I am compelled to inquire about the integration of other significant data sets that your study has access to, such as changes in logging facies, sedimentary features, lithofacies, and sedimentary facies, as indicated by drilling data. My question is why there seems to be a singular emphasis on sediment thickness data when there is a wealth of additional data at your disposal. These other data types are crucial for a comprehensive understanding of the paleogeomorphology of the primary sequence and should be integrated to support and validate each other. For instance, the slope area introduced in the A3-A4 well area should be substantiated by drilling data, which can provide further evidence of slope conditions. A holistic approach that leverages all available data is essential for ensuring a thorough and accurate reconstruction of the paleogeomorphology. It is the complexity of sedimentary systems and the interplay of various depositional processes that necessitate such a multi-faceted analysis.
5. sedimentary facies, specifically the fluvial-delta and shallow lake facies mentioned: I noticed that while these facies are integral to the study, it is not immediately clear whether the interpretations of these facies are based on data collected during this study or if they are derived from other existing studies. Typically, interpretations are most robust when they are supported by data, and such foundational data is crucial for the reader to assess the validity of the conclusions drawn.
6. In section- 4. Result and Verification- Could you please provide further details on how the drilling and lithology data were integrated? Were there specific algorithms, comparative analyses, or modeling techniques employed? Any additional information on this aspect of your study would greatly enhance the clarity and depth of your work.
7. The deposition rates "Vs" and "V0" as key factors in your analysis. Specifically, Vs is noted as representing the deposition rate of a sample during deposition, and V0 is described as the normal lake deposition rate. These rates are fundamental to the equations and models presented in your study, and thus, understanding how they were derived is essential for a comprehensive evaluation of your work. Could you please elaborate on the methodologies and data used to determine these deposition rates? Were there specific experimental setups, observational data, or computational models employed to quantify these values?
I would like to suggest a moderate to major revision.
I have included an annotated PDF that contains all the thoughts I had while reading through the manuscript, as well as suggested revisions that I believe would help the readability and completeness of the work. I hope will help the authors improve the clarity of the text.
**********************************************************
Kind regards,
Author Response
Comment 1: The hypothesis posits that "The genesis and position of the fine-grained deposit center and thickness center are strongly influenced by the subsidence center." While the importance of the subsidence center in shaping the basin's morphology is undeniable, I believe this statement does not fully capture the complexity of the processes at play. It is true that subsidence can significantly impact the thickness of sedimentary deposits. However, the genesis of these centers is also heavily influenced by the depositional environment and the sedimentary processes involved in the settling of basin-center deposits. The supply of sediment to the basin center and the controlling processes are equally critical. To attribute the characteristics of the fine-grained deposit center and thickness center solely to the subsidence center would be an oversimplification. The depositional environment, including factors such as sediment supply, transport mechanisms, and depositional energy, plays a pivotal role in the formation of these centers. These factors contribute to the heterogeneity of sediment distribution and composition, which is often observed in basin analysis.
Response 1: We have observed the phenomenon of non-coincident centers through drilling and seismic data. Meanwhile, we have identified deep-seated magmatic activity as the primary cause of the non-coincident centers through the analysis of magnetic anomalies. This finding is further corroborated by the backstripping calculation of subsidence. Sedimentary environments, including sediment supply and transport mechanisms, are also crucial factors, but this paper focuses more on how deep-seated processes reshape the paleogeomorphology.
Comment 2: Authors mentioned, "The rationale for restoring paleogeomorphology is substantiated by the sedimentary context and paleowater depth conditions." However, it is imperative to consider that if our interpretations and analyses for restoring paleogeomorphology are solely based on these two factors, they necessitate a thorough examination of precise sedimentological data and facies analysis. Relying solely on sediment thickness, lithology, or grain size may not provide a reliable foundation for our conclusions. Sedimentary systems are inherently complex, and it would be an oversimplification to assume that deeper areas are consistently characterized by finer-grained mudstone and shallower regions by coarser sandstone. Such generalizations do not always hold true, as autogenic and allogenic processes during the deposition of sedimentary sequences can influence and complicate these relationships. Therefore, it is crucial to incorporate a comprehensive suite of sedimentological and facies data to ensure the accuracy of our paleogeomorphology restoration efforts. This will allow us to account for the intricate interplay of depositional processes and better understand the sedimentary environment of the past.
