This manuscript presents the results coming from a boat mission on the Demerara Plateau, its area corresponds to a paleo Triple point during the Atlantic opening and so a connection between Central and Equatorial Atlantic. The study is focus on samples coming from pre-Albian sedimentary rocks that correspond to the early rifting history. Through microfacies characterisation and zircon U-Pb and Fission Track analysis Authors propose a source-to-sink model for the pre-Albian period and put it in perspective with its regional opening meaning.

This study is the first since a while to sample rocks older than the well-known Late-Albian offshore regional unconformity and so is already a useful contribution. I highlight that the sampling was performed by a sea floor dragging that significantly decrease the samples' age determination, but authors make it clear. Regarding the sampling approach, U-Pb and thermochronology are appropriated method to reconstruct both source and sedimentary history. Based on U-Pb results, authors demonstrated that the source of pre-Albian sediments are mainly Phanerozoic rocks, that was already supposed but never demonstrated. Based on thermochronology they propose two events that affected the source rocks: one at ~170 Ma related to a thermal heating and a second at ~120 Ma corresponding to a source’s exhumation. Authors correlated these two events the opening mechanism, confirming recent research (Basile et al 2020, Derycke et al 2021).
I agreed on most of the conclusion, but I think that thermochronology discussion needed an improvement (discuss the origin of the 170 Ma ages, develop of the origin and implication of the 120 Ma event). On a broader level, there is a lack of continuity in the discussion, and I think a reorganisation can help to improve the reader comprehension. I feel l that the manuscript suffers from a lack of main thread, maybe because it is missing a simple message. You should try to answer the question, “why is it useful to reconstruct the source history during the EA opening?”, and for me, you propose a potential answer in the last sentence of the conclusion. Rearrange the manuscript at this light should solution most of my comments.

See attached documents for detailed comments.

Authors had deeply changed parts of main text including presentation/discussion/conclusion of the U-Pb and FT data on zircon. The name/abstract/introduction has been adapted to better fit with this modification. Those modifications answer most of my comments and, from my point of view, improve significative the consistency and logic of the article. I note that the figures have been modified too following some of my comments.
My only comments on will be on the discussion/conclusion: authors quickly presented a total exhumation of ~8km between 120 and 100Ma based on a geothermal gradient of 30°/km, and them discuss this high value with a model and other papers. I agree on this, but the exhumation is probably overestimated as we can expect an increase in the geothermal gradient in this geodynamique condition.

From a broad perspective I agree on most of the article adaptation, and I recommend it for publication.