Austin Long
Datos Biográficos
| ID | 3607184 |
|---|---|
| NOMBRE | Austin Long |
| NOMBRES | Austin |
| APELLIDO | Long |
| FIRMA | LONG A |
| AFILIACIONES | University of Arizona |
| VERIFICADO | No |
| TOTAL DE OBRAS | 74 |
| TOTAL DE CITAS | 469 |
| TOTAL COMO AUTOR | 73 |
| TOTAL COMO EDITOR | 1 |
| PRIMER AÑO DE PUBLICACIÓN | 1962 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2020 |
| ÍNDICE H | 13 |
Conceal or Reveal? Managing Clandestine Military Capabilities in Peacetime Competition
International political outcomes are deeply shaped by the balance of power, but some military capabilities rely on secrecy to be effective. These “clandestine capabilities” pose problems for converting military advantages into political gains. If clandestine capabilities are revealed, adversaries may be able to take steps that attenuate the advantages they are supposed to provide. On the other hand, if these capabilities are not revealed, then ad…
How long until midnight? Intelligence-policy relations and the United States response to the Israeli nuclear program, 1959–1985
Why did the United States fail to stop Israeli acquisition of nuclear weapons? Existing research argues that patrons such as the U.S. should have an easy time halting proliferation by militarily and economically vulnerable clients. Nevertheless, Israel acquired nuclear weapons with relatively little American opposition. Utilizing extensive primary source research, we argue that problematic intelligence-policy relations hindered U.S. efforts to ar…
The Limits of Damage Limitation
Charles Glaser and Steve Fetter argue that the United States should not pursue a nuclear damage-limitation capability against China: U.S. nuclear superiority is impossible to maintain beyond the short term, and its pursuit will provide few benefits while incurring serious costs.1 In an extended arms race, however, we argue that U.S. damage-limitation capabilities are far more technically plausible than Glaser and Fetter conclude. Further, damage …
The al-Qaeda Franchise
In February 2016, Director of National Intelligence James Clapper testified to the Senate Armed Services Committee that “Al-Qa’ida’s affiliates have proven resilient and are positioned to make gains in 2016, despite counterterrorism pressure that has largely degraded the network’s leadership in Afghanistan and Pakistan.” This assessment, coming after nearly 15 years of global counterterrorism efforts led by the United States, was surely dishearte…
The MAD Who Wasn't There
What do nuclear weapons mean for the stability of the military balance? Mutually assured destruction (MAD) describes a stalemated balance of power where nuclear adversaries possess survivable retaliatory capabilities that ensure neither side can escape devastation in an all-out nuclear war. Moreover, the strong form of this empirical claim, which one might term “deep MAD,” is that mutual vulnerability is an inalterable and unchangeable condition.…
After Isaf
The conclusion of the International Security Assistance Force (ISAF) mission in Afghanistan at the end of 2014 has generated substantial uncertainty about the duration and level of international commitment to Afghanistan. The fate of local allies of international forces is therefore deeply in doubt. This article is of necessity speculative rather than empirical, but it attempts to draw on the history of previous intervention in Afghanistan as wel…
Is There an Oil Weapon
What is the relationship between oil and coercion? For decades states have worried that their dependence on oil gives producers a potential lever of coercion. The size, integration, and sophistication of the current oil market, however, are thought to have greatly attenuated, if not eliminated, the coercive potential of oil. The best way to analyze the current global oil market is by viewing it as a series of distinct market segments, from upstre…
Stalking the Secure Second Strike
Secure second strike nuclear forces are frequently held to be easy to procure. Analysts have long argued that targeting intelligence against relocatable targets like submarine launched and land mobile ballistic missiles is difficult to obtain. However, the scholarly consensus on intelligence for counterforce operations is seriously overdrawn. Both during and after the Cold War, the United States developed substantial intelligence capabilities to …
Nato Special Operations
Whack-a-Mole or Coup de Grace? Institutionalization and Leadership Targeting in Iraq and Afghanistan