Response 2: The study does not simply assume that finer grain size equates to deeper water centers; however, in the research area, finer grain size is indicative of deeper water. Under the specific conditions of the subsiding lacustrine basin in the research area, fault activity tends to stagnate, with the primary sediment source being the Hupijiao Uplift to the north. The northern part of the research area, characterized by specific oxidized mudstone, high sand content (around 60%), and thick sandstone layers containing gravel, reflects a relatively shallow water environment. In contrast, the southern part of the research area, with reduced mudstone and low sand content devoid of gravel, indicates a deep-water environment.
Comment 3: Authors outlined, "The residual thickness approach for studying paleogeomorphology is based on the premise that the original sedimentary thickness of the strata being investigated remains relatively constant prior to denudation. In this method, a marker layer underneath the strata is chosen as the isochronous datum plane. The residual thickness between the datum plane and the top interface of the ancient geomorphology is utilized to describe the morphology of the ancient landforms that are being restored." My inquiry pertains to the nature of the marker layer and the basis for its selection. Specifically, I have raised concerns about whether the determination of this layer is solely based on composition and lithology, which, if so, may not be entirely reliable. I would like to clarify that while lithology can serve as an initial guide in identifying potential marker layers, it is not the sole criterion for selection. The reliability of the residual thickness approach hinges on the identification of a truly isochronous datum plane, which requires a layer that is time-equivalent across the study area. To ensure the accuracy of our paleogeomorphological reconstructions, geologists incorporate biostratigraphic data and sequence boundaries that provide age constraints and corroborate the isochronous nature of the chosen marker layer. This integration of sedimentological, biostratigraphic, and chronostratigraphic information is crucial for a robust interpretation of the ancient landforms.
Response 3: The selection criteria for the marker horizon are simple identification, widespread regional occurrence, and good trackability. The selection of the T30 interface as the marker horizon is not only based on lithology and composition, but also because the T30 interface represents an unconformity formed by the Yuquan Movement. In the Xihu Sag, this unconformity exhibits large-scale angular discordance, and its geological age is approximately 33.5 Ma(Tapponnier et al., 1986; Liu et al, 2020).
Tapponnier, P.; Peltzer, G and Armijo, R. On the mechanics of the collision between India and Asia. Geological Society, London, Special Publications, 1986, 19(1), 113-157.
Liu, J. S.; Xu, H. Z.; Jiang, Y. M.; Wang, J and He, X. J. Mesozoic and Cenozoic basin structure and tectonic evolution in the East China Sea basin. Acta Geologica Sinica, 2020, 94(3), 675-691.
Comment 4: In this study, authors have delineated the paleogeomorphology based on sediment thickness data, identifying the centers of layer thickness and fine-grained deposits, as well as classifying slope areas. While the use of sediment thickness data is a standard approach, I am compelled to inquire about the integration of other significant data sets that your study has access to, such as changes in logging facies, sedimentary features, lithofacies, and sedimentary facies, as indicated by drilling data. My question is why there seems to be a singular emphasis on sediment thickness data when there is a wealth of additional data at your disposal. These other data types are crucial for a comprehensive understanding of the paleogeomorphology of the primary sequence and should be integrated to support and validate each other. For instance, the slope area introduced in the A3-A4 well area should be substantiated by drilling data, which can provide further evidence of slope conditions. A holistic approach that leverages all available data is essential for ensuring a thorough and accurate reconstruction of the paleogeomorphology. It is the complexity of sedimentary systems and the interplay of various depositional processes that necessitate such a multi-faceted analysis.
Response 4: Seismic data, drilling, and core-related information have already been utilized in practical problem-solving. For example, the identification and interpretation of the T30 and SB31.2 interfaces have incorporated paleontological, astronomical cyclicity, and well logging data. However, in terms of the paleo-geomorphological restoration research that we are actually focused on, the paper does not provide extensive argumentation and description.
