小藻礁灰岩（Stromatolitic limestone）
产地：山东省新泰市
特征：
叠层石灰岩的一种，藻体较小，平面上呈小同心圆状，剖面上为向上凸起的弧形，分叉现象明显。主要成分为方解石（CaCO3），约占80%以上，其次为少量白云石、玉髓、海绿石。碳酸盐成分是受蓝绿藻丝状体所分泌出的胶状黏液控制，使其所捕获的各种漂移的灰泥球粒在表面上呈叠层状、球状、掌状等富屑纹层，因而使石灰岩具粒屑结构、残余生物结构以及叠层构造、块状构造和隐藻类构造等。小藻礁灰岩具有较高的孔隙率，同时它比周围同时期沉积物要高得多。
小藻礁灰岩呈浅灰色、浅黄色，表面凹凸不平，具各式纹层，质地坚硬，密度2.7g/cm，抗压强度100~150MPa。小藻礁石灰岩CaO含量较高，通常为48%~50%，但SiO2含量也较高，于2.4%~8.6%之间，加酸起泡。由于含CaO较高，MgO适量，多在2%左右，因此是较好的熔剂灰岩和水泥原料。此外由于表面有特殊的叠层石纹层，因而常用于建筑装饰面料。
采集人：陈勇、颜世永、裴仰文、王健、段忠丰
Stromatolitic limestone
Provenance: Xintai, Shandong, China
Characteristics:
Stromatolites (/stroʊˈmætəlaɪts, strə-/) or stromatoliths (from Greek στρώμα, strōma, mattress, bed, stratum, and λίθος, lithos, rock) are layered bio-chemical accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms (microbial mats) of microorganisms, especially cyanobacteria. Fossilized stromatolites provide ancient records of life on Earth by these remains, some of which date from more than 3.5 billion years ago. Lichen stromatolites are a proposed mechanism of formation of some kinds of layered rock structure that are formed above water, where rock meets air, by repeated colonization of the rock by endolithic lichens.
A variety of stromatolite morphologies exists, including conical, stratiform, branching, domal, and columnar types. Stromatolites occur widely in the fossil record of the Precambrian, but are rare today. Very few ancient stromatolites contain fossilized microbes.
Gatherers: Chen Yong, Yan Shiyong, Pei Yangwen, Wang Jian, Duan Zhongfeng