Targeting the leadership of terrorist and insurgent groups has become a major component of US strategy since the attacks of September 11, 2001. Despite attracting modest scholarly attention, the conditions that increase or decrease the efficacy of leadership targeting remain unclear. A major limitation of current scholarly work is the lack of exploration of the internal organization of these groups and the relationship of that organization to lea…
Green on Blue’
From January 2011 to December 2012 there were more than 60 attacks by members of Afghan National Security Forces on members of the US and coalition forces, with more taking place in the last six mo
Enlisting Islam for an Effective Afghan Police
Establishing an effective police force has eluded both the Afghan government and ISAF. Increasing the prominence of Islamic policing will complement current efforts to defeat the insurgency
The Quiet Americans? CIA, NSA, and Counterinsurgency
The contribution of the U.S. intelligence community (IC) to counterinsurgency operations past and present has gone largely underappreciated, in part because of the pervasive secrecy surrounding most of the IC's activities. A review of two recently declassified histories of Central Intelligence Agency (CIA) and National Security Agency (NSA) involvement in Vietnam in the 1960s provides insight into the historical contributions of these agencies to…
Going Nowhere Fast
April 01 2010 Going Nowhere Fast: Assessing Concerns about Long-Range Conventional Ballistic Missiles Austin Long, Austin Long Austin Long is Assistant Professor at Columbia University's School of International and Public Affairs and a member of Columbia's Saltzman Institute of War and Peace Studies. He thanks Brendan Green, Robert Jervis, Joshua Rovner, Jack Snyder, and Caitlin Talmadge for helpful comments. Search for other works by this author…
Combating Jihadism
Journal Article Combating Jihadism: American Hegemony and Interstate Cooperation in the War on Terrorism by Barak Mendelsohn Get access Combating Jihadism: American Hegemony and Interstate Cooperation in the War on Terrorism by Barak Mendelsohn. Chicago, IL, University of Chicago Press, 2009. 304 pp. $45.00. Austin Long Austin Long Columbia University Search for other works by this author on: Oxford Academic Google Scholar Political Science Quart…
Small is Beautiful
Space as a Strategic Asset – By Joan Johnson‐Freese
The Anbar Awakening
The United States and it allies in Iraq have embraced a tribal strategy to provide security and fight al–Qaeda in Mesopotamia. This approach is not new. Saddam Hussein also sought to use tribal alliances to provide internal security. His experience, and that of the present–day Coalition, demonstrates the prospects and perils of using tribes to provide security. Tension exists between the United States’ two main strategic goals of defeating al–Qae…
Osirak Redux? Assessing Israeli Capabilities to Destroy Iranian Nuclear Facilities
Does Israel have the ability to conduct a military attack against Iran's nuclear facilities similar to its 1981 strike on Iraq's Osirak reactor? The Israeli Air Force has significantly upgraded its equipment since the early 1980s, but the Iranian nuclear complex is a much harder target than was the Osirak reactor. Iran has three facilities that are critical for nuclear weapons production: a uranium conversion facility, an enrichment facility, and…
How Intelligent Is Intelligence Reform
Amy Zegart argues that the U.S. intelligence community suffered an adaptation that left it unprepared to deal with the terrorist threat after the Cold War.1 The core of this apparent failure was its inability to reorganize in response to a radically changed international setting, despite recommendations for reform from a number of prominent commissions and members of Congress. Zegart further argues that this bureaucratic sclerosis resulted from t…
The Perils of Shallow Theory
Additional informationNotes on contributorsJoshua Rovner Joshua Rovner is a doctoral candidate in political science at the Massachusetts Institute of Technology and a member of the MIT Security Studies Program. In Spring 2005, he was visiting professor of international relations at Clark University, Worcester, Massachusetts. Austin Long Austin Long is a doctoral candidate in political science at the Massachusetts Institute of Technology and a mem…
Validity of Ams Dates on Maize from the Tehuacán Valley