Comment 5: sedimentary facies, specifically the fluvial-delta and shallow lake facies mentioned: I noticed that while these facies are integral to the study, it is not immediately clear whether the interpretations of these facies are based on data collected during this study or if they are derived from other existing studies. Typically, interpretations are most robust when they are supported by data, and such foundational data is crucial for the reader to assess the validity of the conclusions drawn.
Response 5: Previous research has extensively characterized the sedimentary facies of the study area (Zhang et al., 2019; Lou et al., 2023). However, as the primary focus of this paper is on the methodologies for reconstructing ancient landscapes, a detailed examination of the sedimentary facies is beyond the scope of the current study.
Lou, Min.; Cai, H.; He X.K.; Liu, Y.H.; Huang, X.; Zhang, X.G and Liu H.F. Application of seismic sedimentology in characterization of fluvial-deltaic reservoirs in Xihu sag, East China Sea shelf basin. Petroleum Exploration and Development, 2023, 50(1), 138-151.
Zhu, Y. X.; Huang, D. W.; Wang, H.; He, X. K.; Shi, Y and She, Y. M. Sedimentary setting of thick sandstone in the 3rd member of the Oligocene Huagang Formation in A gas field in the **hu Sag, East China Sea Basin. Oil Gas Geol, 2019,40(6), 1226-1235.
Comment 6: In section- 4. Result and Verification- Could you please provide further details on how the drilling and lithology data were integrated? Were there specific algorithms, comparative analyses, or modeling techniques employed? Any additional information on this aspect of your study would greatly enhance the clarity and depth of your work.
Response 6: In the process of reconstructing the true paleogeomorphology, we use parameters such as rock porosity, rock specific gravity, zircon age, and compaction coefficient to backstrip and calculate the subsidence thickness. Specifically, we employ the Airy equilibrium model（Airy, 1855）.
|
Surface water density |
1000kg m3 |
|
Mantle density |
3200kg m3 |
|
Sandstone skeleton density |
2700kg m-3 |
|
Mudstone skeleton density |
2600kg m-3 |
|
Sandstone surface porosity |
0.46 |
|
Mudstone surface porosity |
0.46 |
|
Sandstone compaction coefficient |
0.33×10-3m-1 |
|
Mudstone compaction coefficient |
0.43×10-3 m-1 |
|
Age of SB31.23 |
31.2Ma |
|
Age of T30 |
33.5Ma |
Airy, G. B. On the Computation of the Attraction of Mountain Masses as Disturbing the Apparent Astronomical Latitude of Stations of Geodetic Surveys. Philosophical Transactions of the Royal Society.1855, v. 145,101-104
Comment 7: The deposition rates "Vs" and "V0" as key factors in your analysis. Specifically, Vs is noted as representing the deposition rate of a sample during deposition, and V0 is described as the normal lake deposition rate. These rates are fundamental to the equations and models presented in your study, and thus, understanding how they were derived is essential for a comprehensive evaluation of your work. Could you please elaborate on the methodologies and data used to determine these deposition rates? Were there specific experimental setups, observational data, or computational models employed to quantify these values?
Response 7: The abundance values of Ir and Co elements in cosmic dust exhibit a clear positive correlation. Given the average abundance of Ir in the Earth's crust is only 0.003 × 10-9, Pettersson and Rotschi (1952) and Goldschmidt (1954) proposed that the Ir content reaching several 10-6 in sedimentary rocks is primarily derived from extraterrestrial matter such as cosmic dust. This has led to the establishment of a relationship between the Ir element and sedimentation rate:
(1)
Vs' and A'(Ir) are respectively the sedimentation of sediments under normal conditions. Product rate and Ir abundance values (standard values) vs and A(Ir) are to be measured. The deposition rate of samples and the abundance value of Ir.
According to the good correlation between Ir and Co in the stratum and considering the influence of provenance on the abundance value of Co in the sedimentary stratum, Zhou (1997) and others put forward a new method to calculate the deposition rate by using the abundance value of Co with reference to formula.
