Adirondack Lowlands Research Articles

Timing of anatexis in the eastern Adirondack Highlands: Implications for tectonic evolution during ca. 1050 Ma Ottawan orogenesis

U-Pb sensitive high-resolution ion microprobe (SHRIMP) analyses of zircons from migmatitic metapelites in the eastern Adirondack Highlands demonstrate that substantial anatexis took place ca. 1050 Ma during the late, but still high-grade, ca. 1090–1050 Ma Ottawan orogeny. These results contrast with data from metapelites of the southwestern Adirondack Highlands and Adirondack Lowlands, which indicate that anatexis occurred ca. 1200–1160 Ma, during the Shawinigan orogeny and subsequent (ca. 1155 Ma) anorthosite-mangerite-charnockite-granite (AMCG) magmatism. Ca. 1180–1150 Ma zircons from this western regime do not contain ca. 1050 Ma (Ottawan) metamorphic overgrowths. The absence of ca. 1050 Ma Ottawan anatexis and overgrowths in the Adirondack Lowlands is explained by the observation that, consistent with titanite cooling ages, post–1150 Ma temperatures did not exceed ~700 °C. In the southwestern Adirondack Highlands, the absence of ca. 1050 Ma anatexis can be accounted for by earlier dehydration of metapelites during ca. 1180–1150 Ma Shawinigan-AMCG metamorphism. The occurrence of ca. 1050 Ma anatexis and formation of metamorphic zircons in the eastern Adirondacks cannot be explained by higher temperatures, because geothermometry indicates that all of the Adirondack Highlands reached a nearly uniform 750–800 °C during this period. Accordingly, the occurrence of ca. 1050 Ma Ottawan anatexis in the eastern regime is interpreted to be the result of: (1) infl uxes of hydrous fl uids at ca. 1050 Ma, or (2) decompression melting during late extensional exhumation. A recently recognized low-angle late Ottawan (ca. 1050 Ma) fault system may have provided both fl uid conduits and footwall decompression. The sense of displacement along the shear zone has not yet been unequivocally determined, but preliminary investigations of kinematic indicators demonstrate normal displacement. Thus, this structure may be an analogue of the ca. 1050 Ma northwest-dipping Carthage–Colton zone normal fault system that juxtaposed the Adirondack Lowlands against the Adirondack Highlands. In this context, these fault zones form a quasi-symmetrical core complex or gneiss dome, within which the high-grade core of the Adirondack Highlands was tectonically exhumed. A similar east-dipping, along-strike normal fault in Quebec (Tawachiche shear zone) exhumed the eastern Morin and Lac Taureau terranes at ca. 1050 Ma and may merge with the eastern Adirondack shear zone described here.

Timing of anatexis in metapelites from the Adirondack lowlands and southern highlands: A manifestation of the Shawinigan orogeny and subsequent anorthosite-mangerite-charnockite-granite magmatism

Anatectic leucogranites are common in metapelites within both the highlands and lowlands terranes of the Adirondack Mountains of northern New York State. The formation of these igneous bodies, which are folded in the lowlands and commonly mylonitized in the highlands, has been widely considered an event accompanying the ca. 1050 Ma Ottawan orogeny, during which metamorphic grade reached granulite facies in the highlands, while the lowlands experienced amphibolite facies metamorphism. Sensitive high-resolution ion microprobe (SHRIMP) analyses of zircons separated from leucosomes and melanosomes in both the southern highlands and the lowlands indicate that primary anatexis occurred ca. 1180–1160 Ma, and is thus a manifestation of heating during the earlier Shawinigan orogeny (ca. 1210– 1160 Ma) and associated anorthosite-mangerite-charnockite-granite (AMCG) magmatism (ca. 1165–1150 Ma). The absence of Ottawan overgrowths on Shawinigan zircons in these leucosomes suggests that by Ottawan time the rocks were too dry for further melting or zircon growth to occur. However, electron microprobe analyses of monazites from the southern highlands reveal multiple age zones, including cores with ages of ca. 1170–1180 Ma, consistent with primary growth during Shawinigan orogenesis, complex zones formed ca. 1140–1155 Ma during AMCG magmatism, and ca. 1050–1020 Ma formed during Ottawan orogenesis and high-grade metamorphism. Throughout the Adirondacks, leucosomes and melanosomes contain older, ca. 1320 Ma, zircons that are considered to be remnant detrital zircons derived from arc rocks of the Elzevirian terrane. The apparent absence of Archean detrital zircons suggests that the protoliths of the metapelites were deposited in restricted basins that did not receive detritus from the Superior craton.

