Complex sentence: The Australasian strewnfield is the youngest and largest of the tektite strewnfields, with recent estimates suggesting that the field may cover 10% -30% of the Earth's surface.
Split into simpler sentences: The Australasian strewnfield, covering at least one-tenth of the Earth's surface, is the largest and the youngest of the tektite strewnfields. Also, some recent estimates suggest that the strewn field may cover 30% of the Earth's surface.