(2)
Vs' and A'(Co) are the deposition rate and Co abundance values of standard samples, A "(Co) is the background abundance value of Co in the provenance of the studied sample, and K is the contribution value of provenance CO to the sample. Because there is a good correlation between Co and LREE in provenance, and the distribution of LREE in surface rocks is stable, the value of K can be found by formula (3) get.
(3)
Because the settling rate of cosmic dust is constant, the total amount of Co from cosmic dust in the stratum with an area of S and a thickness of H can be expressed as follows:
V(Co) is the sedimentation rate of Co from cosmic dust in the stratum, which is 6.48× 10-7g/cm2a, and Vs is the sedimentation rate of rocks.
In the absence of biological enrichment and volcanic activity, Co in sedimentary strata mainly comes from cosmic dust and provenance. So:
(5)
ρ is the density of sedimentary rocks (or sediments), A(Co) is the abundance value of Co in the measured samples, A"(Co) is the abundance value of Co in the original provenance, and w(Co) is the redistribution Coefficient of provenance Co in sedimentary rocks, that is, when A" (co) is a value of 10-6, the abundance value of Co from provenance in sediments.
The content of Co is mainly affected by the particle size of sedimentary rocks. According to the empirical formula, we can calculate the value of w(Co) from the particle size of the measured samples.
D is the particle size of sedimentary rocks.
Synthesizing formula (4) and formula (5), it is obtained:
V0 is based on the previous studies on the deposition rate in continental lake basins（Zhou and Wu, 2000; Wang et al 2017; Sun, 2021）.
Zhou, Y.Q.; Wu, Z.P. Study on the Time Compositional Units of Hiatus Surface[M]. Beijing: Geological Publishing House, 2000.
Wang, F.; Liu, X.; Deng, X.; Li, Y. H.; Tian, J. C.; Li, S. X and You, J. Q. Geochemical characteristics and environmental implications of trace elements of Zhifang Formation in Ordos Basin. Acta Sedimentologica Sinica, 2017, 35(6), 1265-1273.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear Authors,
I have reviewed your manuscript titled: Paleogeomorphology Restoration of Post-rift Basin from 2 Volcanic and Differential Subsidence Retrospect. I appreciate the interesting topic. The findings have the potential to contribute to future research of similar cases. However, I believe that several major changes are necessary for the manuscript to be suitable for publication.
One critical issue of this manuscript is the lack of a strong association between the study's outputs and other previous or similar studies, which weakens the support for the key findings. The first sentence of the Discussion section stated “many advantages” of the research, but these points remain vague and are only described within the narrow context of the study area. To strengthen the manuscript, it is essential to compare and integrate these findings with similar approaches and studies that have been previously published.
Incorporating a comparative analysis will not only situate the current research within the broader scientific discourse but also highlight its unique contributions and relevance. This study should logically discuss its limitations, restrictions, and requirements, which will help to clarify its advantages and demonstrate a thorough understanding of the subject matter. Addressing these aspects will provide a more balanced and critical perspective, enhancing the overall credibility and impact of the research.
Other comments and suggestions are;
Title: It should include the study area, since this manuscript is studying particular the East China Sea Shelf Basin”.
Throughout the manuscript, revise as East China Sea “S”helf “B”asin.
Abstract: The first sentence (Line 11-12) is uncertain.
Introduction: This section presents several aspects, but its chaotic structure hinders the reader's understanding of the authors' intentions and research focus. The Introduction should be significantly revised and improved to clearly state the importance of the problem being addressed, identify the gaps in current knowledge, and outline the objectives of the study or the specific research question. Additionally, given that the study area is the "East China Shelf Basin," the significance of this area should be thoroughly introduced to underscore the relevance and impact of the research.
Regional Geological Conditions: This section should describe the geographic and geologic outline of the East China Shelf Basin, including its location, size, and sediment thickness, to provide a comprehensive introduction to the study area.
Figure 1a: The inset map is too small to recognize text and outlines. Change the color of the red box to distinguish it from the color of the seismic profile line for better clarity.
Figure 1c: Provide a description of the terms T30 and SB31.2 for better understanding.
