The geology of the Jurupa Mountains, San Bernardino and Riverside Counties, California
The geology of the Jurupa Mountains, San Bernardino and Riverside Counties, California
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加利福尼亚州圣贝纳迪诺县和河滨县朱鲁帕山脉的地质
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发表时间：
1950
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通讯作者：
E. M. MacKevett
中科院分区：
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作者：
E. M. MacKevett
朱鲁帕山脉位于加利福尼亚州圣贝纳迪诺县和河滨县的西部。朱鲁帕山脉的地理中心位于洛杉矶以东约 44 英里、河滨市西北 7 英里处。该报告描述了大约 15 平方英里的区域。
结晶岩石构成了朱鲁帕山脉的大部分，并且可能是南加州岩基典型岩石的最北暴露部分。朱鲁帕山脉最古老的车是一系列前基岩时代的变沉积岩，其年龄很可能是三叠纪的。该系列由石英黑云片麻岩、不纯石英岩、黑云石英片岩、大理岩、钙硅酸盐接触岩和角闪石片岩组成，按丰度顺序排列。典型地，这些岩石作为侵入岩体之间的隔膜出现。最大的大理石和接触岩矿床位于詹森采石场，该地区以其稀有矿物而闻名。圣马科斯辉长岩出现在后来侵入岩中的一些富含角闪石的岛状体中，它是最古老的岩基岩石。 Bonsall 英云闪岩是朱鲁帕山脉中分布最广泛的岩石。它在其接触点附近含有丰富的包裹体，并且通常具有良好的叶理和线理。伍德森山花岗闪长岩是一种具有多种结构变化的淡色岩石。它通常以大块巨石状的形式出现，是该地区最耐侵蚀的岩石之一。朱鲁帕山脉有丰富的伟晶岩脉，其特点是大胆的肋状露头。冲积层主要以扇状物质的形式存在，局部被风成沙覆盖，几乎包围了朱鲁帕山脉。
朱鲁帕山脉位于佩里斯断层的北部。朱鲁帕山脉没有明确已知的断层。朱鲁帕山脉的岩基岩石可能是通过一系列过程的组合形成一系列岩体的，其中停止是最重要的。
朱鲁帕山脉的经济资源是用于制造水泥的大理石，以及主要用于碎石的花岗闪长岩和英闪长岩。此外，还存在一些废弃的黄金矿区。其中大部分位于片麻岩或片岩内的石英纵梁上。
The Jurupa Mountains are in the western parts of San Bernardino and Riverside Counties, California. The geographical center of the Jurupa Mountains is about 44 miles east of Los Angeles and 7 miles northwest of Riverside. This report describes an area of approximately 15 square miles.
Crystalline rocks comprise the bulk of the Jurupa Mountains and probably are the northernmost exposures of the rocks typical of the Southern California batholith. The oldest rooks in the Jurupa Mountains are a series of pre-batholithic metasedimentary rooks which are questionably Triassic in age. This series is composed of quartz-biotite gneiss, impure quartzite, biotite-quartz schist, marble, calc-silicate contact rocks, and amphibole schist, listed in order of abundance. Characteristically, these rocks occur as septa between the intrusive plutons. The largest deposits of marble and contact rocks are at Jensen quarry, a locality renowned for its rare minerals. San Marcos gabbro occurs in a few hornblende-rich island like bodies within the later intrusive looks, and it is the oldest of the batholithic rocks. Bonsall tonalite is the most widespread rock in the Jurupa Mountains. It contains abundant inclusions near its contacts, and commonly has good foliation and lineation. The Woodson Mountain granodiorite is a leucocratic rock that has several textural variations. It generally crops out in large boulder-like masses and is one of the most erosion-resistant rocks in the area. Pegmatite dikes are abundant in the Jurupa Mountains and are characterized by bold, rib-like outcrops. Alluvium, mainly in the form of fan material that is locally overlain by aeolian sand, practically surrounds the Jurupa Mountains.
The Jurupa Mountains are in the northern part of the Perris fault block. No definitely-known faults occur in the Jurupa Mountains. The batholithic rocks of the Jurupa Mountains were probably emplaced as a sequence of plutons by a combination of processes of which stoping was the most important.
The economic resources of the Jurupa Mountains are marble, for making cement, and granodiorite and tonalite, mainly for rip-rap. In addition, several abandoned gold prospects are present. Most of these are on quartz stringers within the gneiss or schist.