Depositional setting, taphonomy and geochronology of new fossil sites in the Catskill Formation (Upper Devonian) of north-central Pennsylvania, USA, including a new early tetrapod fossil

Broussard, David; Trop, Jeffrey M.; Benowitz, Jeff; Daeschler, Edward B.; Chamberlain, John A.; Chamberlain, Rebecca B.

doi:10.1016/j.palaeo.2018.07.033

Cited by 16 publications

(17 citation statements)

References 37 publications

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“…Fourteen samples were previously analyzed through traditional 40 Ar/ 39 step-heat geochronology at the University of Alaska Fairbanks Geochronology Lab and published in Brueseke et al (2019). Forty-six different igneous rock samples were analyzed by 40 Ar/ 39 Ar geochronology at the University of Alaska Fairbanks Geochronology Lab using the single-grain fusion 40 Ar/ 39 Ar geochronology method (Broussard et al, 2018). Rock samples were crushed using a stainless-steel mortar and pestle, then sieved using 500-1000 micron sieves.…”

Section: ■ Methodsmentioning

confidence: 99%

Geochemical and geochronological records of tectonic changes along a flat-slab arc-transform junction: Circa 30 Ma to ca. 19 Ma Sonya Creek volcanic field, Wrangell Arc, Alaska

et al. 2019

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The Sonya Creek volcanic field (SCVF) contains the oldest in situ volcanic products in the ca. 30 Ma–modern Wrangell Arc (WA) in south-central Alaska, which commenced due to Yakutat microplate subduction initiation. The WA occurs within a transition zone between Aleutian subduction to the west and dextral strike-slip tectonics along the Queen Charlotte–Fairweather and Denali–Duke River fault systems to the east. New 40Ar/39Ar geochronology of bedrock shows that SCVF magmatism occurred from ca. 30–19 Ma. New field mapping, physical volcanology, and major- and trace-element geochemistry, coupled with the 40Ar/39Ar ages and prior reconnaissance work, allows for the reconstruction of SCVF magmatic evolution. Initial SCVF magmatism that commenced at ca. 30 Ma records hydrous, subduction-related, calc-alkaline magmatism and also an adakite-like component that we interpret to represent slab-edge melting of the Yakutat slab. A minor westward shift of volcanism within the SCVF at ca. 25 Ma was accompanied by continued subduction-related magmatism without the adakite-like component (i.e., mantle-wedge melting), represented by ca. 25–20 Ma basaltic-andesite to dacite domes and associated diorites. These eruptions were coeval with another westward shift to anhydrous, transitional-tholeiitic, basaltic-andesite to rhyolite lavas and tuffs of the ca. 23–19 Ma Sonya Creek shield volcano; we attribute these eruptions to intra-arc extension. SCVF activity was also marked by a small southward shift in volcanism at ca. 21 Ma, characterized by hydrous calc-alkaline lavas. SCVF geochemical compositions closely overlap those from the <13 Ma WA, and no alkaline lavas that characterize the ca. 18–10 Ma eastern Wrangell volcanic belt exposed in Yukon Territory are observed. Calc-alkaline, transitional-tholeiitic, and adakite-like SCVF volcanism from ca. 30–19 Ma reflects subduction of oceanic lithosphere of the Yakutat microplate beneath North America. We suggest that the increase in magmatic flux and adakitic eruptions at ca. 25 Ma, align with a recently documented change in Pacific plate direction and velocity at this time and regional deformation events in southern Alaska. By ca. 18 Ma, SCVF activity ceased, and the locus of WA magmatism shifted to the south and east. The change in relative plate motions would be expected to transfer stress to strike-slip faults above the inboard margin of the subducting Yakutat slab, a scenario consistent with increased transtensional-related melting recorded by the ca. 23–19 Ma transitional-tholeiitic Sonya Creek shield volcano between the Denali and Totschunda faults. Moreover, we infer the Totschunda fault accommodated more than ∼85 km of horizontal offset since ca. 18 Ma, based on reconstructing the initial alignment of the early WA (i.e., 30–18 Ma SCVF) and temporally and chemically similar intrusions that crop out to the west on the opposite side of the Totschunda fault. Our results from the SCVF quantify spatial-temporal changes in deformation and magmatism that may typify arc-transform junctions over similar time scales (>10 m.y.).

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Section: ■ Methodsmentioning

confidence: 99%

Geochemical and geochronological records of tectonic changes along a flat-slab arc-transform junction: Circa 30 Ma to ca. 19 Ma Sonya Creek volcanic field, Wrangell Arc, Alaska

et al. 2019

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“…We applied 40 Ar/ 39 Ar single-grain fusion detrital geochronology (Hodges et al, 2005;Broussard et al, 2018) to the modern river sediment samples and the Tanana Basin strata samples. We applied 40 Ar/ 39 Ar muscovite geochronology incremental step-heating analysis (McDougall and Harrison, 1999) to pure muscovite separates (1000-250 μm grain size) from the 16 bedrock samples from the Alaska Range suture zone and the single Birch Creek schist basement sample at the Suntrana type section.…”

Section: Ar/ 39 Ar Muscovite Geochronology Methodsmentioning

confidence: 99%

A river runs through it both ways across time: 40Ar/39Ar detrital and bedrock muscovite geochronology constraints on the Neogene paleodrainage history of the Nenana River system, Alaska Range

