All posts by John C. Menzies

SWARM Tracks Oceanic Flow Magnetism

Remarkably the ESA Swarm satellite constellation data has yielded evidence of a very weak but not unsurprising magnetic field generated by the movement of planetary scale oceanic currents.  The signal strength is however exceedingly weak and being 20,000 times less than the lithospheric signature took four years of data to elucidate.

When salty ocean water flows through Earth’s magnetic field, an electric current is generated, and this, in turn, induces a magnetic signal.  However, the field generated by tides is tiny and extremely difficult to measure – but Swarm has done just this in remarkable detail. (see the above video).

Nils Olsen, from the Technical University of Denmark, said, “We have used Swarm to measure the magnetic signals of tides from the ocean surface to the seabed, which gives us a truly global picture of how the ocean flows at all depths – and this is new.

“Since oceans absorb heat from the air, tracking how this heat is being distributed and stored, particularly at depth, is important for understanding our changing climate.

“In addition, because this tidal magnetic signal also induces a weak magnetic response deep under the seabed, these results will be used to learn more about the electrical properties of Earth’s lithosphere and upper mantle.”

Read More

Olsen, N., D. Ravat, C. C. Finlay, and L. K. Kother
LCS-1: A high-resolution global model of the lithospheric magnetic field derived from CHAMP and Swarm satellite observations
Geophys. J. Int.211, 1461–1477, doi:10.1093/gji/ggx381 2017

Detailed Lithospheric Magnetics – 250 Metre Resolution

ESA has just released the most detail magnetic data on the lithosphere from its Swarm three satellite constellation.  Launched on 22 November 2013, Swarm is the fourth in a series of pioneering Earth Explorer research missions, following on from GOCE, SMOS and CryoSat. Is also ESA’s first constellation of satellites to advance our understanding of how Earth works.

This is the most detailed map ever of the tiny magnetic signals generated by Earth’s lithosphere. The map, a video of which is seen here.  The data is being used to understand more about Earth’s geological history, is thanks to four years’ of measurements from ESA’s trio of Swarm satellites, historical data from the German CHAMP satellite and observations from ships and aircraft.

Erwan Thebault from the University of Nantes in France said, “This is the highest resolution model of the lithospheric magnetic field ever produced.  “With a scale of 250 km, we can see structures in the crust like never before. And, we have gained even finer detail in some parts of the crust, such as beneath Australia, where measurements from aircraft have mapped at resolution of 50 km.

“This combined use of satellite and near-surface measurements gives us a new understanding of the crust beneath our feet, and will be of enormous value to science.”

Map of field vertical component Z, at the Earth’s surface from the LCS-1 model for spherical harmonic degrees n-16-185. Green lines are isochrones.

Most of Earth’s magnetic field is generated deep within the outer core by an ocean of superheated, swirling liquid iron, but there are also much weaker sources of magnetism. The Swarm constellation has been used to yield some discoveries about these more elusive signals, such as that from Earth’s lithosphere. A small fraction of the magnetic field comes from magnetised rocks in the upper lithosphere, which includes Earth’s rigid crust and upper mantle. This lithospheric magnetic field is very weak and therefore difficult to detect from space. As new oceanic crust is created through volcanic activity, iron-rich minerals in the upwelling magma are oriented to magnetic north at the time and solidified as the magma cools. Since magnetic poles flip back and forth over time, the solidified magma due to mantle upwelling at mid-oceanic ridges forms magnetic ‘stripes’ on the seafloor which provide a record of Earth’s magnetic history. These magnetic imprints on the ocean floor can be used as a sort of time machine, allowing past field changes to be reconstructed and showing the movement of tectonic plates from hundreds of million years ago until the present day.

More: 

ESA Swarm Overview

Swarm Press Release

 

Mt Semeru Volcano Trek – YOU Are Invited

Mt Semeru -Indonesia (Courtesy Indo Trekkers)

I am planning a trek up Java’s highest (and active) volcano, Mt Semeru at 3,676m ASL.  The trek will start in Jakarta with flights to Malang and then vehicles to the start of the trek.   Schedule:

  • Arrive Jakarat May 6th
  • Depart to Malang May 7th
  • Return to Malang and Jakarta May11th.

Cost including all accomodation from 6th through the 11th inclusive, including 2 nights in Jakarta and two dinners which will include presentations from local geologists, transfers, all meals (dedicated camp cook) and personal porter.  A data package on the geology and volcanology of East Java will be provided in paper and GIS formats prior to departure.  Cost includes . COST:  US$1,100

This is a demanding trek, no climbing skills required however.  Please message us in the event that you wish to participate. Does not include travel/medical insurance coverage.  You will be required to show proof of coverage and execute a waiver before participation.

