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SCOTT D. SAMSON |
PROFESSORGEOCHEMISTRY |
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Department of Earth Sciences Office: 317 Heroy Geology Laboratory Phone: 315.443.5298 |
My primary research interests are related to the chemical evolution of the Earth's continental crust and oceans and the tectonic/chemical evolution of orogenic belts. Research projects involve the use of the Sm-Nd, Rb-Sr, and U-Pb isotopic systems, and major and trace element chemistry, to solve a wide variety of geological problems. A few of the current projects my students are involved in are described below.
Correlation of Ordovician bentonites in the Taconic Basin - new geochemical methods: Numerous K-bentonites occur throughout the Taconic Foreland basin of the New York and Quebec. They have essentially identical physical features, making correlation of individual bentonites by traditional methods almost impossible. However, we have developed new geochemical techniques that can be used to identify individual beds. These correlations allow for ultra-high resolution since the bentonites were deposited in the course of days to months, a geological instant. This has led to a construction of a new chronostratigraphic framework for the Taconic basin, that is of unprecedented precision.
Alleghanian Granites as probes of deep Appalachian crust: One of the fundamental manifestations of the collision of Laurentia with Gondwana at the end of the Paleozoic was the production of granitic magmas. The origin of the these magmas with respect to continental collision isn't known, nor is the influence of the different terranes that the granites intruded known. We are working on the question of the origin of these granites to try to constrain large-scale models of Alleghanian orogenesis. Simultaneously we are using the plutons as probes of the nature of the unexposed crust of the southern Appalachian orogen. Our latest avenue of research is to determine the crystallization age of the granites, using high-precision U-Pb zircon and monazite dating techniques, to search for temporal trends in the isotopic data and to search for the presence of ancient zircon xenocrysts. These new data would go far towards reconstructing the history of generation of these bodies. A new NSF grant has recently been awarded for continuation of this research.
Terrane discrimination in the southern Appalachians Although it has now been recognized that the southern Appalachians, like many orogens, are composed of a mosaic of individual tectonostratigraphic terranes, it is often difficult to determine the relationships of the terranes to one another by standard methods of terrane analysis. My students and I have successfully demonstrated that the Milton belt and Carolina slate belt, usually considered parts of the same terrane, have significantly different isotopic characteristics suggesting that they are unrelated crustal blocks. Comparable studies are now beginning in other regions, such as the Goochland terrane and Raleigh belt, to determine what, if any, relationship these regions have to other Appalachian terranes. Our data is the first of its kind in the southern Appalachians and is having a major impact on all of the traditional tectonic and paleogeographic models.
U-Pb and Nd-Pb isotopic study of the Cadomia terrane, northern France: In search of basement The Cadomia terrane is one of the fundamental Neoproterozoic circum-Atlantic terranes. The relationship of this terrane to the other Neoproterozoic terranes is not well known, because of a lack of geochemical and isotopic data from these terranes, and because of the lack of knowledge of the characteristics of the basement of these terranes. We have proposed to study the nature of the basement in the Cadomia terrane in the only regions where it is exposed, the English Channel Island of Guernsey and the La Hague peninsula of Normandy. The project will include high precision U-Pb dating of basement gneisses, of single detrital zircons from paragneisses thought to be the oldest known Cadomian rocks, and dating of zircon xenocrysts within latest Proterozoic granitic plutons. In addition, the basement gneisses and Proterozoic plutons will be analyzed for Nd and Pb isotopic compositions. This data will then be used to compare Cadomia to other Neoproterozoic terranes such as the Avalon and Carolina terranes. This project is in collaboration with geologists from Oxford Brookes University in England. A NSF proposal supports this research and provide funds for a postdoctoral fellow (Jeremy Inglis) and a graduate research assistant.
