The water being cleared, you have just "finished" the Chozo ruins site. Of course there are still dozens of things to do here, but with the Varia suit in your possession, you can now withstand the heat of the Magmoor Caverns, the highway of Tallon IV. Coincidentally, the door just opposite you happens to open on an elevator which descends to Magmoor.
Proceed to the Sun Tower Access.
Sun Tower Access
Scan: Pulse Bombu
The only thing interesting in this room is your first encounter with a Pulse Bombu, which happens to currently be invincible, since you don't have the Wave Beam. You may be tempted to spend hours crawling around in the water under the ledge looking for secret upgrades. Don't. To the best of my knowledge there's nothing there.
Proceed to the Sun Tower.
Sun Tower
Scan: Chozo Lore: Contain
Someday you'll roll down. Today you can say "ouch." Just jump. Kill the bugs, scan your scan and proceed to the Burning Trail.
Path: Transport to Magmoor Caverns North, Transport to Chozo Ruins North, Burning Trail, Save Station Magmoor A, Burning Trail.
Burning Trail
Scan: Grizby
Proceed to Lake Tunnel.
Lake Tunnel
Scan:
Proceed to Lava Lake
Lava Lake
Scan: Magmoor, Puffer
Proceed to the Pit Tunnel
Pit Tunnel
Scan: Triclops
Proceed to the Triclops Pit