Late Albian dinoflagellate cyst paleobiogeography as indicator of asymmetric sea surface temperature gradient on both hemispheres with southern high latitudes warmer than northern ones
Masure, E.; Vrielynck, B. (2009). Late Albian dinoflagellate cyst paleobiogeography as indicator of asymmetric sea surface temperature gradient on both hemispheres with southern high latitudes warmer than northern ones. Mar. Micropaleontol. 70(3-4): 120-133. dx.doi.org/10.1016/j.marmicro.2008.11.004
In: Marine Micropaleontology. Elsevier: Amsterdam; New York; Oxford; Tokyo. ISSN 0377-8398; e-ISSN 1872-6186, more
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| Author keywords |
Late Albian; dinoflagellate cysts; northern hemisphere; southernhemisphere; thermal gradient; climate |
| Abstract |
Late Albian temperature sensitive dinoflagellate cysts are characterized in order to better understand mid-Cretaceous sea surface temperature gradients. Distribution maps of thirty-seven species recovered from one hundred fifty outcrops and deep sea drilling holes (ODP, DSDP) Sites located from low and high paleolatitudes over the two hemispheres (75°N–70°S) are encountered. Fifty years of published data available in eighty-seven articles have been considered and synthesized using a database coupled with a Geographical Information System (GIS). The continuous and disjoint biogeographic patterns of dinocyst species along latitudes define seven climatic belts, four in the northern hemisphere (high, mid-high, mid-low, low latitude belts) and three in the southern hemisphere (low, mid-low, mid-high latitude belts). Dinocysts restricted along latitudes are temperature sensitive species. Limit ranges of temperature sensitive dinocysts of mid-low and mid-high latitude belts reveal mixing belts, located at 40–45°N and 50°–70°S. They represent major palaeofrontal systems as paleosubtropical fronts with strongly mixed water column. The northern frontal system (40–45°N) was located as in the modern ocean. The large southern frontal system (50°S–70°S) was 10°–20° poleward to Antarctica. Semi-quantitative temperature range limits for mid-Cretaceous dinoflagellates and SST gradients in the two hemispheres are suggested by setting dinocyst climatic belts against estimated d18O temperature curve from fish teeth. A paleoecological classification is suggested. Latitudinal distribution of extant temperature sensitive dinoflagellate cysts follows the asymmetric modern temperature gradient. Asymmetric latitudinal ranges of Late Albian dinocyst species of mid-low latitude belts restricted between 45°N and 70°S demonstrate asymmetric temperature gradients with southern high latitudes being warmer than northern high latitudes. |
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