Lu-Hf and PbSL geochronology of apatites from Proterozoic terranes: A first look at Lu-Hf isotopic closure in metamorphic apatite

The mineral apatite is characterized by elevated and highly variable Lu/Hf ratios that, in some cases, allow for single-crystal dating by the Lu-Hf isotopic system. Apatites from the Adirondack Lowlands and Otter Lake area in the Grenville Province, and from the Black Hills, South Dakota, yield Lu-Hf ages that are consistently older than their respective Pb step leaching ages. Isotopic closure for the Lu-Hf system, therefore, occurs before U-Pb system closure in this mineral. In the Adirondack Lowlands, where H 2O activity was low, Lu-Hf systematics of cm-sized apatite crystals remained undisturbed during upper amphibolite facies metamorphism (∼700 to 675 °C) at 1170–1130 Ma. The relatively old Lu-Hf ages of 1270 and 1230 Ma observed for these apatites correlate with decreasing crystal size. In contrast, apatite from the fluid-rich Otter Lake area and Black Hills yields unrealistically low apparent Lu-Hf closure temperatures, implying that in these apatites, fluids facilitated late exchange. The Lu-Hf ages for the metamorphic apatites were thus controlled either by the prevailing temperature and grain size, or by fluid activity.

Structural and U/Pb chronology of superimposed folds, Adirondack Mountains: implications for the tectonic evolution of the Grenville Province

The Grenville Province of eastern Laurentia formed during Mesoproterozoic events that led to the formation of the supercontinent of Rodinia. Structural analysis and U-Pb geochronology of the Piseco antiform in the southern Adirondack Highlands part of the Grenville Province has shed new light on the geology and structural history of this orogen. An outcrop positioned on the northern limb of the Piseco antiform near Wells, NY, contains a major F 1 fold refolded by regional F 2 and F 3 axes. This is the first recognized large-scale F 1 fold in the Adirondack Highlands. Foliated leucocratic gneiss and deformed metagabbro dikes in the core of the antiform have yielded single-grain U-Pb zircon ages of 1172.4±2.2 and 1165.4±1.3 Ma, respectively. Discordant pegmatitic veins that crosscut the foliation in the metagabbro have yielded an estimated 207Pb/ 206Pb age of 1052.4 Ma. The geochronological data have several important implications. The 1172 Ma age of the Wells leucocratic gneiss is virtually identical with that of the syntectonic Hyde School gneiss, Rockport granite, and Wellesley granite from the Adirondack Lowlands and Frontenac terrane of the Central Metasedimentary Belt, thus extending the known distribution of magmas of this age to the southern Adirondack Highlands. We relate these syntectonic granitoids and F 1 folds to the suturing of the ca. 1350–1250 Ma Adirondack Highlands-Green Mountain arc to the composite arc terrane and Laurentia at 1220–1170 Ma. The 1165 Ma deformed metagabbro contains the S 2 but not the S 1 foliation, and we correlate the metagabbro with the ca. 1170–1125 Ma AMCG suite, interpreted to have formed in response to orogenic collapse and delamination following the collision. The Wells leucocratic gneiss and gabbro were folded by reclined isoclinal F 2 folds and upright F 3 folds, and cut by apparently undeformed ca. 1052.4 Ma pegmatitic dikes. Since the discordant pegmatites cut the S 1, S 2, and S 3 foliations which postdate the ca. 1090 Ma Hawkeye granite, the timing of F 2 and F 3 deformations is constrained between ca. 1090 and 1052.4 Ma. This interval corresponds to the ca. 1090–1040 Ma Ottawan Orogeny in the Adirondacks, related to the continent-continent collision of the Laurentian margin with another continent, possibly Amazonia.

Early History of the Carthage‐Colton Shear Zone, Grenville Province, Northwest Adirondacks, New York (U.S.A.)

