Tectonic controls on fault zone flow pathways in the Rio Grande rift, New Mexico, USA

Abstract

We assessed tectonic controls on the spatial and temporal distribution of fault zone flow pathways in the Rio Grande rift (New Mexico, USA) by using fault zone calcite cements as a geochemical record of syntectonic fluid flow. Cement d 18 O, d 13 C, and 87 Sr/ 86 Sr values indicate that older, large-displacement master and basin-margin faults were cemented by more isotopically evolved basinal brines than younger intrabasin faults. These data suggest that diagenetic fluids in basin-bounding faults equilibrated predominantly with downdip Paleozoic carbonates. In contrast, intrabasin faults transmitted fluids from shallow stratigraphic sources. This pattern of flow pathways is linked to the systematic distribution of sediments and faults that record rift evolution, which dictated spatial and temporal variations in fault zone architecture and permeability structure. Our results indicate that the depths from which fluids can be transported in active rift basins ultimately depend on both tectonically mediated variations in the grain size of syntectonic sediments entrained in fault damage zones and fault displacement magnitude.

Reading a 400,000-year record of earthquake frequency for an intraplate fault

“…This comparison shows no correlation between the timing of vein formation and glacial/interglacial cycles. This result is consistent with previous work showing that calcite in the Loma Blanca fault zone was controlled by upward migrating, endogenic fluids rather than shallow, meteorically derived fluids (20,29).…”

“…Alternatively, postseismic increases in the least compressive horizontal stress around normal faults may promote pore collapse at depth, also driving the upward migration of fluids (25,28). Although the exact mechanism responsible for fluid migration and vein formation in the Loma Blanca fault zone remains unknown, previous research has shown that fluids precipitating calcite cements in this and other basin-margin faults of the Rio Grande rift likely originated from several kilometers beneath the current exposures (29). Because postseismic fluid flow has been shown to begin as little as a few days after normal fault rupture (25), the timing of calcite precipitation is a reasonable proxy for the timing of individual earthquakes.…”

Spatiotemporal history of fault–fluid interaction in the Hurricane fault, western USA

“…To the east of the Colorado Plateau, along the Rio Grande rift, exhumed basin-bounding and intra-basin normal faults preserve a record of syntectonic changes to fault zone permeability due to groundwater flow and mineralization in poorly lithified siliciclastic sediments (Mozley and Goodwin, 1995;Heynekamp et al, 1999;Caine and Minor, 2009;Williams et al, 2015). These studies document progressive fluid flow localized along faults due to deformation and carbonate cementation that result in the compartmentalization of basin-hosted aquifers.…”

Influence of basement rocks on fluid evolution during multiphase deformation: the example of the Estamariu thrust in the Pyrenean Axial Zone

“…However, in its southwestern termination, it juxtaposes the Devonian Rueda Formation against the Stephano-Permian Erill Castell Formation. The Erill Castell Formation developed during the late to post-orogenic collapse of the Variscan belt (Lago et al, 2004;Martí, 1991Martí, , 1996Ziegler, 1988), evidencing the reactivation of the Estamariu thrust during the Alpine orogeny (Poblet, 1991;Saura, 2004). Rocks cropping out around the Estamariu thrust and the Cerc basin range from upper Ordovician to Miocene (Fig.…”