Geos 201: map of tectonic plate boundaries divergent boundary atlantic ocean 3.1 divergent boundaries; the mid-oceanic ridge near iceland draw a horizontal ine (dashed ar not) under the flat part of tha ocean at the 70m mak now use the other ponts a-f to make iines or dots (ynu choose) at the bottom of the itho d ferant places naded in points ao, then connect the dots with a amooth curve that mirrors the topogrsphic surtace. - draw in another lino that expresses he 7-km thickness of oosanic erust and 35 km thick coetinertal cust withn your äthaspheric mass. you wll quickly snd that bhis crust ie estromely thin at this scale of map and croas-section label and ightly oolor in the cnusts, and lithopshere and aslanosphine with colored penals northern atlantic ocean ridge a' 0 krm 200 km 400 km 600 km