[
    {
        "id": "authors:ep4np-d7t46",
        "collection": "authors",
        "collection_id": "ep4np-d7t46",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150327-103946761",
        "type": "book_section",
        "title": "The interaction of the Cretaceous/Tertiary Extinction Bolide with the atmosphere, ocean, and solid Earth",
        "author": [
            {
                "family_name": "O'Keefe",
                "given_name": "John D.",
                "clpid": "O'Keefe-J-D"
            },
            {
                "family_name": "Ahrens",
                "given_name": "Thomas J.",
                "clpid": "Ahrens-T-J"
            }
        ],
        "contributor": [
            {
                "family_name": "Silver",
                "given_name": "Leon T.",
                "clpid": "Silver-L-T"
            },
            {
                "family_name": "Schultz",
                "given_name": "Peter H.",
                "clpid": "Schultz-P-H"
            }
        ],
        "abstract": "The mechanics of large-scale (~10-km diameter) asteroidal, cometary, and meteoroid swarm impact onto a silicate Earth covered by water and a gas layer (atmosphere) demonstrate that only ~ 15% to ~ 5% of the energy of 15 to 45 km/s bolides is taken up directly during the passage through the ocean and atmosphere, respectively. Upon impact with the Earth, ~ 10 to 10^2 times the bolide mass of water or rock can be ejected to the stratosphere: however, only ~0.1 bolide masses is in < 1 \u03bcm particles. The vaporized, melted, and (< 1 mm) solid ejecta transfer up to ~40% of their energy to the atmosphere and possibly oceanic surface water, giving rise to a short, possibly lethal (to large animals) heating pulse. The initial high-speed ejecta that lofted to and above the stratosphere early in the cratering flow is enriched in bolide material and has concentrations of extraterrestrial material in the range of those measured (0.01 to 0.2) in the Cretaceous/Tertiary (C/T) boundary layer. We suggest that the origin of the C/T boundary layer is this ejecta, which is heavily shocked and in the < l-\u03bcm range and, hence, once entrained in the stratosphere may be spread worldwide. Penetration of the atmosphere by the bolide creates a temporary hole in the atmosphere surrounded by strongly shocked air. The resultant inward and upward flow of the shocked atmosphere backward along the bolide trajectory lofts the vapor, fine-melted and solid ejecta to heights greater than 10 km. The larger, millimeter- to centimetersize, melt droplets that are lofted by this mechanism reenter the atmosphere and may represent microtektites and tektites. Sufficient impact-induced vapor, melted and comminuted silicate is ejected to stratospheric heights to markedly reduce the light levels at the Earth's surface. The short-term effects of heating, followed by dust and possibly water-cloud deck induced worldwide cooling, provide several mechanisms to cause severe environmental stress to biota and possibly give rise to the varied and massive extinctions that occurred at the C/T boundary.",
        "doi": "10.1130/SPE190-p103",
        "publisher": "Geological Society of America",
        "publication_date": "1982"
    },
    {
        "id": "authors:5rpe5-1x523",
        "collection": "authors",
        "collection_id": "5rpe5-1x523",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150327-104703758",
        "type": "book_section",
        "title": "Extinction of the dinosaurs: A 1982 understanding",
        "author": [
            {
                "family_name": "Schopf",
                "given_name": "Thomas J. M.",
                "clpid": "Schopf-T-J-M"
            }
        ],
        "contributor": [
            {
                "family_name": "Silver",
                "given_name": "Leon T.",
                "clpid": "Silver-L-T"
            },
            {
                "family_name": "Schultz",
                "given_name": "Peter H.",
                "clpid": "Schultz-P-H"
            }
        ],
        "abstract": "The objective record appears to be that the dinosaur fauna of the latest Maastrichtian (i.e., latest Cretaceous) was chiefly (and perhaps exclusively) restricted to the Western Interior Seaway of the United States and southern Canada and included fewer than 20 species distributed among approximately 15 genera and 10 families. In the late Maastrichtian, as has been known for many years, sea level went down by 150 to 200 m in the western interior. The interior seaway (along which the dinosaurs were living) dried up and seasonality increased and habitable area was reduced as widespread flood plains yielded to uplifted, restricted basins. This occurrence of a gradually changing ecology correlated with animal extinction conforms to the observed pattern characteristic of many other times in the fossil record. If this pattern applies to dinosaurs as well, then the extinction of the dinosaurs is neither necessarily nor reasonably attributable to any extraterrestrial event. In addition, it appears that the magnitude of the extinction is greatly over estimated because a very small number of species and genera were actually responsible for the familial extinctions.",
        "doi": "10.1130/SPE190-p415",
        "publisher": "Geological Society of America",
        "publication_date": "1982"
    }
]