First Thermogenic Oil Seeps Discovered Onshore Jamaica

The recent discovery of two thermogenic oil seeps 70 km apart onshore Jamaica, suggests that a previously unrecognised hydrocarbon system may well be present.

Windsor Gas Seep

A natural gas seep at St Ann, Windsor, in northern  Jamaica is a well-known tourist attraction and money earner for locals, offering amongst other things, its healing properties (hey, whatever does it for you man!). These recent discoveries are the first reported oil seeps.

Chris Machette-Downes visited the seep and  reported:

The seep is of dry gas and is guarded enthusiastically by a local Rastafarian. My attempts to sample the gas in 2006 were met with some resistance as using a gas syringes in the sacred spring was considered offensive until some Jamaican dollars were presented. The gas proved to be very dry, almost pure Methane, but with an isotopic signature that suggests that it is thermogenic in origin. The origin is unknown, but a Cretaceous or older source is indicated. The St Ann’s Great River Inlier is one of the 26 Cretaceous inliers that occur on the Island in an otherwise Tertiary setting.

Jamaica Oil and Gas Potential

The JEBCO Alliance in 2004 undertook a multiclient study and reported that  of the 11 wells drilled in Jamaica, all but one encountered oil and gas shows.  They identified three petroleum systems in the data with the most important being a middle Eocene pro-delat source.  In the offshore Walton #1 well the middle Eocene occupied a 700 metre interval.  JEBCO defined reservoir objectives within the middle Eocene, delta-associated sequence, reef sequences and detrital products.  Assuming a 50% fill of the mapped carbonate targets would imply potential for 2.8 BBO or 10.6 Tcf.

The Windsor #1 well was drilled in northern Jamaica near the St Ann gas seep and encountered oils similar to others in the Caribbean Region.

Remarkably, the three broad elements that comprise the essence of the Caribbean plate (the Lower Nicaraguan Rise, or Siuna Terrane; the Upper Nicaraguan Rise, or Chortis; and part of the Great Caribbean Arc or northern periphery of the Caribbean plate or platelets) can also be identified though petroleum geochemistry. Windsor #1 well in the north of the island was drilled in a terrain that has strong affinities with the geology of the Yucatan in Mexico. If one compares the oil fingerprint, using gas chromatography-mass spectrometry and stable isotope ratio distributions, there is a near identical match with the Belmopan oil found in Belize, 1,000 km to the west. The match is so close that it is as if the Belmopan field has been cut in two, with one portion perhaps residing on the North Coast of Jamaica in what is called the North Coast Block.  Chris Machette-Downes

Comparison of oils from Windsor #1, Jamaica, a Belmopan field oil from Belize and the Smackover Formation in Arkansas Image After Machette-Downes, C., Jebco Alliance 2004
Seep Sampling Program and Results

CGG GeoConsulting and the Petroleum Corporation of Jamaica (PCJ) have announced the discovery of two independent live oil seeps from different parts of the island of Jamaica. This significant find marks the first documented occurrence of ‘live’, or flowing, oil from onshore Jamaica and will be of particular interest to oil explorationists focused on Central America and the Caribbean.

Live oil seeps in Jamaica

The oil seeps were found during fieldwork for a recently completed multi-client Robertson Study (Red Book) of the petroleum potential of on- and offshore Jamaica entitled ‘Petroleum Geological Evaluation of Jamaica’ made jointly by CGG GeoConsulting and PCJ. Subsequent detailed geochemical analyses confirmed the oil seeps originate from two separate Cretaceous source rocks. These results are included within the study, which gives a detailed account of the petroleum geology of this frontier region of the Caribbean. It comprises over 1,300 new geochemical, biostratigraphic and sedimentological analyses of over 800 individual outcrop, well, corehole and seep samples collected from Jamaica.

Jamaica and its offshore basins remain relatively underexplored. Oil or gas shows have been seen in ten of the eleven exploration wells drilled to date. The discovery of these seeps indicates the presence of working petroleum systems on the island that are generating and expelling liquid hydrocarbons to the surface. The Robertson Study offers a valuable tool for oil explorationists to quickly become familiar with the geology of Jamaica and is available for purchase from CGG.

