Wandering in Rock Country: One Rock, One Story

By Tien C. Lee

What is beyond the beauty of a piece of rock? How does a stand-alone rock come into being naturally? The book presents more than 100 pieces of stories for various rocks, most of which originate from desert, beach, and hillside in Southern California. The author points out the observables with the naked eye and explains their occurrences, putting together the principles of physics, chemistry, biology, and geology, which you know as common sense but the application of which you may not yet think about. To name just a few examples: it describes features of nature’s destruction and rejuvenation in sediments and carbonates; it tells the origin of geode, agate, chalcedony, and volcanic bombs; it argues natural carving and piercing of quartz through cyclic water freezing and ice thawing in the desert; it ponders ventifact and varnish as well as lichen (algae/fungi) growth on desert rocks; it considers fracturing and cracking in shaping the rocks by decompression expansion due to erosion and cooling contraction due to tectonic uplifting; and it addresses liquefaction by ground shaking and erratic sediment distribution by ice rafting and climate change.

• Language: English
• Publisher: LifeRich Publishing
• Release date: Dec 12, 2018
• ISBN: 9781489720238

Tien C. Lee

Tien C. Lee is an Emeritus Professor of Geophysics at the University of California, Riverside, California, USA. He was educated as a geologist/geophysicist. He has published peer-reviewed articles in seismology, geoelectricity, hydrogeology, potential field, and terrestrial heat flow. He has also published two books: ‘Applied Mathematics in Hydrogeology (1999)’ and ‘Thus I Came -- short stories that I have been privileged to relate (2017).’ Since his retirement in 2009, he has engaged in writing a book about his rock collections for the general public. It is a show-and-tell book, intended to inspire storytelling, real or imaginary, about commonly available rock specimens for rock hobbyists and enthusiasts as well as aspiring geologists.

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Copyright © 2019 Tien C. Lee.

Interior Graphics Credit: Tien C. Lee

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Because of the dynamic nature of the Internet, any web addresses or links contained in this book may have changed since publication and may no longer be valid. The views expressed in this work are solely those of the author and do not necessarily reflect the views of the publisher, and the publisher hereby disclaims any responsibility for them.

ISBN: 978-1-4897-2025-2 (sc)

ISBN: 978-1-4897-2024-5 (hc)

ISBN: 978-1-4897-2023-8 (e)

Library of Congress Control Number: 2018914077

LifeRich Publishing rev. date: 12/10/2018

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Educated as a geologist/geophysicist, I have dealt with geophysics and hydrogeology on projects ranging from mathematical modeling in the laboratory to hand-on application in the field. On the job, along hiking trails, and in rural housing subdivisions in southern California, I picked up a variety of rocks, some of which carry fascinating geological stories. I thought about doing something educational with my collection but never got around to it. Now, well into retirement, my promise is long overdue. This book is dedicated to my grandchildren, who will soon be ready to read it; and to my wife, Zora, who has shared joy and pain with me along my career path. The book title, Wandering in Rock Country, captures the essence of an opportunistic rock collection. I try to write one story for each rock specimen.

All rock images are photographed from my collections, supplemented with a few field pictures. Specimens have not been altered or enhanced except for some with obvious saw-cut faces or minor smoothing of rough edges on rare occasions. Most specimens were essentially picked from free-standing, loose pieces of rocks in southern California. Source locations, showing my best recollection, are not based on written records. Also, as my writing proceeds, I add stories on new specimens that were purchased or gifted to me.

This book is not a product of systematic study for scientific endeavor; it is a show-and-tell presentation, based on observations of hand specimens. Some questions raised here could be resolved by instrumental analyses, but I have preferred to restrict my interpretations to what can be seen with the unaided eye. After all, observation of a rock’s beauty is all we can do in the field. Beyond beauty, however, does a particular rock have an interesting story to be told?

I have visited many museums over the years. Many exhibit rare, eye-catching mineral specimens. Although I appreciate the beauty and rarity, most of us have little chance of seeing those fascinating specimens in the field. I would like to know more about specimens than the information generally given in display name tags. What is the geological story behind each specimen? It will be beneficial if the display narrative can be more informative to the visitors.

For better or worse, I attempt here to set an example. I stretch my imagination and try to make up a short story for each stone. The book is divided into five chapters (categories) and the stories are sequenced in orders of figure numbering. The rock identifications are given in general terms with minimal usage of scientific jargon for more refined name classification. Some pieces might be misidentified or misinterpreted because natural staining, varnishing, or patination could have masked their true identities.

All stories are independent of one another; hence the readers can flip to any figure without losing continuity in context. In preparation of the draft manuscript, each story (text and picture) was mostly limited to one paper page (8 ½ x 11 inches) but as needed I let it flow over sometimes. The final format in print or blog may be inadvertently altered. Also, to avoid repetition, some pictures are presented without stories. I do not have an exotic mineral or rock collection, but I hope my story-telling about commonly available rocks is educational or entertaining to some rock hobbyists and enthusiasts as well as aspiring geologists.

