Stirling Brook ("Carnelian Creek"), Warren Township, Somerset Co., New Jersey, USA
|Latitude & Longitude (WGS84):||40° 38' 37'' North , 74° 28' 27'' West|
|Latitude & Longitude (decimal):||40.64366,-74.47417|
|Köppen climate type:||Cfa : Humid subtropical climate|
Ref.: A Quest for New Jersey Minerals, Robert Speiser(1978):10. A stream running through the Watchung Mountains. This stream is also known locally as "Carnelian Creek."
3 valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
174.1 - 201.3 Ma
Age: Early Jurassic (174.1 - 201.3 Ma)
Stratigraphic Name: Preakness Basalt
Description: (Olsen, 1980) - Dark-greenish-gray to black, very-fine-grained, dense, hard basalt composed mostly of intergrown calcic plagioclase (An55-60) and clinopyroxene (pigeonite and augite). Crystals are generally less than 1 mm (0.04 in) long, but locally feldspar crystals are larger than 1.3 cm (0.5 in.). Small spherical to tubular cavities (gas-escape vesicles) may be filled by zeolite minerals or calcite. Consists of at least three major flows. Prominent amydaloidal zones occur at most contacts between flows. A thin, 2 to 8 m (6.6-26 ft) bed of siltstone (Jps) separates the lower flows. The basal 20 m (66 ft) of the lowest flow is commonly highly vesicular or brecciated. Radiating slender columns 20 to 71 cm (8-28 in) wide, caused by shrinkage while cooling, are most abundant in the highest flow. The small, circiular extrusive body forming Round Top west of Oldwick is identified as Preakness Basalt by geochemistry and position above the Orange Mountain Basalt (Houghton and others, 1992). Thickness ranges from 250 m (820ft) (Olsen and others, 1989) to 320 m (1,050 ft).
Comments: Newark Supergroup, Brunswick Group (Lyttle and Epstein, 1987). Units Jp and Jps are described together on printed map. The units were split into separate records and appropriate descriptions for each were used.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.