You used Window|split to split the window into top and bottom panes (or right
and left panes).
I'm assuming you did top and bottom and when you scroll right or left the top
and left both move in sync.
I don't think you can change this. But you may find this ok.
Window|New window
Window Arrange|Horizontal.
Now you have two separate windows into the workbook. And they can be showing
the same worksheet. The good news is that you can scroll independently on each.
Excel tries to remind you with an indicator in the title bar:
book1.xls:1
book1.xls:2
When you're tired of viewing the multiple windows, you can close the one you
don't need by selecting that one and hitting ctrl-F4.
Splitting into panes vertically allows unsynchronized horizontal
scrolling, and splitting panes horizontally allows unsynchronized
vertical scrolling. To get the effect of two vertical panes with
unsynchronized vertical scrolling, choose Window/New Window, and
Window/Arrange/vertical.