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Superplumes and Global Magmatism
Resources containing information about the Cretaceous superplume event and its effects on global magmatism.
- Geochemical evidence for a mid-Cretaceous superplume. This is an abstract of an online journal (Geology) article which presents geochemical compositions of basalts from the Polynesian &amp;amp;quot;superswell&amp;amp;quot; region of the South Pacific. The geochemical data from the basalts, along with their ages, are interpreted as indicating a deep-mantle plume origin and superplume activity in the region as old as 90-150 million years ago. This page also includes information on how to purchase the full text article. (more info)
- The biogeochemical consequences of the mid-Cretaceous superplume. This journal article (published in the Journal of Geodynamics) proposes that large amounts of carbon were liberated from submarine methane clathrate deposits during the mid-Cretaceous superplume event. Evidence for this hypothes is based on carbon isotope records of marine carbonates, marine organisms, and terrestrial plants. The author speculates that possible effects of this disruption on the global carbon cycle may have included widespread oceanic anoxia and changes in land plants at mid- to high-latitudes. (more info)
Resources containing information about Cretaceous intrusive bodies.
- Cretaceous Paleogeography of the Southwestern U.S.. The complex tectonic evolution of southwestern US is explained with these detailed paleogeographic maps of this region. Significant geologic features such as the Cordilleran volcanic arc, the Cordilleran fold and thrust belt, incipient Laramide uplifts, foreland basin and Western Interior seaway are depicted in this series of maps. Discussions of important geologic features, concepts and the tectonic evolution of the southwestern US during the Cretaceous accompany the maps. ( This site may be offline. )
- Geology Fieldnotes: Capitol Reef National Park, Utah. This Capitol Reef National Park site contains park geology information, park maps, photographs, visitor information, and a teacher feature (resources for teaching geology with National Park examples). Geologic data includes descriptions of the Waterpocket Fold, a monocline formed in the Laramide Orogeny and made of sedimentary rock. Also covered is erosion, and details about the Cathedral Valley outcrop of gypsum. This formation is Permian to Cretaceous in age (270-80 million years old). (more info)
- Geology Fieldnotes: Glacier Bay National Park and Preserve, Alaska. This park is home to the Fairweather Mountains, which formed during the Laramide Orogeny, as well as many glaciers. The site includes introductory information about glacial formation and icebergs, links to park maps, and visitor information. (more info)
- Geology Fieldnotes: Grand Teton National Park, Wyoming. This National Park Service resource includes information about geology, park maps, visitor information, photographs, and links to other sites about this park. Geologic information spans the entire history of the park, beginning 2.5 billion years ago (Precambrian) to the present. Details about the different rock types and their formation, mountain building through plate tectonics and the Laramide Orogeny, formation of valleys and canyons, volcanism in the area, and erosion by glaciers are all covered. (more info)
- Global Paleogeographic Views of Earth History. This site supplies 26 global paleogeographic maps that illustrate how Earth may have appeared throughout the last 600 million years. Realistic colors for geographic features were derived from satellite images and adjusted to portray climate and vegetation on the maps. Maps were created as rectangular images then wrapped around a sphere to convey a global view. An extensive list of references used is provided at the bottom of the page. ( This site may be offline. )
- Mantle Plumes and Mountain Building. This page presents an abstract from the American Scientist March-April 1999 issue. It discusses how the westward progress of the North American plate over the relatively stationary Yellowstone plume during the past 75 million years may explain geological features as diverse as the Laramide Orogeny, the distended Basin and Range Province, and the accretion of exotic terranes along the continent's west coast. Some sample figures from the article that illustrate the path of the hot spot across North America, as well as a cross section of the subduction zone over the past 70 million years, are also included. Other links included are: relief maps of the United States, physiographic provinces of the United States, geomorphology from space, a story on plate tectonics by the United States Geological Survey, a plate motion calculator, and various geology links. (more info)
