A new silicate intercomparison standard for¹⁸O analysis     

Irving Friedman  Jim D. Gleason 《Earth and Planetary Science Letters》1973,18(1):124

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A Predictive Model for Locating Early Holocene Archaeological Sites Based on Raised Shell‐Bearing Strata in Southeast Alaska,USA     

Risa J. Carlson  James F. Baichtal 《Geoarchaeology》2015,30(2):120-138

A predictive model for locating early Holocene archaeological sites in southern Southeast Alaska was developed based on shell‐bearing raised marine deposits. Fieldwork included coring of select‐raised marine strata, measuring their elevations, and radiocarbon dating the associated shell samples within the cores. A subset of the data was used to produce a relative sea‐level curve spanning the Holocene. The relative sea‐level curve suggests that sites favorable for habitation between 9200 and 7000 ¹⁴C yr B.P. should be found 16–22 ± 1 m above present zero tide. The sea‐level curve and new high‐resolution digital elevation models allowed reconstruction of past shorelines at various elevations. Surveys to test the model found and recorded over 70 archaeological sites from present sea level up to 32 m above present zero tide. Eleven new sites were within the targeted elevation range and radiocarbon dated to 9280–6890 ¹⁴C yr B.P. Initial investigations indicate these older sites are rich in microblade and pebble tool technology. The new early Holocene sites indicate more extensive early maritime settlement of Alaska than implied by previous studies and contribute to our understanding of the early movement of people into North America.  相似文献   

Possible Mesozoic age of Ellenville Zn-Pb-Cu(Ag) deposit,Shawangunk Mountains,New York     

J. D. Friedman  J. E. Conrad  E. H. McKee  F. E. Mutschler  R. E. Zartman 《Mineralium Deposita》1994,29(6):474-487

Ore textures, epithermal open-space filling of Permian structures of the Alleghanian orogeny, and largely postorogenic mineralization of the Ellenville, New York, composite Zn-Pb-Cu(Ag) vein system, provide permissive evidence for post-Permian mineralization. Isochron ages determined by ⁴⁰Ar/³⁹Ar laser-fusion techniques for K-bearing liquid inclusions in main-stage quartz from the Ellenville deposit additionally suggest a Mesozoic time of mineralization, associated with extensional formation of the Newark basin. The best ⁴⁰Ar/³⁹Ar total-fusion age range is 165 ± 30 to 193 ± 35 Ma. The Mesozoic ⁴⁰Ar/³⁹Ar age agrees with that of many other dated northern Appalachian Zn-Pb-Cu(Ag) deposits with near-matching lead isotope ratios, and adds new evidence of Jurassic tectonism and mineralization as an overprint to Late Paleozoic tectonism at least as far north as Ellenville (lat. 41°43N).  相似文献   

The role of vegetation and bed-level fluctuations in the process of channel narrowing     

Jonathan M. Friedman  W.R. Osterkamp  William M. Lewis Jr. 《Geomorphology》1996,14(4):341-351

A catastrophic flood ire 1965 on Plum Creek, a perennial sandbed stream in the western Great Plains, removed most of the bottomland vegetation and transformed the single-thalweg stream into a wider, braided channel. Following eight years of further widening associated with minor high flows, a process of channel narrowing began in 1973; narrowing continues today. The history of channel narrowing was reconstructed by counting the annual rings of 129 trees and shrubs along a 5-km reach of Plum Creek near Louviers, Colorado. Sixty-three of these plants were excavated in order to determine the age and elevation of the germination point. The reconstructed record of channel change was verified from historical aerial photographs, and then compared to sediment stratigraphy and records of discharge and bed elevation from a streamflow gaging station in the study reach. Channel narrowing at Plum Creel: occurs in two ways. First, during periods of high flow, sand and fine gravel are delivered to the channel, temporarily raising the general bed-level. Subsequently, several years of uninterrupted low flows incise a narrower channel. Second, during years of low flow, vegetation becomes established on the subaerial part of the present channel bed. In both cases, surfaces stabilize as a result of vegetation growth and vertical accretion of sediment.  相似文献   

Painting Pictures of Ourselves: Researcher Subjectivity in the Practice of Feminist Reflexivity     

Risa Whitson 《The Professional geographer》2017,69(2):299-306

In this article, I argue that researchers need to carefully distinguish the concepts of subjectivity and positionality in feminist reflexive practice, as an explicit focus on researcher subjectivity has the potential to provide additional insights into the research process that go beyond a focus on relational positionality. Drawing on examples from my own research, I argue that examining one's subjectivity as a researcher opens up a consideration of emotional reactions to research; lets us reconsider the importance of feelings of (dis)affiliation and (dis)comfort in the research process; and helps us to recognize that the dreams and desires of researchers about themselves and their research participants can play an important role in the research process. Moreover, researcher subjectivity attunes us to ways in which our subjectivities shift through the research process and are intimately connected to and mediated by the process of research and our interactions with our research participants.  相似文献   

Galaxy–galaxy lensing: dissipationless simulations versus the halo model     

Rachel Mandelbaum  Argyro Tasitsiomi  Uro&#; Seljak  rey V. Kravtsov  Risa H. Wechsler † 《Monthly notices of the Royal Astronomical Society》2005,362(4):1451-1462

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How does the virus spread?     

Samuel R. Friedman 《GeoJournal》2012,77(4):449-449

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Book reviews     

Gerald M. Friedman  Lilla Zadory  Klaus Rother  Hans-J. Bayer  E. Doerpinghaus  T. E. Keliher  Alexander Zaporozec  Jarmo Eronen  Brigitta Hartung-Kagi 《GeoJournal》1988,16(1):126-130

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Stability theory of relativistic stars     

John L. Friedman 《Journal of Astrophysics and Astronomy》1996,17(3-4):199-211

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Carbonate Sediments and Their Diagenesis (Developments in Sedimentology, 12): R.G.C. Bathurst. Elsevier,Amsterdam, 1971, 640 pp., 24 tables, 359 illus., 1200 lit. refs., Dfl. 90.00     

Gerald M. Friedman 《Sedimentary Geology》1973,9(1):74-75

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