MacNeish and Eubanks (2000) reject the AMS radiocarbon dates on maize from the Tehuacán Valley, claiming that the specimens were contaminated with a substance called Bedacryl. We do not believe that the dated fragments were contaminated, and we review the processes by which they were selected and analyzed. We also describe Bedacryl and conclude that, had it been present as a contaminant, the resulting 14C ages should have been older rather than y…
AMS Dating Mammoth Bones
Fossilized Siberian mammoth remains are important indicators of environmental change in the Late Pleistocene. The NSF-Arizona AMS Laboratory radiocarbon results on amino acid separations compare well with mammoth bone collagen from the same specimens treated by HCl and dated by beta counting (the Russian Academy Geological Institute Radiocarbon Laboratory). Neither laboratory was aware of the other's dates for these comparisons. The results coinc…
Prehistoric Maize Evolution in the Tehuacan Valley
The 14 C Content of Lithium Metal Used in Benzene Synthesis
The lithium reagent used in the synthesis of benzene for 14 C dating contributes insignificant 14 C in high-precision measurements on 7 g benzene samples. Blank experiments on three different batches of lithium yielded small amounts of carbon, most of which probably originated as “memory” in the reaction vessel
Testing Contemporaneity and Averaging Radiocarbon Dates
Techniques for pragmatically interpreting arrays of radiocarbon dates are given. These include weighted averaging, statistical rejection of data, and the evaluation of contemporaneity. Commonly encountered situations are discussed with several actual examples to illustrate these procedures. This paper is Contribution No. 70, Department of Geosciences, University of Arizona
First Direct AMS Dates on Early Maize From Tehuacán, Mexico
The Tehuacán region in Central Mexico is thought to be the locale of origin of Zea mays , or maize, a cultivated plant pivotal in the development of agriculture in the Americas (MacNeish, 1981, 1985). The age of the earliest maize, and its rate of dispersal are thus important components of cultural development in the New World. We have secured permission from the Federal Government of Mexico to date critical specimens from Tehuacán, which represe…
Ground Sloth Extinction and Human Occupation at Gruta Del Indio, Argentina
A new set of radiocarbon dates from a rockshelter in Mendoza, Argentina addresses the question of the temporal overlap between the presence of an unidentified extinct ground sloth (cf., Mylodontidae) and evidence of human activity. Dung balls on the cave floor, evidently deposited by sloth, are overlain by charcoal, apparently of cultural origin. 14 C dates, mostly on charcoal and dung from this shelter, calibrated using recently published curves…
High-Precision Radiocarbon Dating of Bristlecone Pine from 6554 to 5350 BC
New results of radiocarbon dating of ca 100 decadal bristlecone pine samples from 6554 BC to 6084 BC and from 5820 to 5350 BC are presented. Using 3 new 2.5L counters filled to ca 3atm with carbon dioxide, high-precision dating has been performed by this laboratory for more than two years. Demonstration of the precision and accuracy of these counters is presented using ±2‰ measurements from the Spörer minimum period. For the older samples, ±3‰ me…
Stalking the Secure Second Strike
Secure second strike nuclear forces are frequently held to be easy to procure. Analysts have long argued that targeting intelligence against relocatable targets like submarine launched and land mobile ballistic missiles is difficult to obtain. However, the scholarly consensus on intelligence for counterforce operations is seriously overdrawn. Both during and after the Cold War, the United States developed substantial intelligence capabilities to …
Arizona Radiocarbon Dates III
Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison o…
Prehistoric Maize Evolution in the Tehuacan Valley
The Anbar Awakening
The United States and it allies in Iraq have embraced a tribal strategy to provide security and fight al–Qaeda in Mesopotamia. This approach is not new. Saddam Hussein also sought to use tribal alliances to provide internal security. His experience, and that of the present–day Coalition, demonstrates the prospects and perils of using tribes to provide security. Tension exists between the United States’ two main strategic goals of defeating al–Qae…
Separation and 14 C Dating of Pure Pollen from Lake Sediments
