IRTG-StRATEGy - Georesources

163-G 4.2

Anonymous — Fri, 25 Sep 2015 10:17:20 +0000

10|2018 – 09|2021

Magmatic-hydrothermal processes forming epithermal Sn-Ag ore deposits in NW Argentina

M.Sc. Malte StoltnowGFZ Potsdam P.D. Dr. Philipp WeisGFZ Potsdam Dr. Volker LüdersGFZ Potsdam apl. Prof. Dr. Uwe AltenbergerPotsdam University Dr. Robert TrumbullGFZ Potsdam Prof. Dr. Pablo CaffeJujuy National University (ARG)Raúl Becchio, Ph.D.Salta National University (ARG)Dr. Marcelo ArnosioSalta University (ARG)

The Puna Plateau in NW Argentina hosts a variety of economic Sn-Ag and Ag deposits which are believed to be analogues to the polymetallic epithermal deposits of the southern Bolivian Sn belt. However, while the Bolivian deposits have a clear association to Miocene magmatism, a direct connection to magmatic intrusions is lacking for the Argentinian deposits so far. Recent studies of fluid inclusions hosted in quartz and ore minerals from the giant Pirquitas deposit have revealed compelling evidence that the hydrothermal system was characterized by mixing of magmatic fluids and meteoric water. In the follow-up PhD project, we will extend fluid inclusion studies to new deep wells in the area of the Pirquitas deposit and to the Cinchillas deposit, which is also located in the Puna Plateau but has a different style of Ag mineralization. The PhD candidate will perform geochemical studies of Pb and S isotopic compositions and fluid inclusions in ore and gangue minerals (microthermometry, Raman spectroscopy, LA-ICPMS, noble gas isotopes). In addition, the candidate will use numerical modelling to resolve the magmatic-hydrothermal transition from an inferred porphyry system at depth to the epithermal regime at shallower levels, using the constraints obtained from data of the Pirquitas system.

10|2015 – 09|2018

Magmatic and hydrothermal processes in the Andean Cu-Au and Sn-Ag ore belts of NW Argentina

The Cenozoic central Andes host orogen-parallel belts of magmatic-related ore deposits with contrasting metal associations (Fe, Cu-Au, vs. polymetallic, Sn-Ag). This project will investigate the role of magmas vs. hydrothermal fluids in metal transport and metallogenesis. There a close linkages to projects G3.5 and G4.1. Besides the potential role of magma processes (differentiation, fluid saturation), other important factors to be studied are the roles of local basement composition and deformation for the metal enrichment, transport, and deposition (faults and shear zones – link to project 10). Both belts are located in an E-W region of 70-km width, and the mineralization and magmatism belong to the main metallogenic epoch in the S central Andes (12-15 Ma), so the geodynamic scenario can be considered invariable. We hypothesize that the different metal associations are controlled by different magma compositions, which depend on source characteristics in addition to the conditions of magma genesis and differentiation, especially oxygen fugacity and volatile contents. To test the roles of magma composition and hydrothermal fluids, the PhD candidate will combine standard geochemistry and petrology of ore and wall rocks with fluid-inclusion studies, melt inclusions and ore minerals with SIMS ion probe analysis, Raman spectroscopy, LA-ICPMS, IR microthermometry, and stable gas isotopes.

Working Package:

WP4 - Georesources

Temporal Process:

Intermediate

Dr. Louis DesanoisGFZ Potsdam Dr. Robert TrumbullGFZ Potsdam Dr. Volker LüdersGFZ Potsdam apl. Prof. Dr. Uwe AltenbergerPotsdam University Raúl Becchio, Ph.D.Salta National University (ARG)Prof. Dr. Pablo CaffeJujuy National University (ARG)

163-G 4.1

Anonymous — Fri, 25 Sep 2015 10:16:27 +0000

10|2018 – 09|2021

Magmatic processes, fluid-rock interaction and provenance of Nb-Ta and REE mineralizations in NW Argentina

M.Sc. Enrico RibackiUniversity of Potsdam apl. Prof. Dr. Uwe AltenbergerPotsdam University Dr. Robert TrumbullGFZ Potsdam Dr. Volker LüdersGFZ Potsdam Prof. Dr. Monica López de LuchiBuenos Aires University (ARG)Dr. Raúl LiraMuseum of Mineralogy Córdoba (ARG)Dr. Clara CisternaTucumán University (ARG)Dr. José Pablo LopezTucumán University (ARG)Raúl Becchio, Ph.D.Salta National University (ARG)

