Articles | Volume 13, issue 9
© Author(s) 2022. This work is distributed underthe Creative Commons Attribution 4.0 License.
Multiscale lineament analysis and permeability heterogeneity of fractured crystalline basement blocks
- Final revised paper (published on 09 Sep 2022)
- Supplement to the final revised paper
- Preprint (discussion started on 27 Apr 2022)
- Supplement to the preprint
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
: Report abuse
RC1: 'Comment on egusphere-2022-255', Anonymous Referee #1, 04 Jun 2022
- AC1: 'Reply on RC1', Alberto Ceccato, 11 Jul 2022
RC2: 'Comment on egusphere-2022-255', Anonymous Referee #2, 29 Jun 2022
- AC2: 'Reply on RC2', Alberto Ceccato, 11 Jul 2022
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Alberto Ceccato on behalf of the Authors (11 Jul 2022) Author's response Author's tracked changes Manuscript
ED: Referee Nomination & Report Request started (11 Jul 2022) by Stefano Tavani
RR by Anonymous Referee #1 (04 Aug 2022)
ED: Publish subject to minor revisions (review by editor) (04 Aug 2022) by Stefano Tavani
AR by Alberto Ceccato on behalf of the Authors (04 Aug 2022) Author's response Author's tracked changes Manuscript
ED: Publish as is (04 Aug 2022) by Stefano Tavani
ED: Publish as is (04 Aug 2022) by Federico Rossetti(Executive editor)
AR by Alberto Ceccato on behalf of the Authors (18 Aug 2022) Author's response Manuscript
Review of the manuscript “Multiscale lineament analysis and permeability heterogeneity of fractured crystalline basement blocks” by Alberto Ceccato and coauthors.
The paper presents a multiscale geometrical analysis of lineaments within a granodiorite pluton in the basement of the southwestern Norway, based on the interpretation of a DTM (Digital Terrain Model) at the 1:100000, 1: 25000 and 1:5000 scale, and an UAV-mapped zone at the 1:100 scale.
The paper is well written, and figures are adequately illustrating the results. The proposed methodology combines several methods used in previous studies, including box-counting on lineament maps, fracture orientations, fracture length cumulative distributions, fracture spacing distribution along virtual scanlines, fracture intensity and density at multiple scales. The analytical procedure is repeated also on fractures subdivided by set, allowing to define a hierarchical organization of the fracture network, with fractures controlling the network at the regional scale (type B fractures) and the other sets (type A fractures) having effects at smaller scales. These data are then discussed on the basis of detailed field and petrophysical data published by the same authors, and a conceptual model of the fracture permeability of the Rolvsnes granodiorite is proposed.
The paper is well suited to be published in this journal. I have some concerns about the analytical design and methodological approach, as discussed in the general comments below. Due to these issues, the paper needs some revisions before publication.
Line by line comments
Lines 12-14: check this statement, which contradicts the following sentence (is there a scale-invariant spatial distribution or not?). See also general comment 1.
Line 14: the symbol is missing
Line 49 – Paragraph 1.2 doesn’t seem necessary; the structure of the paper is quite conventional. Consider removing this paragraph, which basically anticipates the information given in a more detailed way in the Geological setting and Methods sections.
Lines 98 – 106: it would be useful to introduce in Fig. 1 a sketch shoving the orientation of the structures (faults and fractures) associated with each tectonic stage. Here, you could add some information about the dip angles: are fractures all subvertical, therefore justifying your analytical approach in map view? Are there oblique sets?
Lines 114 – 119: the relationships with the offshore reservoir could be mentioned in the introduction.
Line 120: delete “Materials and”
Lines 159 – 199: I’m a little confused about the procedure of fitting single-scale and multiscale cumulative distributions. For single scale data, you test three possible distributions and score the best one fitting truncated or non-truncated data. For multiscale analysis, you assume that all distributions are fitted by a power law, without truncation. I think that you should clarify your reasoning here. You might try to fit the multiscale power law distribution by using truncated data (see for instance Chabani et a., 2021).
Lines 229 – 230 and 237 – 238: 3 intersections per scan line are very few for these considerations – if your dataset does not fulfil the requirements for a statistically meaningful analysis, it’s better not to perform that analysis.
Lines 242 – 251: this is merely a list of the number of picked lineaments – could you add some qualitative description about length, intersections, orientations? The lack exposure below the sea level can be introduced here.
Line 252: already commented, consider the effects of the fragmented exposures.
Line 275: remove reference to Dichiarante et al., 2020
Lines 271 and following lines: here, you could mention which of the datasets meet the minimum number of 200 fractures (now only in the supplementary material)
Lines 282 – 287: as commented above, the multiscale cumulative length distribution is not that robust, because there is a significant range of fracture lengths which is not covered by data (the tens of metres range), and both the large scale fracture lengths (1:100) and the small scale fracture lengths (1:100000) are not fit by a power law (if I understood well Table 3). To overcome this last point, you might consider only the part of the distributions having a power-law distribution for the multiscale fit. Lower and upper cut of the power-law distributions can be obtained statistically with the MLE method of Clauset et al (2009) (https://aaronclauset.github.io/powerlaws/).
Line 298: what does it mean a decreasing trend?
Line 300: “.;” > “,”
Lines 321-322: see comment above about cumulative length distribution.
Line 327: and what about P21?
Lines 339 – 340: it is probably Fig. 6 and not 5
Line 347: check the sentence
Line 373 and following lines: as suggested in the general comments, the possible biases due to the outcrop shapes are not considered. I suggest evaluating them as well.
Clauset, C.R. Shalizi, and M.E.J. Newman, "Power-law distributions in empirical data" SIAM Review 51(4), 661-703 (2009)