The Natural History of Martha’s Vineyard. Questions to answer: How old is the Vineyard? How did it...

The Natural History of Martha’s Vineyard

Questions to answer:

How old is the Vineyard? How did it form? How did it get the shape and unique features? What about the fauna and flora, and the variety

of ecosystems here? How is the island changing (ecologically)? How have humans affected the island? What is the future of Martha’s Vineyard?

How old is Martha’s Vineyard?

Geologic Time

Is Martha’s Vineyard “old”? What is “old”? How old is the Earth? How old is the Solar System, and the Universe

(since the Big Bang)?

The Geologic Time Scale

A better view?

The Pleistocene Epoch

Started about 1.8 million years before the present (ybp). About a third of the way into it, the Earth’s climate

began to change. We do not know why.

THE GREAT ICE AGE BEGAN. It is called the Pleistocene Ice Age.

The Pleistocene Ice Age

Started around 1,000,000 ybp. Consists of perhaps four or five “stages” or “cycles”. The climate slowly cooled, then slowly warmed, then

cooled, then warmed . . . Stages of the Pleistocene Ice Age: Nebraskan, Kansan,

(Iowan), Illinoisan, and Wisconsinan. Wisconsinan - most recent (started about 100,000 ybp,

ended only recently). There is evidence everywhere.

The Wisconsinan Stage

Lasted about 100,000 years. It is the final stage of the Pleistocene Ice Age

(or is it?) The best understood. The most evidence.

The Great Ice Age!

Views from the North Pole.

Glaciation in North America during the Wisconsinan Stage of the Pleistocene Ice Age

Other Ice Ages

There have been several other Ice Ages, besides the Pleistocene, during Earth’s long history.

First one at least 2.3 BILLION ybp, others at 950 million, 450 million, 250 million.

The Earth’s climate has changed many many times.

Effects of the Pleistocene Ice Age

Sea level changes. Plants and animals (migrations, major mammal

extinction). Humans!

Sea level dropped as much as 300 feet at times of peak glaciation! How did this change the coastlines of the world?

The fauna of the Pleistocene was very different from today. Many mammals have since gone extinct.

The most famous Pleistocene mammal had to be the woolly mammoth. There were four different species of mastadons and mammoths (elephants).

Mammoth and mastadon fossils are numerous and still commonly found. Some are even frozen with skin, fur, and internal organs still intact. Possible source of DNA?

The extinct saber tooth tiger was a ferocious predator.

There also existed a seven foot long beaver in North America. It is obviously now extinct.

This a fossil of the tooth.

And what about the human species?How were humans affected by the Ice Age?

Some believe that humans hunted the mammoth to extinction.

Summary:

The Pleistocene Ice Age appears to be over, or we are simply in a warm stage in between the Wisconsinan Stage and the next stage.

Either way,these stages take thousands of years to develop, so don’t hold your breath.

Certainly, the Earth is currently getting warming (Global Warming), and it may be due to human pollution, speeding it up.

Only time - geologic time - will tell.