Palaeoenvironmental dynamics of Holocene shoreface bryoliths from the southern coast of Brazil
Palaeoenvironmental dynamics of Holocene shoreface bryoliths from the southern coast of Brazil
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巴西南部海岸全新世岸面苔藓化石的古环境动力学
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
D. Bassi
中科院分区：
文献类型：
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作者：
F. Tâmega;Paula Spotorno;P. Dentzien‐Dias;F. S. Buchmann;L. Vieira;K. Macario;Merinda C Nash;R. Guimarães;H. Francischini;D. Bassi
自由生活的有涂层结核床（珊瑚藻、苔藓虫、堆形有孔虫）形成浅水碳酸盐生物底栖生境，对人类干扰敏感，恢复缓慢。全新世苔藓岩，形状从近球形，近盘状到近椭圆形，分散在前沙丘中。沿着巴西最南端海岸的Hermenegildo和Concheiros do Albardão海滩绵延30公里（Santa Vitória do Palmar市，南里奥格兰德州）。形成苔藓石的主要苔藓虫种是Biflustra holocenica Vieira，Spotorno-Oliveira和Tâmega sp. nov.内部苔藓石排列，一般不对称，显示多层和旋转生长的菌落，包裹双壳牡蛎puelchana。苔藓虫和附属珊瑚的特点外苔藓石表面。Gastrochaenopsis（由双壳类的钻石虫（Lithophaga patagonica））和Caulostrepsis从内部到外表面遍布苔藓石。研究bryoliths，起源于一个滨面设置在约。7910-7620 cal. yr BP和在随后的风暴波，被重新沉积到前滨和前沙丘（约。5700 cal. yr BP），其中bryoliths最终被石化。
Beds of free-living coated nodules (coralline algae, bryozoans, acervulinid foraminifera) create shallow-water carbonate biogenic benthic habitats, which are sensitive to human disturbance and slow to recover. Holocene bryoliths, ranging from sub-spheroidal, sub-discoidal to sub-ellipsoidal in shape, were found scattered in the foredunes in ca. 30-km stretch along the Hermenegildo and Concheiros do Albardão beaches on the southernmost coast of Brazil (Santa Vitória do Palmar municipality, Rio Grande do Sul State). The dominating bryozoan species forming the bryolith is Biflustra holocenica Vieira, Spotorno-Oliveira and Tâmega sp. nov. The inner bryolith arrangement, generally asymmetrical, shows multilamellar and circumrotatory growth of colonies that envelop the bivalve Ostrea puelchana. Bryozoans and subordinate corals characterize the outer bryolith surfaces. The ichnogenera Gastrochaenolites (made by the boring bivalve Lithophaga patagonica) and Caulostrepsis occur throughout the bryoliths, from the inner part up to the outer surface. The studied bryoliths, originated in a shoreface setting at ca. 7910–7620 cal. yr BP and during subsequent storm waves, were resedimented onto the foreshore and foredunes (to ca. 5700 cal. yr BP) where the bryoliths were finally fossilized.