Rutan Hill (also called ''Volcanic Hill'') is the local name for a hill on the United States Geological Survey Branchville 7.5-minute map.Aurousseau, M, and HS Washington (1922) ''The Nephelite Syenite and Nephelite Porphyry of Beemerville, New Jersey.'' The Journal of Geology. 30(7):571-586.United States Geological Survey (1954
''Branchville Quadrangle New Jersey- Sussex Co. 7.5 minute Series (Topographic)''
United States Geological Survey, Reston, Virginia.United States Geological Survey (2011) ''Branchville Quadrangle New Jersey- Sussex Co. 7.5 minute Series (Topographic)'' United States Geological Survey, Reston, Virginia. It is located about south-southwest of Colesville, New Jersey in the Wantage Township, of Sussex County,

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. Rutan Hill rises about above the adjacent creek valley to an elevation of just over . This hill lies entirely within private, posted property.Mordy, R, (nd
''New Jersey’s Own Volcano: An ancient Volcano Turned Into Prime Real Estate.''Atlas Obscura.
/ref> This nondescript hill is the surface expression of a

diatreme A diatreme, sometimes known as a maar-diatreme volcano, is a volcanic pipe formed by a gaseous explosion. When magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the ...

that is the northern part of the Late

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...

Beemerville Alkaline Complex.Ghatge, SL, DL Jagel, and GC Herman, (1992
''Gravity investigations to delineate subsurface geology in the Beemerville intrusive complex area, Sussex County, New Jersey.''
Geologic Map Series no. 92-2. New Jersey Geological Survey, Dept. of Environmental Protection and Energy, Division of Science and Research, Trenton, New Jersey.Maxey, LR (1976) ''Petrology and geochemistry of the Beemerville carbonatite-alkalic rock complex, New Jersey.'' Geological Society of America Bulletin. 87(11):1551-1559 The surface exposures of the Beemerville Alkaline Complex consist of two large

nepheline syenite Nepheline syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are al ...

pluton In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

s; a nearby diatreme (Rutan Hill); and several other nearby and much smaller

dikes Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * Dikes, ...

, sills, and diatremes. The two large nepheline syenite plutons are located south-southwest of Rutan Hill along the contact between the Martinsburg and Shawangunk formations and on the southeast side of

Kittatinny Mountains Kittatinny Mountain (Lenape: Kitahtëne) is a long ridge traversing primarily across Sussex County in northwestern New Jersey, running in a northeast-southwest axis, a continuation across the Delaware Water Gap of Pennsylvania's Blue Mountain ...

. The dikes or sills consist either of

phonolite Phonolite is an uncommon extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grained) to porphyritic (mixed fine- and coarse-grained). Phonolite is a variation of the igneous ...

, tinguaite,

lamprophyre Lamprophyres () are uncommon, small-volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks, and small intrusions. They are alkaline silica-undersaturated mafic or ultramafic rocks with high magnesium oxid ...

micromalignite, lamprophyre micromelteigite, or

carbonatite Carbonatite () is a type of intrusive rock, intrusive or extrusive rock, extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals. Carbonatites may be confused with marble and may require geoche ...

. The Beemerville Alkaline Complex also includes several lamprophyric diatremes that contain

xenolith A xenolith ("foreign rock") is a rock fragment (country rock) that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term ''xenolith'' is almost exclusively used to describe inclusions in igne ...

s of

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

s and

gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...

and autoliths of carbonatite, potassic

syenite Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). Some syenites contain larger proport ...

, and lamprophyre micromelteigite. Rutan Hill is the surface expression of the largest of the lamprophyric diatremes within the Beemerville Alkaline Complex. This diatreme contains a small plug-like body of nepheline syenite that is about in diameter and is choked with variety of angular to subangular xenoliths and autoliths. The xenoliths consist of

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

and

graywacke Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lit ...

, fine-grained pale-blue

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

, cream-colored fine-grained

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

, and gneiss. The autoliths consist of nepheline syenite, micromelteigite, and carbonatite. The matrix consists of an extremely fine-grained groundmass with fine-to coarse-grained megacrysts of

biotite Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more alumino ...

diopside Diopside is a monoclinic pyroxene mineral with composition . It forms complete solid solution series with hedenbergite () and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull ...

aegerine Aegirine is a member of the clinopyroxene group of inosilicate minerals. Aegirine is the sodium endmember of the aegirine-augite series. Aegirine has the chemical formula Na Fe Si2 O6 in which the iron is present as Fe3+. In the aegirine-augite ...

augite Augite is a common rock-forming pyroxene mineral with formula . The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees. Characteristics Augite is a solid solution in the pyroxene group. ...

orthoclase Orthoclase, or orthoclase feldspar (endmember formula K Al Si3 O8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture," because its two cleavage planes are at right angles t ...

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...

apatite Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common e ...

, and

nepheline Nepheline, also called nephelite (), is a rock-forming mineral in the feldspathoid groupa silica-undersaturated aluminosilicate, Na3 K Al4 Si4 O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites ...