CGG sampling live oil seep, Jamaica

Sophie Zurquiyah, Senior Executive Vice President, Geology, Geophysics & Reservoir, CGG, said: “This exciting discovery of live oil onshore Jamaica, based on our joint study with PCJ, builds a strong case for the island as an attractive region for future oil exploration within the Caribbean. The insights and promising outcome of the study demonstrate the value that CGG’s broad geoscience expertise combined with the integration of field geology, laboratory analyses and seismic interpretation can bring for high-grading frontier regions for future oil exploration.”

Original Article

Morgan Stanley predicting lithium carbonate prices to fall by 45% to 2020

Morgan Stanley report today that they expect lithium carbonate prices to drop from the current level of US$ 13,375/t to US$ 7,030/t by 2020.  This is far lower than the consensus view after lithium prices surged 100% in the last 2 years.

Substantial supply increases are driving their forecast, with Morgan Stanley reporting that the largest producers in Chile are planning on adding 500,000 tonnes per year in new mine supply by 2025.  This supply would swamp the anticipated growth in demand from battery production.  Indeed Morgan Stanley predict that the lithium market will go into surplus in 2019… and stay there.

The firm has downgraded two of the largest producers, Albemarle Corporation (NYSE: ALB) and Sociedad Quimica y Minera S.A. (SQM: NYSE SQM)  which are planning to bring an additional 200,000 tonnes of lithium on stream by 2025.  This will cement the position of Chile as the largest global producer with a  >30% share.

Most of the lithium hopefuls listed on western stock-exchanges have used lithium carbonate prices in the range of US$11,000 and 13,500/t in economic studies and the majority of these projects would struggle if prices were to tumble.  Given the rush to lithium of recent times and the nature of commodity markets we suspect that Morgan Stanley are likely correct.  Even a dramatic increase in market penetration for electric cars (which now seems increasingly unlikely given the growing trend away from government subsidies) would do little to change the supply demand dynamic in the coming few years unless the fall in price is sufficiently steep as to stop or delay some of the larger projects now being contemplated.  Now that is always a possibility.

An exception may be spodumene producers like Pilbara Minerals Limited (ASX: PLS) which showed a >50% return on investment in a planned expansion at a spodumene price of US$550/t, a 60% discount to the current spot.

Drillhole cross-section Pilgangoora lithium mine

 

 

Institutional Investors led the way in proxy fights in 2017 and won!

Canadian law firm Fasken Martineau DuMoulin LLP has released its as always engaging review of proxy contests in Canada during 2017.

A proxy fight is an unfriendly contest for the control of in this case, a public listed company.  Proxy fights usually occur when shareholders become unhappy with management’s behaviour (corporate governance) or where economic outcomes are disappointing and generally involve disputes over directorships and management positions.

The disaffected group, sometimes a corporate activist, will solicit the proxies of shareholders via a proxy solicitation.  A proxy allows for an individual or institution to become the shareholders authorised representative.

Incumbent directors and management have a number of distinct advantages over the disaffected shareholder group.  They have access to the corporate treasury and can use it in a largely unrestricted manner, they can hire very expensive proxy solicitation firms, can engage in disparaging public relations campaigns though their existing public relations and shareholder list channels and lastly they can rely on the corporations law requirements to easily disqualify entire actions or individual proxies.  Boards can simply ignore the actions of disaffected groups who then must rely on the courts to seek remedy.

I have been involved in a number of proxy battles.  I have initiated and managed two and actively participated in a  third, all of which were  resounding successes for the dissidents.  A proxy fight should not be considered lightly,  it can be very public, is time-consuming and expensive and outcomes can be uncertain.  

The Fasken study concludes:

The number of proxy fights is about the same for the last three years, 2015-2017

75% of proxy contests targeted small capitalisation companies
Unlike 2016, when management dominated and largely lost,  institutional investors dominated the proxy contests in Canada during 2017 and won

If you get the opportunity attend the Fasken lectures at their offices in Toronto during the 2018 PDAC.   They were most informative in 2017.  Contact them here.

Resources

Ethical boardroom Article
How do proxy fights work
Typical proxy solicitation firm
Harvard Law School Library  – Proxy fights

We are Back – Blame the SQuirreL

https://flic.kr/p/6jnhP8
An eastern fox squirrel. (Photo: Dawn/flickr)

Why am I always getting the Blame.  I had nothing to do with the lack of posts on this Blog I was far too busy with gathering fat-rich nuts, defending my territory and finding a mate before the winter.  Nope nothing to do with me.

OK  – it was not the Squirrel but the SQL  – our bad!

This is the culprit, a corrupt SQL file that did not allow any posts! Nothing to do with Squirrels as such.

