GEOLOGY OF THE PIEDMONT IN NEW JERSEY

J. Michael PollockNew Jersey Audubon

Adapted for Summer Field Studies 2012

CHRONOLOGIC HISTORY

Reading “Prong”HIGHLANDS

Newark “Prong”

Manhattan SchistPrecambrian (>570 MYbp)

Paleozoic (570-245 MYbp)

Triassic/Jurassic (245-144 MYbp)

Cretaceous (144-66.4 MYbp)

Tertiary (66.4-1.6 MYbp)

Pangaea

About 200 Million years agoNew Jersey (approx)

Continental Rifting—Part 1

New Jersey—about 200 MYbp and following

Basaltic magma rises along rift valley faults

Steens Mountain (Southeast Oregon)

NEW JERSEY IN THE TRIASSIC?

TRIASSIC/JURASSIC Rifting of the Continent of Pangaea

• Mid-continent desert• Development of a basin bounded by faults• Filling of (Newark Basin) with sediments shed

from the Appalachian Mountains

TRIASSIC/JURASSIC Rifting of the Continent of Pangaea

• Mid-continent desert• Development of a basin bounded by faults• Filling of (Newark) basin with sediments shed

from Appalachian Mountains

• Basalt lava flows (Watchung ridges)• Emplacement of “intrusive” magma (Palisades,

Sourland Mtn)• Early Dinosaurs

Duke Farms

Sourland Mtn.

Round Valley Chimney Rock

Hudson River

Palisade Sill (red)

Ramapo Fault

First Watchung ridge

Newark Basin (North--cross-section today)

Highlands

NEWARK BASIN(South--cross-section today)

Normal Faults

Basin filled (and deformed) as it formed

GEOLOGIC MAP FOR DUKE FARMS/SOURLAND MOUNTAIN

Duke Farms (fenced area)

Sourland Mountain (Somerset Co. Park)

South Branch outcrop

PIEDMONT UNITS

Jurassic diabase

Triassic red shale (Passaic)

Triassic gray shale (Passaic)

Triassic gray shale (Lockatong)