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Mineral Resources > Online Spatial Data > Geology > by state > New York Geology

Geologic units in Rockland county, New York

Manhattan Formation (A Member) (Middle Ordovician) at surface, covers 0.6 % of this area

Manhattan Formation (A member) - sillimanite-garnet-muscovite-biotite-quartz- plagioclase schists; calcite marble and calcsilicate rock at base.

Lithology: schist; marble; calc-silicate rock

Amphibolite (Middle Proterozoic) at surface, covers 1 % of this area

Amphibolite - commonly biotitic; garnetiferous, pyroxenic, in and adjacent to Adirondack Highlands.

Lithology: amphibolite

Hornblende granite and granite gneiss (Middle Proterozoic) at surface, covers 17 % of this area

Hornblende granite and granite gneiss - with subordinate leucogranite.

Lithology: granite; granitic gneiss

Poughquag Quartzite (Cambrian) at surface, covers < 0.1 % of this area

Poughquag Quartzite - (includes local Dalton Formation at base)-locally conglomeratic.

Lithology: quartzite; conglomerate

Garnet-bearing gneiss and interlayered quartzite (Middle Proterozoic) at surface, covers < 0.1 % of this area

Garnet-bearing gneiss and interlayered quartzite - contains varying amounts of biotite, garnet, sillimanite; minor marble, amphibolite, rusty paragneiss.

Lithology: gneiss; quartzite; marble; amphibolite; paragneiss

Biotite-quartz-plagioclase gneiss (Middle Proterozoic) at surface, covers 0.8 % of this area

Biotite-quartz-plagioclase gneiss - with subordinate biotite granitic gneiss, amphibolite, calcsilicate rock.

Lithology: gneiss; granitic gneiss; amphibolite; calc-silicate rock

Stockton Formation (Upper Triassic) at surface, covers < 0.1 % of this area

Stockton Formation - Predominantly medium- to coarse-grained, light-gray, light-grayish-brown, or yellowish- to pinkish-gray arkosic sandstone and medium- to fine-grained, violet-gray to reddish-brown arkosic sandstone; with lesser, reddish to purplish-brown, silty mudstone, argillaceous siltstone, and shale. Some coarse-grained sandstone in lower part contains thick beds of conglomerate (Trsc) which have been mapped in the vicinity of Stockton. Sandstone, deposited in high-gradient stream channels, is mostly planar bedded with scoured bases containing pebble lags and mudstone rip-up clasts. Upper part of channel beds are burrowed. Large-scale trough crossbeds occur in some very coarse grained sandstone beds; smaller scale trough and climbing-ripple cross lamination occur in the upper part of channel sequences and in finer grained sandstone beds. Typical floodplain mudstones are irregularly thin bedded and extensively burrowed. Floodplain beds are thicker and more numerous in the central Newark basin, near the Delaware River. Thickness of the unit (including Trsc) near Stockton is about 1,240 m (4,068 ft).

Lithology: arkose; fine-grained mixed clastic; siltstone; shale

Palisade Diabase (Early Jurassic) at surface, covers 7 % of this area

Palisade Diabase

Lithology: diabase

Hornblendite (Upper Ordovician) at surface, covers < 0.1 % of this area

Hornblendite

Lithology: hornblendite

Brunswick Formation (Upper Triassic) at surface, covers 12 % of this area

Brunswick Formation - mudstone, sandstone and arkose.

Lithology: mudstone; sandstone; arkose

Passaic Formation Sandstone and Siltstone facies (Lower Jurassic and Upper Triassic) at surface, covers < 0.1 % of this area

Passaic Formation Sandstone and Siltstone facies - Sandstone (JTrps) is interbedded grayish-red to brownish-red, medium- to fine-grained, medium- to thick-bedded sandstone and brownish-to-purplish-red coarse-grained siltstone; unit is planar to ripple cross-laminated, fissile, locally calcareous, containing desiccation cracks and root casts. Upward-fining cycles are 1.8 to 4.6 m (6-15 ft) thick. Sandstone beds are coarser and thicker near conglomerate units (JTrpcq, JTrpcl). Maximum thickness about 1,100 m (3,610 ft).

Lithology: sandstone; siltstone

Brunswick Formation (Upper Triassic) at surface, covers 5 % of this area

Brunswick Formation - sandstone, siltstone and mudstone.

Lithology: sandstone; siltstone; mudstone

Pyroxene-hornblende-quartz-plagioclase gneiss (Middle Proterozoic) at surface, covers 4 % of this area

Pyroxene-hornblende-quartz-plagioclase gneiss.

Lithology: mafic gneiss

Hammer Creek Formation (Upper Triassic) at surface, covers 10 % of this area

Hammer Creek Formation - conglomerate.

Lithology: conglomerate

Interlayered amphibolite and granitic, charnockitic, mangeritic, or syenitic gneiss (Middle Proterozoic) at surface, covers 7 % of this area

Interlayered amphibolite and granitic, charnockitic, mangeritic, or syenitic gneiss.

Lithology: amphibolite; gneiss

Brunswick Formation (Upper Triassic) at surface, covers 24 % of this area

Brunswick Formation - sandstone and conglomerate.

Lithology: sandstone; conglomerate

Ladentown diabase and baslatic lava (Upper Triassic) at surface, covers 0.4 % of this area

Ladentown diabase and basaltic lava

Lithology: diabase; basalt

Passaic Formation Conglomerate and Sandstone facies (Lower Jurassic and Upper Triassic) at surface, covers < 0.1 % of this area

Passaic Formation Conglomerate and Sandstone facies - Conglomeratic sandstone (JTrpsc) is brownish-red pebble conglomerate, medium- to coarse-grained, feldspathic sandstone and micaceous siltstone; unit is planar to low-angle trough cross laminated, burrowed, and contains local pebble layers. Unit forms upward-fining sequences 0.5 to 2.5 m (1.6-8 ft) thick. Conglomeratic sandstone thickness exceeds 800 m (2,625 ft).

Lithology: conglomerate; sandstone; siltstone

Rusty and gray biotite-quartz-feldspar gneiss (Middle Proterozoic) at surface, covers 2 % of this area

Rusty and gray biotite-quartz-feldspar gneiss - rusty facies contains variable amounts of garnet, sillimanite, cordierite, graphite, sulfides; minor marble and calcsilicate rock.

Lithology: gneiss; marble; calc-silicate rock

Garnet-biotite-quartz-feldspar gneiss (Middle Proterozoic) at surface, covers 0.4 % of this area

Garnet-biotite-quartz-feldspar gneiss - quartzite, quartz-feldspar gneiss, calcsilicate rock.

Lithology: gneiss; quartzite; calc-silicate rock

Olivine pyroxenite (Upper Ordovician) at surface, covers < 0.1 % of this area

Olivine pyroxenite - in part with poikilitic hornblende; local peridotite.

Lithology: pyroxenite; peridotite

Balmville Limestone (Middle Ordovician) at surface, covers 0.3 % of this area

Balmville Limestone - Vermont: Whipple Limestone.

Lithology: limestone

Diorite with hornblende and/or biotite (Upper Ordovician) at surface, covers 0.3 % of this area

Diorite with hornblende and/or biotite.

Lithology: diorite