Abstract The Adirondack Mountains expose two distinct tectonic elements of the Proterozoic Grenville Province of northeastern North America: the Adirondack Lowlands and Highlands. The Lowlands are located along the eastern edge of the Metasedimentary Belt, and the Highlands form the western portion of the Granulite Terrane. The two are separated by the Carthage‐Colton Shear Zone (CCSZ). U/Pb titanite and 40Ar‐39Ar hornblende ages in the Lowlands are ca. 100 m.yr. older than in the Highlands, across the CCSZ. While both the Lowlands and the Highlands record a history of metamorphism during the Elzevirian Orogeny (ca. 1150 Ma), only the Highlands record evidence of a major phase of Grenvillian thermotectonic activity (Ottawan Orogeny) at ca. 1090–1030 Ma. Proposed tectonic models require that the Lowlands were either laterally separated from the Highlands or were at structurally higher levels during this metamorphism. New U/Pb and 40Ar‐39Ar ages from titanite and hornblende‐bearing mylonites in the Dana Hil...

Late Proterozoic (ca. 930 Ma) extension in eastern Laurentia

The northwest-dipping Carthage-Colton shear zone, located near the eastern margin of the Grenville province in northern New York, separates the Adirondack Lowlands of the Metasedimentary Belt from the Adirondack Highlands of the Granulite Terrane. Published U/Pb sphene ages are 1156‐1103 Ma in the Lowlands and 1050‐ 982 Ma in the Highlands, indicating an ;100 m.y. offset in metamorphic ages across the boundary. Our reported hornblende 40 Ar39 Ar ages are ;1060 Ma in the Lowlands and ;950 Ma in the Highlands. This confirms the offsets in sphene ages across the Carthage-Colton shear zone and indicates an average cooling rate in both the Lowlands and the Highlands of 18‐28/ m.y. over ;100 m.y. Biotite 40

Hornblende geothermometry of amphibolite layers of the Popple Hill gneiss, north‐west Adirondack Lowlands, New York, USA

The exchange reaction tschermakite+2 diopside+2 quartz=tremolite+2 anorthite (HPCQ), in combination with the thermodynamic database TWQ (version 1.02, Berman, 1991), has been evaluated for its usefulness as a geothermometer. This reaction, which is both water conserving (independent of water fugacity) and which does not require the presence of garnet, is well suited for studying pyroxene‐bearing amphibolites. As an application of this geothermometer, we have re‐examined the amphibolites occurring in the Popple Hill gneiss of the Adirondack Lowlands of New York, USA, to better understand the magnitude of temperature variation preserved in the amphibolites themselves in this classic locality. At an assumed constant pressure of 7 kbar, the temperatures range from 619 to 682 °C from Edwards to Pierrepont and are uncorrelated with either distance along the strike of the region or with modal mineralogical variations. Hornblende exhibits a narrow compositional range suggesting that there has been little or no thermal gradient along the strike of the Lowlands. Temperatures recorded just north of Colton are, however, distinctly higher (694–758 °C). Although it is likely that the Popple Hill gneiss amphibolites experienced some effects of progressive metamorphism, particularly in the vicinity of Colton, the variations in modal mineralogy are most likely the result of such factors as local variations in the bulk chemistry of the protolith and in the fugacity of H2O due to infiltration of diluting species (e.g. CO2, CH4), rather than a regional temperature variation. Temperatures recorded by the HPCQ geothermometer reported here are similar in magnitude and geographic trend to those reported for graphite–calcite carbon‐isotope thermometry by Kitchen & Valley (1995), suggesting that peak metamorphism in the Adirondack Lowlands involved laterally extensive and fairly uniform isotherms.

Precise zircon geochronology in the Adirondack Lowlands and implications for revising plate-tectonic models of the Central Metasedimentary Belt and Adirondack Mountains, Grenville Province, Ontario and New York

New high-precision, single-grain dating of leucogranites from the Adirondack Lowlands, dated previously by multigrain zircon methods at ca. 1416 Ma (Wellesley Island) and ca. 1285-1230 Ma (Hyde School Gneiss), has yielded U-Pb zircon ages of ca. 1172 Ma, identical to that of Rockport granite of the Frontenac terrane. In addition, sensitive high resolution ion microprobe (SHRIMP) zircon dating of the intrusive Antwerp-Rossie suite in the Adirondack Lowlands indicates a maximum emplacement age of ca. 1207+26-11 Ma which fixes a minimum age for deposition of regional metasedimentary rocks that it crosscuts. These results remove apparent chronological discrepancies across the St. Lawrence River, thus expanding the significance of the Rockport granite and Hyde School Gneiss and requiring modification of plate-tectonic models for the Central Metasedimentary Belt and Adirondack Mountains in the interval ca. 1350-1125 Ma.

