Response to Comments on " Reconciliation of the Devils Hole climate record with orbital forcing " (original) (raw)
Related papers
Reconciliation of the Devils Hole climate record with orbital forcing
The driving force behind Quaternary glacial-interglacial cycles and much associated climate change is widely considered to be orbital forcing. However, previous versions of the iconic Devils Hole (Nevada) subaqueous calcite record exhibit shifts to interglacial values ~10,000 years before orbitally forced ice age terminations, and interglacial durations ~10,000 years longer than other estimates. Our measurements from Devils Hole 2 replicate virtually all aspects of the past 204,000 years of earlier records, except for the timing during terminations, and they lower the age of the record near Termination II by ~8000 years, removing both ~10,000-year anomalies.The shift to interglacial values now broadly coincides with the rise in boreal summer insolation, the marine termination, and the rise in atmospheric CO2, which is consistent with mechanisms ultimately tied to orbital forcing.
Chapter 10 Summary of Evidence for a Young Earth from the
2013
Abstract. This chapter summarizes the technical results of the RATE Project and evaluates the significance of the overall project. The main purpose of the RATE Project was to investigate radioisotopic processes and rock-dating methods to determine why the conventional model for the age of the earth is not consistent with a young-earth time frame. The RATE team offers a scientific alternative favoring the thousands-of-years scenario for the age of the earth rather than simply critiquing the conventional billions-of-years scenario. The major result of the project is that nuclear decay processes appear to have been accelerated during brief periods in earth history. Some of the discussion addresses unresolved problems and objections that will likely be raised by critics. 1
Climate of the Past, 2013
Past atmospheric CO 2 concentrations reconstructed from polar ice cores combined with its ∆ 14 C signature as conserved in tree-rings provide important information both on the cycling of carbon as well as the production of radiocarbon (Q) in the atmosphere. The latter is modulated by changes in the strength of the magnetic field enclosed in the 5 solar wind and is a proxy for past changes in solar activity. We perform transient carbon-cycle simulations spanning the past 21 kyr using Bern3D-LPX, a fully featured Earth System Model of Intermediate Complexity (EMIC) with a 3-D ocean, sediment and a dynamic vegetation model. Using the latest atmospheric IntCal09/SHCal04 radiocarbon records, we reconstruct the Holocene radiocar-10 bon fluxes and the total production rate. Our carbon-cycle based modern estimate of Q ≈ 1.7 atoms cm −2 s −1 is lower than previously reported by and more in line with Kovaltsov et al. (2012).
Radioisotopes and the Age of the Earth
Institute for Creation Research …, 2000
RATE is an acronym applied to a research project investigating radioisotope dating sponsored by the Institute for Creation Research and the Creation Research Society. It stands for Radioisotopes and the Age of The Earth. This article summarizes the purpose, history, and intermediate findings of the RATE project five years into an eight-year effort. It reports on the latest status of the research on helium diffusion through minerals in granitic rock, accelerated nuclear decay theory, radiohalos, isochron discordance studies, case studies in rock dating, and carbon-14 in deep geologic strata. Each of the RATE scientists will present separate technical papers at the Fifth International Conference on Creationism on the details of this research.
Call for an improved set of decay constants for geochronological use
Geochimica et Cosmochimica Acta, 2001
The accuracy of radioisotopic ages is, at present, limited by the accuracy of radioactive decay constants. A literature survey reveals that decay constants used in geo-and cosmochronology usually are assigned uncertainties of ca. 1% but that there are very much larger unaccounted discrepancies between decay constants reported by different "counting groups" as well as differences between results derived from counting experiments and from the comparison of ages obtained on the same samples by utilizing different radioactive clocks. An extension and partial revision of the decay constants recommended in 1976 for adoption in geoand cosmochronology by the International Union of Geological Sciences (IUGS) appears both desirable and feasible, given the analytical improvements of the last 20 years. We call for a concerted effort to achieve improvements in the near future. For this it will be necessary to rigorously evaluate counting biases in counting determinations, initial daughter contamination for ingrowth experiments, and the existence of truly "point-like" geological events for age comparison approaches.
