We currently have 4 ongoing projects in Spain. The field localities are at A.) Ribera Alta, B.) Orduna, and C.) Gernicka. Locations are shown in the northern part of Spain on the Google Earth image below.  Information pertaining to the three field areas are provided in the following sections.

1. One current project entails measurement of paleo-thermal halo dimensions around a structurally shallow diapir in the western Pyrenees of northern Spain (Nick Downs, former M.S. student advisee of Andrew Hanson). For this project, we sampled Miocene strata within a single geologic unit along transects that extend from near the diapir's margin out into adjacent areas that are presumed to have not been effected by the high heat flux within the diapir. The diapir is located in the Ribera Alta area, is oval in shape, and approximately 2.5 km wide and 4.75 km long. We used vitrinite reflectance to constrain the paleo-temperatures and our initial results are shown in the following figure. Because this diapir is structurally shallow, our hypothesis was that vitrinite values would be elevated adjacent to the diapir compared to values derived from samples that are more than 10 km away from the diapir. The diapir is shown in pink on the geologic map which is overlain on the Google Earth image of the area in the following figure. The vitrinite data (red dots on the map) did not support our hypothesis, instead we found suppressed vitrinite values near the eastern margin of the diaper with higher values as you move away from the diaper; vitrinite values on the western margin of the diapir are higher, possibly related to the proximity to a significant structural front further to the west or to ongoing fluid flow that is localized along the western margin of the diapir. Based on current data, we interpret a suppressed anomaly that is about 2x the diapirs diameter along its eastern margin.

   ONGOING WORK

   We collected additional mudstone samples during our 2012 field season in order to better constrain thermal variation along the eastern transect (shown as blue dots). These analyses are in progress.

   
   

2. Our second focus area in the Pyrenees is around the diapir located at Orduna. Here the diapir is roughly circular with an average diameter of about 3.5 km. Strata surrounding the diapir are Coniacian in age, and this diapir represents a deeper structural level than the one at Ribera Alta. Similar to our strategy at Ribera Alta, we sampled around the diapir as well as along transects within the same geologic unit as they extend many kilometers away from the diapir. Our hypothesis pertaining to the Orduna diapir was that values near the diapir will be suppressed compared to those measured farther away from the diapir. This project was part of Nick Downs' thesis project. The diapir is shown in pink on the geologic map which is overlain on the Google Earth image of the area in the following figure.

   
   
   
   
3. Our third focus area in the Pyrenees is from an area east of Gernicka near the northern coast of Spain. At this locality, we were able to sample Albian strata that crop out both above and below a weld that resulted from evacuation of an allochthonous salt body. Our hypothesis is that sub-salt samples will have depressed vitrinite values and those from supra-salt will be elevated. This project was also part of Nick Downs' thesis project. Remnant salt is shown in pink on the geologic map which is overlain on the Google Earth image of the area in the following figure. Samples to the north of the weld are supra-salt, whereas those south of the weld are sub-salt. The data show that the maturity values are lower near the diapir root and that they become more elevated as you move away from the diapir despite being taken from progressively higher stratigraphic intervals. We interpret a slight change in thermal maturity between the samples from existing transect data based on whether they are sub-salt vs supra-salt (white circles on following map) but the data are limited so we’ve collected additional samples (red circles) from this area in order to more fully characterize the thermal story.
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5. The Bakio diapir extends from onshore to offshore and is surrounded by deeper water latest Albian/early Aptian to Cenozoic siliciclastic turbidites, some of which contain carbonate breccia blocks. We observed cleavage, calcite filled veins with slickenlines, and small faults near the margins of this diapir. Our goal at Bakio is to document very near diapir thermal conditions.

   
   
   

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