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Download Geology of the New Jersey Highlands and Valley and Ridge Provinces
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Geology of the New Jersey Highlands and Valley and Ridge Provinces Rich Volkert New Jersey Geological Survey Rock cycle Present distribution of tectonic plates Eurasian plate Arabian plate African plate Indian plate Part I Geology of the New Jersey Highlands Highlands Physiographic Province Area of scenic and rugged terrain encompassing 1,000 square miles Mountainous uplands of northeasttrending ridges underlain by rocks resistant to erosion Broad, flat valleys (e.g., Pequest, Long, Musconetcong, Vernon) underlain by less resistant Proterozoic rocks and/or younger shale and limestone Wawayanda Mt. 1,496 ft. ¿ a Franklin Boonton t M Chester Washington Pi e dm on t p m u J y n n Je d n a y ll e dge a V Ri Age of rocks in the Highlands (million years ago) Distribution of Proterozoic rocks in eastern North America ~960 ~1300 * Highlands (continued) Most ancient part of State Remnant of mountain belt formed from colliding tectonic plates (proto North and South America) Metamorphic Rocks Characterized by parallel alignment of minerals (foliation) High temperature/pressure (1300o -1400o F, 5,000 atm, buried ~15-20 mi). Rocks soft, easily folded Exposed at the surface due to uplift and the erosion of overlying rocks NJ Highlands Zone of metamorphism Geologic Map of the Highlands Distribution of Proterozoic rocks More than 30 different Proterozoic rock units recognized (mainly granites, gneisses, marble) Complex folding and faulting Area shown Rock types of the Highlands Granite Widespread, common igneous rock crystallized from magma underlies 50% of Highlands medium to coarse grained, massive textured Composed mainly of minerals quartz and feldspar Byram granite Lake Hopatcong granite Mount Eve granite Pompton Pink Granite Smithsonian NMNH Riverdale quarry 1 in. ----- St Pauls, Paterson Gneiss Widespread, common metamorphic rock Underlies 45% of Highlands Formed from metamorphism of igneous or sedimentary rocks Igneous gneiss Sedimentary gneiss Underlies 5% of Highlands Metamorphosed marine limestone Marble Composed of calcium carbonate Host rock for zinc deposits Quarried for cement, fertilizer, ornamental stone Limecrest quarry, Sparta Faults Compression Fractures along which rocks have broken and been offset Faults form from compressional or extensional forces, or both May have high- or low-temperature deformation features Occur at all scales - variable lengths and widths Important conduits for water and contaminant movement Extension Distribution of faults in the Highlands New York ¿ a Valley and Ridge Piedmont Oakland s d n a l h g i H Morristown Bernardsville Boonton po a m a R lt u fa t n o m d e i P ¿ a Low-temperature (brittle) faults -----20 ft. High-temperature (ductile) faults Joints Fractures along which there has been no movement Mainly due to extensional forces; pressure release during uplift Variably spaced from inches to several feet Important conduits for water and contaminant movement Folds Bends in rock from compressional forces 1 billion years ago Wide range in size (inches to thousands of feet) Arched upward = anticline; arched downward = syncline 1ft. -------- 1 in. ---- Economic Geology of the Highlands Iron ore Zinc ore Graphite ore Radioactive ore Mica deposits Serpentine deposits Crushed stone - Deposits are >1billion years old - Metamorphosed at high temperature - Complexly folded and faulted - More than 400 mines. Mostly underground, some surface workings. Depths range from –10’s of ft. to -2,900 ft. Iron ore (magnetite) 1710-1966 Zinc deposits (1770-1987) Zinc ore Zincite Willemite Franklin mine (1770-1954) Franklinite Sterling Hill mine (1772-1987) Fluorescence Fluorescence is due to the presence of manganese in the atomic structure of these minerals Franklin and Sterling Hill mines produced >360 minerals, 33 unique to NJ Willemite (green) Calcite (red) Graphite deposits (1848-1928) Graphite ore - Composed of metamorphosed carbon from billion-year-old microorganisms -13 mines, mainly in eastern Highlands -mined from surface and shallow underground workings Annandale mill, Clinton Twp. circa 1928 Radioactive ore - Mica deposits - Serpentine deposits Radioactive ore (1900’s) Mica (pre 1868) Serpentine (1848-1900) Crushed stone Geologic Hazards in the Highlands Earthquakes Landslides and slope failure Sinkholes Abandoned mines Radon Earthquake activity - Most common in the Highlands - Mostly low magnitude - Occur mainly along faults - Caused by sudden release of energy from locked crustal blocks along faults Epicenter * Focus Landslides and slope failure Pattenburg Lk Mohawk Rock fall Sinkholes Form in soluble rock (marble or limestone) from dissolution of rock by acidic water H2O + CO2 = H2CO3 Abandoned mines Ringwood Byram Twp Rockaway Twp Jefferson Twp Ringwood Radon Uranium has a geochemical affinity for rocks with high potassium (granite) Uranium has a valence charge of +6 (incompatible element) Radioactive minerals “Misfit” cation not easily incorporated in atomic structure of earlier formed minerals. Becomes concentrated in late stage magmas, most commonly in granite Uranium 238 Radium 226 Granite Radon 222 Decay of uranium to radon gas Part II Geology of the Valley and Ridge Age (~365) Paleozoic rocks of the Highlands and Valley and Ridge Provinces - Northeast-trending ridges - Broad, northeast-trending valleys - Highest point 1803 ft. - Sedimentary rocks deposited on land and in shallow sea -Rocks range in age from 540 to 365 million years Million years ago (~540) Vernon Valley Valleys underlain by relatively soft and easily eroded shale and limestone Musconetcong Valley Green Pond Mountain Ridges underlain by resistant conglomerate and sandstone Kittatinny Mountain “Puddingstone” Depositional environment of sedimentary rocks in the Valley and Ridge conglomerate limestone sandstone shale Economic Geology of the Valley and Ridge Copper (~1659-1911) Pahaquarry mine (depth)? Kittatinny Mountain Silurian sandstone Crushed stone Limestone quarries Lime, concrete, fertilizer Slate Roofing Chalkboards Glacial geology of the Highlands and Valley and Ridge Provinces - Three major ice advances, each of ~ 5,000 years duration: ~ 2 million to 800,000 years ~130,000 years ~21,000 years - Ice as much as 2,000 ft thick in northern NJ - Advances separated by warmer interglacial stages Remnants of glaciation Glacial polish Striations Glacial erratic Sand & gravel Glacially-influenced landscapes Heaters pond Vernon marsh Great Meadows Modern (post-glacial) erosional processes Physical weathering Physical breakdown of rock without chemical alteration (frost wedging, plant roots, lichen, running water, human activity) Enhanced by faulting and jointing of rock Turns large rocks into small ones for removal by wind or runoff, and then transport by streams Chemical weathering Hydrolysis Oxidation Carbonation Chemical breakdown of constituent minerals in rock Oxidation – breaks down iron and sulfur in minerals Hydrolysis – removes Na, Ca, K and alters minerals to clay Carbonation – dissolves calcite in marble Groundwater cycle of the Highlands and Valley and Ridge Fractured bedrock aquifers Precipitation The New Jersey Highlands experiences the greatest precipitation in the State due to physiography and other factors. Clean water for drinking and recreation Lunch time!