Deep-seated processes in the Andean crust, now exposed by tectonics and erosion in the foreland, are integral parts of the resource-forming systems under investigation. After recycling of continental crust by partial melting and magmatism, hydrothermal fluids of magmatic and/or meteoric origin are key agents for a range of processes that form and modify metallic ore deposits. This project will investigate a range of granite-pegmatite related rare earth element (REE) and Sn-Ta-Nb-Li mineralization types in the San Luis range of NW Argentina. The goals are to assess the relative influence of magma composition, particularly the S-type vs. A-type granite composition, in the metals enrichment, and to determine the role of fluids in mineralization. We will concentrate on well-characterised metamorphic complexes and their intruding granitoids of the San-Luis range (Eastern Sierras Pampeanas), where compositionally distinct pegmatites occur: predominantly intragranitic mostly Ordovician Nb-Y-F pegmatites related to water-poor and fluorine-rich melts and mostly Ordovician Li-Cs-Ta pegmatites related to water-rich peraluminous melts and emplaced either in the metamorphic complexes or in their intruding granitoids. These will be compared with similar occurrences further north in Sierras Pampeanas. A small but significant part of the work will follow the alteration of the NYF pegmatites to obtain proxies for provenance studies of critical elements (source to sink) and the research will also help constraining the sources of granite magmas and the role of the interplaying between recycling of continental crust and juvenile additions.

10|2015 – 09|2018

Provenance and transport of Sn (Nb-Ta) and REE from the pre-Andean crustal basement: primary mineralization and secondary enrichment processes

This project will investigate the primary source rocks for Sn (and Nb-Ta) and rare earth elements (REE) in the pre-Andean basement rocks (granites, pegmatites, metamorphic complexes) and the enrichment/mobilization processes related to chemical (hydrothermal alteration or weathering) and mechanical processes (ductile or brittle deformation in fractures and ductile shear zones). The investigation will focus on selected field occurrences of Palaeozoic granites, pegmatites, and their highly deformed metamorphic equivalents of the pre-Andean crustal basement, especially of the Salta Province. For the REE minerals especially (carbonates, phosphates, fluor-carbonates, oxides), there is substantial redistribution related to solubility-reprecipitation processes in the deep crust (e.g. lode deposits in shear zones) as well as surface adsorption in weathered exposures (e.g. heavy REE enrichment in clays: Longnan-type deposits). Because tin minerals and coltan (Nb-Ta ore) from pegmatite fields are commonly mined in alluvium (placers), it is critically important to understand how secondary processes (alteration, chemical and mechanical weathering) affect the criteria used for provenance identification. Therefore, the major aim of the project will be to analyse the origin and enrichment processes of the rare elements in primary (magmatic) as well as in secondary (fluid- and structurally controlled) environments. Emphasis will fall on studies in Salta province, because of the geological situation, including rare element pegmatites, and the direct links with project [G 2.2] working on the reactivation of fault zones and project [G 3.5], which addresses the role of basement composition for metal enrichment in near-surface volcano-tectonic complexes. Close collaboration with project [G 4.2] and the Argentine metallogenesis projects will extend the scope of investigation to places best suited to study the relevant processes (e.g., shear zones, alteration/weathering profiles, etc.). The research will combine modern techniques of mineralogical, microstructural and (isotope) geochemical analysis with field campaigns to examine key localities best suited to study the chemical and mechanical alteration of primary mineralization. The relevance of this study is in the field of mineral exploration primarily, i.e., for orogenic structurally-controlled REE deposits, and also for the growing field of provenance certification to control conflict ores.

Working Package:

WP4 - Georesources

Temporal Process:

Long Term

M.Sc. Melanie LorenzPotsdam University apl. Prof. Dr. Uwe AltenbergerPotsdam University Dr. Robert TrumbullGFZ Potsdam Prof. Dr. Roland OberhänsliPotsdam University Prof. Dr. Monica López de LuchiBuenos Aires University (ARG)Prof. Dr. Pablo CaffeJujuy National University (ARG)Raúl Becchio, Ph.D.Salta National University (ARG)

163-G 3.4

Anonymous — Fri, 25 Sep 2015 10:15:35 +0000

10|2018 – 09|2021

Testing long-term controls of sedimentary basin architecture in the broken foreland II

M.Sc. Michele VallatiUniversity of Potsdam Prof. Dr. Maria MuttiPotsdam University

Disparate and diachronous basin stratigraphies control petroleum prospects for both conventional and unconventional resources.. The spatial variability of the strata and associated depositional geometries exert a fundamental control on the migration of fluids and determine if hydrocarbons are trapped close to the area where they were generated.

