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Jersey City, NJ, United States

Volkert R.A.,New Jersey Geological Survey | Monteverde D.H.,New Jersey Geological Survey | Friehauf K.C.,Kutztown University of Pennsylvania | Gates A.E.,Rutgers University | And 2 more authors.
Memoir of the Geological Society of America | Year: 2010

Small deposits of Neoproterozoic ironstone in the New Jersey Highlands are hosted by the Chestnut Hill Formation, a terrestrial sequence of siliciclastic rocks, sparsely preserved felsic and mafic volcanic and tuffaceous rocks, and thin limestone metamorphosed at greenschist-facies conditions. Sediments of the Chestnut Hill Formation were deposited in alluvial, fluvial, and lacustrine environments in a series of fault-bounded subbasins along the Iapetan eastern Laurentian margin. Ironstone occurs mainly in the upper part of the sequence in sandstones, quartzites, fine-grained tuffs, tuffaceous sediments, and carbonate-bearing beds. Ore is massive to banded and contains the assemblage hematite ± magnetite, which is locally associated with tourmaline and Fe silicates + sericite + calcite + chlorite ± quartz. Ironstone alternates with clastic bands, and sedimentary structures in ore bands and clastic bands are consistent with alternating chemical and clastic sedimentation deposited synchronously. Chestnut Hill rocks exhibit geochemical compositions that are dissimilar to typical sedimentary and volcanic rocks. They display evidence for two stages of postdiagenetic alteration. The first stage involved widespread potassium metasomatism, which produced increased values of K, Ba, and Rb that are not correlated with increased Fe or other hydrothermal elements. The metasomatizing fluid may have been basinal water heated during emplacement of Chestnut Hill volcanic rocks. The second stage produced alteration of Chestnut Hill rocks, and also Mesoproterozoic rocks along the footwall contact of the deposits, by hydrothermal fluids likely from a volcanogenic source. The ironstone deposits were formed by hydrothermal processes related to extension during formation of continental rift subbasins in the New Jersey Highlands. Iron was sourced from Fe-rich Mesoproterozoic rocks at depth, where it was leached by hydrothermal fluids that migrated upward along extensional faults. Iron and other metals were precipitated in permeable basin sediments and chemically favorable volcanic rocks, as well as precipitated directly as chemical sediment. © 2010 The Geological Society of America. All rights reserved. Source


Miller K.G.,Rutgers University | Sherrell R.M.,Rutgers University | Browning J.V.,Rutgers University | Field M.P.,Rutgers University | And 5 more authors.
Geology | Year: 2010

We directly link iridium (Ir) anomalies in New Jersey to the mass extinction of marine plankton marking the Cretaceous-Paleogene (K-Pg) boundary. We confirm previous reports of an Ir anomaly 20 cm below the extinction of Cretaceous macrofauna (the "Pinna" bed) with new results from a muddy sand section from Tighe Park, Freehold, New Jersey (United States), but we also show that Ir anomalies correlate with marine mass extinctions at three other clay-rich New Jersey sections. Thus, we attribute the anomaly at Freehold to the downward movement of Ir and reaffirm the link between impact and mass extinction. © 2010 Geological Society of America. Source


Fluvial and glacial deposits in New Jersey, Long Island, and the Hudson valley provide a record of Hudson River drainage since the late Miocene. Late Miocene fluvial deposits record southerly flow across the emerged inner New Jersey shelf. In the late Miocene-early Pliocene this drainage incised, shifted southwesterly, and discharged to the shelf south of New Jersey. During late Pliocene or Early Pleistocene glaciation, discharge to the shelf in the New York City area was established. This drainage incised and stabilized in the Early and Middle Pleistocene and remained open during pre-Wisconsinan (Oxygen Isotope Stage 6? (OIS-6?)) and late Wisconsinan (OIS-2) glacial advances. During late Wisconsinan retreat, moraine deposits dammed the valley at the Narrows to form Lake Albany. From 19 to 15.5 kyr BP (all dates in 14C yr), Hudson drainage was directed eastward into the Long Island Sound lowland. Drainage of Lake Wallkill into Lake Albany at 15.5 kyr BP breached the Narrows dam and initiated the unstable phase of Lake Albany, which was controlled by eroding spillways, first on the moraine dam, then on emerged lake-bottom in the mid-Hudson valley. Marine incursion between 12 and 11 kyr BP limited fluvial incision of the lake bottom, stabilizing the Quaker Springs, Coveville, and upper Fort Ann spillways. Lowering sea level between 11 and 10 kyr BP allowed incision from the upper to lower Fort Ann threshold. Sediment eroded by lake outflows between 15 and 10.5 kyr BP was trapped in the glacially deepened lower valley. Little inland sediment reached the shelf after 20 kyr BP. © 2009 The Authors, Journal compilation © 2009 The Boreas Collegium. Source


