Intrusion vs. inversion at the rims of the Northwest German Basin: the gravity highs of Bramsche and Pritzwalk revisited. 3D structural modelling by the aid of the "Digital Geotectonic Atlas"

德国西北部盆地边缘的侵入与反转：重新审视布拉姆舍和普利兹沃克的重力高点。

• 批准号: 5410120
• 负责人: Professor Dr. Hans-Jürgen Götze
• 金额: --
• 依托单位: Abteilung Geologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5410120?language=en
• 关键词: Intrusion; vs.; inversion; rims; Northwest

One of the still unsolved problems of regional importance for the both evolution and present structure of the Northwest German Basin concerns the existence or non-existence of the so called "Massif of Bramsche" and, farther to the East, the "East Elbian Massif in the area of Pritzwalk". Both regions are characterized by extremely high Bouguer gravity and positive magnetic field anomalies and were interpreted in terms of mafic intrusions (plutons) at depths of some 6 - 10 km. The high thermal maturity in the southern area of the Lower Saxony Basin, the CO2 - risk and missing reservour properties are being regarded as an aftermath of the intrusion of the Bramsche massif, which is supposed to have intruded into the crust in the Upper Cretaceous. The existence of a similar massive in the area of the "Pritzwalk high" (Mecklenburg/Brandenburg) has been doubted over the last decade: According to recent geophysical investigations the masses causing the strong positive anomaly are no longer assumed to arise from shallower depths but arise from the lower crust. Regarding the area of the positive gravity anomaly of Bramsche, its former interpretation was called into question on the base of to more recent findings: It was demonstrated that the level of maturities along boreholes is more likely to be explanined by an increased amount of burial with subsequent tectonic inversion and not due an intrusion. Additionally, vp/vs ratios of 1.72 do not point to a gabbroic body but more likely to a dolomite. If this instrusion in the suspected form never existed, the regional structural and thermal development of the southern rim of the Northwest German Basin would need to be judged differently. The existence of possible Mesozoic and Paleozoic gas reservoirs in the vicinity of the high would also need to be re-evaluated. The "Geotectonic Atlas of NW Germany" (BGR, Hannover) contains a unique collection of geoscientific information and a compilation of digital depth information representing both the structure and physical properties of a sedimentary basin. The compilation is based on data, experience and knowledge from long-standing hydrocarbon investigations in the NW German basin. Therfore, it offers the chance to foster interdisciplinary studies and the development of research and modelling with strong ties to model database concepts and modelling techniques. Using the data set provided by the atlas, it is possible to find answers to questions related to the evaluation of models for the evolution of the basin rims, and to 3D modelling of geological processes and structures. The questions that arise can be addresed without further time consuming and expensive data acquisition outside the laboratory.

对于德国西北部盆地的演化和现在的结构来说，仍然具有区域重要性的问题之一是所谓的“布拉姆舍地块”的存在或不存在，再往东则是“普利兹沃克地区的东埃尔比安地块”。这两个地区都具有极高的布格重力和正磁场异常，并被解释为大约6-10公里深处的镁铁质侵入体(深成岩体)。下萨克森盆地南部地区的高成熟度、二氧化碳风险和缺失的储集层被认为是布拉姆舍地块入侵的后果，该地块被认为在上白垩世侵入了地壳。在过去的十年里，在“普里兹瓦克高压”(梅克伦堡/勃兰登堡)地区是否存在类似的块体一直受到怀疑：根据最近的地球物理调查，引起强烈正异常的质量不再被认为来自较浅的深度，而是来自下地壳。关于布拉姆舍重力正异常的地区，其先前的解释受到了质疑，因为最近的发现表明，沿钻孔成熟度的水平更有可能是随着随后的构造反转而增加的埋藏量，而不是由于侵入作用。此外，1.72的Vp/VS比值并不指向辉长岩，而更有可能指向白云岩。如果这种可疑形式的注入从来不存在，那么德国西北部盆地南部边缘的区域构造和热发展将需要得到不同的判断。还需要重新评估隆起附近是否存在可能的中生界和古生界气藏。“德国西北部大地构造地图集”(汉诺威BGR)载有独特的地球科学信息集合和代表沉积盆地结构和物理性质的数字深度信息汇编。这份汇编是基于德国西北部盆地长期碳氢化合物调查的数据、经验和知识。因此，它提供了促进跨学科研究以及与模型数据库概念和建模技术紧密联系的研究和建模的发展的机会。利用地图集提供的数据集，有可能找到与盆地边缘演化模型的评价以及地质过程和结构的三维建模有关的问题的答案。出现的问题可以解决，而不需要在实验室外获得更多耗时和昂贵的数据。