Passage: Iceland is an island country at the confluence of the North Atlantic and Arctic Oceans, east of Greenland and immediately south of the Arctic Circle, atop the constructive boundary of the northern Mid-Atlantic Ridge about 860 km (530 mi) from Scotland and 4,200 km (2,600 mi) from New York City. One of the world's most sparsely populated countries, Iceland's boundaries are almost the same as the main island -- the world's 18th largest in area and possessing almost all of the country's area and population.

Question: Based on this passage, what type of plate boundary does iceland lie on?
Steam of consciousness below:
The relevant information is: Iceland is an island country at the confluence of the North Atlantic and Arctic Oceans, east of Greenland and immediately south of the Arctic Circle, atop the constructive boundary of the northern Mid-Atlantic Ridge about 860 km (530 mi) from Scotland and 4,200 km (2,600 mi) from New York City.
So, the answer is the constructive boundary of the northern Mid-Atlantic Ridge.