Throughout the manuscript, including Section 3.2.2, ensure that the principles of subsidence analysis, backstripping, compaction, and basin reconstruction are properly referenced to support the methodology and enhance the credibility of the study. There are many classical and recent references, which can be;
Bond, G.C., Kominz, M.A. (1984) Construction of tectonic subsidence curves for the early Paleozoic miogeocline, southern Canadian rocky mountains: implications for subsidence mechanisms, age of breakup, and crustal thinning. GSA Bulletin 95, 155–173.
Lee, E.Y., Novotny, J., Wagreich, M. (2019). Subsidence Analysis and Visualization for Sedimentary Basin Analysis andModelling. SpringerBriefs in Petroleum Geoscience & Engineering. Springer, Cham.
Lee, E.Y., Novotny, J., Wagreich, M. (2020). Compaction trend estimation and applications to sedimentary basin reconstruction (BasinVis 2.0). Applied Computing & Geosciences 5, 100015.
Sclater, J.G., Christie, P.A.F. (1980) Continental stretching: an explanation of the post-Mid-Cretaceous subsidence of theCentral North Sea basin. Journal of Geophysical Research 85, 3711–3739.
Figure 7b is unclear to understand.
Figure 8b: Tectonic subsidence? Post-rift period is predominant with thermal subsidence.
Comments on the Quality of English Languagemoderate English revision will help.
Author Response
Comment 1: One critical issue of this manuscript is the lack of a strong association between the study's outputs and other previous or similar studies, which weakens the support for the key findings. The first sentence of the Discussion section stated “many advantages” of the research, but these points remain vague and are only described within the narrow context of the study area. To strengthen the manuscript, it is essential to compare and integrate these findings with similar approaches and studies that have been previously published.
Incorporating a comparative analysis will not only situate the current research within the broader scientific discourse but also highlight its unique contributions and relevance. This study should logically discuss its limitations, restrictions, and requirements, which will help to clarify its advantages and demonstrate a thorough understanding of the subject matter. Addressing these aspects will provide a more balanced and critical perspective, enhancing the overall credibility and impact of the research.
Response 1: Agree. Thank you for pointing this out. We made an analysis and comparison of the previous methods of paleogeomorphology restoration, and expounded the advantages of this method in order to better understand the theme of the article. Mention exactly where in the revised manuscript this change can be found-Page11, Line35-343
Comment 2: Title: It should include the study area, since this manuscript is studying particular the East China Sea Shelf Basin”.
Throughout the manuscript, revise as East China Sea “S”helf “B”asin.
Response 2: Agree. We changed the title: Paleogeomorphology Restoration of Post-rift Basin from Volcanic and Differential Subsidence Retrospect inside from Xihu Sag, East China Sea.
Comment 3: Abstract: The first sentence (Line 11-12) is uncertain.
Response 3: The first sentence of the abstract aims to express that, in post-rift basins, the centers of formation thickness, subsidence, and fine-grained deposit (alternatively referred to as the water depth center) do not completely coincide. However, typically in post-rift basins, these three centers do overlap.
Comment 4: Introduction: This section presents several aspects, but its chaotic structure hinders the reader's understanding of the authors' intentions and research focus. The Introduction should be significantly revised and improved to clearly state the importance of the problem being addressed, identify the gaps in current knowledge, and outline the objectives of the study or the specific research question. Additionally, given that the study area is the "East China Shelf Basin," the significance of this area should be thoroughly introduced to underscore the relevance and impact of the research
Response 4: Agree. We have made targeted modifications to the introduction to make the structure more compact and emphasize the research content and objectives of the article. Mention exactly where in the revised manuscript this change can be found-Page2, Line47,55-60,67-70,87-91
Comment 5: Regional Geological Conditions: This section should describe the geographic and geologic outline of the East China Shelf Basin, including its location, size, and sediment thickness, to provide a comprehensive introduction to the study area.
