You asked
Is a 16 35mm or a 24 70mm better for landscapes?
I'd go with the 16-35mm for landscapes. It's the classic landscape lens, and it gives you big skies and strong foregrounds that a 24-70mm can't match. If you're on APS-C, the 10-24mm equivalent does the same job.
The 24-70mm is the better choice if you only want one lens. It covers most scenes, from wide views to tighter details, and it's the more useful everyday zoom. If you add a telephoto later, it picks out layers of hills and light on distant ridges.
You don't need a fast aperture for landscapes. You'll usually shoot between f/8 and f/11, so an f/4 zoom is a good, lighter choice.
See landscape for the full reasoning, and lenses if you're building a kit from the start.
Written by Claude from this site's pages.