A vexing little corruption that took the good people at Urban Design in Phonm Penh a day to resolve.  I strongly recommend Urban Design Studio for innovative and unique graphic and website designs.  From simple (!) logo design, to entire branding campaigns and website development, this team is exceptionally professional and cost competitive.

Urban Design Studio -Strongly Recommended for your corporate and website designs.

You can contact Urban Design Here.  Ask for Mark Lind or Sreychen Sok.

Now that we are back online –  its time to publish some materials.  There are a few projects that are evolving including a study of the relationship between CFCs and ozone, an analysis of the reported Fukushima radiation levels and releases and much more.

3D Animations – Recsk Cu-Au Deposits, Hungary

Following the publication of the paper (noted below) on the epithermal portion of the Recsk metallogenic system in Hungary here are 3D models from the entirely concealed Cu-Au mineralized intrusive bodies and related Cu-Au skarns and outbound Zn-Pb replacement bodies.

Ore Mineralogy and Fluid Inclusion Constraints on the Temporal and Spatial Evolution of a High-Sulfidation Epithermal Cu-Au-Ag Deposit in the Recsk Ore Complex, Hungary

video
play-sharp-fill

A 3D fly-though of the Recsk Cu-Au deposit showing the drilling, channel samples and interpolated copper grade shells.  A full set of 100 metre spaced section steps through the deposit from north to south over several kilometres.

video
play-sharp-fill

A section through the Recsk deposit with drilling and copper grade shells.  The section is 200 metres thick and the 0.3% grade shell is 800 metres high and 1,000 metres wide.  The Cu-Au skarn mineralisation can be seen dipping gently away from the large intrusive body.  The intrusion is open at depth below 1,200 metres. The top of the 10.3% copper grade shell is approximately 400 metres below the surface.

This 3D Model is based upon 156,000 metres of surface drilling over 35 square kilometres, 9km of underground development and 90,000 metres of underground drilling.

The Recsk metallogenic centre consists of a deep and entirely preserved mineralised intrusive and intermediate and high sulphidation epithermal deposits exposed at surface.  The epithermal deposits are located close to the apex of the intrusion.  The diorite intrusion is hosted by a thick sequence of Eocene carbonates unconformably overlain by a volcanic edifice.  Adjacent to the intrusion the carbonates host thick Cu-Au skarns.  Outbound of the Cu-Au skarns, Zn-Pb replacement bodies have been intersected in wide spaced drillholes.  In this video we present a section through the deposit.  The 3D model is based upon 156,000 metres of drilling from surface, 9 km of underground sampling on the 700 and 900 metre levels and 89,000 metres of underground diamond drilling.  Underground access was provided by two 1,200 metre deep shafts, 2,000 metres apart.  The shafts have an 8 metre internal diameter and are concrete lined.  No mining has been undertaken at the deeper Recsk mineralisation aside from bulk metallurgical sampling.

 

 

A Ketogenic Diet Extends Longevity and Healthspan

A very interesting study in Cell Metabolism demonstrates that energy-controlled high-fat low carbohydrate diets are not detrimental to health, but rather a ketogenic diet (with a very high proportion of fat) extends lifespan and slows age-related decline in physiological function in mice.

Graphical abstract. Study shows increased longevity, improved motor function and memory in aging mice and no weight gain where calorific intake is managed.

For information on ketogenic diets in humans

Download the Full Paper

Calorie restriction (CR) has long been shown to increase longevity in animal models.  However longitudinal studies in humans are not possible.  The exact mechanism for contributing to increased longevity in CR animal models remains unresolved however it has long been recognised that CR induces a shift from carbohydrate to fat metabolism.  Low carbohydrate diets (LCD) have been shown to induce a shift from carbohydrate towards fatty acid oxidation metabolism.

In this paper the authors have studied the most extreme LCD, the ketogenic diet in an animal model.  They studied mice by strictly regulating their diet and generated three cohorts:  LCD group fed 70% of their kcal as fat, a KD group fed 89% of their kcal as fat and a control group fed 65% of their kcal as carbohydrate.

The results of the study have confirm earlier studies which showed that a KD promoted an anti-inflammatory metabolic state with elevated blood ketone levels comparable to CR.  This study however goes well beyond previous studies following the population from birth to post-mortem. The primary objective of this study was the evaluate the influence of LCD and KD on longevity and health-markers in mice.

