How can I clone a Terrain object? (Not the reference)

I'm trying to create a procedural terrain generator based on Simplex Noise. I have an array of terrain objects and the problem is that when I fill this array with the function Instantiate() but it generates only a reference to the original terrain object so when I edit the heights of a single terrain i get all the terrains with the same shape. So, how do I copy a Terrain object without reference?

This is the code which generates the tile from the original tile:

 int x = (j - buffer / 2) + currentTile.x;
 int z = (i - buffer / 2) + currentTile.z;
 TerrainTile tile = new TerrainTile (x, z);
 tile.tileTerrain = Instantiate (terrainBase, new Vector3 (x * tileSize, 0, z * tileSize), Quaternion.identity) as Terrain;
 tile.tileTerrain.transform.gameObject.SetActive (true);
 return tile;

TerrainTile is a class i made:

 class TerrainTile
 {
        public Terrain tileTerrain;
        public int x;
        public int z;

        public TerrainTile (int x, int z)
        {
            this.x = x;
            this.z = z;
        }
 }