During the Middle Miocene, an extensive lake district existed along the southern margin of today’s Swabian Alb (Baden–Württemberg). Sediments include a wide range from marls to pure carbonates of lacustrine and palustrine origin that contain microbialites studied here. These sediments are part of the Obere Süßwassermolasse known as Silvana Beds. Macroscopically the studied microbialites show a distinctive layering with an alternation of whitish and tan-colored layers. Petrographic thin sections as well as SEM studies reveal a microstructure of the microbialites comprising an unbranched filament zone formed by erect and parallel calcified filaments as well as a zone of branching filaments forming shrubs of the Dichothrix morphotype. We define two patterns of mineralization for the studied microbialites: (1) shape-retentive mineralization: successive carbonate precipitation along the filament surface. (2) shape-obscuring mineralization: clusters of clotted micritic precipitates along and within the vicinity of micro-sparitic tubules that probably represent remains of the former cyanobacterial sheaths.

在中新世期间，今天的施瓦本阿尔布（巴登-符腾堡）南缘存在一个广阔的湖区。沉积物范围广泛，从泥灰岩到湖泊和沼泽起源的纯碳酸盐，其中含有本文研究的微生物岩。这些沉积物是 Obere Süßwassermolasse 的一部分，称为 Silvana Beds。从宏观上看，所研究的微生物岩表现出独特的分层，白色和棕褐色层交替。岩相薄片和扫描电镜研究揭示了微生物岩的微观结构，包括由直立和平行的钙化丝形成的不分枝丝区域以及形成双根丝菌形态型灌木的分枝丝区域。我们为所研究的微生物岩定义了两种矿化模式：（1）形状保持矿化：沿着细丝表面连续碳酸盐沉淀。 (2) 形状模糊的矿化：沿着微晶石管及其附近的凝结的泥晶沉淀物簇，可能代表了以前的蓝藻鞘的残余物。