To dream of a chasm signifies an obstacle that is creating much anxiety for you.

You need to work through the difficulty and overcome this obstacle in your life.

Perhaps you are afraid of taking the plunge.

To dream that you are falling into a chasm symbolizes the depths of your subconscious. You are afraid and/or uncertain as to what you will discover about yourself and about your hidden feelings and fears.

The chasm may also represent your primal fears and feelings of falling into a pit of despair.

Perhaps you are in a state of depression or wallowing in your negative feelings.

Alternatively, the dream could denote your lack of spirituality.