I'd say about a grand canyons worth over 50% of the earth and less over another 25%.
Here, you tell me how much earth was displaced and suspended in the waters when the fountains of the deep opened up?
But it is all where it is supposed to be, in what were once valleys and depressions, only very little on the mountain tops as further weathering moves even more into the valleys. It;s your concept of time which is flawed - not the depth.
Waters rose and land sunk during the flood and others rose afterwards. What you think of as mountains were once ocean floor - and therefore sedimentary rock????? Established by the many marine fossils and corals found on mountain tops.
http://www.britannica.com/EBchecked/topic/424338/ocean-basin/285023/Deep-sea-sediments
"The sediment cover in the Pacific basin ranges from 300 to 600 metres (about 1,000 to 2,000 feet) thick, and that in the Atlantic is about 1,000 metres (3,300 feet)."
http://en.wikipedia.org/wiki/Grand_Canyon
"and attains a depth of over a mile (6,093 feet or 1,857 meters)."
But everyone's theories leave out one important fact. The continued deposit of sedimentary layers on a timetable not compatible with your theory of time or depth of water.
Every ruin 1,000 years old or more is buried in layers where they are not kept up for the public.
http://t3.gstatic.com/images?q=tbn:ANd9GcQ-HUWYV_5Hvr1tGlfxBiEv8ta2WVV1aVQehwR7Cbx7z1-gL1FYcQ
http://www.canterburytrust.co.uk/catpress/wp-content/uploads/2010/10/rubb03a.jpg
Showing just how incorrect is the belief that this layering takes millions of years (mainstream) and is due only to sediments in water (creationists). Both of you got it wrong. Only the top layering is from post-flood. The dinosaurs went extinct long before man and the animals with him were created. Easily checked just by finding out what the Hebrew word
hayah really means.
"And the earth "became - hayah" desolate and waste, and darkness "became - hayah" upon....."
So that the dinosaurs were created in a time prior to man is not surprising. Nor the fact there have been 5 previous creations and destruction's, with man being the sixth.
http://en.wikipedia.org/wiki/Extinction_event
And when it goes extinct the 6th time, there will be a 7th creation. But just seeing the 6 sudden appearances of life or the 5 destruction's of it, calls no similarities to mind?
So far you have told me nothing of the history of the earth, the Bible when interpreted correctly, hasn't already told me.