So, jumping on Katherine's mention of an omniscient narrator.
I can understand why AP didn't use a 100% omniscient narrator. It's interesting, though, that the narrator is maybe a bit more omniscient that I would expect, given all the stuff I've been saying about how the story is essentially from Ennis's POV. I mean, there are a number of times where we learn things that Ennis wouldn't have known at the time -- Jack's memory of the dozy embrace is the most obvious one to me, but there are also some offhand references to things that Ennis wouldn't have known about Jack ("riding more than bulls," for one), or about Alma (her silent thought that what Ennis likes to do doesn't make too many babies), or Aguirre ("ranch stiffs aren't ever any good"). And the descriptions of the natural world, too, are in very erudite language ("somber slabs of malachite") -- they're quite a contrast from the language in the dialogue.
So why does Annie Proulx do this? Does it keep us a bit more distant from the characters? Is the story from the POV of an older Ennis, and we're hearing what old-Ennis thought people were thinking? Does the sophisticated language of the descriptions capture how Ennis feels about the natural world, even if he wouldn't use those words?
Am I thinking too much about this?