We asked... (Delmarva drilling revelations)

 

What has drilling on the lower Delmarva Peninsula revealed about its geological history?

Drilling on the lower Delmarva Peninsula has revealed that a massive asteroid or comet impact 35 million years ago dramatically altered the region's geological makeup. Long before the Chesapeake Bay existed, this event shattered and displaced the ancient rock layers, creating a deep crater that still influences the land and water today.

The big impact and its after-effects

• A buried, deep crater: A huge impact crater, roughly 53 miles wide and a mile deep, is buried under the southern part of the Chesapeake Bay and the lower Delmarva Peninsula. It was discovered through a combination of drilling and seismic surveys, which allowed geologists to map its shape and features.
• Aquifers were destroyed: The impact obliterated ancient aquifers (underground layers of water-bearing rock), creating a massive "breccia lens"—a jumbled mix of rock, sediment, and fractured material. The aquifers today are freshwater on top, but the deeper ones are still mixed with ancient, salty seawater trapped in the crater.
• An inland saltwater pocket: This deep brine has remained trapped within the crater's structure, and its unusually high salinity was a long-standing mystery to scientists before the crater's discovery.
• The origin of the Chesapeake Bay: The impact created a long-lasting depression in the landscape. As sea levels rose and fell over millions of years, rivers in the region converged and were eventually funneled into this low-lying area, ultimately forming the present-day Chesapeake Bay. 

Layers of sediment tell a story

• Layers from old river deltas and seas: The region has been covered and uncovered by the ocean multiple times over millions of years. The deep drill cores show layers of sediment deposited by rivers, including a large river delta system that existed in the Late Miocene epoch, and marine deposits from ancient seas.
• "Exotic" plant fossils: Microscopic fossils of plant material found in the sediments are not native to the area, showing that the region's environment has changed significantly over time.
• A record of changing climates: Younger layers of sediment show fluctuations between periods of warm and cold temperatures. For example, some layers show a warm-temperate environment, while younger ones indicate a cooler climate. 

The peninsula continues to change

• Groundwater vulnerability: The fractured ground and persistent saltwater deep in the crater mean that the area's fresh groundwater is more susceptible to contamination.
• The peninsula is sinking: The entire Delmarva Peninsula is slowly sinking, a long-term effect of the impact crater's influence. This process shapes the landscape and impacts the region's hydrology, even today.

We asked... (Pocomoke north of the river?)

 

Why didn't Pocomoke City establish businesses and residences on the north side of the Pocomoke River?

Several factors limited the establishment of businesses and residences on the north side of the Pocomoke River, including the historical origins of the town, geographic and environmental barriers, and the pattern of railroad development. 

Geographic and environmental factors

• The Great Cypress Swamp: The Pocomoke River flows from the Great Cypress Swamp in the north, creating a landscape of inaccessible wetlands. This made the area immediately north of the river difficult to build on.
• Difficult drainage: For centuries, heavy rains would cause the water to back up into the drainage ditches on the flat farmlands, leaving the fields sodden for days and unsuitable for development. The land on the south side of the river proved to be higher and more suitable for early settlement.
• Spoil banks from dredging: In the post-World War II era, an 18-mile stretch of the river was dredged and channelized to improve drainage for agriculture. The dredged material was deposited along the riverbanks, creating elevated "spoil banks" that further disconnected the floodplain from the river itself. This would have continued to hinder development on the northern side. Historical development
  • Original settlement location: The town that became Pocomoke City began in the late 17th century as a small settlement called Stevens Landing on the south bank of the Pocomoke River, centered around a ferry crossing.
  • Native American territory: Historically, the Nusswattux, a sub-tribe of the Pocomoke Nation, were located on the north side of the river. Land patents and historical records from the 1700s reference the Nusswattux Neck, a territory on the north side of the Pocomoke River.
  • Railroad placement: The town's growth accelerated in the 1880s with the construction of a main railroad line running along the Delmarva Peninsula. This critical transportation link crossed the Pocomoke River at the existing settlement, reinforcing the development on the south side. 
  Infrastructure and logistics
  • Early river commerce: The south side was already established as a center for river commerce and shipping. Key infrastructure like wharves and warehouses for shipping tobacco and lumber were constructed on the south bank.
  • Land-based access: With the main part of town, the railroad, and later the main highway (Route 13), being established on the south side, it was more logical and convenient for businesses and residences to stay centralized near existing infrastructure. 

We asked... (Wallops Island history)

 
Tell me about Wallops Island prior to the U.S. Army establishing a base there. 

Before the U.S. Navy established a base in 1941, Wallops Island was used for grazing livestock and as a hunting and fishing resort. Its history dates back to the 17th century when it was first granted to English surveyor John Wallop. 

Colonial era and early American history

• Grant to John Wallop: The Crown of England granted the island to John Wallop in 1672 (or 1692). The island was then sold and resold several times over the centuries.
• Revolutionary War fort: A small coastal earthwork battery was built on the island during the Revolutionary War, likely to restrict enemy boat traffic. While it did not play a significant role in the conflict, the site remains a rare example of military construction from that period. 

19th and early 20th centuries

• Hunting and fishing club: The Wallops Island Association, Inc., a private club, acquired the island in 1933, though its members had owned the land since at least 1889. The club built a large clubhouse and hotel for its members and their families, who used the island for fishing, swimming, and hunting.
• Livestock grazing: The island's remote location also made it a suitable place for grazing livestock.
• U.S. Life-Saving Service and Coast Guard:
  • In 1883, the U.S. Life-Saving Service constructed its first station on the island, but it was destroyed by a hurricane in 1933.
  • The Coast Guard later constructed a new lifeboat station and observation tower in 1936, which it operated until 1947. The station's mission was to rescue sailors and salvage cargo from damaged ships. 

Transition to government control

• Navy expansion during WWII: The U.S. Navy commissioned the 
  Chincoteague Naval Air Station
   in 1941 on the nearby mainland and established the Naval Aviation Ordnance Test Station on Wallops Island itself.
• NACA acquires land: The National Advisory Committee for Aeronautics (NACA), the predecessor to NASA, leased part of the island from the Wallops Island Association in 1945 to establish a rocket launch site.
• Eminent domain: Following World War II, the federal government took permanent ownership of Wallops Island via eminent domain. By 1950, the resort clubhouse had been claimed by shoreline erosion, and the federal government had relocated the island's wild ponies to nearby Chincoteague. 
• 

My father's first job after high school was as a dump truck driver on Wallops Island. At that time, the only vehicle assess was the ferry which docked at the end of Pierce Taylor Road near Mappsville. The current bridge wasn't constructed until at least 1960.

Your friend,
Slim