In the first phase of this project, our team has focused on understanding basin-scale controls over the complex spatial distribution of depositional facies in the postrift basin in NW Argentina. The multi-scale stratigraphic architecture reflects the interplay of extrinsic and intrinsic processes, ranging from inherited topography, tectonics, climate and sediment supply and resulted in the superposition at different temporal scales of clastics and carbonates sedimentary facies.

We now plan to focus on quantitative outcrop studies over two comparative basins to better constrain the rules determining the interplay of clastic and carbonate sedimentation. Which roles play the different controls on the basin stratigraphic evolution? How do clastics and carbonates reflect climatic processes? The diverse depositional realms provide archives of the dominant climate dynamics. Carbonate deposition is the product of biogechemical processes induced by increased alkalinity and salinity in the shallow water setting. Do the characterisation and quantification of sedimentary 3D facies distribution in outcrops provide reliable analogues for exploration, at both reservoir and regional scales?

10|2015 – 09|2018

Testing long-term controls of sedimentary basin architecture in the broken foreland

The spatial architecture of sedimentary facies in a basin exert a fundamental control over the patterns of fluid flow and determines the regional distribution of possible reservoirs and seal units. The distribution of sedimentary facies can be predicted to some extent by sequence stratigraphic theories. These models offer a conceptual framework to extrapolate facies distribution at a regional scale in 2D, ranging from continental to basinal. However, as soon the scale of observation increases, these models are not able to represent the geological complexity and facies variability in a realistic way. Furthermore, these concepts are rarely applied in 3D. Field studies reveal much more complex facies mosaics and patterns than predicted by 2D-models. Here, we will characterize the 3D facies distribution and sedimentary architecture evolution of a post-rift basin at different temporal and spatial scales prior to its evolution as a foreland basin. More specifically, the goal is to model the above mentioned parameters by coupling integrative seismic data, petrographic investigations of well logs, and outcropping sedimentary successions. Specific attention will be given to sedimentary discontinuities that often point to noteworthy events or record significant modifications of the environmental conditions, but also have the potential to affect fluid flow behavior and to compartmentalize reservoirs. Petrographic and geochemical analyses will be used to identify environmental parameters and assess diagenetic overprint in various limestone intervals. The outstanding quality of the sedimentary successions of several subbasins of the Salta Group (Yacoraite Formation) in NE Argentina offers a fantastic natural laboratory to study spatial facies variability in a postrift basin. The integration of facies analysis and stratigraphic units together with petrographic and geochemical studies on their bounding unconformities will provide data to test the role of extrinsic and autocyclic controls (tectonic, climate and sediment supply, inherited topography) on the stratigraphic successions. Constrained by stratigraphic and sedimentological information from field, well-log, and seismic data, numerical forward modeling will provide a valuable tool for testing stratigraphic correlations and the geological hypotheses controlling their occurrence. We will employ numerical modeling (DIONISOS, Petrel) to explore hypotheses concerning their occurrence and spatial distribution. This project will thus contribute to characterizing and quantifying sedimentary 3D facies distribution in outcrops (analogs for subsurface exploration) at basin and reservoir scales and to evaluate controls over their vertical and lateral stratigraphic architecture.

Working Package:

WP3 - Basin Modeling

Temporal Process:

Long Term

M.Sc. Wera SchmidtPotsdam University Prof. Dr. Maria MuttiPotsdam University Prof. Dr. Claudia GalliJujuy National University (ARG)

163-G 3.1

Anonymous — Fri, 25 Sep 2015 10:13:20 +0000

10|2018 – 09|2021

Quantification of Central Andes growth and erosion in relation to sedimentation in the Neuquén and Colorado basins - a source-to-sink approach

Lic. Román FealGFZ Potsdam Dr. Robert OndrakGFZ Potsdam Prof. Dr. Matias GhiglioneBuenos Aires University (ARG)Prof. Dr. Laura GiambiagiCuyo National University (ARG)Prof. Manfred Strecker, Ph.D.Potsdam University

