The flow of energy and nutrients between trophic levels is affected by both the trophic structure of food webs and the diversity of species within trophic levels. However, the combined effects of trophic structure and diversity on trophic transfer remain largely unknown. Here we ask whether changes in consumer diversity have the same effect as changes in resource diversity on rates of resource ...

Complex impedance data were collected for eight sandstones at various levels of water saturation (S,) in the frequency range of 5 Hz to 4 MHz. The measurements were made using a two-electrode technique with platinum electrodes sputtered onto the flat faces of diskshaped samples. Presentation of the data in the complex impedance plane shows clear separation of the response due to polarization at...

Mineralogical and paleocurrent studies of Amasiri Sandstone, a member Ezeaku Group outcropping as ridge in Abini were done to determine the quantitative values component minerals for proper designation facies sandstone direction paleocurrent. Sampling, measurements, petrographic X-ray diffraction (XRD) analyses employed achieve results. Three highly indurated beds white fine – medium, angular -...

Abstract Initial detrital composition and authigenic alterations during diagenesis of three sandstone types are related to their mechanical properties. Sandstones were prepared for geotechnical standard tests [density, uniaxial compressive strength (UCS), Young’s modulus ( E ), strain at failure ? )] thin sections petrographic analyses (point counting). UCS ranges from 3 62 MPa positively corre...

U–Pb ages of 637 new detrital zircons Triassic sandstones from the Northwestern Sichuan Basin (NWSB), together with petrology and paleocurrent data, are used to constrain sediment provenance tectonic–paleogeographic evolution western Yangtze Block. The age data for Lower generally show populations at ∼1,850 Ma, 980–705 680–510 290–230 Ma a minor cluster ∼2.4 Ga. Such spectrum features eastward ...

The external-detector method of fission-track (FT) dat­ ing is capable of providing FT ages for individual mineral grains. As a result, tliis method when applied to dating detrital zircons in unreset sandstone samples has much potential for resolving the depositional age and provenance of the samples. One problem is that individual FT grain ages for detrital zircons usually have fairly low prec...

The provenance of Early Cretaceous sandstones dredged on the northern margin Demerara Plateau, offshore French Guiana and Suriname, reveals sediment routing system that prevailed through Equatorial Atlantic rifting. Fission-track analysis U–Pb dating 310 111 detrital zircons, respectively, have been performed. Microfacies inherited cooling ages suggest were deposited in shallow marine environme...

An extensive detrital zircon U-Pb data set (n = 6324 dates) from Eocene to Miocene sandstones and modern river sands establishes the onset of arc magmatism forearc uplift along Cascadia convergent margin in southwestern Oregon (United States). Middle late marine strata Coos Bay area were primarily sourced Klamath Mountains coeval Clarno-Challis volcanoes central and/or Idaho. Ancestral Cascades...

This study reports the first-ever detrital zircon provenance investigation of sandstones Kamlial Formation, exposed in Kashmir Basin along Kohala–Bagh road section (Muzaffarabad, Pakistan). Analysis probability density plots U-Pb ages displayed a major age population clustered around ?400–1200 Ma and minor ?1600–1900 Ma. In addition, scattered existed between ?2000 3000 pattern resembled strong...