Mineralogy, Geochemistry, and Stable Isotopes (C, O, S) of Hot Spring Waters and Associated Travertines near Tamiahua Lagoon, Veracruz, Gulf of Mexico (Mexico)
, Marco Antonio Rubio-Ramos 4 and Jesús Solé 2
Round 1
Reviewer 1 Report
The manuscript by Porras Toribio et al., presents a very interesting case of an aragonite travertine in a coastal area containing rocks that are oil reservoirs. Additionally, the spring activity was related to human activities in the area, therefore anthropogenic. The chemistry of these carbonates, of the associated mineral phases and waters is presented here with the aim of identify the origin of the waters feeding the hot springs, as well as the potential factors leading to aragonite precipitation. In summary, I think this manuscript is appropriated to be published, after moderate corrections, in Minerals.
The manuscript is well organized, the abstract is illustrative of the work presented here, and the title is also appropriated. The Methods section is very well explained, and the methodology applied by the authors look completely appropriate to achieve the main goals they proposed. Maybe this Methods section is a bit long, so try to make it slightly shorter would be recommendable.
I miss some petrographic descriptions in Results section that include the type of facies (crystalline crusts, rafts, etc.) and crystal morphologies. Mentions to fibrous aragonite crystals or similar can be found in the Discussion section but not in the Results section, where they should be. The distribution of the different facies as well as of the aragonite need some clarifications; is there any variation from the spring to the distal areas in facies and mineralogy? Is aragonite precipitating from waters with temperatures below 30 oC? This can be of importance in the discussion about the factors controlling aragonite precipitation.
Figures and tables are generally good. However, some improvements are recommended. Figure 2: colours could be slightly different; it is difficult to distinguish the Miocene (conglomerate) from the Quaternary (lagoon sediment). Maybe different colours would help to make the figure clearer and more visual.
Table 2: please put in bold the headings of the different portions of the table. The same in Table 3. Table A1 has a confusing heading, please reorganize that.
Some detailed comments and questions are the following:
L. 17-18: I think this phrase needs revision. Formally the shot spring does not precipitate travertine. Travertine does precipitate from waters emerging from a hot spring, or travertine is forming around a hot spring. Maybe something like: “Laminated travertine forms in and around an active hot spring in…” (just changing the order within the sentence). The same in Lines 78-79.
Line 22: it is generally accepted to reserve the name sinter for the silica analogues of travertines. Duricrust is a term of common use in soil science that may be confusing in this context. So, in my opinion would be better to delete sinter duricrusts or change to travertine.
L. 43: maybe “shallow” is not a good term to describe travertines (nor tufas); shallow implies that these are mainly submerged sedimentary systems. However, travertines display a wide range of situations from relatively deep lacustrine-like subenvironments (fitting with “shallow”) to subaerial.
L. 55-56: it is true that the most common situation is that of aquifer rocks dissolved by hard waters are carbonates. However, there are other situations that are not uncommon at all. Siliceous rocks of different origins as volcanic (for example, your reference 10 or Gibert et al., 2009 in Argentina, etc.), plutonic and metamorphic rocks (Giampouras et al., 2019, 2020) may supply Ca and other elements found in travertine.
L. 166-167: does it work at low vacuum conditions? Please, clarify how it works without sputtering of gold, carbon or similar.
L. 288: I would suggest avoid the use of abiotic. It literally means without life. Microbes are present even in the most extreme cases of high crystal growth rates (see Shiraishi et al., 2019; Okumura et al., 2013 Geobiol. Journal). Other question is how much they influence the final result. I would suggest terms like “dominantly abiogenic/inorganic”.
L. 300: lamination can be associated with changes in precipitation rates, but also with other factors and these variations can be periodic or not. Each lamination needs to be studied to understand what exactly it means. See for example that the meaning and rhythm of the lamination in the case of an anthropogenic system strongly dominated by interruptions in water flow and CaCO3 precipitation (see Rodriguez-Berriguete et al. 2018) is not the same to that of systems with other sedimentary/hydrological dynamics (see for example your references 19-21). The time represented by each lamina or sets of laminae can also be different in each case. Also, in Line 316 would be recommended to change abiotic to abiogenic.
L. 378-393: maybe a short description of the mineral habits of the main minerals of this travertine would be nice.
L. 431: white or while?
L. 462-465: the isotope fractionation equation you used is that of Kim et al., 2007; however, this equation works in the range of 0-40 oC. I do not know if this equation can be satisfactorily used above its range and if it may work. Other equations can be appropriated as for example that of Zhou & Zheng (2003) (0-70 ºC). Please, clarify why you choose the equation.