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Rainbow over mosque at Tourtit |
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Laughing girls in Morocco
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Landscape near Ourzazate
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Ph.D. Geology (Geochemistry), 1990, University of Arizona
M.S. Geology, 1986, University of Minnesota
B.S. Geology, 1984, Oregon State University
Professor, 2002-present: Department of Earth Sciences, Syracuse University
Department Chair and Jessie Page Heroy Professor, 2002-2007: Department of Earth Sciences, Syracuse University
Associate Professor, 1996-2002: Department of Earth Sciences, Syracuse University
Assistant Professor, 1990-1996: Department of Earth Sciences, Syracuse University
NATIONAL SCIENCE FOUNDATION
($239,070) Chronology and tectonic evolution of the southern Anti-Atlas orogen, Morocco 7/01-6/04
($109,812) Paleogeography of the Carolina terrane: Constraints from detrital zircon ages 1/1/00-12/31/02
($120,000) Technician support (Phase II): Radiogenic Isotope, Stable Isotope, and XRF laboratories at Syracuse University 12/99-11/01
($189,455) Magmatic and deformational history of the Cadomian orogenic belt, North Armorican Massif
7/1/99-6/30/01
($303,071) Collaborative Research: Structure of the crust and upper mantle beneath the Tibet plateau interior (INDEPTH III) 9/97-8/2000 (Co-Pi with K.D. Nelson)
($181,750) Origin and evolution of the Cadomia terrane: Systematic characterization of basement 2/97-1/99
($150,000) Technician support: Radiogenic Isotope, Stable Isotope, and XRF laboratories at Syracuse University 9/96-8/99
($99,885) Tectonic setting and magmatic evolution of eastern Laurentia in late Paleozoic time:
constraints from high precision U-Pb dating of Alleghanian granites 1/95-12/97
NATIONAL GEOGRAPHIC SOCIETY
($18,000) Remote Sensing and geochronologic study of the Anti-Atlas Mountains, Morocco
(co-PI with Dr. K. Hefferan, Univeristy of Wisconsin) 11/00-12/01
* Samson , S.D., D'Lemos, R.S., Miller, B.V. & Hamilton, M.A. (2005) Neoproterozoic palaeogeography of the Cadomia and Avalon terranes: constraints from detrital zircon U–Pb ages, J. Geol. Soc., Lond. 162 , 65-71.
* Inglis, J.D., D’Lemos, R.S., Samson, S.D. & Admou, H. (2005) Geochronological Constraints on Late Precambrian intrusion, metamorphism, and tectonism in the Anti-Atlas Mountains, J. Geol. 113, 439 - 450.
* Owens, B.E. & Samson , S.D. (2004) Nd isotopic constraints on the magmatic history of the Goochland terrane, easternmost Grenville crust in the southern Appalachians, GSA Special Paper 197 , 601-608.
* Samson , S.D., Inglis, J.D., D'Lemos, R.S., Admou, H., Blichert-Toft, J. & Hefferan, K. (2004) Geochronological, geochemical, and Nd–Hf isotopic constraints on the origin of Neoproterozoic plagiogranites in the Tasriwine ophiolite, Anti-Atlas orogen, Morocco, Precambrian Research 135 , 133–147.
* Inglis, J.D., Maclean, J.S., Samson , S.D., D'Lemos, R.S., Admou, H. & Hefferan, K. (2004) A precise U-Pb zircon age for the Bleïda granodiorite, Anti-Atlas, Morocco: implications for the timing of deformation and terrane assembly in the eastern Anti-Atlas, J. Afr. Earth Sci. 39 , 277-283.
* Thomas, W.A., Becker, T.P., Samson , S.D. & Hamilton, M.A. (2004) Detrital zircon evidence of a recycled orogenic foreland provenance for Alleghanian clastic-wedge sandstones, J. Geol. 112 , 23-37.
* Inglis, J.D., D’Lemos, R.S., Samson, S.D. & Miller, B.V. (2004) Timing of Cadomian deformation and magmatism within La Hague, NW France, J. Geol. Soc., Lond. 161, 1-12.
* Patchett, P.J. & Samson , S.D. (2003) Isotopic evolution and crustal growth history, In: Rudnick (ed.) Treatise of Geochemistry 3 , The Crust, Elsevier-Pergamon, Oxford, 321-348.
* Moecher, D.P., Samson , S.D. & Miller, C.F. (2004) Precise time and conditions of peak Taconian granulite facies metamorphism in the southern Appalachian orogen, U.S.A., with Implications for zircon behavior during crustal melting events, J. Geol. 112 , 289-304.
* Inglis, J.D., Samson , S.D., D'Lemos, R.S. & Hamilton, M. (2004) Evidence for Neoproterozoic crustal thickening within the Paleoproterozoic basement of Cadomia, La Hague, NW France, Precambrian Research , 134 (3-4) 293-315.
* Samson , S.D., D'Lemos, R.S., Blichert-Toft, J. & Vervoort, J. (2003) U-Pb geochronology and Hf-Nd isotope compositions of the oldest Neoproterozoic crust within the Cadomian Orogen: new evidence for a unique juvenile terrane, Earth Planet. Sci. Lett. 208 , 165-180.
* Hefferan, K., Admou, H., Hilal, R., Karson, J., Saquaque, A., Samson , S., & Kornprobst, J. (2002) Proterozoic blueschist-bearing mélange in the Anti-Atlas Mountains, Morocco, Precambrian Research 118 , 179-184.
* Miller, B.V., Samson , S.D. & D'Lemos, R.S. (2001) U-Pb geochronological constraints on the timing of plutonism, volcanism, and sedimentation, Jersey, Channel Islands, UK, J. Geol. Soc., Lond. 158 , 243-252.
