Relative sea level fluctuations during the early Whiterockian (Middle Ordovician): Insights from discontinuity surfaces in the Antelope Valley Limestone, NV

Conference · Wed Mar 31 23:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5096490

Siewers, F D ^[1]

---

1. Univ. of Illinois, Urbana, IL (United States). Dept. of Geology

Detailed stratigraphic, sedimentologic and diagenetic investigation of six sections of the Whiterockian Antelope Valley Limestone in central and southern Nevada reveal numerous sedimentary discontinuities which permit subdivision of the sections into sedmentologically-related facies successions. These discontinuities occur principally in strata of the lower Whiterockian Histiodella altifrons and Histiodella sinuosa Zones representative of continental margin oncolitic shoal, outer shelf, and slope depositional environments. The discontinuities recognized are: subaerial erosion surfaces in the oncolite shoal facies within the H. altifrons Zone; submarine hardgrounds in oncolite shoal, outer shelf and slope facies within the H. sinuosa Zone; and phosphatic omission surfaces in the slope facies within the H. sinuosa Zone. The subaerial erosion surfaces subdivide the otherwise homogeneous oncolitic facies into several sedimentary packages which may correspond with rhythmically-bedded coarsening-upward successions observed in coeval outer shelf sections. The submarine hardgrounds and phosphatic omission surfaces subdivide the outer shelf and slope sections into shallowing-upward successions and mark important periods of non-deposition. While none of the discontinuity surfaces have thus far been correlated confidently between sections, their spatial and temporal distribution suggest: (1) during H, altifrons time, sedimentation in oncolite shoal and outer shelf settings was either keeping pace with or exceeding relative sea level rise; and (2) during at least part of H. sinuosa time, sedimentation in outer shelf and slope settings was greatly outpaced by relative sea level rise.

• OSTI ID: 5096490
• Report Number(s): CONF-9305259--
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:5; ISSN GAAPBC; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CARBONATE ROCKS
DEPOSITION
DEVELOPED COUNTRIES
DIAGENESIS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
LEVELS
LIMESTONE
NEVADA
NORTH AMERICA
ORDOVICIAN PERIOD
PALEOCLIMATOLOGY
PALEONTOLOGY
PALEOZOIC ERA
ROCKS
SEA LEVEL
SEDIMENTARY ROCKS
STRATIGRAPHY
USA
VARIATIONS