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Author Topic:   Mechanisms of sea transgression and regression
Faith 
Suspended Member (Idle past 434 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 3 of 16 (806607)
04-26-2017 9:04 PM
Reply to: Message 2 by edge
04-26-2017 8:06 PM


... the Cretaceous Period seems to be a time of increased ocean ridge volcanism (i.e., wide bands of Cretaceous sea floor on either side of the mid-ocean ridges

What is the evidence that this increased ocean ridge volcanism occurred in the Cretaceous period? What is "Cretaceous sea floor?"


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Faith 
Suspended Member (Idle past 434 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 9 of 16 (806839)
04-28-2017 11:03 AM
Reply to: Message 8 by edge
04-27-2017 11:34 AM


Re: Increased Cretaceous seafloor spreading rates
You see an increase in volcanism into the Tertiary and you see several orogenic episodes starting in the Jurassic.

So, to be clear, is all such dating to time periods done by radiometric methods? When it is said that mountains formed in such a such a time period, that's due to radiometric measurement? Of what, exactly? Is that how the Cratonic transgressions are dated? (And is anyone paying attention to all this in relation to the movement of the Supercontinents and the breakup of Pangaea and all that? Because the seafloor would not have spread as far in the Cretaceous as today for instance. Is all that being taken into account?

ABE: So for instance if Pangaea broke up in the Jurassic there was really not a lot of seafloor formed by the Cretaceous? )

Edited by Faith, : No reason given.


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