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

Glacial Chasm

Wayward Swordtooth

Ramunap Excavator

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 ETB

Springheart Nantuko

Simic Growth Chamber

Spelunking

Play Simic Growth Chamber. When it enters, Amulet of Vigor, Simic Growth Chamber and Springheart Nantuko trigger.
Resolve the Amulet of Vigor trigger, untapping Simic Growth Chamber.
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.

Combos with "Wayward Swordtooth"