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"

对于德国西北部盆地的演化和现在的结构来说，一个尚未解决的区域性重要问题是所谓的“布拉姆切地块”的存在与否，以及更往东的“普里茨瓦克地区的东埃尔比亚地块”。这两个地区的特征都是极高的布格重力和正磁场异常，并根据6 - 10公里深度的基性侵入（岩体）来解释。下萨克森盆地南部地区的高热成熟度、CO2风险和储层缺失被认为是Bramsche地块侵入的结果，该地块在上白垩世侵入地壳。在过去的十年里，在“普里茨沃克高地”（梅克伦堡/勃兰登堡）地区是否存在一个类似的地块一直受到怀疑：根据最近的地球物理调查，造成强烈正异常的地块不再被认为来自较浅的深度，而是来自较低的地壳。关于Bramsche的正重力异常区域，根据最近的发现，对其先前的解释提出了质疑：研究表明，钻孔的成熟度水平更可能是由随后的构造反转增加的埋藏量来解释的，而不是由于入侵。此外，1.72的vp/vs比值并不表明是辉长岩，而更有可能是白云岩。如果这种疑似形式的侵入物从未存在过，则需要对德国西北部盆地南缘的区域构造和热发育进行不同的判断。在隆起附近是否存在可能的中生代和古生代气藏也需要重新评估。“德国西北部大地构造地图集”（BGR, Hannover）包含独特的地球科学信息集合和数字深度信息汇编，代表了沉积盆地的结构和物理性质。该汇编基于德国西北部盆地长期油气勘探的数据、经验和知识。因此，它提供了促进跨学科研究的机会，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。利用地图集提供的数据集，可以找到与盆地边缘演化模型评估以及地质过程和构造三维建模有关的问题的答案。出现的问题可以解决，而无需在实验室之外进一步耗时和昂贵的数据采集。

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.