Old Earth Creationism
Old Earth Creationism (OEC) is the traditional Christadelphian understanding of the origin of the Universe. It has frequently been combined with the "Gap Theory".
One of the most influential non-Christadelphian advocates of OEC in the 20th Century was Baptist academic Bernard Ramm (1919-1962).
Old Earth Creationism with "Gap"
Main article: The "Gap Theory".
This world view, also known as "Old Earth, Young Creation" (OEYC) was espoused by Dr John Thomas.
Transition from Young-earth to Old-earth Creationism
Sometimes a Christian who has accepted Young Earth Creationism (YEC) finds the geological evidence for an ancient earth a challenge to world-view and faith together. An example of this was Glenn R. Morton, a geophysicist whose story is published here (alternatively here). A paragraph from it that is encouraging for Christadelphians:
Being through with creationism, I was almost through with Christianity. I was thoroughly indoctrinated to believe that if the earth were not young and the flood not global, then the Bible was false. I was on the very verge of becoming an atheist. During that time, I re-read a book I had reviewed prior to its publication. It was Alan Hayward's Creation/Evolution (Triangle, 1985). Although I had reviewed it prior to its publication in 1985, I hadn't been ready for the views he expressed. He presented a wonderful "Days of Proclamation" view which pulled me back from the edge of atheism. Although I believe Alan applied it to the earth in an unworkable fashion, applied differently, his view had the power to unite the data with the Scripture. That is what I have done with my views. Without that I would now be an atheist. There is much in Alan's book I agree with and disagree with, but his book was very important in keeping me in the faith. While his book may not have changed the debate totally, it did change my life