Early Triassic Conversion from Source to Sink on the Southern Margin of the North China Craton: Constraints by Detrital Zircon U-Pb Ages

Round 1

Reviewer 1 Report

The manuscript discusses the provenance of Lower Triassic sedimentary rocks from the Yiyang area from the Northern China Craton. The study presents petrography of 17 samples and detrital zircon geochronology from 2 samples from the Liujiagou- and Heshanggou Formations. Both petrography and detrital zircon geochronology are used to discuss the provenance of the studied rocks and from this to discuss the Mesozoic basin development in the Northern China Craton.

I find that the manuscript contain interesting data, a well-funded discussion, it is well organized and include the necessary sections and tables and figures. My main concern is that language in the text in often quite poor and certain aspects are not well described mainly due the language issues, it seems. Figure caption could be expanded for most of the figures and I think that the method section should be expanded.

Title: Could maybe include that the study concerns Triassic rocks.

Abstract: OK but language should be improved.

1 Introduction: Should be improved – mainly the language.

2 Geological setting: OK – however the last section is poorly written.

3 Sampling and analytical methods: Overall OK, but the zircon U-Pb method should be improved - it is not ambiguously enough just to refer to a 10 years old article for analytical parameters.

4 Results: Needs better explanations – especially the second paragraph in section 4.1 is not well written and it is difficult to follow the logic.

5 Discussion: OK

6 Conclusion: OK

Figures overall OK - but text in the caption should be expanded.

Figure1: OK - but why are the study are not shown as a Mesozoic basin? Also there is a lot of reference to NQOB and SQOB and in the conclusion there is reference to IMPU, why are none of these shown in figure 1?

Figure 2: OK

Figure 3: OK

Figure 4: OK

Figure 5: OK

Figure 6: OK

Figure 7: OK - but explain in the caption to which unit the samples (Y-L and Y-H) belong.

Figure 8: OK – but like in figure 7 but explain in the caption to which unit the samples (Y-L and Y-H) belong.

Figure 9: OK – might be helpful to explain in the caption how the diagrams are ordered.

Figure 10: OK

Table 1: OK

Line 9: Using “the” too much (and check throughout the text).

Line 30-32: “As the….” Suggest that some point is made, but the point is missing.

Line 30-32: I can see that basins depend on orogens but how does orogens depend on basins?

Line 35: “Zircons have…” rewrite sentence. E.g. Zircon grains are robust and resistant to weathering and due to high closure temp record igneous events.

Line 45: “, which experienced…” this sentence does not make sense.

Line 48-54: “However…” Very long sentence and very difficult to understand what the point is. Try to split sentence and check the language.

Line 62: What is meant with “ synchronous work published previously”?

Line 86: “inherits …” seems to be the wrong word. Maybe “has the same…” is better.

Line 87-90: “With…” poor language – reformulate sentence.

Line 97-111: This explanation of the sedimentary units should be improved - both in language and in detail. What is e.g. “rich boulder clay…”?

Line 114: “in the Yiyang area and sampling…” change to “with stratigraphic location shown..”

Line 118: “minimize the influence of composition..” what is meant by this?

Line 133-145: Should be expanded and e.g. include what isotopes that have been measured.

Line 158: “Finally…” seems misplaced.

Line 158: What statistical requirements?

Line 168: “In contrast…” what is the contrast – needs better explanation.

Line 168-176: Also this section could be improved both in language and in detail.

Line 179-185: Try to reformulate sentence. Maybe break it up into several sentences.

Line 199: P: plagioclase; K: F-feldspar – not in figure!

Line 210: “The 104…” change to “In sample Y-L …..102 of 104 UPb age data yield…”

Line 213: Change structure to texture.

Line 216: Change classified to grouped.

Line 216-217: How are the grouping made? Describe in more detail what criteria are used.

Line 238: Change classified to grouped.

Line 241-244. Poor language – try to reformulate.

Line 248: “..is associated…” maybe use correlated.

Line 251: “two groups at 1000-900 and 850-700 Ma” where is this shown?

Line 261: “highly consistent…” maybe use correlate.

Line 268-277: Language should be improved in this section.

Line 303: add from – from NQOB

Line 314: Starting a new section with “In contrast…” seems odd – in contrast to what?

Line 314-315: Describe what is meant with “outstanding characteristic..”.

Line 316: “indicative of the typical provenance…” poor language and not a good description.

Line 328: “On the basis on…” maybe shorten to “Available literature suggest that ….”

 Line 338: Explain in more detail about palaeocurrent – what is changing and how?

Line 343: “Additionally….” Long sentence and poor language – try to reformulate.

Line 367-368: Poor language - try to reformulate sentence.

Reviewer 2 Report

The work applies a traditional approach to the study of provenance
 of the sediments in order to provide important constraints on the basin formation and orogenic processes, as suggested by the numerous bibliographical references.

The paper needs just some changes.

Line 114

“sampling location is all shown in Figure 2b”

It could be clearer to include the sampling locations also in fig.2a

Line 120

“Two samples of sandstones”: describe better. Where are they from?

They could be shown on the map in fig.2a and in Figure 3