Base-Level Fluctuation Controls on Migration of Delta Lobes: A Case Study from the Paleogene Shahejie Formation in the Huimin Depression, Bohai Bay Basin, NE China

Round 1

Reviewer 1 Report

Dear Authors,

I finished the review of your manuscript entitled " Base-level fluctuation controls on migration of delta lobes: a case study from the Paleogene Shahejie Formation in the Hui-3 min Depression, Bohai Bay Basin, NE China", which I found it interesting and with merits to become suitable for publication. However, the manuscript needs substantial retooling and amendment before it can be accepted for publication. My main comments are as follows:

(1)  Establishment of the sequence stratigraphic framework is the foundation of the depositional systems analysis. Thus, the authors should introduce the sequence stratigraphic framework first and then disrobe the depositional systems.

(2)  What are the relationships between HST, TST, LST and the four fourth-order sequences? It is not recommended to use both three-order and fourth-order sequences in one paper.

Please consult recent references about the basin fill of rift basins. For example.

Maravelis, A.G., Boutelier, D., Catuneanu, O., Seymour K.St. and Zelilidis, A. (2016). A review of tectonics and sedimentation in a forearc setting: Hellenic Thrace Basin, north Aegean Sea and mainland Greece. Tectonophysics 674, 1–19.

Liu Entao, Wang Hua, Li Yuan, et al. 2014. Sedimentary characteristics and tectonic setting of sublacustrine fans in a half-graben rift depression, Beibuwan Basin, South China Sea. Marine and Petroleum Geology, 52: 9-21.

(3)  The evidences for the changes in both accommodation space and base-level fluctuations are needed in the paper. For example, during the deposition of MSC3, the accommodation space decreased and the base-level decreased. There is no evidence to support such interpretations. Rift basins have their accommodation history strongly related to their mechanical subsidence regime, with episodic pulses of extension that create space for sediment accumulation at very fast rates. Is there any controlling effect of tectonic quiescence in accommodation space in this study area? I strongly suggest you give evidence for the evolution of base-level changes.

(4)  The is no sedimentological evidence to support the interpretation of the depositional environments. I strongly suggest the authors to include a comprehensive facies analysis section with the description of the rock images being separate from the interpretations. Some useful works that could help the authors prepare the section could be:

Huang, Y., Yao, G., Fan, X., 2019. Sedimentary characteristics of shallow-marine fans of the Huangliu Formation in the Yinggehai Basin, China. Mar. Pet. Geol. 110, 403-419.

(5)  Sequence sand control model: how about the controlling effect of sediment supply, tectonic activity and paleogeomorphology?

(6)  Introduction: Given the mention of research significance in the abstract.

Author Response

Thanks a lot for the constructive comments by the reviewer!

(1)  Establishment of the sequence stratigraphic framework is the foundation of the depositional systems analysis. Thus, the authors should introduce the sequence stratigraphic framework first and then disrobe the depositional systems.

Re: Thanks a lot for the reasonable suggestion! We introduced the sequence stratigraphic framework at first and sedimentary facies secondary in revision.

 

(2)  What are the relationships between HST, TST, LST and the four fourth-order sequences? It is not recommended to use both three-order and fourth-order sequences in one paper.

Please consult recent references about the basin fill of rift basins. For example.

Maravelis, A.G., Boutelier, D., Catuneanu, O., Seymour K.St. and Zelilidis, A. (2016). A review of tectonics and sedimentation in a forearc setting: Hellenic Thrace Basin, north Aegean Sea and mainland Greece. Tectonophysics 674, 1–19.

Liu Entao, Wang Hua, Li Yuan, et al. 2014. Sedimentary characteristics and tectonic setting of sublacustrine fans in a half-graben rift depression, Beibuwan Basin, South China Sea. Marine and Petroleum Geology, 52: 9-21.

Re: Thanks a lot for the reasonable suggestion! We followed it in revision by replace HST, TST, LST by base-level cycles. And thanks again for references recommended.

 

(3)  The evidences for the changes in both accommodation space and base-level fluctuations are needed in the paper. For example, during the deposition of MSC3, the accommodation space decreased and the base-level decreased. There is no evidence to support such interpretations. Rift basins have their accommodation history strongly related to their mechanical subsidence regime, with episodic pulses of extension that create space for sediment accumulation at very fast rates. Is there any controlling effect of tectonic quiescence in accommodation space in this study area? I strongly suggest you give evidence for the evolution of base-level changes.

Re: Thanks a lot for the correction! We made a mistake in this paragraph. And we corrected it in the revision.

 

(4)  The is no sedimentological evidence to support the interpretation of the depositional environments. I strongly suggest the authors to include a comprehensive facies analysis section with the description of the rock images being separate from the interpretations. Some useful works that could help the authors prepare the section could be: Huang, Y., Yao, G., Fan, X., 2019. Sedimentary characteristics of shallow-marine fans of the Huangliu Formation in the Yinggehai Basin, China. Mar. Pet. Geol. 110, 403-419.

 

Re: Thanks a lot for the reasonable suggestion! We followed it in revision. And thanks a lot for the reference recommended.

 

(5)  Sequence sand control model: how about the controlling effect of sediment supply, tectonic activity and paleogeomorphology?

Re: Thanks a lot for the reasonable suggestion! We added these factors in discussion in revision.

 

(6)  Introduction: Given the mention of research significance in the abstract.

