Filters: Tags: Paleosols (X)
8 results (6ms)|
Filters
Contacts
(Less)
|
This study provides a detailed pedogenic evaluation of two Upper Triassic (Late Norian through Rhaetian) stratigraphic intervals in New Mexico in order to assess the climate and ecology of the Latest Triassic, which ended in a mass extinction. The two study areas are located in north?central and east-central New Mexico and are separated by 200 km. Each section contains abundant paleosols of varying maturity with features that reflect an arid to semiarid climate. There is little pedogenic variation throughout the strata at each location, and a typical paleosol profile is about 1 m thick and has an AB?Bw?Bk?BC horizon succession. Bkm, Bss, Bssk, or Bssg horizons are present in some paleosols. Micromorphological features...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Chinle Formation,
New Mexico,
Palaeogeography, Palaeoclimatology, Palaeoecology,
Paleoclimate,
Paleosols,
This report provides detailed (1:63,360-scale) surficial-geologic mapping in the Dalton Highway area, from the Sagavanirktok to the Itkillik Rivers, in the west-central Philip Smith Mountains quadrangle. The map area extends from the northern flank of the Endicott Mountains into the Arctic Foothills province.
The Halfway House site in interior Alaska is arguably the most studied loess deposit in northwestern North America. The site contains a complex paleomagnetic and paleoenvironmental record, but has lacked the robust chronologic control that would allow its full potential to be exploited. Detailed reexamination of stratigraphy, paleomagnetics and tephrostratigraphy reveals a relatively complete marine isotope stage (MIS) 6 to Holocene record constrained by the Old Crow (124 ± 10 ka), VT (106 ± 10 ka), Sheep Creek-Klondike (ca. 80 ka), Dominion Creek (77 ± 8 ka) and Dawson (ca. 30.2 cal ka BP) tephras. We show two well-developed paleosols formed during Marine Isotope Stages (MIS) 5e and 5a, while MIS 5c and 5b are...
Categories: Publication;
Types: Citation;
Tags: Alaska,
Halfway House,
Loess,
Magnetic susceptibility,
Marine isotope stage 5,
In upland areas of Canyonlands National Park, Utah, thin deposits and paleosols show late Quaternary episodes of eolian sedimentation, pedogenesis, and climate change. Interpretation of the stratigraphy and optically stimulated luminescence ages of eolian and nearby alluvial deposits, their pollen, and intercalated paleosols yields the following history: (1) Eolian deposition at ca. 46 ka, followed by several episodes of alluviation from some time before ca. 40 ka until after 16 ka (calibrated). (2) Eolian deposition from ca. 17 ka to 12 ka, interrupted by periods of pedogenesis, coinciding with late Pleistocene alluviation as local climate became warmer and wetter. (3) A wetter period from 12 to 8.5 ka corresponding...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado Plateau,
Geological Society Of America Bulletin,
eolian dust,
paleoclimate,
paleosols,
Shapefiles showing the extent of the Dugger, Minshall-Buffaloville, Seelyville, and Springfield Coal Members derived from coal-test records, mine-map notation, and interpretations of geophysical logs. Information was included in the USGS National Coal Resources Data System (NCRDS).
Categories: Collection,
Map;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Brazil Formation,
Danville Coal Member,
Dugger Formation,
Earth Mapping Resources Initiative (Earth MRI),
Indiana (IN),
The Halfway House site in interior Alaska is arguably the most studied loess deposit in northwestern North America. The site contains a complex paleomagnetic and paleoenvironmental record, but has lacked the robust chronologic control that would allow its full potential to be exploited. Detailed reexamination of stratigraphy, paleomagnetics and tephrostratigraphy reveals a relatively complete marine isotope stage (MIS) 6 to Holocene record constrained by the Old Crow (124 ± 10 ka), VT (106 ± 10 ka), Sheep Creek-Klondike (ca. 80 ka), Dominion Creek (77 ± 8 ka) and Dawson (ca. 30.2 cal ka BP) tephras. We show two well-developed paleosols formed during Marine Isotope Stages (MIS) 5e and 5a, while MIS 5c and 5b are...
Categories: Publication;
Types: Citation;
Tags: Alaska,
Halfway House,
Loess,
Magnetic susceptibility,
Marine isotope stage 5,
Modern biological soil crusts develop under semiarid to arid conditions and are characterized by diverse communities of micro- and macro-organisms. The upper meter of the Upper Cretaceous capping sandstone member of the Wahweap Formation in Grand Staircase-Escalante National Monument, Utah contains an outcrop of an ancient biological soil crust preserved in matrix-rich quartz sandstone. The interpretation is based in comparison with modern biological soil crust analogs, specifically similarities in morphological expression, sorting, and proximity to associated eolianites. This study reports on this rarely recognized type of paleosol, a biological soil crust and discusses the sedimentologic and paleoclimatic implications....
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Biological soil crusts,
Cretaceous,
Eolian,
Paleosols,
Sedimentary Geology,
During 2006 and 2007 the Alaska Division of Geological & Geophysical Surveys conducted reconnaissance surficial-geologic mapping in segment 1 of the Alaska Highway corridor, which straddles the Alaska Highway through the Tanana River valley from Delta Junction to the eastern boundary of the Mt. Hayes Quadrangle. Surficial-geologic deposits were initially mapped by interpreting ~1:63,360-scale, false-color infrared aerial photographs taken in August 1980 and field verified in 2006-2007.
|
|
