"People assume a bar, I think, largely because that's what we have on the Earth" - James W. Head

So there's a huge detach between the idea of blue-Mars and real-Mars. You see, the south hemisphere exists. 

The southern Noachian highlands are dated by crater counting to make the surface at least 4.1 - 3.7 billion years old. There are magnetic bits in the Noachian south, but they are not heterogeneous. They are not oriented in a particular direction, implying that the lithosphere was still somewhat plastic when they were made, and they seem to have been destroyed by giant impactors, and are not present in or around the largest southern craters. Taken together this implies that when Mars had a magnetosphere, was also when the crust was still semi-molten, at least 4.1 billion years ago. 

This LPI is searching for answers. Mostly, it's identifying the questions. What does this mean about Mars atmosphere at that time and later? After-all, the craters have not been eroded... much. 

• I like the slide at 7:30 just for giving us a nice guideline. Multi-ringed craters are probably older.
• At 13:00 a slide showing sort of the old model, or the model that is under interrogation in planetary science. 
• The slide at 13:50 I just want to mention for my own reference. That beautiful map showing the headwaters for Jezero crater is one I think I may refer to in the future.
• Slide at 15:50 is where the problems kick in. If Mars had precipitation at all, it wasn't much, but the Noachian highlands still need an explanation for how much water they did cycle. This continues to be an unresolved and hotly debated topic. 
• So now you see the debate. The slide at 16:20 and the slide at 15:00, are showing incompatible modeling. The data supporting one model conflicts with the other, and they must be resolved to find real-Mars. 
• Slide at 17:30 details the ongoing questions to answer. Q2 will be very hard to answer, questions 3 & 6 seem more likely to get answers in the next few years. 

So this lecture wraps up a topic that I promise you, planetary scientists are almost willing to kill each other over right now. There's a lot at stake. Blue-Mars has no harborage in the Hesperian anymore, and may not have room in the Noachian either.