The italicized text, if any, gives my philosophical or personal reflection about a stone’s story. Skip those distractions if you are interested only in the story of the rock.

Originally I had planned to give an imaginative nickname as a flavor to each stone. I tried this idea by asking for suggestive names from pupils at a primary school. I was very impressed by and pleased with their enthusiastic responses, but I was overwhelmed by the variety of imaginative names offered for every slide shown. Imagination is in the eyes of beholders, indeed! So, let us fantasize the stones in our own preferable ways.

Not intended for an academic pursuit, this book does not cite any reference, nor provides an index. It is written for personal collection with some daring, original thought. For relevant or more information, however, search for any keywords on the internet. My claimed observations and interpretations could be provocative, contentious, or even outrageous to some readers. Now, please let us pause for a moment! Few serious geologists would tell a story based on one piece of rock specimen alone. My version of each story is just a beginning for the complete narrative to be told. One must visit outcrops, observe rock samples in the context of their surroundings, make laboratory analyses, and synthesize data by modeling to generate a convincing geological model or story. Obviously I did not do what I have recommended. But let us see what we can say about each individual piece of rock specimen.

Acknowledgment

I thank Dr. John G. Bolm, one of the first Americans I met 50 years ago, for comments on parts of a very early version of the draft manuscript. He did not necessarily agree with my viewpoints and I have changed my own opinions a few times, especially after I have access through Orange Belt Mineral Society (OBMS) of San Bernardino, California, to cut some rocks for better visual identification. Dr. Bolm could not wait for my never-ending addition to and revision of the text. To my sorrow, he passed away in early 2018. Now is the time to wrap up.

It has been years since I began to write something about my collection and make the display stands for the specimens. Please spare me for flip-flop along the way in my writing styles. I hereby relinquish my mental burden of collecting rock specimens over the years by releasing this unorthodox book. Thanks for browsing through it and please comment on my mistakes by informing me at [e-mail]. You can also visit my blog site: [e-mail] for a slightly different version of my rock stories.

Contents

Preface

Acknowledgment

A Crude Guide to ID Rocks in the Field

Chapter

1     A SILICA WORLD

2     CARBONATE PLAY

3     HARD ROCK SHOW

4     SOFT-ROCK TALK

5     DIVERSIFICATION

Glossary

A Crude Guide to ID Rocks in the Field

A rock is named for its occurrence, texture, and mineral composition, not its chemical composition. If you stand in the field, you see sedimentary, igneous, or metamorphic rocks. If you have a rock specimen in hand, try to determine what type it is and what it may be called.

Is the specimen fossil-bearing? An affirmative answer means you have a sedimentary rock; otherwise it still can be anything. Is it layered? Smooth layer interface implies sedimentary origin but intertwining one (‘dog teeth’ biting into each another) is metamorphic; the latter also displays shining, silky luster and can be magnetic. Are the grains visible? If the grains are fairly uniform in size and type and are isolated by matrix of finer particles (concrete-cement like), the specimen is sedimentary; if the grains (crystals) interlock one another, it is igneous. Grains in metamorphic rocks tend to be isolated and have rough contact with their individual surroundings.

If the grains are not visible, it can be siltstone or shale and may not be visibly distinguishable from metamorphic slate; well, the latter tends to be splintering, denser and pliable for making the so-called slate tiles. If the specimen is jumbled with grains of various shape, size, and type, you are holding a piece of landslide debris or products of other near-surface chaos or disasters.

Igneous rocks are light (felsic), intermediate, or dark (mafic) in color. If the crystals are visible, they are respectively granite, diorite, and gabbro. Those are plutonic rocks, meaning the magma has solidified at depths for the crystals to slowly grow and interlock with each other. If the magma (lava) extrudes to the ground surface, rapid cooling produces much finer grained volcanic rocks: light rhyolite, intermediate andesite, and dark basalt. Igneous rocks are classified according to artificially agreed relative compositions of rock forming minerals: light-colored quartz, K-feldspar, Na-Ca-plagioclase, and dark-colored mica, amphibole, and pyroxene. Defying our wish, nature has its own way of occurrence and we modify the names accordingly. For example, granodiorite for diorite with appreciable contents of K-feldspar and quartz, and tonalite for ‘granite’ that is short of alkaline feldspar (orthoclase). Sometimes an igneous rock may bear visible crystals (phenocrysts) imbedded in crytocrystalline groundmass or glass, it is porphyritic and the rock is so named with adjective for a dominant feature. Occasionally we encounter ultramafic rocks such as pyroxenite and olivine-rich peridotite that have been exposed through deep crustal erosion or catapulted by