We have developed and tested a practical device for manually separating pollen from pollen concentrates in sufficient quantity for AMS 14 C dating. It is a combination of standard, commercially available equipment handled in a clean room by an individual trained to recognize pollen. A typical example requires about 15–20 h of hand-picking under the microscope. We show the usefulness of this procedure with results on a mid-Holocene segment from a …
Arizona Radiocarbon Dates IV
C 14 measurements reported here were made in this laboratory between December 1, 1961 and October 1, 1962. Sample descriptions are classified as follows: I. Tree-ring dated samples. II. Modern shells from Santa Barbara County, California. III. Archaeologic samples. IV. Palynologic samples. V. Geologic samples. VI. C 14 content of caliche. VII. Water samples. VIII. Modern organic sample
AMS Radiocarbon Dating of Bones at Arizona
Modern bone contains ca 25% protein material, most of which is collagen. Amino acids separated from collagen isolated from bone are suitable for 14 C dating of fossil bone, but attempts to carry out this procedure on bones seriously depleted in protein can yield erroneous 14 C dates. Amino-acid analysis of fossil bone gives quantitative information on the degree of preservation of its organic component. Also, the relative abundance of the amino-a…
A Suggested Quality Assurance Protocol for Radiocarbon Dating Laboratories
The current intercomparison of data from 14 C laboratories reveals significant variability among liquid scintillation laboratories, suggesting that identical samples submitted to different laboratories may yield values that differ by much more than expected on a purely statistical basis. Erroneous dates (recently corrected) by a well-established 14 C laboratory give rise to further concern for quality 14 C data. Thus, it is incumbent on each labo…
Early Corn Remains from Tumamoc Hill, Southern Arizona
The tandem accelerator mass spectrometer provided critical dating of corn remains in Archaic levels of juxtaposed Archaic and Hohokam occupations on Tumamoc Hill in Tucson, Arizona. This new radiometric technology confirmed an Archaic placement suggested by stratigraphy and artifact distributions. The small sample of intact remains resembles other directly-dated early corn in the Southwest and reinforces an interpretation of preceramic cultivator…
Is There an Oil Weapon
What is the relationship between oil and coercion? For decades states have worried that their dependence on oil gives producers a potential lever of coercion. The size, integration, and sophistication of the current oil market, however, are thought to have greatly attenuated, if not eliminated, the coercive potential of oil. The best way to analyze the current global oil market is by viewing it as a series of distinct market segments, from upstre…
Radiocarbon Dating of Corn
Nine samples from well-dated prehistoric sites in the southwestern United States have been radiocarbon dated in order to determine the accuracy of14C dates on corn. The results indicate that a normalized and calibrated14C date on corn is as accurate an estimate of the sample's age as is a14C date for any other material. This accuracy has implications not only for future selection of14C samples but also for interpretation of existing dates on corn…
The MAD Who Wasn't There
What do nuclear weapons mean for the stability of the military balance? Mutually assured destruction (MAD) describes a stalemated balance of power where nuclear adversaries possess survivable retaliatory capabilities that ensure neither side can escape devastation in an all-out nuclear war. Moreover, the strong form of this empirical claim, which one might term “deep MAD,” is that mutual vulnerability is an inalterable and unchangeable condition.…
Osirak Redux? Assessing Israeli Capabilities to Destroy Iranian Nuclear Facilities
Does Israel have the ability to conduct a military attack against Iran's nuclear facilities similar to its 1981 strike on Iraq's Osirak reactor? The Israeli Air Force has significantly upgraded its equipment since the early 1980s, but the Iranian nuclear complex is a much harder target than was the Osirak reactor. Iran has three facilities that are critical for nuclear weapons production: a uranium conversion facility, an enrichment facility, and…
Smithsonian Institution Radiocarbon Measurements V
Included in this list are analyses made during 1967 and the first half of 1968 with equipment and techniques previously employed here. All methane was produced in the bomb reactor
