碳酸盐岩振动液化地震序列

新建立的振动液化地震序列系碳酸盐软沉积物中的强地震事件记录，包括地震液化阶段产生的泄水脉、液化变形；液化停止后的地面下沉构造；地震引起的津浪丘状层与浊积岩等序列单元。这个序列来自大区域的野外实践总结，反映了一次强地震事件的全过程，并在理论上得到统一的解释。序列将为野外地质学家在碳酸盐层中识别事件提供对比的标准。根据振动液化地震记录，本文首次提出古郯庐带概念，并对其地质意义进行了初步讨论。     

Is the Bayan Obo ore deposit a micrite mound? A comparison with the Sailinhudong micrite mound

The origin of the Bayan Obo ore deposit, the largest REE deposit in the world, has long been debated and various hypotheses have been proposed. Among them is that the Bayan Obo ore deposit is correlated with and has the same origin as the Sailinhudong micrite mound in the southern limb of the Bayan Obo synclinorium. To test this model, the Bayan Obo ore deposit and the Sailinhudong micrite mound are systematically compared for their geological features, elemental geochemistry, and C, O, and Mg isotopic geochemistry. We show that the Bayan Obo ore deposit and the Sailinhudong micrite mound are both calcareous, lens-like in shape, lack bedding features, and are both hosted in a sedimentary formation that consists of clastic sediments and carbonates, unconformably overlying the Archaean–Palaeoproterozoic crystalline basement. However, their geochemical characteristics differ markedly. Compared with the Sailinhudong micrite carbonates, the Bayan Obo ore-hosting dolomite marbles are strongly enriched in LREEs, Ba, Th, Nb, Pb, and Sr, and have very different (PAAS)-normalized REE patterns. Sailinhudong micrite carbonates have higher δ¹³C_PDB and δ¹⁸O_SMOW values, falling into the typical sedimentary field, but the Bayan Obo ore-hosting dolomites are isotopically intermediate between primary igneous carbonatite and typical sedimentary limestone. The δ²⁶ Mg values of the Sailinhudong micrite carbonates are lighter than those of normal Mesoproterozoic sedimentary dolostone, while those of the Bayan Obo ore-hosting dolomite marble are isotopically heavier, similar to δ²⁶ Mg of mantle xenoliths and Bayan Obo intrusive carbonatite. We conclude that the Bayan Obo ore deposit is not correlated with the Sailinhudong micrite mound; it is neither a micrite mound nor an altered micrite mound.     

柴达木盆地跃进地区下干柴沟组上段藻丘灰岩储层特征

柴达木盆地跃进地区下干柴沟组上段 (E3 2 )为一套碳酸盐岩与泥岩互层或夹层的地层。研究揭示这套碳酸盐岩形成于滨浅湖环境,岩石类型有陆屑泥晶灰岩、藻团块灰岩、藻泥晶灰岩、颗粒灰岩、藻纹层灰岩及藻叠层灰岩。其中,藻纹层灰岩及藻叠层灰岩 (藻丘 )储集物性极佳并含油,混合水白云化及大气淡水淋溶是该套储层形成的主要原因。特大孔 +(微 )细喉组合、大孔 +(微 )细喉组合是主要的孔喉组合类型。自然电位高负值、视电阻率极高值、过井地震剖面强反射特征是追踪这套含油藻丘灰岩时空展布的重要依据。上述研究成果对跃进地区的油气勘探和开发均具重要意义。     

北京西山及邻区寒武系顶部微晶丘特征及层序地层学意义

北京西山,河北涞源及山西浑海等地位于寒武系－奥陶系界面处的厚层块状“纯灰岩”实际是由微晶方解石,丛状或丝状蓝绿藻,碎屑等共同营造而成的大型微晶丘,具明显的丘状外貌及侧向地层向微晶丘顶部的上部,地球化学特征也显示出与周围同期地层的不同及与土覆冶里组中层纹状叠石灰岩的相似性,内部岩石微相有：藻粘结灰岩相,具有规则孔洞藻占结灰岩相,碎屑藻粘结灰岩相（藻间为黄褐色白云岩砾块,砾屑灰岩及砂屑灰岩）内部有７个     

Composite Stratigraphy of the Sailinhudong Group and Ore-bearing Micrite Mounds in the Bayan Obo Deposits,Inner Mongolia,China

Based on studies of sequence stratigraphy, event stratigraphy, biostratigraphy and lithostratigraphy, it is concluded that the Sailinhudong Group is a part of the Bayan Obo Group. Some trilobite fragments are first found in thin sections of the rock from the lower part of the Sailinhudong Group and some Ordovician acritarchs and chitinozoans are also found in this group. A formationa unit of carbonate seismites is first recognized in the upper part and a huge micrite mound is first identified at the top. Dolomite, the host rock of the super giant Bayan Obo Fe-Nb-REE deposits, is neither an igneous carbonatite nor a common bedded sedimentary carbonate, but a huge micrite mound. It has the same macroscopic characters as the micrite mounds at the top of the Sailinhudong Group, which suggests that they should be of the same horizon. According to the fossils, the Sailinhudong and Bayan Obo Groups should be of the Early Palaeozoic rather than the Middle Proterozoic. The new discovery and new idea will throw l     

Biofilm-related calcification,sediment trapping and constructive micrite envelopes: a criterion for the recognition of ancient grass-bed environments?

Micrite envelopes are a common feature in carbonate sediments and are typically associated with the micrite filling of borings produced by microendolithic organisms. These are referred to as 'destructive micrite envelopes' and have long been recognized as reflecting an important early diagenetic process. Recent analysis of sediments collected from back-reef environments at Discovery Bay, north Jamaica, however, has demonstrated 'envelope' formation on the surfaces of carbonate grains, clearly distinct from the micrite filling of microborings. Such constructive envelopes occur almost exclusively in sediments from grass-bed environments and are always intimately associated with 'biofilms' comprising abundant mucilage, cyanobacteria, bacteria and diatoms. It is suggested that these envelopes represent a product of both biologically mediated micrite precipitation (occurring within the biofilm mucilage and around the biofilm components, i.e. cyanobacteria and diatoms) and associated trapping of carbonate mud and fine-grained sediment. Their recognition only within grass-bed sediments may enable their use as a diagnostic feature of grass-bed environments or vegetation-stabilized substrates in the rock record.     

内蒙古腮林忽洞群综合地层和白云鄂博矿床赋矿微晶丘

据层序地层，事件地层，生物地层和岩石地层研究，腮林忽洞群是白云鄂博群的一部分。于腮 林忽洞群下部层位的岩石切片中首次发现三叶虫屑，并首次分离出奥陶系疑源类及几丁虫化石；于上部层位首次识别出碳酸盐震积岩组及顶部巨型微晶丘。