But why Ichinoseki..? Why head down south...? Because it's quite famous for a few great places, but if I had to choose one place to visit then I'd highly recommend the Geibi Gorge, especially in winter, where you can witness beautiful snow covered Chinese landscape vistas from a wooden gondola. Almost surreal.
Something about being seranaded by a boat captain an ancient tune from his womb, and weather worn face while navigating his way down a narrow waterway replete with flora and carps, and these huge soaring cliffs reaching upwards to 60 meters in the backdrop. If you're lucky and can go there on a heavy snow day you will be in for a real epic experience.
The whole boat trip including the short break you get is about 90 minutes. 1500 yen per person.
Boats depart ever hour on the hour. You can pick up a lunch box and some sake for the trip. In the summer and spring the canopies come off.
The geological relavance is only significant for those who understand geology. People who come to Geibi do so to absorb the abundant natural beauty and wonder of Iwate's backcountry. This is an ancient gorge and a masterpiece in and of itself. I love winters in Japan!