Dating the Vostok ice core record by importing the Devils Hole chronology
Journal of Geophysical Research: Atmospheres, 2001
The development of an accurate chronology for the Vostok record continues to be an open research question because these invaluable ice cores cannot be dated directly. Depth-to-age relationships have been developed using many different approaches, but published age estimates are inconsistent, even for major paleoclimatic events. We have developed a chronology for the Vostok deuterium paleotemperature record using a simple and objective algorithm to transfer ages of major paleoclimatic events from the radiometrically dated 500,000-year ␦ 18 O-paleotemperature record from Devils Hole, Nevada. The method is based only on a strong inference that major shifts in paleotemperature recorded at both locations occurred synchronously, consistent with an atmospheric teleconnection. The derived depth-to-age relationship conforms with the physics of ice compaction, and internally produces ages for climatic events 5.4 and 11.24 which are consistent with the externally assigned ages that the Vostok team needed to assume in order to derive their most recent chronology, GT4. Indeed, the resulting V-DH chronology is highly correlated with GT4 because of the unexpected correspondence even in the timing of second-order climatic events that were not constrained by the algorithm. Furthermore, the algorithm developed herein is not specific to this problem; rather, the procedure can be used whenever two paleoclimate records are proxies for the same physical phenomenon, and paleoclimatic conditions forcing the two records can be considered to have occurred contemporaneously. The ability of the algorithm to date the East Antarctic Dome Fuji core is also demonstrated. This paper is not subject to U.S.
Orbital climate forcing of δ 13 C excursions in the late Paleocene-early Eocene (chrons C24n-C25n)
Paleoceanography, 2003
1] High-resolution stable carbon isotope records for upper Paleocene-lower Eocene sections at Ocean Drilling Program Sites 1051 and 690 and Deep Sea Drilling Project Sites 550 and 577 show numerous rapid (40-60 kyr duration) negative excursions of up to 1%. We demonstrate that these transient decreases are the expected result of nonlinear insolation forcing of the carbon cycle in the context of a long carbon residence time. The transients occur at maxima in Earth's orbital eccentricity, which result in high-amplitude variations in insolation due to forcing by climatic precession. The construction of accurate orbital chronologies for geologic sections older than 35Mareliesonidentifyingahigh−fidelityrecorderofvariationsinEarth′sorbitaleccentricity.Weusethecarbonisotoperecordsassucharecorder,establishingarobustorbitallytunedchronologyforlatestPaleoceneearliestEoceneevents.Moreover,thetransientdecreasesprovideameansofprecisecorrelationamongthefoursitesthatisindependentofmagnetostratigraphicandbiostratigraphicdataatthe<105−yearscale.Whiletheeccentricity−controlledtransientdecreasesbearsomeresemblancetothemuchlarger−amplitudecarbonisotopeexcursion(CIE)thatmarksthePaleocene/Eoceneboundary,thelattereventisfoundtooccurnearaminimuminthe35 Ma relies on identifying a high-fidelity recorder of variations in Earth's orbital eccentricity. We use the carbon isotope records as such a recorder, establishing a robust orbitally tuned chronology for latest Paleoceneearliest Eocene events. Moreover, the transient decreases provide a means of precise correlation among the four sites that is independent of magnetostratigraphic and biostratigraphic data at the <10 5 -year scale. While the eccentricity-controlled transient decreases bear some resemblance to the much larger-amplitude carbon isotope excursion (CIE) that marks the Paleocene/Eocene boundary, the latter event is found to occur near a minimum in the 35Mareliesonidentifyingahigh−fidelityrecorderofvariationsinEarth′sorbitaleccentricity.Weusethecarbonisotoperecordsassucharecorder,establishingarobustorbitallytunedchronologyforlatestPaleoceneearliestEoceneevents.Moreover,thetransientdecreasesprovideameansofprecisecorrelationamongthefoursitesthatisindependentofmagnetostratigraphicandbiostratigraphicdataatthe<105−yearscale.Whiletheeccentricity−controlledtransientdecreasesbearsomeresemblancetothemuchlarger−amplitudecarbonisotopeexcursion(CIE)thatmarksthePaleocene/Eoceneboundary,thelattereventisfoundtooccurnearaminimuminthe400-kyr eccentricity cycle. Thus the CIE occurred during a time of minimal variability in insolation, the dominant mechanism for forcing climate change on 10 4 -year scales. We argue that this is inconsistent with mechanisms that rely on a threshold climate event to trigger the Paleocene/Eocene thermal maximum since any threshold would more likely be crossed during a period of high-amplitude climate variations.