- North American Orogenies. This web-site contains files showing simple cross sections of one or more states in selected North American orogenies (mountain building events). Major structures, elements, and rock units are shown. The orogenies covered here include the Wopmay, Taconic, Acadian, Alleghanian, Palisades, Antler, Ancestral Rockies, Sonoman, Sevier and Laramide. ( This site may be offline. )
- Tertiary Paleogeography and Tectonic History, Central Arizona. This website presents images and text depicting the paleogeography and tectonic evolution of central Arizona during the Tertiary period. Emphasis is on an evolving Oligocene to Miocene drainage system that documents the existence of the Mogollon Rim, the southern physiographic boundary of the Colorado Plateau. The goal of this page is to demonstrate the evolution of stream systems in relation to complex, dynamic, tectonic events in the Southwest including the Laramide orogeny, Cenozoic core complexes, Basin and Range faulting, and Cenozoic volcanism. This is done through photographs, stratigraphic columns and cross-sections of area geology. ( This site may be offline. )
- The Formation of Pangaea: The Making of a Supercontinent. This site explains the events during the Paleozoic era that led up to the formation of the Pangaea supercontinent in the Mesozoic era. The existence in the Paleozoic era of the supercontinent Gondwanaland, the continents Laurentia and Baltica, and smaller continental masses are explained as well as the later collisions which created mountains by folding of the Earth's crust, (orogenies) such as the Acadian, Appalachian, Urals, and Laramide orogenies. (more info)
- The PLATES Project. Contains animations of plate tectonic movement through geologic history (under the headings 'Reconstructions' and 'Movies'). Several maps with plate motion arrows are shown under the heading of 'Teaching'. Lawrence Lawver and Ian Dalziel of the University of Texas Institute for Geophysics (UTIG) are Principal Investigators of the PLATES Project. (more info)
- Tour of Park Geology: Mountain Building. This site provides links to tours of National Parks, National Monuments, and Recreation Areas associated with major mountain building periods. The parks are divided into groups by mountain building events: Appalachian, Laramide, and others. Where appropriate, links are provided to park geology, maps, photographs, geologic research, related links, visitor information, multi-media, and teacher features (resources for teaching geology with National Park examples). The list includes places such as: Delaware Water Gap National Recreation Area, Shenandoah National Park, Devils Tower National Monument, Mt. Rushmore National Monument, Yosemite National Park, and more. (more info)
- Mesozoic Plutonism in the central Sierra Nevada Batholith: A review of works on mineralogy and isotopes in relation to models for batholith formation. This webpage, developed by a student as part of a "Tectonics of the Western U.S." course at the University of Colorado, is a useful summary of past and current ideas about the origin of the Sierra Nevada batholith in California. The page contains informative text, color graphics, supplementary explanations of relevant isotope systems, a list of references, and a page of related links. ( This site may be offline. )
Resources containing information about Cretaceous volcanism and its impacts on the earth system.
- Late Cretaceous. This site provides a list of links to paleogeographic reconstructions for several time slices within the Cretaceous Period. These include 100 million, 90 million, 80 million and 70 million years ago. Paleogeographic maps are arranged by age and emphasize tectonics, depositional systems and paleogeography. Short discussions of paleogeography, tectonic evolution and historical geology accompany some of the maps. ( This site may be offline. )
- The Extinction Files (BBC). This is a useful brief module on the general occurrences, mechanisms and theories behind mass extinctions. Answers are given to commonly asked questions, and links are included at the end of the module to numerous extinction resources. ( This site is likely no longer available. )
- What Killed The Dinosaurs?: The Great Mystery. This site presents theories about why the dinosaurs became extinct. The first page provides background information covering not only the "great dying" at the K-T boundary but also the mass extinction at the end of the Paleozoic Era. The author covers six factors that complicate the study of mass extinction including time resolution, the Signor-Lipps Effect, and falsifiability. A link then takes the reader to a second page where invalid extinction hypotheses are explained. These range from "hay fever killed the dinosaurs" to "the dinosaurs just faded away," (no causation implied). The final link leads us to current thinking about extinction including volcanism, plate tectonics, and the Alvarez Hypothesis. (more info)