Book Chapters

Abundant and well-preserved diatoms and silicofl agellate assemblages are documented through a complete late Eocene sequence, ODP Hole 1090B, recovered from the southern Agulhas Ridge in the sub-Antarctic South Atlantic. A sequence of Cestodiscus (diatom) species occurrence events involving C. pulchellus var. novazealandica, C. fennerae, C. antarcticus, C. convexus, C. trochus, and C...

DEFINITION. The Pascagoula Map Turtle, Graptemys gibbonsi, is a large riverine species that exhibits pronounced sexual dimorphism, where females attain a maximum carapace length (CL) of 295 mm and males a maximum of 141 mm (Lovich et al. 2009). Mean adult female CL (248 mm) can be well over twice the mean CL of adult males (104 mm; Gibbons and Lovich 1990, Lovich et al. 2009). In...

Northeastern Tibetan Plateau growth illuminates the kinematics, geodynamics, and climatic consequences of large-scale orogenesis, yet only recently have data become available to outline the spatiotemporal pattern and rates of this growth. I review the tectonic history of range growth across the plateau margin north of the Kunlun fault (35°–40°N) and east of the Qaidam basin (98°–107°E)

The chemical character of mafic rocks from the Arctic Alaska–Chukotka terrane records rifting of continental crust during the early Paleozoic, possibly during the Ordovician. The mafic rocks are part of a metamorphosed Neoproterozoic to Devonian continental margin sequence preserved in a Mesozoic metamorphic terrane, the Nome Complex, of Seward Peninsula, Alaska. Protoliths of the mafic...

The Arctic Alaska–Chukotka terrane is a microcontinent with an origin exotic to Laurentia. We used a sensitive high-resolution ion microprobe (SHRIMP) to date nine samples of Neoproterozoic rock and five samples of Devonian rock from the Brooks Range and Seward Peninsula of Alaska and from the Chukotka Peninsula of northeastern Russia. Felsic magmatism occurred at 968 Ma and 742 Ma in...

Detrital zircons from the Nome Complex, a metamorphic terrane in northern Alaska, reveal important constraints on the early Paleozoic history of the Arctic Alaska–Chukotka terrane, a microcontinental block with an origin exotic to Laurentia. Twenty-two samples (17 in this study, five previously published) produce three detrital zircon population patterns (called themes), indicating that...

Both instrument design and capabilities of fluorescence spectroscopy have greatly advanced over the last several decades. Advancements include solid-state excitation sources, integration of fiber optic technology, highly sensitive multichannel detectors, rapid-scan monochromators, sensitive spectral correction techniques, and improve data manipulation software (Christian et al., 1981...

The tectonic evolution of the Arctic realm, particularly in the Mesozoic, remains a subject of considerable uncertainty. The nature of the crustal entities involved, their origins, and the nature, location, and age of major tectonic boundaries are incompletely studied and understood (Pease, 2011). The largest piece of continental crust of uncertain origin that plays a role in Arctic...

A detailed study of the Pb isotope geochemistry of Zn-Pb(-Ag-Au-Ba-F) stratabound sulfide deposits within metasedimentary rocks of the Neoproterozoic to Mississippian(?) Nome Complex provides key information for understanding deposit genesis and crustal evolution. A total of 106 new analyses of galena (and other sulfi des) and metasedimentary rocks hosting the deposits shows that (1) Pb...

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This chapter provides an overview of geochemical modeling that applies to water–rock interactions under ambient conditions of temperature and pressure. Topics include modeling definitions, historical background, issues of activity coefficients, popular codes and databases, examples of modeling common types of water–rock interactions, and issues of model reliability. Examples include...

Rural landscapes in the Andes are characterized by an impressive diversity of natural environments and by multiple resource assets. This is particularly the case in the tropical realm where the ecological altitudinal zones of the tierra caliente, the tierra templada, the tierra fria and the tierra helada offer a remarkable range of agricultural potential. This is complemented by a...