Precise zircon geochronology in the Adirondack Lowlands and implications for revising plate-tectonic models of the Central Metasedimentary Belt and Adirondack Mountains, Grenville Province, Ontario and New York

Precise zircon geochronology in the Adirondack Lowlands and implications for revising plate-tectonic models of the Central Metasedimentary Belt and Adirondack Mountains, Grenville Province, Ontario and New York

Sm-Nd and U-Pb Isotopic Evidence of Juvenile Crust in the Adirondack Lowlands and Implications for the Evolution of the Adirondack Mts.

Sm-Nd investigations of Hyde School Gneiss yield $T_{DM}$ ages only slightly older than U-Pb zircon emplacement ages thus indicating substantial addition of juvenile, calcalkaline crust to the Adirondack lowlands at ca. 1300 Ma. Juvenile crust of similar age has been recognized within the Adirondack highlands, the Elzevir terrane further to the northwest in Canada, and in the Green Mts. of Vermont suggesting the presence of an extensive magmatic arc at that time. While the precise nature of the arc remains uncertain, an Indonesian analogue is favored. U-Pb zircon ages of ca. 1150-1160 Ma are reported for lowlands samples of syenitic and granitic rocks belonging to the anorthosite-mangerite-charnockite-granite (AMCG) suite that also occurs in the highlands, as well as in the Canadian sector of the Frontenac terrane. The regional occurrence of these anorogenic intrusions indicates that the Adirondack highlands and Frontenac terrane, including the Adirondack lowlands, constituted a single, contiguous entity by ca. 1160 Ma. Monazite ages from AMCG rocks and metamorphic zircons from Hyde School Gneiss indicate that the last high grade metamorphism (i.e., upper amphibolite facies) in the Adirondack lowlands occurred at ca. 1150 Ma. The presence of 1050 Ma granulite facies assemblages east of the Carthage-Colton mylonite zone (CCMZ) in the highlands indicates the presence of a discontinuity across the CCMZ, which may manifest ca. 1050 Ma downfaulting of the lowlands block along the northwest dipping CCMZ in response to verthickened crust during the Ottawan orogeny.

Retrograde deformation within the Carthage-Colton Zone as recorded by fluid inclusions and feldspar compositions: tectonic implications for the southern Grenville Province

The Carthage-Colton Zone (CCZ), located in the northwestern portion of the Proterozoic Adirondack terrane, forms the boundary between the Adirondack lowlands and highlands and is characterized by textures indicative of ductile deformation. Samples from three rock types have been collected from this zone: (1) pyroxene bearing syenite gneisses of the Diana igneous complex; (2) paragneiss samples from near the northwestern boundary of the Diana complex; (3) a quartz-rich metasediment. Feldspar geothermometry performed on the Diana metasyenites shows that porphyroclasts are relict igneous grains that formed atT≈900° C, while dynamic recrystallization occurred at temperatures as low as 470 to 550° C as shown by the compositions of feldspar neoblasts. All samples examined in this study from the CCZ contain a suite of CO2-rich fluid inclusions that are distinctive both texturally and in their microthermometric behavior (Th=-27.7 to-7.1° C) as compared to CO2-rich Adirondack fluid inclusions that do not lie within this zone (Th=-45.9 to +31.0° C). The results from fluid inclusion microthermometry and feldspar geothermometry restrict the conditions of dynamic recrystallization to temperatures and pressures of 400 to 550° C and 3 to 5 kbar. The retrograde pressure-temperature path must pass through these conditions. Similar fluid inclusion results have been obtained from the Parry Sound Shear Zone (PSSZ) which is a Grenvillian shear zone that is located in Southern Ontario (Lamb and Moecher 1992). However, the inferred retrogradeP-T paths for these two areas, the CCZ and the PSSZ, are different and this difference may be a result of late deformation along shear zones that are located between the two areas.