L. 643-647: about the factors leading to precipitation of aragonite instead of calcite, temperature may favour supersaturation in both aragonite and calcite; there are many cases of high temperature spring waters (>60 ºC) precipitating calcite but not aragonite (see for example Jones et al., 2000). The presence of cations such as Sr may favour the formation of aragonite instead of calcite by helping in its nucleation and also being easily incorporated into aragonite (Sunagawa et al., 2007; Dietzel et al., 2004); however, supersaturation should be reached, and calcite generally requires lower supersaturation than aragonite (Fernández-Díaz et al., 1996). Mg but also other ions (SO42-, Na, etc.) may have an inhibitory effect on calcite precipitation that may help to reach higher supersaturations without calcite precipitation, allowing aragonite precipitation. Therefore, aragonite formation could be driven or controlled by combination of several factors. In fact, you collected samples from low temperature sites where aragonite precipitated, but also in those with higher temperatures. The solubility and physic-chemical state of the waters should evolve from the spring to the distal areas. Therefore, should be a mechanism that allows the water to precipitate aragonite, despite the decrease in temperature (increase in solubility of carbonates), progressive decrease in pCO2 due to degassing, and inhibiting calcite precipitation along the deposit. Please, consider all these questions in the discussion.
L. 659: this is the first time where I clearly see a description of the crystal morphology. Please include descriptions in Results section.
L. 660: add 2 to CO
L. L. 671-672: not sure of this statement. Maybe something less strict, like dominantly inorganic, would be better. The role of microbes even in high temperature environments can be varied (see Jones & Renaut, 2010). They may act as templates or they may play a secondary role in laminae or other facies formation, although even in such cases may help to imprint some final features to the travertine (your references 19-21, 77, and also Rodríguez-Berriguete et al., 2018).
L. 690-693 and 697-698: please, consider that although the origin of the carbonate maybe are the Mesozoic limestones, other possibilities should be taken into account: mixing of waters within the aquifer, contributions from other rocks (non-carbonates), and different fractionations due to processes within the aquifer (dissolution/degassing of CO2, precipitation of minerals like ankerite, calcite, or others) may impact the final isotope signal and chemical water composition. Sr values may be of help.
L. 736-737: please check the grammar
L. 737-738: this is an important question. Why such change in temperature? Different water sources, mixing of waters, differences in flow velocity within the aquifer (fast flow from deeper points to the surface in the spring, very slow movement in other points allowing cooling of water), …? At this respect, see an example of diagenesis of lacustrine rocks due to circulation of waters that also deposited travertine at surface (Rodríguez-Berriguete et al., 2017). Where waters have a fracture to reach the surface, they move through it. However, these waters can also flow slowly through more permeable rocks producing dissolutions, cementations and strong neomorphism, which implies lost or gain of Ca, carbonate, etc. and the incorporation of minor elements.
L. 742-743: extensional zone?
L. 749-750: 18O signature of waters and then of the carbonates precipitated from them is strongly linked to meteoric waters feeding the aquifer. Isotopic shifts are not very common in most systems, even in those with relatively high water-temperatures. Therefore, is hard to say that the oxygen isotope signal could be indicative of meteogene or thermogene origin of the CO2. This can be done by using just 13C, as it was defined by Pentecost (2005). For example, waters forming the deposits of your reference 77 have meteoric values, related to those of rainwaters of the area and being compatible to aquifer recharge at relatively high altitudes, above 1600 m asl.
L. 755-757: it is not clear why low Ba and high Sr points to limestones and evaporites as source rocks. Why carbonates and evaporites and no other types of rocks? See Rodríguez-Berriguete and Alonso-Zarza, 2019: this is an example of aragonite with low Ba and relatively high Sr contents in a setting lacking carbonates and evaporites. Please, explain better how you reached this conclusion about the source rocks.
L. 785-786: better “oil reservoir” or “reservoir rock”?
Congrats for your very nice work! All the best
Author Response
Please, see the attached document.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Mineralogy, geochemistry, and stable isotopes (C, O, S) of low-temperature hot spring waters and associated travertines from the Tamiahua Lagoon, Veracruz, Gulf of Mexico
Israel Porras Toribio, Teresa Pi Puig, Ruth Esther Villanueva-Estrada, Marco Antonio Rubio, and Jesús Solé
This work described water and minerals from a hot spring close to a coastal lagoon in Mexico. It shows comprehensive data on mineralogy, elemental composition and stable isotopes in travertine minerals along with analysis of nearby waters. They conclude that the influences of temperature and the mixed origin of brines predominate on the minerals and elemental composition of the travertines.
The contributions of microorganisms to the travertines minerals and structures were considered negligible. Was this assumption based on observations, or was it based on the temperature measured (70oC), which is close to the maximum temperature where photosynthetic microorganisms have been observed? On the other hand, there are thermophiles and hyperthermophiles able to thrive on hydrocarbons, sulfide and Fe(II) oxidation, and thus photosynthesis is not a sine qua non condition for microbial life in such settings.
Minor considerations:
Line 2 (Title): the travertines are not from the lagoon; please correct the title.
Line 18: Please state that this place is in Mexico.
Line 25: gypsum and/or anhydrite?
Lines 43-46: This sentence states that all travertines arise in hot spring settings. Please correct it.