Response 5: Thank you for pointing this out. I agree with comments. Therefore, We added relevant contents in the regional Geological Conditions. Mention exactly where in the revised manuscript this change can be found- Page3, Line96-101
Comment 6: Figure 1a: The inset map is too small to recognize text and outlines. Change the color of the red box to distinguish it from the color of the seismic profile line for better clarity.
Response 6: Agree. We enlarged the inset map and changed the color of the red box. Mention exactly where in the revised manuscript this change can be found-Page3, Line105-108
Comment 7: Figure 1c: Provide a description of the terms T30 and SB31.2 for better understanding.
Response 7: We deleted Figure 1c in order to create unnecessary misunderstanding.
Comment 8: Throughout the manuscript, including Section 3.2.2, ensure that the principles of subsidence analysis, backstripping, compaction, and basin reconstruction are properly referenced to support the methodology and enhance the credibility of the study.
Response 8: Agree. According to these articles, we revised some terms. Mention exactly where in the revised manuscript this change can be found-Page1, Line21; Page6, Line180, 201; Page8, Line253 and so on
Comment 9: Figure 7b is unclear to understand
Response 9: Figure 7b shows the paleo-water depth recovered by semi-quantitative element ratio in Well C2 and the paleo-water depth quantitatively recovered by using Co element.
Comment 10: Figure 8b: Tectonic subsidence? Post-rift period is predominant with thermal subsidence.
Response 10: Tectonic subsidence includes the concept of thermal subsidence. In the post-rift stage, the amount of thermal subsidence in the study area is approximately equal to the amount of tectonic subsidence. In order to avoid ambiguity, we have modified Figure 8b. Mention exactly where in the revised manuscript this change can be found-Page13, Line396
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsDear Authors,
Thank you for your revisions. Some minor comments are suggested.
The title is still quite awkward due to the phrase "retrospect inside from.” How about changing it to: "Paleogeomorphology Restoration of Post-Rift Basin: Volcanic Activity and Differential Subsidence influences in the Xihu Sag, East China Sea."
Line 21: Consider rephrasing to "Software computing quantitative subsidence."
Lines 55-70 require proper and additional references, particularly when discussing the formation of the East China Sea Shelf Basin. For the concepts of subsidence analysis and thermal evolution, I suggest the following references:
Lee et al. (2019) "Subsidence Analysis and Visualization: For Sedimentary Basin Analysis and Modelling." https://doi.org/10.1007/978-3-319-76424-5
Kim et al. (2020) "Numerical Modelling to Evaluate Sedimentation Effects on Heat Flow and Subsidence during Continental Rifting." Geosciences. https://doi.org/10.3390/geosciences10110451
The English writing should be improved, but I believe MDPI will manage this aspect.
Comments on the Quality of English LanguageThe English writing should be improved.
Author Response
Comments 1: The title is still quite awkward due to the phrase "retrospect inside from.” How about changing it to: "Paleogeomorphology Restoration of Post-Rift Basin: Volcanic Activity and Differential Subsidence influences in the Xihu Sag, East China Sea."
Response 1: Agree. We have, accordingly, revised the title. Thank you for pointing this out. Mention exactly where in the revised manuscript this change can be found-Page1, Line1-4.
Comments 2: Line 21: Consider rephrasing to "Software computing quantitative subsidence."
Response 2: Thank you for pointing this out. We agree this comment. The semantics are clearer after the modification. Mention exactly where in the revised manuscript this change can be found-Page1, Line21.
Comments 3: Lines 55-70 require proper and additional references, particularly when discussing the formation of the East China Sea Shelf Basin. For the concepts of subsidence analysis and thermal evolution, I suggest the following references:
Lee et al. (2019) "Subsidence Analysis and Visualization: For Sedimentary Basin Analysis and Modelling." https://doi.org/10.1007/978-3-319-76424-5
Kim et al. (2020) "Numerical Modelling to Evaluate Sedimentation Effects on Heat Flow and Subsidence during Continental Rifting." Geosciences. https://doi.org/10.3390/geosciences10110451
Response 3: Agree. Thank you for pointing this out. These additional references can greatly enhance the credibility of the article. Therefore, we have added relevant references. Mention exactly where in the revised manuscript this change can be found-Page2, Line66.