Age, Field, and Petrological Relationships of the Hyde School Gneiss, Adirondack Lowlands, New York: Criteria for an Intrusive Igneous Origin

Alaskitic and tonalitic rocks constituting Hyde School Gneiss (HSG) occur in 14 domical bodies in the Adirondack lowlands. Recent models have interpreted these bodies as metamorphosed rhyolitic and dacitic ash-flow deposits forming the basal member of a regional stratigraphic package. In contrast, this paper presents criteria and evidence for an intrusive origin for HSG. Field evidence includes intrusion breccias and complex crosscutting relationships involving mafic layers resembling synplutonic dikes. Petrological constraints supporting an intrusive origin include: (1) the common occurrence of quartz-mesoperthite hypersolvus assemblages; (2) magmatic features in tonalitic, trondhjemitic, and alaskitic facies; (3) local occurrences of orthopyroxene in all facies of HSG; and (4) the development of marginal garnet-sillimanite gneiss with corundum-spinel-garnet-sillimanite assemblages yielding paleotempera-tures of 780°-810°C and interpreted as restite remaining after anatexis of country rock metapelite by intrusions of hypersolvus granitoids. U-Pb zircon ages reported here suggest that the majority of the HSG was intruded at ca. 1230 Ma, contemporaneous with high-grade metamorphic activity in the Adirondacks and elsewhere in the SW sector of the Grenville Province. Geochronological evidence from a leucogranitic rock crosscutting metasediments on Welles-ley Island suggests that these metasediments are older than .

High-frequency seismic noise as a function of depth

Abstract Evidence is presented supporting the view that high-frequency seismic noise decreases with increased depth. Noise amplitudes are higher near the free surface where surface-wave noise, cultural noise, and natural (wind-induced) noise predominate. Data were gathered at a hard-rock site in the northwestern Adirondack lowlands of northern New York. Between 15- and 40-Hz noise levels at this site are more than 10 dB less at 945-m depth than they are at the surface, and from 40 to 100 Hz the difference is more than 20 dB. In addition, time variability of the spectra is shown to be greater at the surface than at either 335- or 945-m depths. Part of the difference between the surface and subsurface noise variability may be related to wind-induced noise. Coherency measurements between orthogonal components of motion show high-frequency seismic noise is more highly organized at the surface than it is at depth. Coherency measurements between the same component of motion at different vertical offsets show a strong low-frequency coherence at least up to 945-m vertical offsets. As the vertical offset decreases, the frequency band of high coherence increases.

Serendibite from the northwest Adirondack Lowlands, in Russell, New York, USA

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The role of synmetamorphic igneous rocks in the metamorphism and partial melting of metasediments, Northwest Adirondacks

Field and petrologic studies along the Adirondack Lowlands — Highlands boundary near Harrisville, NY, indicate that heat from the synmetamorphic intrusion of the Diana syenite complex (intrusion temperature of ∼1,050° C) played a major role in the local metamorphic thermal regime and was responsible for extensive partial melting of adjacent metasedimentary units (Major Paragneiss of Engel and Engel). Metamorphic temperatures inferred from two — feldspar and spinel — quartz assemblages decrease from 850–950° C along the Diana — metasediment contact to 650–700° C, 2–3 km away from the contact. Metamorphic pressures are 7±0.5 kb as determined from coexisting plagioclase — garnet — sillimanite — quartz, kyanite — sillimanite, and garnet — rutile — ilmenite — sillimanite — quartz (GRAIL). In the paragneiss, migmatites consisting of quartz — microcline perthite — sodic plagioclase leucosomes are generally concordant with the melanosome consisting of biotite — sillimanite — garnet — spinel — plagioclase ±corundum±cordierite. Qualitatively the amount of partial melt and occurrences of corundum-bearing assemblages decrease away from the Diana contact. Activity of H2O inferred from coexisting biotite — sillimanite — quartz — garnet — K-feldspar ranges from 0.01 to 0.17 and is five to ten times lower in corundum-bearing rocks.

Thermometry and barometry of some amphibolite–granulite facies rocks from the Otter Lake area, southern Quebec