The results of this study include:

  • The results clearly demonstrate that lifespan is increased in mice consuming a KD  when a feeding strategy is followed that mitigates weight gain in adult mice.  It is often assumed that a high-fat diet will shorten life expectancy  however, this study indicate that a calorie-controlled LCD started in middle-aged mice does not have a negative impact on aging.  Further evidence does not support the idea that level of protein is primarily responsible for the increased longevity;
  • This study shows that a KD slows cognitive decline and preserves motor function in aging mice.  KD maximizes and preserves forelimb grip strength with age. Respiratory quotient was decreased by an LCD or a KD compared to a control diet.
  • KD mice showed glucose intolerance however insulin sensitivity after a 4 hr fast was enhanced by a KD if compared to the LCD, indicating that insulin signalling is functioning normally in mice fed a KD
  • Ketones would appear to positively impact muscle homeostasis and may play an important role as neuro-protective signalling molecules
  • The level of acetylated p53, a key tumour suppressor protein, was 10-fold higher in liver after 1 month on a KD and as a likely consequence, incidence of tumours at time of death, particularly histiocytic sarcoma, was decreased with a KD

For information on ketogenic diets in humans

Download the Full Paper

A Ketogenic Diet Extends Longevity and Healthspan in Adult Mice

Megan N. Roberts, Marita A. Wallace, Alexey A. Tomilov, Zeyu Zhou, George R. Marcotte, Dianna Tran, Gabriella Perez, Elena Gutierrez-Casado, Shinichiro Koike, Trina A. Knotts, Denise M. Imai,
Stephen M. Griffey, Kyoungmi Kim, Kevork Hagopian, Fawaz G. Haj,
Keith Baar, Gino A. Cortopassi, Jon J. Ramsey, Jose Alberto Lopez-Dominguez

ABSTRACT

Calorie restriction, without malnutrition, has been shown to increase lifespan and is associated with a shift away from glycolysis toward beta-oxidation. The objective of this study was to mimic this meta­bolic shift using low-carbohydrate diets and to deter­mine the influence of these diets on longevity and healthspan in mice. C57BL/6 mice were assigned to a ketogenic, low-carbohydrate, or control diet at 12 months of age and were either allowed to live their natural lifespan or tested for physiological func­tion after 1 or 14 months of dietary intervention. The ketogenic diet (KD) significantly increased median lifespan and survival compared to controls. In aged mice, only those consuming a KD displayed preser­vation of physiological function. The KD increased protein acetylation levels and regulated mTORC1 signaling in a tissue-dependent manner. This study demonstrates that a KD extends longevity and healthspan in mice.

The Evolution of the High-Sulfidation Epithermal Cu-Au-Ag Recsk Deposit in Hungary

This paper in the latest edition of Economic Geology by Ágnes Takács,  Ferenc Molnár,  Judit Turi,  Aberra Mogessie,
 John C. Menzies examines the evolution of the outcropping epithermal mineralisation at Recsk in Hungary.  The epithermal deposit sits close to the apex of a large intrusive body which does not outcrop but was defined by systematic diamond drilling to 1,200 metres over a 35km2 area.  While the outcropping HS epithermal mineralisation was sporadically mined, the unexposed porphyry and related skarns and replacement bodies was not exploited.  The deeper mineralisation has been evaluated with 156,000 metres of drilling from surface and 90,000 metres of diamond drilling from underground development on two levels accessible via two 1200 metre deep, 8 metre internal diameter concrete lined shafts.  There is considerable potential for the discovery of both additional mineralised bodies (this paper suggests an as yet undiscovered intrusive to the north of the known body) and extensive skarn mineralisation around the periphery of the intrusion.

