New SH - For Love of the GameI started a position several months ago in GV. I have been looking closer to home for companies to invest in, Nevada is a few hours drive and a great place to be speculating. I will be on the Railroad property on my birthday, July 25th. I cannot think of a better way to spend my 62nd, boots on the ground, asking geological questions that have come up during my DD, looking at core to get a view into the subsurface... My experience as a gold mine geologist included a Nevada/California (Hart) deposit that was mineralized in hydrothermal breccias, in Miocene rhyolite. Not quite like Railroad, but hydrothermal breccias and hydrothermal alteration patterns have similar characteristics regardless of rock-type. The presence of collapse breccias in last years Gold Standard Ventures drilling suggests that the Carlin Trend breccia suite is present on the property. The collapse breccias are typically at the bottom of the Carlin breccia suite, with high-grade zones usually occupying the crackle breccia at the top of the breccia stack.
This is an exciting time for this company. I have talked with Dave Mathewson and Jonathan Awde. They are working with a better view of the subsurface from the 2010 drilling, this current drill campaign has focused targets, exciting! I look forward to digging deeper myself, a visit to the surrounding countryside will set the framework for me.
I will post more about Railroad and point to the geologic literature and my observations of the geology that lead me to invest in Gold Standard Ventures.
I am a shareholder, Not investment Advice DYODD
A paper worth reviewing is;
https://econgeol.geoscienceworld.org/cgi/content/abstract/101/2/347
2006 SEG
Igneous Geology of the Carlin Trend, Nevada: Development of the
Eocene Plutonic Complex and Significance for Carlin-Type Gold Deposits
MICHAEL W. RESSEL*
Department of Geological Sciences, University of Nevada, Reno, Nevada 89557-0088
AND CHRISTOPHER D. HENRY†
Nevada Bureau of Mines and Geology, University of Nevada, Reno, Nevada 89557-0088
Abstract
The Carlin trend contains the largest concentration of Carlin-type gold deposits in the world. Two major controversies
about these giant gold deposits have been their age, which is now firmly established as Eocene, and
the source of heat, fluids, and metals, which remains debated. We present data that demonstrate an intense period
of Eocene magmatism coincided in time and space with deposit formation and was arguably the primary
heat source. Geologic studies over the last 40 years have emphasized the stratigraphy and structure of Paleozoic
sedimentary rocks, which are the major ore hosts. However, four igneous episodes affected the Carlin
trend, in the Jurassic, Cretaceous, Eocene, and Miocene. A Jurassic diorite-granodiorite laccolith and related
dikes were emplaced at about 158 Ma in the northern Carlin trend. A Cretaceous granite intruded the northcentral
part of the trend at 112 Ma. Abundant Eocene dikes intruded along most of the trend and were accompanied
by lavas in a large volcanic field along the southwest edge of the trend between ~40 and 36 Ma.
Miocene rhyolite lavas erupted just west of and across the southern part of the trend at ~15 Ma.
Exposed Eocene rocks consist predominantly of silicic to intermediate dikes, lavas, and epizonal intrusions,
which we interpret to be sourced from a large Eocene plutonic complex underlying the Carlin trend. Eocene
dikes are present in most deposits, are generally altered, but, with a few exceptions, were poor ore hosts. Distinct
Eocene igneous suites, which are restricted to specific areas of the trend, are from north to south: (1) 40.3
to 39.0 Ma rhyolite to dacite dikes in the northern Carlin trend, centered approximately on the Betze-Post deposit
and the richest part of the trend; (2) 37.6 Ma porphyritic rhyolite dikes including those that host ore at
the Beast deposit; (3) 38.6 Ma intermediate to silicic intrusions of Welches Canyon; (4) 38.1 to 37.4 Ma andesite
to dacite lavas and shallow intrusions of the Emigrant Pass volcanic field; (5) 36.2 Ma rhyolite dikes in
the Emigrant Pass field that are indistinguishable from the 37.6 Ma suite except for age and location; and (6)
~37.5 Ma rhyolite to dacite intrusions and lavas of the southern Carlin trend (Rain subdistrict). Additionally, a
few basaltic andesite dikes were emplaced at 37.8 Ma near Dee in the northernmost part of the trend and at
38.2 Ma near Rain. The petrography, distribution, and age of the Eocene igneous suites and aeromagnetic data indicate that each suite is underlain by a major, silicic pluton. The longer lived suites require either multiple plutons or longlived magma chambers. All Eocene dikes cannot have come from any single magma chamber, for example,
from a chamber beneath the Welches Canyon intrusions as proposed by some. In this case, some igneous suites
would have been emplaced only 12 to 15 km north of the northern edge of the source pluton, would not have
been emplaced above or symmetrically around the source pluton, and would be distinct in age from the proposed
source pluton. These requirements are not consistent with the distribution and age of the igneous suites.
The combined data for the Eocene igneous rocks require a plutonic complex about 50 km long (northsouth),
essentially coincident with the northern and central Carlin trend, and between 12 and 23 km across,
underlying an area of ~1,000 km2. This complex was emplaced over ~4 million years that coincided with the
formation of the Carlin-type deposits of the Carlin trend. Although many factors contributed to the formation
of the deposits and the Carlin trend, magmatic heat was abundant in the right place and at the right time to
generate the deposits. The Carlin trend may be the largest concentration of Carlin-type deposits because the
Eocene igneous episode there was the largest and longest lived of the Great Basin.