Play Glacial Chasm either from your hand or from your graveyard.
When Glacial Chasm enters the battlefield, its second ability triggers, causing you to sacrifice another land you control.
Play any land from your graveyard.
At the beginning of your next upkeep, Glacial Chasm's cumulative upkeep ability triggers, allowing you to choose not to pay the cost and sacrifice it instead.
Repeat.

Prevent all damage that would be dealt to you

Lock

Glacial Chasm

Ramunap Excavator

Wayward Swordtooth

Play Simic Growth Chamber. When it enters untapped due to Spelunking, Simic Growth Chamber and Springheart Nantuko trigger.
Holding priority, activate Simic Growth Chamber by tapping it, adding {G}{U}.
Resolve the Simic Growth Chamber trigger, returning it from the battlefield to your hand.
Resolve the Springheart Nantuko trigger, causing you to pay {1}{G} to create a token copy of Wayward Swordtooth.
Because of the additional Wayward Swordtooth token, you can play an additional land this turn. 
Repeat

Infinite creature tokens

Infinite landfall triggers

Infinite creature ETB

Infinite blue mana

Infinite card draw

Infinite draw triggers

Infinite green mana

Springheart Nantuko

Spelunking

Simic Growth Chamber

Play Gruul Turf. When it enters, Amulet of Vigor, Gruul Turf and Springheart Nantuko trigger.
Resolve the Amulet of Vigor trigger, untapping Gruul Turf.
Holding priority, activate Gruul Turf by tapping it, adding {R}{G}.
Resolve the Gruul Turf trigger, returning it from the battlefield to your hand.
Resolve the Springheart Nantuko trigger, causing you to pay {1}{G} to create a token copy of Wayward Swordtooth.
Because of the additional Wayward Swordtooth token, you can play an additional land this turn. 
Repeat.

Gruul Turf

Amulet of Vigor

Combos with "Wayward Swordtooth"