Geologic Time Line

Black Point Geologic Time Line

300-245 million years ago (mya):The supercontinent Pangaea was formed when the continents Godwana & Laurentia and the microcontinent meguma came together.

275 mya: The bedrock that makes up the shore along the ocean at Black Point, Narragansett Pier Granite, is formed in a magma chamber 9-12 miles below the earth’s surface.

200 mya: Pangea breaks up forming the current North America and Europe continents.

2.58 mya:* The beginning of the Quarternary Period, which is an ice age. An ice age is when there is ice at one or both poles and is characterized as periods of glacial advances. The glacial advances are often incorrectly called ice ages.

190,000-130,000 years ago: The Illinoian Glacier advance. Material from this glacier has been found on Block Island and Nantucket.

125,000-75000 years ago: The Sangamon (also Eemian) interglacial period.  Much warmer than today, boreal forests grew above the Arctic Circle where there is now tundra.

75,000-15,000 years ago: The Wisconsinan Glacier, the most recent of many glacial advances in the last 2.7 million years, covers the entire northeast. It reached a maximum 26,000-22,000 years ago and extended just past Block Island. Sea level at that time was 300-350 feet lower than present and the shoreline was 70 miles south of Block Island.

22,000 years ago: The glacier is retreating and leaves the Ronkonkoma moraine on Long Island and Block Island and the Pt. Judith moraine in Narragansett. 

19,000 years ago: The glacier continues to retreat and leaves a recessional moraine which extends from Wakefield to Westerly and then continues to Fishers Island and Long Island.

11,500 years ago: Beginning of the current interglacial period, the Holocene.

3,000 years ago: Sea level and the coastline have returned to near what it is today.

*Things change as new technology and evidence is uncovered, “Roadside Geology of Connecticut and Rhode Island” was published in 2008, and says 1.8 mya. In 2009 the International Committee on Stratigraphy changed it to 2.58 mya.