气候变化领域集成服务门户(CCPortal): Facies architecture and across-shelf variability of an extensive Lower Triassic (Smithian) microbial carbonate mound complex in the western U.S.

CCPortal

DOI	10.1016/j.palaeo.2019.02.007
	Facies architecture and across-shelf variability of an extensive Lower Triassic (Smithian) microbial carbonate mound complex in the western U.S.
	Jeffrey B.M.; Elrick M.; Atudorei V.; Lucas S.G.
发表日期	2019
ISSN	0031-0182
起始页码	42
结束页码	56
卷号	521
英文摘要	Widespread Lower Triassic microbial carbonates occur after the end-Permian mass extinction (EPME) and are commonly attributed to reduced metazoan competition after the EPME, or to paleoceanographic conditions that suppressed metazoan abundance and increased ocean carbonate saturation. Testing these hypotheses requires direct spatial (versus temporal) linkages between Lower Triassic microbial deposits and lithologic or geochemical proxy evidence for environmental perturbations. This study uses facies within and associated with an extensive Lower Triassic (Smithian) microbial carbonate mound complex, which developed across a > 400-km-wide middle-to-inner shelf in southern Utah, U.S.A., to assess potential controls on microbial carbonate development. Middle-shelf microbial mounds (1–2 m tall) are composed of stromatactis-rich peloidal boundstones that are laterally linked by microbial intermound beds. Inner-shelf microbial mounds (<1 m) are composed of microbial laminites that are linked by flat-lying microbial laminite intermound beds. Both mound types nucleated atop non-mound microbial carbonates in deep- to shallow-subtidal environments and aggraded during sea-level rise. During sea-level fall, mounds broadened, shortened, and terminated growth when higher current energies inhibited substrate stability and mat nucleation. Middle- and inner-shelf mound morphologies and facies differences reflect across-shelf accommodation space variations and proximity to nearshore terrigenous sediment influx. Sparse, but persistent benthic fauna and bioturbation in all microbial facies and the lack of lithologic indicators of bottom-water anoxia indicate sufficient O 2 levels to support animal life. The broad Utah shelf study area implies that shelf-edge, upwelling-derived, carbonate-saturated waters did not control microbial carbonate precipitation. Regional controls on microbial mound complex development include deposition during sea-level rise along a wide shallow shelf that maximized the areal extent of clear-water, low-energy subtidal environments and promoted growth of prolific photosynthesizing microbial communities. Probable global controls include the post-EPME reduction in skeletal metazoan competition, which permitted microbial mats to flourish, and elevated global-ocean carbonate saturation states and promoted extensive carbonate precipitation. © 2019 Elsevier B.V.
英文关键词	Carbonate saturation; Early Triassic; End-Permian mass extinction; Microbial mound; Subtidal carbonates
语种	英语
scopus关键词	abundance; anoxia; benthic fauna; bioturbation; carbonate; deposition; growth; mass extinction; metazoan; microbial community; microbial mat; paleoceanography; Permian; precipitation (chemistry); saturation; sea level change; subtidal environment; Triassic; United States; Utah; Animalia; Metazoa
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151012
作者单位	Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States; New Mexico Museum of Natural History, 1801 Mountain Rd. NW, Albuquerque, NM 87104, United States
推荐引用方式 GB/T 7714	Jeffrey B.M.,Elrick M.,Atudorei V.,et al. Facies architecture and across-shelf variability of an extensive Lower Triassic (Smithian) microbial carbonate mound complex in the western U.S.[J],2019,521.
APA	Jeffrey B.M.,Elrick M.,Atudorei V.,&Lucas S.G..(2019).Facies architecture and across-shelf variability of an extensive Lower Triassic (Smithian) microbial carbonate mound complex in the western U.S..Palaeogeography, Palaeoclimatology, Palaeoecology,521.
MLA	Jeffrey B.M.,et al."Facies architecture and across-shelf variability of an extensive Lower Triassic (Smithian) microbial carbonate mound complex in the western U.S.".Palaeogeography, Palaeoclimatology, Palaeoecology 521(2019).