The Seward Peninsula is a remnant of the Beringia subcontinent that linked Alaska and Siberia during periods of low sea levels during ice ages.
The region was mostly untouched by glaciers during the ice age.
The preserve lands can be described by five physiographic zones: the northern coastal plan, the rolling stream-dissected uplands, the Imuruk lava plateau, the Kuzitrin flats, and the Bendeleben Mountains.

The Seward Peninsula is primarily composed of metamorphic blueschist, with deposits of sand, gravel, silt, loess and a few glacier-deposited moraines.
The area around Cape Espenberg includes a series of relict beach ridges like those found farther north at Cape Krusenstern.
These deposits are found mainly in the coastal plain, where they form a system of lagoons and barrier bars or spits.
The rolling uplands lie inland and to the south of the coastal plain.
The Serpentine Hot Springs and Trail Creek Caves are in this region of limestone, marble and other minerals.

Volcanic activity in the interior has left areas of basalt on the Imuruk lava plateau.
The volcanic activity has been recent — the Lost Jim lava flow is estimated to be only 1,000 to 2,000 years old, produced from around 75 vents.
The largest vent is the Lost Jim Cone, about 75 feet (23 m) high.
One remnant of volcanism is the presence of hot springs.
The Serpentine Hot Springs produce water at a temperature of 140 °F (60 °C) to 170 °F (77 °C), and have been used for millennia by local people.
Granite tors are another volcanic remnant, formed underground and exposed by erosion.
Bering Land Bridge has the four largest and northernmost maar lakes in the world at Espenberg, formed by phreatomagmatic eruptions leaving round craters.
The ages of the lakes range from 100,000–200,000 years at Whitefish Maar, to 50,000 years at North Killeak Maar, 40,000 years at South Killeak Maar, and 17,500 years at Devil Mountain Maar.

The action of ice and permafrost produces features such as polygonal ice wedges and pingos.
The Seward Peninsula is a remnant of the Beringia subcontinent that linked Alaska and Siberia during periods of low sea levels during ice ages. The region was mostly untouched by glaciers during the ice age. The preserve lands can be described by five physiographic zones: the northern coastal plan, the rolling stream-dissected uplands, the Imuruk lava plateau, the Kuzitrin flats, and the Bendeleben Mountains.
The Seward Peninsula is primarily composed of metamorphic blueschist, with deposits of sand, gravel, silt, loess and a few glacier-deposited moraines. The area around Cape Espenberg includes a series of relict beach ridges like those found farther north at Cape Krusenstern. These deposits are found mainly in the coastal plain, where they form a system of lagoons and barrier bars or spits. The rolling uplands lie inland and to the south of the coastal plain. The Serpentine Hot Springs and Trail Creek Caves are in this region of limestone, marble and other minerals.
Volcanic activity in the interior has left areas of basalt on the Imuruk lava plateau. The volcanic activity has been recent — the Lost Jim lava flow is estimated to be only 1,000 to 2,000 years old, produced from around 75 vents. The largest vent is the Lost Jim Cone, about 75 feet (23 m) high. One remnant of volcanism is the presence of hot springs. The Serpentine Hot Springs produce water at a temperature of 140 °F (60 °C) to 170 °F (77 °C), and have been used for millennia by local people. Granite tors are another volcanic remnant, formed underground and exposed by erosion. Bering Land Bridge has the four largest and northernmost maar lakes in the world at Espenberg, formed by phreatomagmatic eruptions leaving round craters. The ages of the lakes range from 100,000–200,000 years at Whitefish Maar, to 50,000 years at North Killeak Maar, 40,000 years at South Killeak Maar, and 17,500 years at Devil Mountain Maar.
The action of ice and permafrost produces features such as polygonal ice wedges and pingos.
Bering Land Bridge National Preserve