.Eby, G. N. (2004
''Petrology, geochronology, mineralogy, and geochemistry of the Beemerville alkaline complex, northern New Jersey.''
In JH Puffer and RA Volkert, eds., pp. 52-68, Neoproterozoic, Paleozoic, and Mesozoic Intrusive Rocks of Northern New Jersey and Southeastern New York. Twenty-First Annual Meeting Geological Association of New Jersey, Mahwah, New Jersey. Rutan Hill and the associated Beemerville Alkaline Complex are the surface exposures of a much larger alkaline igneous intrusion that underlies the Beemerville, New Jersey area.Anonymous (nd
''Geologic cross section of northern New Jersey, depicting bedrock geology of Beemerville area.''
New Jersey Geological Survey, Dept. of Environmental Protection and Energy, Division of Science and Research, Trenton, New Jersey. Note: Units SObs and SObu correspond to Silurian-Ordovician nepheline syenite and urtite. Unit Omr is the Ordovician

Martinsburg Shale Martinsburg may refer to: Places In the United States: *Martinsburg, Indiana * Martinsburg, Iowa * Sandy Hook, Kentucky, originally incorporated as Martinsburg *Martinsburg, Missouri * Martinsburg, Ripley County, Missouri * Martinsburg, Nebraska * ...

. This igneous intrusion is part of the larger Cortlandt-Beemerville magmatic belt. They occur at the western end of the Cortlandt-Beemerville magmatic belt, which spans parts of northern New Jersey and southeastern New York. The Cortlandt complex, New York, defines the eastern end of this belt. Between the Beemerville alkaline complex and the Cortlandt igneous complex, this magmatic belt consists of a linear, almost east-west trending, zone of lamprophyre and

felsic In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted with mafic rocks, whi ...

dikes.Ratcliffe, NM (1981) ''Cortlandt-Beemerville magmatic belt: A probable late Taconian alkalic cross trend in the central Appalachians.'' Geology 9(7):329-335. The currently accepted age for the emplacement Beemerville Alkaline Complex is 420 ± 6 Ma. This age is derived by the

fission track dating Fission track dating is a radiometric dating technique based on analyses of the damage trails, or tracks, left by fission fragments in certain uranium-bearing minerals and glasses. Fission-track dating is a relatively simple method of radiomet ...

titanite Titanite, or sphene (from the Greek ''sphenos'' (σφηνώ), meaning wedge), is a calcium titanium nesosilicate mineral, Ca Ti Si O5. Trace impurities of iron and aluminium are typically present. Also commonly present are rare earth metals in ...

. Mean

fission-track age of 156 ± 4 Ma is interpreted to represent the time the rocks of the complex were last at temperatures of 60 °C to 100 °C. Previously, Rb-Sr and

K–Ar dating Potassium–argon dating, abbreviated K–Ar dating, is a radiometric dating method used in geochronology and archaeology. It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar). Potassium ...

from the nepheline syenite at Beemerville yielded ages of about 435 ± 20 Ma (444 Ma. using current decay constants) for the Beemerville Alkaline Complex. All of these dates are consistent with the observations that the dikes of the Beemerville Alkaline Complex crosscut folded and foliated

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

of the Martinsburg Formation as young as early Late Ordovician but are not known to intrude younger rocks. Based upon emplacement models for diatremes it can be inferred that the diatreme that forms Rutan Hill is the throat of an ancient, extinct

volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are ...

.Kjarsgaard, BA (2007
''Kimberlite Pipe Models: Significance for Exploration.''
In B Milkereit, ed., pp. 667-677, Proceedings of Exploration 07: Fifth Decennial International Conference on Mineral Exploration. Decennial Mineral Exploration Conferences, Toronto, Ontario, Canada. However,

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

following its

eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...

has either completely destroyed the

volcanic cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and ...

and any superficial volcanic deposits associated with it or any remaining volcanic deposits lie deeply buried as none have been mapped at the surface within the Beemerville area. This igneous complex was emplaced and the volcanic activity, which was presumably associated with it, occurred during the end of the

Taconic Orogeny The Taconic orogeny was a mountain building period that ended 440 million years ago and affected most of modern-day New England. A great mountain chain formed from eastern Canada down through what is now the Piedmont of the East coast of the Unit ...

in the late

period. The temporal association with this Ordovician tectonism suggests that this magmatic activity may be related to fracturing of mantle rock at the junction of two Taconic age tectonic salients that intersect in the New York region. The tectonic setting of the intrusive belt is unusual because it is associated in space and time within the zone of compressional mountain building that defined the Taconic Orogeny. At that time, the western half of the

Iapetus Ocean The Iapetus Ocean (; ) was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale (between 600 and 400 million years ago). The Iapetus Ocean was situated in the southern hemisphere, between the paleoco ...

lying along the east coast of North America was closing, being

subducted Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

beneath the Taconic (or Bronson Hill) Island Arc.

References

External links

*Anonymous (nd
Beemerville main nepheline-syenite mass, Libertyville, Wantage Township, Sussex Co., New Jersey, USA.Mineral database.
*Ebb, GN (2004

Department of Environmental, Earth, and Atmospheric Sciences. University of Massachusetts, Lowell, Massachusetts. {{coord, 41.245513, -74.676084, region:US, format=dms, display=title Extinct volcanoes Landforms of Sussex County, New Jersey Geology of New Jersey Volcanism of New Jersey Hills of New Jersey Papakating Creek watershed