Smithsonian Institution Radiocarbon Measurements II
These analyses were performed from November 1963 to November 1964 with equipment and techniques essentially unchanged since the previous date list. Unless otherwise noted all samples were submitted by Smithsonian staff members, each of whom was most helpful in supplying information pertaining to the samples and in discussion of results
Small is Beautiful
High-Sensitivity Radiocarbon Dating in the 50,000 to 70,000 bp Range without Isotopic Enrichment
Calculations show the possibility of detecting 14 C remaining after 10 or 11 decay half-lives in natural materials, such as wood, using commercially available liquid scintillation (LS) detectors. Assuming in-situ 14 C production has contributed insignificantly to the measured 14 C, one can calculate finite ages approaching 70 ka. In practice, defensible finite age determinations involve careful considerations of several critical elements in the p…
Report On the Workshop On the Calibration of the Radiocarbon Dating Time Scale
From the 10th International Radiocarbon Conference held in Bern, Switzerland and Heidelberg, Germany, August 19-26, 1979
Whack-a-Mole or Coup de Grace? Institutionalization and Leadership Targeting in Iraq and Afghanistan
Targeting the leadership of terrorist and insurgent groups has become a major component of US strategy since the attacks of September 11, 2001. Despite attracting modest scholarly attention, the conditions that increase or decrease the efficacy of leadership targeting remain unclear. A major limitation of current scholarly work is the lack of exploration of the internal organization of these groups and the relationship of that organization to lea…
Validity of Ams Dates on Maize from the Tehuacán Valley
MacNeish and Eubanks (2000) reject the AMS radiocarbon dates on maize from the Tehuacán Valley, claiming that the specimens were contaminated with a substance called Bedacryl. We do not believe that the dated fragments were contaminated, and we review the processes by which they were selected and analyzed. We also describe Bedacryl and conclude that, had it been present as a contaminant, the resulting 14C ages should have been older rather than y…
Intercomparison of High-Precision 14 C Measurements at the University of Arizona and the Queen's University of Belfast Radiocarbon Laboratories
High-precision measurements were completed concurrently at the University of Arizona and the Queen's University of Belfast on blind samples of Irish oak originally measured for the 1986 radiocarbon calibration curve. Subsequent single-year Sequoiadendron results were decadally averaged and compared with published results on decadal Douglas-fir samples. The results of these intercomparisons show that the Arizona high-precision results compare favo…
Arizona Radiocarbon Dates III
Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison o…
Arizona Radiocarbon Dates IV
C 14 measurements reported here were made in this laboratory between December 1, 1961 and October 1, 1962. Sample descriptions are classified as follows: I. Tree-ring dated samples. II. Modern shells from Santa Barbara County, California. III. Archaeologic samples. IV. Palynologic samples. V. Geologic samples. VI. C 14 content of caliche. VII. Water samples. VIII. Modern organic sample
Arizona Radiocarbon Dates V
With few exceptions the C 14 measurements reported here were made in this laboratory between October 1, 1962 and November 1, 1963
Smithsonian Institution Radiocarbon Measurements I
The radiocarbon dating laboratory at the Smithsonian Institution, Division of Radiation and Organisms, was established in September 1962. After careful calibration with known samples and refinements in the methane synthesis system, routine analysis of samples was begun in the spring of 1963
Smithsonian Institution Radiocarbon Measurements II
These analyses were performed from November 1963 to November 1964 with equipment and techniques essentially unchanged since the previous date list. Unless otherwise noted all samples were submitted by Smithsonian staff members, each of whom was most helpful in supplying information pertaining to the samples and in discussion of results
Smithsonian Institution Radiocarbon Meaurements III
Most of these analyses were performed during 1965 with equipment and techniques previously employed at this laboratory. A cold (−40°C) charcoal trap stage was added to the CO 2 purification to remove radon, which eliminates the lag time between CH 4 preparation and counting (Long, 1965b)