Line 113: modified from Maldonado Lee et al., 2004?
Line 122: Is TL for Tamiahua Lake? Please maintain the same nomenclature throughout the text.
Line 122: area of 30 km2?
Line 124: fire estiguished?
Line 132: Please provide a title for Figure 3.
Line 185: did you use CoKα and CuKα at the same time?
Line 246: Is the hydrothermal system of the Tamiahua Lagoon, or the lagoon region region?
Lines 253-255: Respectively does not fit well, since there are 5 analysis and 4 bottles of brines.
Lines 263-264: It is not clear the role of polyethersulfone.
Lines 264-265: What was the final concentration of HNO3?
Line 288: The same as the comment for line 122.
Lines 293-295: Did you consider the possibility that chemotrophic microorganisms living on crude oil or sulfide oxidation could thrive in the travertines and change the patterns of mineral deposition? Anyway, this sentence is not very clear must be re-written, specially on line 295 (“not being closer to”).
Lines 302-303: What do you mean by “actual formation”?
Line 326 (Figure 5): Please increase the size of lettering in the figures, specially (d). Please maintain lettering size throughout the figure.
Line 327 (caption of Figure 5): Please provide a title for the figure.
Line 329 (caption of Figure 5): What do you mean by “radial habits”? Crystalline habits, of arrangement of crystals?
Lines 331, 333 and 339: what are the samples 1.2 cima, 1.1 and Tam AC? They are not listed in Table S1 (there is no other comprehensive list of samples). Please maintain nomenclature of the samples throughout the manuscript. Use of quotation marks, parenthesis and/or citation of Table S1 could also help understanding that these are the names of the samples and to follow the other results obtained from them.
Line 343 (Figure 6): The images in this figure would fit better if they were separated into two figures. Maybe you could separate aragonite from the other minerals.
Line 384: Was fluorite identified only by SEM? How was goethite identified in the SEM, considering that there are other Fe oxides in the sample?
Line 385: Is SEM for scanning electron microscopy?
Line 394 (Figure 7): Spectra in (a-c) are very confusing because there is too many marks for minerals. Maybe it would be better if the main peaks for each mineral were marked with letters.
Line 396 (Caption of Figure 7): Please be consistent in the names of the samples throughout the manuscript.
Lines 397-411 (Figure 8): Please mark the images and the spectra a-e. Please mark in the images the detrital quartz, celestine crystals, and native sulfur crystals. Where all these minerals identified by XRD? If not, how where they identified?
Line 418: Please put some marks showing where are quartz, celestite and aragonite in the figure. With such a variety of minerals, how can you be sure of their identification? Have you done EDS in this area? A minor issue: please maintain either celestine or celestite throughout the text.
Line 422: Table 2?
Line 422: I could not find Figure 9.
Line 423: It TL for Tamiahua Lagoon? Please be consistent throughout the text.
Figure 10a: The names of some ions are incomplete. Are they Cl-, HCO3- and CO32-??
Figures 10a and 10b: Please join the figures and make a single caption.
Line 535: In Table 5 Li+ is 20 mg/L in the terraces. Please correct the text or the table.
Figures 11a and 11b: Please put the captions of figure 11 a and b together.
Line 585: possibly?
Line 638: Calcite occurs in Tamiahua travertines only as a minor phase of low crystallinity. ?
Lines 658 and 668: Do you mean microfacies, or microfabrics?
Line 680: light rare earth?
Line 692: characteristic of the oil fields?
Line 704: Sulfate reduction by bacteria is known for consuming H+:
2(CH2O)n + SO42- + 2H+ => 2nCO2 + H2S + 2H2O (oxidizing organics)
4H2 + SO42- + 2H+ => H2S + 4H2O (oxidizing H2)
Indeed, in sulfidogenic marine sediments it is common that the pH is one unity above seawater.
Line 706: SO2 or SO42-?
Lines 708-710: The content of this paragraph is irrelevant and/or out of the context.
Lines 724-725 (caption for Figure 13): Please explain in the caption the meaning of the purple stars and the dashed area.
Line 759: analyses?
Line 764: “high content of Mg to Ca in solution” seems out of context or a language mistake.
Author Response
Please, see the attached document.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear Authors, I have reviewed the manuscript entitled: "Mineralogy, geochemistry, and stable isotopes (C, O, S) of low-temperature hot spring waters and associated travertines from the Tamiahua Lagoon, Veracruz, Gulf of Mexico" submitted to Minerals by Porras Toribio et al.
The paper presents new interesting data on hot spring waters and associated travertines from the Tamiahua Lagoon. I have found the manuscript well written and organised although, in some parts, the main text has formatting errors suggesting that the paper was a little bit hurried written. Figure 9 is missed in the main text.
Please, the manuscript should be carefully revised by an expert English speaker. Minor corrections and suggestions are provided in the attached annotated PDF.
Best Regards
Comments for author File: Comments.pdf
Author Response
Please, see the attached document.
Author Response File: Author Response.pdf