* Barr, S.M., Hamilton, M.A., White, C.E. & Samson , S.D. (2001) A late Neoproterozoic age for the Caledonia Mountain Pluton, a high Ti-V layered gabbro in the Caledonia (Avalon) terrane, southern New Brunswick, Atlantic Geology 36 , 157-166.
* D'Lemos, R.S., Miller, B.V.M. & Samson , S.D. (2001) Precise U-Pb zircon ages from Alderney, Channel Islands: growing evidence for discrete Neoproterozoic magmatic episodes in northern Cadomia, Geol. Mag. 138 , 719-726.
* Nagy, E.A., Samson , S.D. & D'Lemos, R.S. (2001) U-Pb geochronologic constraints on the timing of Brioverian sedimentation and regional deformation within the St. Brieuc region of the Neoproterozoic Cadomian orogen, northern France, Precambrian Research 116 (1-2), 1-17.
* Wortman, G.L., Samson , S.D. & Hibbard, J.P. (2000) Precise U-Pb zircon constraints on the earliest magmatic history of the Carolina terrane, J. Geol. 108 , 321-338.
* Samson , S.D., Barr, S.M & White, C.E. (2000) Nd isotopic characteristics of terranes within the Avalon Zone, southern New Brunswick, Canad. J. Earth Sci. 37 , 1039-1052.
* Coler, D.G., Wortman, G.L., Samson , S.D., Hibbard, J.P. & Stern, R. (2000) U-Pb geochronologic, Nd isotopic and geochemical evidence for the correlation of the Chopawamsic and Milton terranes, Piedmont Zone, southern Appalachian Orogen, J. Geol. 108 , 363-380.
* Samson , S.D. & D'Lemos, R.S. (1999) Precise late Neoproterozoic U-Pb zircon age of the syn-tectonic Perelle quartz diorite, Guernsey, Channel Islands, UK, J. Geol. Soc., Lond. 156 , 47-54.
* Miller, B.V., Samson , S.D. & D'Lemos, R.S. (1999) Time span of plutonism, fabric development, and cooling in a Neoproterozoic magmatic arc segment: U-Pb age constraints from syn-tectonic plutons, Sark, Channel Islands, U.K., Tectonophysics 312 , 79-95.
* Wortman, G.L., Samson , S.D. & Hibbard, J.P. (1998) Precise timing constraints on the kinematic development of the Hyco Shear Zone, southern Appalachians, Am. J. Sci. 298 , 108-130.
* Hibbard, J.P., Shell, G.S., Bradley, P.J., Samson , S.D. & Wortman, G.L. (1998) The Hyco Shear Zone: the northern extension of the central piedmont suture in North Carolina and southern Virginia: American, J. Sci. 298 , 85-107.
* Changde, W., Nelson, K.D., Wortman, G.L., Samson , S.D., Yonjun, Y., Jixiang, Li, Kidd, W.S.F. & Edwards, M. (1998) Yadong cross-structure and south Tibet detachment in the East-Central Himalaya (89°-90°E), Tectonics 17 , 28-45.
* Samson , S.D. & D'Lemos, R.S. (1998) U-Pb geochronology and Sm-Nd isotopic composition of Proterozoic gneisses, Channel Islands, U.K, J. Geol. Soc., Lond. 155 , 609-618.
* Karabinos, P., Samson , S.D., Hepburn, J.C. & Stoll, H. (1998) Taconian orogeny in the New England Appalachians: Collision between Laurentia and the Shelburne Falls arc, Geology 26 , 215-218.
* Coler, D.G., Samson , S.D. & Speer, J.A. (1997) Nd and Sr isotopic constraints on the source of Alleghanian granites in the Raleigh Metamorphic belt and Eastern slate belt, southern Appalachians, Chem. Geol. 134 , 257-275
* Wortman, G., Samson , S.D. & Hibbard, J.P. (1996) Discrimination of the Milton and Carolina slate belts, southern Appalachians: A Nd isotopic approach, J. Geol. 104 , 239-247.
* Andersen, B. & Samson , S.D. (1996) Temporal changes in the Nd isotopic composition of sedimentary rocks in the Sevier and Taconic foreland basins: Increasing influence of juvenile sources, Geology 23 , 983-986.
* Samson , S.D. (1996) 40Ar-39Ar and Nd-Sr isotopic characteristics of mid-Ordovician North American K- bentonites: A test of early Paleozoic Laurentia-Gondwana interactions, Tectonics 15 , 1084-1092.
* Samson , S.D., Coler, D.G. & Speer, J.A. (1995) Geochemical and Nd-Sr-Pb isotopic composition of Alleghanian granites in the southern Appalachians: Origin, tectonic setting, and source characterization, Earth Planet. Sci. Lett. 134 , 359-376.
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