2019

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The Alaska Range, the topographic signature of the Denali fault, has an unusual physiography, with the Nenana River sourced from the south side of the divide and traversing along the range front some distance before heading north across the mountain range. Previous researchers suggested that a change from south-flowing to north-flowing drainage occurred at ca. 6 Ma, or early-middle Miocene, during initial phases of Alaska Range uplift. We applied 40 Ar/ 39 Ar dating of detrital micas from modern river sediment (proxy for basinwide source) and strata of the Neogene Tanana Basin (sink for the paleo-Nenana River), located along the northern front of the Alaska Range, to further investigate this hypothesis. In addition, we acquired 40 Ar/ 39 Ar muscovite ages from bedrock for additional source constraints and compared our results to regional geochronology data sets and geological mapping. During the earliest Miocene, the paleo-Nenana River likely flowed south. By the early Miocene, the paleo-Nenana River flowed to the north. During the middle Miocene, drainage reorganization continued, suggesting a variable history of rock uplift in the Alaska Range. By the late Miocene, sediment recycling occurred as the southern extent of the Tanana Basin was uplifted and eroded. The modern Nenana River near Cantwell has a muscovite age signature different than the Tanana Basin strata, implying continued drainage reorganization after the deposition of the Pliocene Nenana Gravel. In summary, the Nenana River drainage changed direction to north-flowing by ca. 18 Ma, driven by tectonism. Drainage reorganization continues today, demonstrating that strike-slip fault transpressive orogens can have complex paleodrainage histories. 40 Ar/ 39 Ar dating to detrital muscovite from strata of the Neogene Tanana Basin (sink for the paleo-Nenana River), located along the northern front of the Alaska Range (Figs. 1 and 3), and to detrital muscovite from modern river sediment (proxy for basinwide source; Fig. 1). In addition, we applied 40 Ar/ 39 Ar dating to GEOSPHERE

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“…1). Geochronological work based on detrital muscovite ages indicate that an exposure up section and 5 km north of the Trout Run locality (Trout Run North of Broussard et al, 2018) Diagnosis-Tristichopterid referred to Eusthenodon and distinguished from Eusthenodon wangsjoi and Eusthenodon bourdoni by the combination of (1) a lack of contact between the posterior supraorbital and intertemporal bones and (2) a vertical, blade-like lamina of the first coronoid that lies labial to the coronoid fangs.…”

Section: Eusthenodon Jarvik 1952mentioning

confidence: 99%

“…1). Broussard et al (2018) provided a relevant review of the sedimentological, taphonomic, and paleoenvironmental context of many of the fossil-bearing localities along this part of the U.S. Route 15/Interstate 99 corridor including the Cogan House Exit Ramp (=Upper Steam Valley) and Powys Curve.…”

Section: Introductionmentioning

confidence: 99%

“…Geological map of Lycoming County, Pennsylvania, U.S.A., showing the position of the Trout Run field locality (N41°22.160′, W77° 04.407′) relative to two other localities (Cogan House Exit Ramp, N41° 26.024′, W77°05.855′; and Powys Curve, N41°20.840′, W77°05.614′) from which tristichopterid fossils have been collected (modified from Broussard et al, 2018). Abbreviations : Dcd , Catskill Formation, Duncannon Member, Famennian; Dcs , Catskill Formation, Sherman Creek Member, Famennian; Mpu , Mississippian and Pennsylvanian strata.…”

Section: Introductionmentioning

confidence: 99%

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Second species ofEusthenodon(Tristichopteridae, Sarcopterygii) from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A., and a review of globalEusthenodonoccurrence

Downs,

Osatchuck,

Goodchild

et al. 2022

Journal of Vertebrate Paleontology

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A new species of Eusthenodon from the Upper Devonian (Famennian) Catskill Formation was collected from associated talus blocks excavated during road construction along the northbound lanes of U.S. Route 15/Interstate 99 near Trout Run in Lycoming County, Pennsylvania, U.S.A. The new species is represented by isolated or partially articulated cranial bones, an anocleithrum, and body scales from several individuals. The new discovery is the second species of Eusthenodon described from the Catskill Formation after Eusthenodon bourdoni, a species found only at the Cogan House Exit Ramp locality, north of and up section from the Trout Run site. The new species is of a larger size category and exhibits qualities that distinguish it from E. bourdoni including a contact between posterior supraorbital and lacrimal bones that excludes the jugal from the orbital margin and scales with an ornamental field incised by radiating grooves. The clarity offered by the Catskill Formation Eusthenodon species informs an historical review of reports on Eusthenodon occurrence that suggests a polydemic but not cosmopolitan distribution of the taxon. A phylogenetic analysis of Tristichopteridae is presented that includes the new species presented here. The Eusthenodon species at Trout Run is the fifth tristichopterid species described from the Catskill Formation and all five are found to belong to a highly nested clade of largely Famennian tristichopterids. With a growing fauna that additionally includes rhizodontids, dipnoans, holoptychiid porolepiforms, megalichthyids, and limbed tetrapodomorphs, the Catskill Formation of Pennsylvania continues to be an important focus for the study of Late Devonian sarcopterygian evolution.

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Depositional setting, taphonomy and geochronology of new fossil sites in the Catskill Formation (Upper Devonian) of north-central Pennsylvania, USA, including a new early tetrapod fossil

Cited by 16 publications

References 37 publications

Geochemical and geochronological records of tectonic changes along a flat-slab arc-transform junction: Circa 30 Ma to ca. 19 Ma Sonya Creek volcanic field, Wrangell Arc, Alaska

Geochemical and geochronological records of tectonic changes along a flat-slab arc-transform junction: Circa 30 Ma to ca. 19 Ma Sonya Creek volcanic field, Wrangell Arc, Alaska

A river runs through it both ways across time: 40Ar/39Ar detrital and bedrock muscovite geochronology constraints on the Neogene paleodrainage history of the Nenana River system, Alaska Range

Second species ofEusthenodon(Tristichopteridae, Sarcopterygii) from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A., and a review of globalEusthenodonoccurrence

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