Volkert R.A.,New Jersey Geological Survey | Aleinikoff J.N.,U.S. Geological Survey | Fanning C.M.,Australian National University
Memoir of the Geological Society of America | Year: 2010

New U-Pb sensitive high-resolution ion microprobe (SHRIMP) ages from zircon and monazite document a 350 m.y. geologic evolution for the New Jersey Highlands. Two pulses of calc-alkaline magmatism that include the Wanaque tonalitic gneiss (1366 ± 9 Ma and 1363 ± 17 Ma) and Losee Suite tonalitic gneiss (1282 ± 7 Ma), dacitic gneiss (1254 ± 5 Ma), and dioritic gneiss (1248 ± 12 Ma) represent the southern continuation of eastern Laurentian margin arc activity. Supracrustal paragneisses, marble, and cogenetic metavolcanic rocks were deposited in a backarc basin inboard of the Losee arc. Ages of 1299 ± 8 Ma to 1240 ± 17 Ma for rhyolitic gneisses provide lower and upper limits, respectively, for the age of the supracrustal succession. Inherited cores in zircon grains from supracrustal rhyolitic gneiss and from Losee Suite rocks yield overlapping ages of 1.39-1.30 Ga and indicate proximity to an older arc source temporally equivalent to the Wanaque tonalitic gneiss. Location of the backarc inboard of the Losee arc implies a northwestdipping subduction zone at this time beneath the eastern Laurentian margin. A-type granite magmatism of the Byram and Lake Hopatcong intrusive suites at 1188 ± 6 Ma to 1182 ± 11 Ma followed termination of arc and backarc magmatism and documents a change to decompression melting of delaminated lithospheric mantle by upwelling asthenospheric mantle. Waning stages of A-type granite magmatism include clinopyroxene granite (1027 ± 6 Ma) and postorogenic Mount Eve Granite (1019 ± 4 Ma). Overgrowths on zircon and monazite give ages of 1045-1024 Ma, fixing the timing of granulite-facies metamorphism in the New Jersey Highlands; other overgrowth ages of 996-989 Ma reflect the thermal effects of postorogenic felsic magmatism and hydrothermal activity associated with regional U-Th-rare earth element (REE) mineralization. © 2010 The Geological Society of America. All rights reserved. Source


Gallagher W.B.,Rider University | Miller K.G.,Rutgers University | Sherrell R.M.,Rutgers University | Browning J.V.,Rutgers University | And 5 more authors.
Bulletin de la Societe Geologique de France | Year: 2012

New data regarding the placement of the Cretaceous-Paleogene (K/Pg) boundary in New Jersey is presented based on a recent campaign of drill coring boundary sections in the Atlantic coastal plain of southern New Jersey. The occurrence of late Maastrichtian mosasaurs worldwide and in New Jersey is reviewed in light of the continuing controversy over the rate and cause of the extinction at the K/Pg boundary. At the Meirs Farm site in Monmouth County, NJ, the biostratigraphic position of mosasaur specimens (Halisaurus platyspondylus, Mosasaurus hoffmann) is related to the occurrence of an iridium excursion of 0.5 ppb (5x background levels) in the basal Hornerstown Formation just above the upper Maastrichtian New Egypt Formation. Other specimens in museum collections obtained during the acme of nineteenth century marl mining are from this area of the Maastrichtian outcrop belt in New Jersey. It is concluded that late Maastrichtian mosasaurs show no diminution of their biogeographic ranges and are not particularly rare in New Jersey in comparison to older mosasaur faunas. Mosasaurs became extinct in association with the collapse of the marine food web at the K/Pg boundary, and were replaced as apical marine predators in the early Danian by a variety of crocodilians. Source

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