Grenville rocks from a 2500 km2 area centered on Otter Lake, Quebec (some 75 km northwest of Ottawa) are in the uppermost amphibolite to lower granulite facies; orthopyroxene occurs occasionally in both metabasic and charnockitic rocks. The temperature of metapmorphism was approximately 675 °C, based upon oxide, feldspar, and garnet–clinopyroxene thermometry. Little thermal gradient could be detected across the area. Carbonate thermometry, using reintegrated calcite compositions, yielded lower temperatures of 600 °C (maximum), while garnet–biotite and other Kd thermometers yielded scattered and for the most part unreasonable results. Metamorphic pressure, calculated from the reaction anorthite = grossular + sillimanite + quartz, was 5.0 ± 0.5 kbar(500 ± 50 MPa). Similar calculations based upon the reactions garnet + quartz = anorthite + orthopyroxene and garnet + quartz = anorthite + clinopyroxene yielded pressures of 5.5–7.0 kbar (550–700 MPa). Pressure calculations based upon assemblages of cordierite–garnet–sillimanite–quartz were less precise, but agreed with the outer estimates. Similar metamorphic temperatures and slightly lower pressures have been estimated for the Adirondack Lowlands of New York. In the Morin Highlands, 100 km east of Otter Lake, and in the Adirondack Highlands, 100 km east of the Adirondack Lowlands, temperatures of metamorphism (700–800 °C) and pressures of metamorphism (6–9 kbar (600–900 MPa)) are both higher. Thus it appears that over an approximate 300 km north–south direction nearly constant metamorphic conditions prevailed at Grenville time. In the east–west direction significant variations in metamorphic grade are recorded; both temperature and pressure markedly increase to the east.

Metamorphic Conditions at the Northern end of the Northwest Adirondack Lowlands

INTRODUCTION Since the now-classic studies of the Engels in the late 1950s and early 1960s (Engel and Engel, 1958, 1960, 1962a, 1962b, Engel and others, 1964), the northwest Adirondack Grenville Lowlands has been cited as an example of progressive meta-morphism from the amphibolite facies in the west and southwest to granulite in the east and northeast. The Engels documented mineralogical changes along a traverse within the lowlands from Emeryville to Colton, New York: muscovite gives way to K-feldspar in pelites, and hornblende and sphene progressively are replaced by pyroxene and oxides in amphibolites. The Engels inferred temperatures of about 500 to 525 °C at Emeryville and a steady increase to about 600 to 625 °C at Colton. Although today we may not agree with the exact temperatures estimated by the Engels, the trends they pointed out are well documented and have established a firm basis for newer, more detailed studies on a local scale, which have the advantage of the results of twenty years9 work in experimental petrology. In this paper I discuss some aspects of the metamorphic phase relations and the implied metamorphic conditions of rocks from a small area at the high-grade end of the Engels9 traverse.

A reinterpretation of the structural and stratigraphic setting of the Balmat-Edwards zinc deposits, Northwest Adirondack Lowlands, New York

A reinterpretation of the structural and stratigraphic setting of the Balmat-Edwards zinc deposits, Northwest Adirondack Lowlands, New York

A structural model for the northwestern Adirondacks based on leucogranitic gneisses near Canton and Pyrites, New York: Summary

INTRODUCTION The origin and structural relationships of leucogranitic gneiss bodies in the Adirondack Lowlands represnnt controversial problems in the Adirondacks. Most of the early published work, as later summarized by Buddington (1939) suggested that these bodies were unconnected intrusive igneous bodies later affected by penetrative deformation and metamorphism. Granitic magma was intruded into the axial zones of major folds to form lens-shaped, concordant masses that he labeled “phacoliths.” A subsequent idea, credited to Bloomer by Engel and Engel (1963), suggested a metasedimentary origin for these bodies. In this model, the granitic masses represent metamorphosed, transformed, layered rocks occupying specific stratigraphic positions in the Adirondack Lowlands. Wynne-Edwards (1967), Lewis (1969), and Carl and Van Diver (1971, 1975) shared this opinion, Foose and Carl (1977) proposed an integrating model to explain the structural setting of the “alaskite” bodies of the Adirondacks Lowlands as parts of a single, extensive, folded sheet.

Metamorphic conditions at the northern end of the northwest Adirondack Lowlands: Summary

Research Article| February 01, 1980 Metamorphic conditions at the northern end of the northwest Adirondack Lowlands: Summary EDWARD F. STODDARD EDWARD F. STODDARD 1Department of Earth and Space Sciences, University of California, Los Angeles, California 90024. Present address: Department of Geosciences, North Carolina State University, Raleigh, North Carolina 27650 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1980) 91 (2): 100–102. https://doi.org/10.1130/0016-7606(1980)91<100:MCATNE>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation EDWARD F. STODDARD; Metamorphic conditions at the northern end of the northwest Adirondack Lowlands: Summary. GSA Bulletin 1980;; 91 (2): 100–102. doi: https://doi.org/10.1130/0016-7606(1980)91<100:MCATNE>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract No Abstract Available. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.