Climate Change and Old Seawater: This Week at Interior


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As the Continents Drifted the Atlantic Ocean at One Point was enclosed and Isolated. Image by USGS.

As the continents drifted, they enclosed and isolated the Atlantic Ocean at one point. Image by USGS.

This week’s Department of the Interior video broadcast include both ancient and modern day earth-changing processes.

Interior’s Secretary Jewell pointed out, for instance, that climate change is a reality that the country must deal with, focusing on South Carolina’s coast which has experienced a one-foot rise in sea level during the past century. In addition, an unexpected ancient sea turned up during the geologic mapping of an asteroid’s crater, in an ocean not yet fully shaped by continental drift to its present size and interconnections.

Here is what else happened this week at Interior: “Secretary Jewell joins National Park Service Director Jonathan Jarvis and other dignitaries to mark the 150th anniversary of the Gettysburg Address; the Secretary travels to South Carolina’s Cape Romain National Wildlife Refuge to talk about public/private conservation efforts; and the President’s all-of-the-above energy strategy pays big dividends, as Interior disburses $14.2 billion to local communities.

Ancient Seawater under Chesapeake Bay

The earth’s river systems, as part of the hydrologic cycle, flow downhill to the oceans within a series of basins separated by watersheds or ridges of higher land. In the process the landscape is worn down and changed through the processes of erosion and deposition.

Occasionally, however, forces from outside the earth’s atmosphere interact with our landscapes and enact change, often catastrophically. Approximately 35 million years ago, such a change occurred in the geographic area now known as Chesapeake Bay.

Chesapeake Crater Boundaries: Bore Within  Inner Rim. Image by USGS.

Chesapeake Crater Boundaries: Bore within inner rim. Image by USGS.

Today the Chesapeake Bay is essentially the Susquehanna River‘s valley floor. It’s the tidal portion of the Susquehanna, an estuary or drowned valley created by rising sea levels. Around 35 million years ago, however, an asteroid smashed into the area creating a huge crater in a smaller, isolated and very saline Atlantic Ocean, creating its own sea.

We know about the crater because scientists have bored into the surface to obtain rock samples and create maps. The unexpected surprise, however, was the discovery of a seawater sediment fossil holding around 3 trillion gallons, the oldest ancient seawater in the world. But no life was discovered or likely to be discovered; although the chemical signature of the ancient ocean has been preserved, the remnants are scattered among countless cracks and pores.

Bone Yard Beach and Climate Change

In Canada, Global Warming has caused sovereignty issues as the prospect of an ice-free Arctic Ocean looms as a reality.

Every physical process, form and function, affected by changing temperatures is being altered. The oceans, for instance, are expanding globally within their basins creating above normal water levels. When water levels rise, it allows waves to break farther inland and break down coastal land and ecosystem barriers. This imperils oceanfront property and increases the potential for flooding.

Historical shoreline of Bulls Island shows severe erosion since 1852. The current rate of  erosion is approximately 20 feet per year. Image by USFWS.

Historical shoreline of Bulls Island shows severe erosion since 1852. The current rate of
erosion is approximately 20 feet per year. Image by USFWS.

One such barrier is South Carolina’s Cape Romain National Wildlife Refuge where the ocean is eating away at the largest, Bulls Island and its Bone Yard Beach, and other barrier islands in the complex. This is an area of the United States expected to experience further rises in sea level of up to five feet by the end of this century.

As reported by Sammy Fretwell, Bulls, the largest island in the wildlife complex at about 5,000 acres, has lost about 425 acres since 1949, according to maps provided by the Fish and Wildlife Service.

Natural Erosion Meets Man-made Destruction

Humans add to the natural erosion destruction of barrier islands by attacking the ecosystems that help to fortify the land. In the case of the refuge, for instance, experts suggest restoration of the Long Leaf Pine forests on the mainland as a way to help offset what federal officials say will be the inevitable march of rising seas.

And the beat goes on!


Chesapeake Bay Program. Bay Geology(2012). Accessed November 24, 2013.

DNRSC. Climate Changes Everything. (2012). Accessed November 24, 2013.

Fears, Darryl. Seawater discovered near the Chesapeake Bay is up to 150 million years old. (2013), Accessed November 24, 2013.

Fretwall, Sammy. U.S. interior chief stunned by eroding S.C. island. (2013). Accessed November 24, 2013.

Mayell, Hilary. Chesapeake Bay Crater Offers Clues to Ancient Cataclysm (2001). Accessed November 24, 2013

Quinn, Rob. Ancient Ocean Found Under Chesapeake Bay. (2013). Accessed November 24, 2013.

Sanford, Ward E. et al. Evidence for high salinity of Early Cretataceous sea water from the Chesapeake Bay crater. (2013). Accessed November 24, 2013.

Science Daily. Oldest Large Body of Ancient Seawater Identified Under Chesapeake Bay. (2013). Accessed November 24, 2013.

USGS. The USGS  Chesapeake Bay Impact Crater Project(2007). Accessed November 24, 2013.

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