Empirical evidence for a celestial origin of the climate oscillations and its implications

We investigate whether or not the decadal and multi-decadal climate oscillations have an astronomical origin. Several global surface temperature records since 1850 and records deduced from the orbits of the planets present very similar power spectra. Eleven frequencies with period between 5 and 100 years closely correspond in the two records. Among them, large climate oscillations with peak-to-trough amplitude of about 0.1 and 0.25°C, and periods of about 20 and 60 years, respectively, are synchronized to the orbital periods of Jupiter and Saturn. Schwabe and Hale solar cycles are also visible in the temperature records. A 9.1-year cycle is synchronized to the Moon's orbital cycles. A phenomenological model based on these astronomical cycles can be used to well reconstruct the temperature oscillations since 1850 and to make partial forecasts for the 21st century. It is found that at least 60% of the global warming observed since 1970 has been induced by the combined effect of the above natural climate oscillations. The partial forecast indicates that climate may stabilize or cool until 2030–2040. Possible physical mechanisms are qualitatively discussed with an emphasis on the phenomenon of collective synchronization of coupled oscillators.     

Organic biogeochemistry of the Darwin Mounds, a deep-water coral ecosystem, of the NE Atlantic

The Darwin Mounds are a series of small (5 m high, 75–100 m diameter) sandy features located in the northern Rockall Trough. They provide a habitat for communities of Lophelia pertusa and associated fauna. Suspended particulate organic matter (sPOM) reaching the deep-sea floor, which could potentially fuel this deep-water coral (DWC) ecosystem, was collected during summer 2000. This was relatively “fresh” (i.e. dominated by labile lipids such as polyunsaturated fatty acids) and was derived largely from phytoplankton remains and faecal pellets, with contributions from bacteria and microzooplankton. Labile sPOM components were enriched in the benthic boundary layer (10 m above bottom (mab)) relative to 150 mab. The action of certain benthic fauna that are exclusively associated with the DWC ecosystem (e.g. echiuran worms) leads to the subduction of fresh organic material into the sediments. The mound surface sediments are enriched in organic carbon, relative to off-mound sites. There is no evidence for hydrocarbon venting at this location.     

The role of playas in pedogenic gypsum crust formation in the Central Namib Desert: a theoretical model

The formation of Namibia's extensive pedogenic gypsum crusts (CaSO₄·2H₂O) is interpreted in a new light. It is suggested that gypsum primarily precipitates at isolated points of evaporitic concentration, such as inland playas, and that deflation of evaporitic‐rich gypsum dust from these playas contributes to the formation of pedogenic gypsum duricrusts on the coastal gravel plains of the Namib Desert surrounding these playas. This study establishes the nature, extent and distribution of playas in the Central Namib Desert and provides evidence for playa gypsum deflation and gravel plain deposition. Remote sensing shows the distribution of playas, captures ongoing deflation and provides evidence of gypsum deflation. It is proposed that, following primary marine aerosol deposition, both inland playas and coastal sabkhas generate gypsum which through the process of playa deflation and gravel plain redeposition contributes to the extensive pedogenic crusts found in the Namib Desert region. Copyright © 2001 John Wiley & Sons, Ltd.     

Neodymium isotopic composition of Quaternary island arc lavas from Indonesia

${}^{143}\text{Nd}{}^{144}\text{Nd}$ ratios measured in Quaternary lavas from Java and the Banda arc of Indonesia range from 0.51242 to 0.51280 and exhibit an inverse correlation with ${}^{87}\text{Sr}{}^{86}\text{Sr}$. Isotopically, the Indonesian samples resemble Andean rather than island arc lavas. The samples from Java plot either within, or adjacent to the mantle array, towards higher ${}^{87}\text{Sr}{}^{86}\text{Sr}$ ratios. Samples from the Banda arc and the anomalous calc-alkaline volcano Papandajan are characterized by relatively low ${}^{143}\text{Nd}{}^{144}\text{Nd}$ and high ${}^{87}\text{Sr}{}^{86}\text{Sr}$ ratios. These characteristics are consistent with the interpretation that subducted terrigenous material was involved in the genesis of these lavas. Furthermore the Banda arc samples appear to lie on a mixing line between isotopic compositions characteristic of the mantle and upper continental crust. A high-K trachyte from the alkaline volcano Muriah, Java, has isotopic characteristics of the mantle (${}^{143}\text{Nd}{}^{144}\text{Nd}\text{= 0.51270}$, ${}^{87}\text{Sr}{}^{86}\text{Sr}\text{= 0.70424}$), which implies that the extreme enrichment in large-ion-lithophile elements in its source must have occurred only shortly before its formation. The inferred ${}^{143}\text{Nd}{}^{144}\text{Nd}$ ratio of the unmodified mantle beneath Java and the Banda arc is lower than that observed in mid-ocean ridge basalt, which may have important implications for a better understanding of the geochemical structure of the mantle.     

Spatial Distribution and Temporal Evolution of Coronal Bright Points

Solar Physics - We present a statistical study of the spatial distribution and temporal evolution of coronal bright points (BPs) by analyzing a continuous set of observations of a quiet-Sun region...     

Latest Pleistocene and Holocene dune construction at the north-eastern edge of the Rub Al Khali, United Arab Emirates

Optical dating of two dune profiles developed in linear dunes in Ras Al Khaimah, United Arab Emirates, has been used to establish the timing and rate of dune accretion. One section at Awafi was over 17 m high, while that at Idhn was over 40 m high. The Awafi dune appears to have accumulated very rapidly ≈10 000 years ago, with a vertical accumulation rate of about 3·3 m ka⁻¹. The Idhn dune appears to have accumulated over the past 1000 years, with 20 m of sediment accumulating in a time period of about 270 years. The Awafi dune may have accumulated in response to the transgression of the Persian Gulf by rising sea levels in late Pleistocene and Holocene times. The Idhn dune may have accumulated rapidly because of intensified human activity, a short-lived climatic event, or because it may periodically be reactivated after erosion by fluvial action at its base.     

INFRA-RED LINE-SCAN IMAGERY: AN EXAMPLE AND AN APPLICATION

The detection of drainage patterns in an area of the Forest of Dean, Gloucestershire, provides an example of the usefulness of infra-red line-scan imagery.     

Early to Middle Devonian granitic and volcanic rocks from the central Gulf of Maine

Cashes Ledge igneous suite in the central Gulf of Maine is represented by 10 granitic and two felsic tuff samples collected from bedrock outcrops using the submersible Alvin in 1971–1972 and archived at the Woods Hole Oceanographic Institute. Laser ablation ICP-MS analyses of zircon grains yielded crystallization ages of 414.9 ± 1.1 Ma and 399.7 ± 1.5 Ma for two alkali feldspar granite samples, 407.0 ± 1.9 Ma for a syenogranite sample, and 384.4 ± 2.3 Ma and 383.9 ± 1.6 Ma for two felsic tuff samples. The samples contain iron-rich mafic minerals, including aegirine-augite, grunerite/ferroedenite, and annite. Most of the samples are alkaline to slightly peralkaline, with high concentrations of SiO₂, Y, Zr, Nb, and REE, strong negative Eu anomalies, and positive epsilon Nd values (1.8 to 3.7). The suite resembles part of a belt of similar Silurian–Devonian rocks with ages between 426 and 370 Ma now recognized in the central part of Avalonia in southeastern New England. They formed in a long-lived, likely extensional regime linked to subduction and subsequent complex transcurrent motions among Ganderia, Avalonia, and Meguma, culminating in the closure of the Rheic Ocean.