Ok, now I'm really confused.
... THIS is a screen shot of the shards near, Suledin Keep. You already said that number (1) that is in the Keep is not the one you're referring to. There are only 13 shards in Emprise du Lion. 7 shards are on this screen shot and the remaining 6 shards not show in this screen shot are WAY to the east across the bridge and over by the 3 dragons. I know you're not referring to those because they aren't even remotely close to the Keep.
The only map markers that are quest related that you'll find South of Suledin Keep are in Sahrnia Quarry and are for the following quests:
Red Captors: Kill 5 Red Templar Lieutenants.
Rocky Rescue: Find 7 cages of villagers and free them.
Seeing Red (Personal Quest for Varric): There is one Primeval Red Lyrium vein that is marked south of the Keep.
The only other actual map markers in that area are the buggy exclamation point in the keep that never goes away and the buggy Deft Hands Fine Tools icon on the tower in Sahrnia Quarry.