HIGHLIGHTS

  • Largely uneroded porphyry-skarn-epithermal metallogenic system of Paleogene age in a subduction-related magmatic hydrothermal environment within the Alpine-Carpathian region
  • Paleogene diorite intrusions and Mesozoic carbonate and silicic shale host rocks contain Cu(-Mo-Au)-porphyry, Cu-Zn(-Fe) skarn, and metasomatic Pb-Zn (carbonate replacement) mineralization from ~400- to at least 1,200-m depth below the surface.
  • Three stages of ore formation
  • Stage 1:  Ore deposition in the porphyry-epithermal transition zone (pyrite, chalcopyrite, tennantite-tetrahedrite, galena, sphalerite; 260°–230°C; logfs2~–11 to –9; logfTe2~ –19 to –14)
  • Stage 2: High- and very high sulfidation state mineralization from tellurium-saturated fluids (e.g., enargite, luzonite, pyrite, native gold, calaverite, hessite, aikinite-bismuthinite; 240°–170°C; logfS2~–7 to –11; logfTe2~–14.8 to –10.5)
  • Stage 3: Late-stage mineralization from tellurium-oversaturated, locally oxidized fluids of an intermediate-sulfidation state (e.g., tennantite-goldfieldite, pyrite, hessite, petzite, native tellurium, kawa-zulite; logfs2~–11 to –15.5; logfTe2 ≥ –10.5)
Geology and mineralization of the Recsk ore complex. (A) Combined geological and topographical map of the studied area. The geology is modified after Pantó (1952) and the tectonics are modified after Rozlozsnik (1939) and Molnár et al. (2008). (B) Topographical map with contoured thickness of the subvolcanic diorite intrusion, mineralized bodies, and historical adits. The locations of high-sulfidation epithermal orebodies are based on the map from Földessy et al. (2008a), and the thicknesses of diorite intrusive stocks intercepted in the 1,200-m-deep drill holes completed in the area are from Baksa (1975). Abbreviations: HS = high-sulfidation, IS = intermediate-sulfidation.
Estimated Ore Resources for the Recsk Ore Complex (data from Fodor et al., 1998; Kontsek et al., 2006)

ABSTRACT

The Recsk ore complex is an example of a largely uneroded porphyry-skarn-epithermal metallogenic system in a subduction-related magmatic hydrothermal environment within the Alpine-Carpathian region. Paleogene diorite intrusions and Mesozoic carbonate and silicic shale host rocks contain Cu(-Mo-Au)-porphyry, Cu-Zn(-Fe) skarn, and metasomatic Pb-Zn (carbonate replacement) mineralization from ~400- to at least 1,200-m depth below the surface. The Mesozoic sedimentary rocks are unconformably overlain by a stratovolcanic sequence of andesitic to dacitic composition that hosts epithermal Cu-Au-Ag and Au-Ag-Pb-Zn mineralization. This study focuses on the shallow high-sulfidation epithermal Cu-Au-Ag mineralization exposed and exploited on Lahóca Hill. The ore mineralogy combined with the microthermometry of quartz- and enargite-hosted fluid inclusions suggest three stages of the ore formation: (1) early-stage ore deposition in the porphyry-epithermal transition zone (pyrite, chalcopyrite, tennantite-tetrahedrite, galena, sphalerite; 260°–230°C; logfs2~–11 to –9; logfTe2~ –19 to –14); (2) high- and very high sulfidation state mineralization from tellurium-saturated fluids (e.g., enargite, luzonite, pyrite, native gold, calaverite, hessite, aikinite-bismuthinite; 240°–170°C; logfS2~–7 to –11; logfTe2~–14.8 to –10.5); and (3) late-stage mineralization from tellurium-oversaturated, locally oxidized fluids of an intermediate-sulfidation state (e.g., tennantite-goldfieldite, pyrite, hessite, petzite, native tellurium, kawa-zulite; logfs2~–11 to –15.5; logfTe2 ≥ –10.5). The observed differences in ore mineral assemblages and trace element compositions of sulfides reflect the temporal and spatial evolution of the ore-forming hydrothermal system. Results of fluid inclusion microthermometry performed by conventional and infrared-light microscopy and Raman spectroscopic studies support a model with lateral flow of shallow hydrothermal fluids. The spatial distribution of paleotemperature data within the high-sulfidation portion of the ore deposit suggests that the fluid flow system is offset from the closest apex of the related mineralized porphyry stock. This could be due to structural complexity related to syn- to postmineralization tectonism and/or due to the presence of an undiscovered intrusion to the north of the known mineralized stock.

Original Research here

Ore minerals and textures of the Lejtakna high-sulfidation epithermal mineralization. (A) Stage 1 assemblage sphalerite within enargite. (B) Intergrowth of stage 2 enargite and luzonite (crossed polars). (C) Resorbed textured and partially replaced enargite crystal fragments in a tennantite-tetrahedrite matrix. (D) Stage 3 assemblage from the central part of the Lejtakna deposit with textures not observed at Lahóca Hill. (E) Framboidal pyrite cemented by galena. (F) Collomorphic pyrite-chalcopyrite assemblage with tennantite-tetrahedrite and sphalerite. (G) Collomorphic pyrite-chalcopyrite-galena assemblage in barite. (H) Intergrowth of pyrite and galena crystals. (I) Planar and cross-laminated layers consisting of pyrite and quartz. Note: Samples E through I are from the shallowest parts of the Lejtanka deposit.