New Hampshire Geology New Hampshire Bedrock Map

Cretaceous Period
(144-65 million years ago)


A Brave New World

Geologic activity during the Cretaceous Period in New Hampshire was basically a continuation of events and processes that occured in the previous Jurassic PeriodMagma from the Earth's interior continued taking advantage of the weak spots in the crust created by the rifting of Pangea.  The infant Atlantic Ocean continued to grow and widen.  The Earth was reshaping itself into a brave new world - again.

New Hampshire was firmly attached to North America and all of the major landscape creation was completed - with one major exception:

weathering and erosion kept up their non-stop work in the middle of a 180 million year episode of activity which continues today.

Another Big Bang?

While there was the constant tedium of about 75 million years of just weathering and erosion shaping the New Hampshire landscape, something dramatic was about to happen, not just to New Hampshire, but to the whole world.

A doomsday asteroid or comet was on a collision course with what is today the Yucatan Peninsula of Mexico.  The resulting ash and smoke clouds from the vaporization of a portion of the planet's crust and its forests for thousands of miles around blocked out the Sun's light and heat.  This  caused extended winter like conditions to take hold on a planet whose dominant animal life form, the dinosaur, relied on the sun's heat to warm their climate and  their bodies so they could live.  The Sun's light and heat also allowed plants to grow.

No light and heat -no food for plant eating dinosaurs.

No plant eating dinosaurs - no meat for meat eating dinosaurs.

No plant eating or meat eating dinosaurs - no more dinosaurs.

No more dinosaurs - no more Cretaceous Period.

Goodbye Pangea, Hello Atlantic Ocean

Below is a map of how the Earth is thought to have looked during the Cretaceous Period.  Pangea is broken up, the Atlantic Ocean is widening and the present day shape of the continents and their respective tectonic plates are starting to look familiar.

(Click on the image for a closer look.)
Image Credit: Christopher Scotese;

What Really Happened To The Dinosaurs?

Most scientists - and the general public - believe an asteroid or comet colliding with the Earth caused the extinction of the dinosaurs.  But since no people were around to witness this event (good thing too, or we would have become extinct with the dinosaurs!), we'll never know for absolutely sure what wiped them out.  Below is cartoonist Gary Larsen's explanation for the demise of the dinosaurs.

The Far Side, by Gary Larson,
 copyrighted 1982,1984 Chronicle Features.