Re: Thanks a lot for the reasonable suggestion! We followed it in revision.

Reviewer 2 Report

Dear authors, congratulations. The study aims to demonstrate the sedimentary facies of Shahejie Formation. The manuscript is well-written. The figures are high quality. I suggest accept.

Author Response

Dear Reviewer,

 

Thanks a lot for your positive comments!

 

Renchao

Reviewer 3 Report

Please see the annotated PDF file of the MS  in which I explained some important key issues of the manuscript.

Here are also some hints for you.

1. The manuscript suffers from poor English writing. It is very hard to understand what the authors wish to say in some sentences. Although I made some editions and corrections in the annotated PDF file, but it is not normally the reviewer’s job. Thus, I strongly recommend the authors to run a serious edition by an English native speaker. Verbs are used in form of simple present mixed by simple past.

2. Terminology are misleadingly used in the text. For example, they used “microfacies” to describe lithofacies, packsand instead of what!!, isogram instead of isopach map, sand dam (was presumably) used instead of sand bar? and tissue structure instead of texture (see line 102 for the last example); and the annotated PDF file for many instances. The authors are strongly recommended to see Reading, 1986; Flugel, 2010 for this fundamental issue.  

3. Citations of the references in the MS text must be given in chronologic order (see lines 55-57 for example).

4. Some figures were inappropriately prepared. For example, the scale division and format of SP, Sonic, Resistivity and GR logs in Figs. 3 and 4 were not prepared in a standard format (See Asquith and Gibson, 1983; Serra, 1984; Rider, 2002 for instances).

5. Many of the data and materials which were used to prepare the article were not introduced in the Method and materials Section. For example, see line 123 in the Result Section, where they talk about core data, while it wasn’t addressed in the Method and materials Section. It is not clear to the readers that the cores are from what well(s)? and how long was the core interval?

6. Interpretations of facies associations and sedimentary structures are not supported by evidences. Seemingly, these interpretations are adapted from literatures and/or they are driven from the authors speculations, rather than to be supported by adequate data, evidences and arguments (see lines 217-239 for instance).

7. It is not clear for me that how the authors distinguished the maximum flooding surface (MFS) and the regressive surface within the depositional sequences (see Fig. 15).

Comments for author File: Comments.pdf

Author Response

Many thanks for the constructive comments by the reviewer! 

 

1. The manuscript suffers from poor English writing. It is very hard to understand what the authors wish to say in some sentences. Although I made some editions and corrections in the annotated PDF file, but it is not normally the reviewer’s job. Thus, I strongly recommend the authors to run a serious edition by an English native speaker. Verbs are used in form of simple present mixed by simple past.

Re: Thanks a lot for your comments and corrections! We followed all your corrections. We also asked a native English speaker, Prof. Nils Lenhardt at University of Pretoria, South Africa to polish the English again.

 

2. Terminology are misleadingly used in the text. For example, they used “microfacies” to describe lithofacies, packsand instead of what!!, isogram instead of isopach map, sand dam (was presumably) used instead of sand bar? and tissue structure instead of texture (see line 102 for the last example); and the annotated PDF file for many instances. The authors are strongly recommended to see Reading, 1986; Flugel, 2010 for this fundamental issue.

Re: Sorry for the abuse of these terminologies! We checked them all in the revision. We changed “microfacies” to “lithofacies” and “detailed sedimentary facies”, “packsand” should be “fine-grained sandstone”. “sand dam” was instead by “sand bar”. “tissue structure” replaced by “texture”. And we revised all annotations in the attached PDF file according to references Reading, 1986; Flugel, 2010.

 

3. Citations of the references in the MS text must be given in chronologic order (see lines 55-57 for example).

Re: Thanks a lot for the reasonable suggestion! We changed the orders of all references in revision.

 

4. Some figures were inappropriately prepared. For example, the scale division and format of SP, Sonic, Resistivity and GR logs in Figs. 3 and 4 were not prepared in a standard format (See Asquith and Gibson, 1983; Serra, 1984; Rider, 2002 for instances).

Re: Many thanks for the reasonable suggestion! We followed it in revision.

 

5. Many of the data and materials which were used to prepare the article were not introduced in the Method and materials Section. For example, see line 123 in the Result Section, where they talk about core data, while it wasn’t addressed in the Method and materials Section. It is not clear to the readers that the cores are from what well(s)? and how long was the core interval?

Re: Thanks a lot for the reasonable suggestion! We added it at the end of the section of Data and Method in revision.

 

6. Interpretations of facies associations and sedimentary structures are not supported by evidences. Seemingly, these interpretations are adapted from literatures and/or they are driven from the authors speculations, rather than to be supported by adequate data, evidences and arguments (see lines 217-239 for instance).

Re: Thanks a lot for the reasonable suggestion! We followed it in revision. Because the lack of wells and cores from the inferred delta plain area, we omitted this paragraph in the revision.

 

7. It is not clear for me that how the authors distinguished the maximum flooding surface (MFS) and the regressive surface within the depositional sequences (see Fig. 15).

Re: Thanks a lot for the reasonable suggestion! This figure is a depositional model for the research area. The maximum flooding surface (MFS) is inferred when the lake transgressive to its highest point at which mudstone well developed and sandstone not developed.

 

Round 2

Reviewer 1 Report

I am glad to see the major changes you have made, which have significantly improved the academic level of this paper. It can be accepted for publication after minor spell and grammar checks.