Selected annotated bibliography of minor-element content of marine black shales and related sedimentary rocks, 1930-65

Mesozoic sedimentary rocks, of both deep- and shallow-water character, are present throughout Italy and well exposed in mountains and river valleys. Detailed studies of these sections by Italian geologists, beginning in the nineteenth century and continuing to this day, have produced a high-resolution biostratigraphy that allows identification of increments of geological time of less than a million years. Early work relied largely on ammonites to define biostratigraphy but was applicable primarily to sediments of Jurassic age. Study of deep-marine pelagic limestones and shales of Cretaceous age were subsequently, in the twentieth century, investigated using planktonic microfossils, the size of a sand grain, and even smaller nannofossils of micron scale. Pioneering work on magnetostratigraphy and cyclostratigraphy, undertaken primarily on Cretaceous sediments cropping out in Marche-Umbria, added further refinement to the measuring of small intervals of time in rock. With this stratigraphic background, distinct lithological and chemical signals, discovered first in Italian sequences, could be recognized world-wide and proven to be of global significance. In particular, the involvement of carbon isotopes has underscored the utility of chemostratigraphy, not only as a further aid to correlation, but also as a testimonial to major environmental change. Most significant in this context are the Cretaceous oceanic anoxic events, whose sedimentary record was first documented from Italy. These events were characterized by the development of organic-rich black shales deposited in waters largely lacking in oxygen during times of extraordinarily high temperatures known as hyperthermals. Hyperthermals, likely driven by supply of carbon dioxide from large-scale volcanic eruptions, illustrate the environmental impact on a planet affected by extreme global warming.

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Minor element content of coexistent Al 2 SiO 5 polymorphs

American Journal of Science ◽

10.2475/ajs.267.3.310 ◽

1969 ◽

Vol 267 (3) ◽

pp. 310-316 ◽

Cited By ~ 9

Author(s):

A. L. Albee ◽

A. A. Chodos

Keyword(s):

Minor Element ◽

Element Content

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Stratigraphic framework of zinc–lead deposits in the northern Cordillera northeast of the Tintina Trench

Canadian Journal of Earth Sciences ◽

10.1139/e79-036 ◽

1979 ◽

Vol 16 (2) ◽

pp. 380-385

Author(s):

Graeme P. McLaren ◽

Colin I. Godwin

Keyword(s):

Sedimentary Rocks ◽

Minor Element ◽

Late Cambrian ◽

Time Space ◽

Stratigraphic Framework ◽

Geologic Map ◽

Carbonate Sequence ◽

Space Projection ◽

Host Rocks ◽

Two Populations

Two major groups of sedimentary rocks hosting zinc–lead deposits in the northern Canadian Cordillera can be distinctly partitioned on the basis of depositional tectonics. A Proterozoic to Early Cambrian succession of carbonates and elastics is separated from a Late Cambrian to Devonian basinal shale and laterally equivalent platformal carbonate sequence by a regional erosional hiatus. This partitioning is emphasized by bimodal minor element distributions in carbonate-hosted sphalerite found throughout these rocks. Two populations of sphalerite, individually contained within the two major groups of host rocks, are separated by a unit that is relatively barren of mineralization. A regional geologic map, diagrammatic cross section, and time–space projection illustrate the stratigraphy, depositional tectonics, and location of sphalerite occurrences, and are presented as a framework for further research.

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Minor element content of sphalerite, Nanisivik lead-ainc deposit, NWT

10.4095/133338 ◽

1992 ◽

Author(s):

D C Harris ◽

D F Sangster

Keyword(s):

Minor Element ◽

Element Content

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Directly Dating Sedimentary Rocks

The Paleontological Society Papers ◽

10.1017/s1089332600001364 ◽

2006 ◽

Vol 12 ◽

pp. 77-105 ◽

Cited By ~ 2

Author(s):

E. Troy Rasbury ◽

Jennifer M. Cole

Keyword(s):

Critical Evaluation ◽

Sedimentary Rocks ◽

Black Shales ◽

Depositional Environments ◽

Radiometric Dating ◽

Geochemical Behavior ◽

Sedimentary Deposits ◽

Future Work ◽

Isotope Systematics

This contribution seeks to provide a summary of radiometric dating techniques that are currently applicable to Phanerozoic sedimentary deposits and therefore relevant to paleontologists. First we overview the assumptions necessary for radiometric dating and introduce isochrons and concordia diagrams as methods for calculating ages and evaluating isotope systematics. We then focus on the four most promising systems: U-Pb dating of carbonates, Re-Os dating of black shales, and U-Pb and Lu-Hf dating of phosphates. We review expected geochemical behavior of daughter and parent isotopes in the context of both marine and terrestrial depositional environments. A critical evaluation of previously published ages and potential directions for future work are provided.

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