Complex sentence: The BIC system is divided into an eastern and western lobe with a further northern extension: it is believed that all three sections of the system were formed around the same time-about 2 billion years ago-and are remarkably similar.
Split into simpler sentences: The BIC system is divided into an eastern and western lobe, with a further northern extension. All three sections of the system were formed around the same time-about 2 billion years ago-and are remarkably similar.