This project follows a source to sink approach relating Central Andes growth with sedimentation in Neuquén and Colorado basins. The working hypothesis is that tectonic mountain growth produces large volumes of eroded rocks and subsidence in the foreland basins that catches those sediments. While contractional tectonics accelerates subsidence rates of foreland basins, periods of neutral tectonics produce low to no accommodation space in the retroarc. On those cases, large portion of sediments will bypass the continent toward the offshore basins, therefore controlling overburden and petroleum generation. The idea is to compare the Central Andes (34°-42°SL) changing tectonics and exhumation rates - source region - with sedimentation rates and volumes of sediments in the Neuquén foreland basin to determine if there is an inverse correlation to the Colorado offshore basin - sink basins - for periods to be defined during data acquisition. In particular, we will test the hypothesis by calculating sedimentation rates in the Colorado offshore basin from available basin models. Sedimentation rates in the Neuquén basin and tectonic and exhumation in the Central Andes can be summarized from a plethora of publicly available data. We will study paradigmatic localities in the Neuquén basin to recognize the appearance of highly condensed stratigraphic sections representing periods of neutral tectonics. Lab analysis will be conducted in order to better constrain and characterize those periods of potential sediment bypass towards the offshore which is of significance for the evolution of the petroleum potential of the region. The project will also contribute to the partner projects [G 3.2] and [G 3.3] by providing data from the sedimentary cover of the region.

10|2015 – 09|2018

Tectono-stratigraphic evolution of the intermontane Salta basin and Chaco-Paraná foreland basin: characterization and evolution of petroleum potential

The evolution of the inter-mountain Salta basin is related to the evolution of the Central Andes. An intracontinental rift was formed by extensional processes and subsequently filled by up to 5500 m sediments from the Neocomian to the Paleogene intercalated by minor volumes of magmatic rocks. This complex constitutes the Salta group. Paleoenvironmental analysis reveals depositional history controlled by tectonic and climatic changes. Deformation of the basin began at the end of the Eocene and resulted in a rapid transition from a rift basin to a foreland basin filled by synorogenic continental deposits. The Chaco-Paraná Basin comprises the undeformed Chaco-Parana plain to the east, and the Subandes, Sierras Pampeanas, and the ranges of the Santa Barbara System to the west. The basin comprises >10 km of sediments spanning the Silurian to the Present. It is asymmetric, with a total stratigraphic thickness of Cenozoic rocks >7.5 km deposited at the western margin that thin eastward. Deformation of the Subandes and the Salta Basin developed since the Eo-Oligocene; and is characterized mainly by in-sequence, thin-skinned thrusting that includes ramp anticlines and passive roof duplexes separated by thrust faults and synclines, although Plio-Pleistocene out-offsequence thrusting has also been reported. The Subandes are home to several major gas discoveries during the last 20 years. The Chaco-Paraná foreland basin, as a frontier exploration area, has a high resource potential (some assessments attribute almost one third of Argentina’s total unconventional hydrocarbon potential to this basin), although exploration concepts are largely unproven. By combining 3D petroleum system modeling techniques with detailed source rock and petroleum-accumulation information, volumetric assessments of petroleum potential can be produced at different scales for basin wide assessments of the possible resource potential. We plan to investigate the evolution of the inter-mountain Salta basin and the Chaco-Parana Basin to deconvoluting its burial and thermal histories as well as source rock maturation, petroleum generation, migration, accumulation and leakage. A detailed basin modeling study is planned which integrates the tectono-stratigraphic evolution, timing of major unconformities, spatiotemporal migration of depocenters, source-rock occurrence and type to elucidate the hydrocarbon generation and migration history of this basin. Special focus will be put on the climatic and tectonic processes operating in the sediment source areas to determine the main variables and forcing conditions controlling the stratigraphic architecture and the distribution of source rocks. Within this context including all information available on the crustal evolution of the NW of Argentina is a pre-requisite. Especially the buildup of the Andes, and fault reactivation and thrusting along the basin margins are important factors in controlling both the burial as well as the maturation and petroleum migration histories. This project will provide an integrated and concise description of the evolution of Salta and Chaco-Parana basin petroleum systems. The project will cooperate closely with projects [G 3.3] and [G 3.4] to define boundary conditions for basin modeling and detailed description of the tectono-stratigraphic and sedimentary evolution of the basin.

Working Package:

WP3 - Basin Modeling

Temporal Process:

Long Term

Intermediate

Dr. Ricardo Ruiz MonroyGFZ Potsdam Dr. Robert OndrakGFZ Potsdam Prof. Dr. Magdalena Scheck-WenderothGFZ Potsdam Prof. Dr. Eduardo RosselloBuenos Aires University (ARG)Prof. Dr. Brian HorsfieldGFZ Potsdam