Postglacial Uplift at Tanquary Fiord, Northern Ellesmere Island, Northwest Territories
Constructs a postglacial uplift curve for the upper part of Tanquary Fiord from radiocarbon ages of marine shells and peat. Data show the head of the fiord to be clear of glacier ice by at least 6500 yr BP. During 6500-5000 yr BP isostatic uplift was at a rate of about 3.5 m/century and subsequently about 25 cm/cent
Smithsonian Institution Radiocarbon Measurements IV
Most of these analyses we obtained during 1966 with equipment and techniques previously employed. Methane from the higher numbered samples was produced in a bomb reactor at pressures up to 1000 psi. Also, many smaller samples were counted in a 700-ml vol counter at 2 atm pressure, which has a background of 1.76 = .02 counts/min
Relict Populations of Drepanopus bungei and Limnocalanus macrurus grimaldii (Copepoda
Reports the occurrence of these two brackish-water copepods in the freshwater layer of Tuborg Lake, at the head of Antoinette Bay, one of the eastern extensions of the Nansen Sound-Greely Fiord system. Drepanopus bungei has been known previously only from the arctic coast of Siberia; it was also found in Disraeli Fiord on the north coast of Ellesmere Island. Tuborg Lake has been cut off from the Arctic Ocean for 3000 yr, hence these species are r…
Smithsonian Institution Radiocarbon Measurements V
Included in this list are analyses made during 1967 and the first half of 1968 with equipment and techniques previously employed here. All methane was produced in the bomb reactor
Arizona Radiocarbon Dates VIII
The carbon isotopic analyses reported here covers the period since the last list (Haynes et al. , 1967) until summer 1969. All results relating to secular C 14 fluctuations in atmospheric CO 2 are now published separately (Damon et al. , 1970). Sample preparation and counting procedures remain essentially unchanged since completion of our conversion to CO 2 in 1960. All δ C 13 values are reported relative to PDB and all C 14 dates, unless otherwi…
Testing Contemporaneity and Averaging Radiocarbon Dates
Techniques for pragmatically interpreting arrays of radiocarbon dates are given. These include weighted averaging, statistical rejection of data, and the evaluation of contemporaneity. Commonly encountered situations are discussed with several actual examples to illustrate these procedures. This paper is Contribution No. 70, Department of Geosciences, University of Arizona
Arizona Radiocarbon Dates Ix
The carbon isotope analyses reported here include all radiocarbon dates run on packrat middens in the United States and Mexico by the Arizona radiocarbon laboratory through October 1977. All samples described below report dates by CO 2 (0.5 or 2.0L) counting. Age calculations are based on a 14 C half-life of 5568 years, using 0.949 NBS oxalic acid as the modern value. Errors, based on counting statistics, are quoted to ± 1δ; infinite ages quoted …
Shasta Ground Sloth ( Nothrotheriops shastense Hoffstetter) at Shelter Cave, New Mexico
Seven coprolites of the extinct Shasta ground sloth ( Nothrotheriops shastense ) were recently discovered in the Los Angeles County Museum collection from Shelter Cave, New Mexico. Three dung balls provided radiocarbon ages of 11,330, 12,330 and 12,430 yr B.P. Packrat ( Neotoma ) middens disclose a xeric juniper woodland at Shelter Cave during the sloth's occupation. Plant cuticles from the dung indicate that the ground sloth had a diet dominated…
Report On the Workshop On the Calibration of the Radiocarbon Dating Time Scale
From the 10th International Radiocarbon Conference held in Bern, Switzerland and Heidelberg, Germany, August 19-26, 1979
Arizona Radiocarbon Dates X
Routine radiocarbon analyses were last reported for the Laboratory of Isotope Geochemistry at the University of Arizona in 1971 (Haynes, Grey, and Long, 1971), and a special date list on packrat middens appeared in 1978 (Mead, Thompson, and Long, 1978). This list presents results obtained from our gas proportional counting facility before its major renovation and before the addition of a liquid scintillation counting system. The characteristics o…
Charcoal production from wood and cellulose
Radiocarbon dating with accelerators requires the manufacture of suitable carbon targets. Carbon yield and 13 C fractionation were investigated for the simple and direct pyrolysis of wood and cellulose to charcoal. Under continuous vacuum removal of evolved volatiles, carbon yields of 35 to 40% and δ 13 C fractionation of −2.5‰ were observed in the pyrolysis of wood to charcoal, whereas yields of 30% and fractionation of −0.8‰ were obtained in th…
On a 50-Year “Climate-Free” δ 13 C Record from Juniper Tree Rings
When used with 14 C records, an accurate reconstruction of the 13 C/ 12 C changes of atmospheric CO 2 may be a key constraint to determining the historic activity of the biosphere as CO 2 source or sink. We recently detailed the derivation of an atmospheric δ 13 C record for 1930–1979 from Arizona juniper tree rings (Leavitt and Long, 1983). Each tree was close to a weather station, allowing us to account for the effects of climate on the tree-ri…
Radiocarbon Dating of Fossil Eggshell
Controlled feeding experiments demonstrate that the 14 C content of the carbonate fraction of fossil avian eggshell should reliably reflect the 14 C activity of feed and contemporary atmospheric CO 2 regardless of amounts of 14 C depleted scratch injested. Consideration of biochemical pathways and exchange rates across lung membranes leads to the possibility that the carbonate fraction may, in some instances, be slightly 14 C depleted. 14 C dates…
High-Precision Radiocarbon Dating of Bristlecone Pine from 6554 to 5350 BC
New results of radiocarbon dating of ca 100 decadal bristlecone pine samples from 6554 BC to 6084 BC and from 5820 to 5350 BC are presented. Using 3 new 2.5L counters filled to ca 3atm with carbon dioxide, high-precision dating has been performed by this laboratory for more than two years. Demonstration of the precision and accuracy of these counters is presented using ±2‰ measurements from the Spörer minimum period. For the older samples, ±3‰ me…
Trends of 13 C/ 12 C Ratios in Pinyon Tree Rings of the American Southwest and the Global Carbon Cycle
An accurate atmospheric 13 C/ 12 C chronology can provide important constraints to models of the global carbon cycle. Trees accumulate carbon from atmospheric CO 2 into growth rings and offer potential for 13 C/ 12 C reconstructions, but results have not been reproducible. This paper presents δ 13 C curves from 5 sites, representing 20 pinyon ( Pinus edulis ) trees, where cores of 4 trees from each site have been pooled into a composite sample. I…
Early Corn Remains from Tumamoc Hill, Southern Arizona
The tandem accelerator mass spectrometer provided critical dating of corn remains in Archaic levels of juxtaposed Archaic and Hohokam occupations on Tumamoc Hill in Tucson, Arizona. This new radiometric technology confirmed an Archaic placement suggested by stratigraphy and artifact distributions. The small sample of intact remains resembles other directly-dated early corn in the Southwest and reinforces an interpretation of preceramic cultivator…
Radiocarbon Dating of Corn
Nine samples from well-dated prehistoric sites in the southwestern United States have been radiocarbon dated in order to determine the accuracy of14C dates on corn. The results indicate that a normalized and calibrated14C date on corn is as accurate an estimate of the sample's age as is a14C date for any other material. This accuracy has implications not only for future selection of14C samples but also for interpretation of existing dates on corn…
Construction of the casa grande by sequential high precision C‐14 dating
Two composite radiocarbon dates on wood beams from a unique, prehistoric building in southern Arizona are the result of growth series subsampling of the beams and statistical evaluation of radiocarbon dates on the subsamples. This procedure avoids some of the problems caused by secular variations in the biospheric 14 C activity and by the dating of specimens grown over a range of years. This procedure yields results similar to more precise tree‐r…
The Atmospheric δ13C Record as Derived from 56 Pinyon Trees at 14 Sites in the Southwestern United States
We have developed a master δ 13 C chronology from 14 pinyon pine sites in 6 states of the southwestern U S. Two of the individual isotopic chronologies, reported here for the first time, and 10 of those previously reported (Leavitt & Long, 1986; 1988) are from sites where cores from 4 trees were pooled prior to analysis, and the other 2 are merged from groups of 4 single-tree chronologies (sites) developed in an earlier phase of research (Leavitt…
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